{"gene":"KEL","run_date":"2026-06-10T02:59:49","timeline":{"discoveries":[{"year":2000,"finding":"The mouse Kell glycoprotein (ortholog of human KEL) is a type II membrane glycoprotein with endothelin-3-converting enzyme (ECE-3) activity, disulfide-linked to the integral membrane protein XK on red blood cells.","method":"Western blot, enzymatic activity assay, Northern blot, cDNA sequencing, genomic organization analysis","journal":"Immunogenetics","confidence":"High","confidence_rationale":"Tier 1 / Moderate — direct enzymatic activity assay and biochemical characterization in mouse model, multiple orthogonal methods (Western blot, enzymatic assay, cDNA/genomic sequencing), consistent with human KEL function","pmids":["11132157"],"is_preprint":false},{"year":2009,"finding":"Targeted disruption of the murine Kel gene abolishes endothelin-3-converting enzyme activity on RBCs, reduces XK protein levels (without affecting XK mRNA), increases RBC Gardos channel activity, blunts the normal endothelin-3-mediated enhancement of Gardos channel activity, reduces intratumoral neovascularization, and mildly affects some motor activities.","method":"Homologous recombination knockout, enzymatic activity assay, Western blot, Northern blot, ion transport assay, tumor implantation model, motor function testing","journal":"American journal of hematology","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — genetic knockout with multiple orthogonal phenotypic readouts including enzymatic assay, ion transport, protein expression, and functional consequence in vivo","pmids":["19544475"],"is_preprint":false},{"year":2000,"finding":"A G-to-C mutation at the splice donor site of intron 3 in the KEL gene causes the Kell-null (Ko) phenotype by abolishing normal splicing; the resulting major transcript skips exon 3 (which encodes the transmembrane domain), introducing a premature stop codon that prevents translation of the C-terminal segment bearing all known Kell antigen positions.","method":"DNA sequencing, RT-PCR, splice site mutation analysis","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — direct sequencing and RT-PCR with mechanistic explanation of null phenotype; multiple orthogonal molecular methods in a single rigorous study","pmids":["11134029"],"is_preprint":false},{"year":1993,"finding":"The KEL gene was localized to chromosome 7q33–35 by fluorescence in situ hybridization, providing evidence that Kell antigenic determinants are encoded by the polypeptide chain rather than associated sugar molecules.","method":"Fluorescence in situ hybridization (FISH) with biotinylated KEL cDNA probe","journal":"Human genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — FISH localization with functional inference; single lab, single method","pmids":["8340113"],"is_preprint":false},{"year":1991,"finding":"The KEL locus was genetically linked to the prolactin-inducible protein locus (PIP) and provisionally assigned to chromosome 7q32–36 by genetic linkage analysis.","method":"Genetic linkage analysis","journal":"Annals of human genetics","confidence":"Low","confidence_rationale":"Tier 4 / Weak — genetic linkage only, no direct functional or mechanistic experiment","pmids":["1683210"],"is_preprint":false},{"year":1996,"finding":"Near-total absence of Kell antigens can result from a combination of homozygosity for Kpa (KEL3) and a splice-site mutation in XK (intron 2), demonstrating that Kell antigen expression is partially governed by XK protein and that both loci act together to regulate surface Kell antigen levels.","method":"Serology, RFLP, XK gene sequencing, family study","journal":"Blood","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — combination of molecular (sequencing, RFLP) and serological methods establishing genetic epistasis between KEL and XK loci","pmids":["8916972"],"is_preprint":false},{"year":2001,"finding":"Point mutations G865A (Glu249Lys) and G863A (Arg248Gln) in adjacent codons of KEL exon 8 cause amino acid substitutions that define the RAZ and VLAN Kell blood group phenotypes, respectively.","method":"DNA sequencing of KEL open reading frame and flanking intronic regions, PCR-based genotyping assays","journal":"Vox sanguinis","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — direct sequencing with confirmatory genotyping assay; single lab, defines molecular basis of antigen variants","pmids":["11904003"],"is_preprint":false},{"year":2006,"finding":"A serine at position 193 of the Kell glycoprotein (encoded by a 577A>T transversion, Ser193), distinct from the canonical Thr193Met KEL1/KEL2 polymorphism, results in expression of an abnormal KEL1 antigen in addition to KEL2, demonstrating that residue 193 is critical for KEL1 antigen expression.","method":"DNA sequencing (genomic and cDNA), flow cytometry, PCR genotyping","journal":"Transfusion","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — cDNA sequencing plus flow cytometry confirming aberrant antigen expression; single lab","pmids":["17076841"],"is_preprint":false},{"year":2008,"finding":"Alternative splicing of KEL gene transcripts occurs in non-reticulocyte cells (total RNA), while reticulocytes express only one normal transcript; Kell glycoprotein is strongly expressed on RBCs but absent or very low on leukocytes.","method":"RT-PCR, nested PCR, sequencing, flow cytometry with monoclonal antibodies","journal":"Chinese journal of medical genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — multiple molecular methods (RT-PCR, sequencing, flow cytometry) in a single study; single lab","pmids":["18841563"],"is_preprint":false},{"year":2009,"finding":"A novel KEL*1,3 allele (KEL1 and KEL3 on the same chromosome) causes approximately 80% reduction in KEL1 surface antigen expression, demonstrating a cis-modifier effect of KEL3 on KEL1 expression.","method":"Serology, flow cytometry, PCR with sequence-specific priming, genomic DNA sequencing of separated parental alleles","journal":"Transfusion","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — phased allele sequencing with quantitative flow cytometry confirms cis-modifier mechanism; single lab","pmids":["19347978"],"is_preprint":false},{"year":2014,"finding":"A synonymous mutation (c.1719C>T) in KEL exon 16 causes complete exon 16 skipping despite being located 16 bases downstream of the 3′ splice site, resulting in a null (silent) KEL allele and contributing to Kmod phenotype when combined with another mod allele.","method":"Genomic and cDNA sequencing from erythroid progenitor-derived cells, serology","journal":"Vox sanguinis","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — cDNA sequencing from cultured erythroid cells directly demonstrates exon skipping; single lab","pmids":["24795954"],"is_preprint":false},{"year":2022,"finding":"GATA1 and KLF1 co-occupy the KEL promoter and are functionally required for KEL transcription; naturally occurring variants in their binding motifs reduce GATA1 and KLF1 binding affinity and KEL transcriptional activity.","method":"ChIP-seq, ATAC-seq, luciferase reporter assays, EMSA, mass spectrometry","journal":"Transfusion","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — functional validation by luciferase assay combined with EMSA and MS confirming TF binding; multiple orthogonal methods in one study","pmids":["38644556"],"is_preprint":false},{"year":2016,"finding":"Anti-KEL immunoprophylaxis prevents alloimmunization through antigen modulation (rapid removal of detectable KEL antigen from circulating RBCs), and this process requires redundant pathways involving both Fcγ receptors and complement (C3); absence of both abolishes immunoprophylaxis efficacy and KEL antigen modulation.","method":"Murine transfusion model using transgenic KEL-expressing RBCs, FcγR/C3 knockout mice, flow cytometry, Western blot, in vitro phagocytosis assay","journal":"Blood","confidence":"High","confidence_rationale":"Tier 2 / Moderate — genetic knockout of both pathways with multiple orthogonal readouts (flow cytometry, Western blot, phagocytosis assay) in single study","pmids":["27688803"],"is_preprint":false},{"year":2017,"finding":"B cells require Type 1 interferon (IFN-α/β) signaling through IFNAR1 to produce alloantibodies against the KEL glycoprotein after transfusion; IFNAR1-deficient B cells fail to differentiate into germinal center B cells and plasma cells in response to KEL-expressing RBCs.","method":"Murine transfusion model, IFNAR1 knockout mice, bone marrow chimeras with cell-specific IFNAR1 deletion, flow cytometry","journal":"Transfusion","confidence":"High","confidence_rationale":"Tier 2 / Moderate — bone marrow chimera experiments with cell-type-specific knockouts and multiple B-cell differentiation readouts; single lab but rigorous genetic dissection","pmids":["28836263"],"is_preprint":false},{"year":2019,"finding":"Influenza infection promotes alloimmunization to transfused KEL-expressing RBCs through a mechanism dependent on recipient Type 1 IFN production; blocking or genetic deletion of Type 1 IFN signaling significantly reduces influenza-induced anti-KEL alloantibody formation.","method":"Murine transfusion model, influenza infection, antibody blockade and genetic knockout of Type 1 IFN signaling, flow cytometric crossmatch","journal":"Transfusion","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — single lab using both antibody blockade and genetic approaches to confirm IFN-dependent mechanism","pmids":["31403208"],"is_preprint":false},{"year":2020,"finding":"Poly(I:C)-induced antiviral responses cause breakthrough anti-KEL alloimmunization despite immunoprophylaxis; this is associated with increased RBC consumption by inflammatory monocytes and elevated MCP-1 and IL-6; poly(I:C) can induce breakthrough alloimmunization even in recipients lacking Type 1 IFN receptors, suggesting additional IFN-independent pathways.","method":"Murine transfusion model, knockout mice (FcγR, C3, IFNAR), cytokine measurement, flow cytometry, Type 1 IFN administration","journal":"Blood","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — mechanistic dissection using multiple knockouts and cytokine profiling; single lab","pmids":["32266378"],"is_preprint":false},{"year":2022,"finding":"KEL promotes cell proliferation in acute erythroleukemia cells, and its downregulation reverses drug resistance to JQ1; KEL expression is associated with gain of H3K27 acetylation and is regulated by cotranscription factors GATA1 and TAL1.","method":"Cell proliferation assay (CCK8), flow cytometry (apoptosis), ChIP-seq/epigenetic analysis, transcription factor binding analysis","journal":"Oxidative medicine and cellular longevity","confidence":"Medium","confidence_rationale":"Tier 2–3 / Weak — functional loss-of-function data with defined cellular phenotype and epigenetic mechanism; single lab","pmids":["35140839"],"is_preprint":false},{"year":2025,"finding":"The Nrf2 activator CDDO-Im suppresses poly(I:C)-induced Type 1 IFN-stimulated gene expression and inhibits anti-KEL IgG alloantibody production after transfusion of KEL-expressing RBCs, in an Nrf2-dependent manner (no effect in Nrf2−/− mice).","method":"Murine transfusion model, Nrf2 knockout mice, pharmacological Nrf2 activation, anti-KEL IgG measurement by flow cytometry, gene expression analysis","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — genetic and pharmacological evidence in a single preprint study; Nrf2 knockout confirms on-target mechanism","pmids":["40235992"],"is_preprint":true}],"current_model":"KEL encodes a type II transmembrane glycoprotein (Kell) that functions as an endothelin-3-converting enzyme (ECE-3/CD238) on red blood cells, where it forms a disulfide-linked complex with XK; XK protein levels depend on Kell expression, and Kell enzymatic activity modulates RBC ion transport (Gardos channel) via endothelin-3 signaling; KEL transcription is driven by GATA1 and KLF1 co-occupying its promoter, and surface antigen expression is modulated in cis by adjacent Kell alleles and in trans by XK; loss-of-function mutations (splice-site, nonsense, frameshift, missense) in KEL cause the Kell-null (Ko) or Kmod phenotypes; in the immune system, alloantibody responses to KEL-expressing RBCs require Type 1 IFN signaling in B cells and are regulated by FcγR/complement-dependent antigen modulation and by the Nrf2 antioxidant pathway."},"narrative":{"mechanistic_narrative":"KEL encodes the Kell glycoprotein, a type II transmembrane red-cell protein that functions as an endothelin-3-converting enzyme (ECE-3) and forms a disulfide-linked complex with the integral membrane protein XK [PMID:11132157]. Genetic disruption of Kell abolishes this enzymatic activity, reduces XK protein levels without altering XK mRNA, and increases Gardos channel activity while blunting the normal endothelin-3-mediated enhancement of that channel, linking Kell catalytic function to red-cell ion transport [PMID:19544475]. The interdependence of the two loci is reciprocal: near-total loss of Kell antigens arises when reduced KEL antigen alleles combine with an XK splice-site mutation, establishing that XK governs surface Kell antigen expression [PMID:8916972]. KEL transcription is driven by GATA1 and KLF1, which co-occupy its promoter and are required for KEL expression, with natural variants in their binding motifs reducing transcription factor occupancy and KEL activity [PMID:38644556]. Loss-of-function mutations cause Kell-null (Ko) and Kmod phenotypes through diverse mechanisms including splice-donor disruption that skips the transmembrane-encoding exon 3 and introduces a premature stop codon [PMID:11134029], and a synonymous exon 16 variant that triggers exon skipping [PMID:24795954], while antigen-defining missense variants map to residues such as position 193 critical for KEL1 expression [PMID:17076841]. Beyond the red cell, the Kell glycoprotein is a model alloantigen: anti-KEL alloantibody responses require Type 1 interferon signaling through IFNAR1 in B cells for germinal center and plasma cell differentiation [PMID:28836263], and immunoprophylaxis acts by FcγR- and complement-dependent antigen modulation [PMID:27688803]. Inflammatory and antiviral stimuli modulate this response, which can be suppressed via the Nrf2 antioxidant pathway [PMID:40235992].","teleology":[{"year":2000,"claim":"Established the molecular identity and enzymatic function of the Kell protein, answering what biochemical activity this blood group antigen carries.","evidence":"Biochemical and enzymatic characterization of mouse Kell ortholog by Western blot, activity assay, and cDNA/genomic sequencing","pmids":["11132157"],"confidence":"High","gaps":["In vivo physiological substrate range beyond endothelin-3 not defined","Structural basis of XK disulfide linkage not resolved"]},{"year":2000,"claim":"Defined a molecular mechanism for the Kell-null phenotype, showing how a splice mutation eliminates the antigen-bearing protein.","evidence":"DNA sequencing and RT-PCR of an intron 3 splice donor mutation showing exon 3 skipping and premature stop codon","pmids":["11134029"],"confidence":"High","gaps":["Does not address the full allelic spectrum of null/mod phenotypes"]},{"year":2009,"claim":"Demonstrated in vivo that Kell catalytic activity controls red-cell ion transport and stabilizes XK, linking enzyme function to physiology.","evidence":"Murine Kel knockout with enzymatic, ion transport, protein expression, tumor, and motor function readouts","pmids":["19544475"],"confidence":"High","gaps":["Mechanism connecting endothelin-3 conversion to Gardos channel regulation not fully traced","Basis of XK destabilization in Kell absence unresolved"]},{"year":1996,"claim":"Established the reciprocal genetic dependence between KEL and XK loci in governing surface antigen levels.","evidence":"Serology, RFLP, XK sequencing, and family study of combined Kpa homozygosity and XK splice mutation","pmids":["8916972"],"confidence":"Medium","gaps":["Molecular basis of XK control over Kell surface expression not mechanistically defined"]},{"year":2009,"claim":"Showed antigen expression is modulated in cis by adjacent KEL alleles, refining how surface antigen quantity is set.","evidence":"Phased allele sequencing with quantitative flow cytometry of a KEL*1,3 allele","pmids":["19347978"],"confidence":"Medium","gaps":["Molecular mechanism of cis-suppression unknown"]},{"year":2022,"claim":"Identified the transcriptional control of KEL, answering how erythroid-specific expression is established.","evidence":"ChIP-seq, ATAC-seq, luciferase reporter, EMSA, and mass spectrometry showing GATA1/KLF1 co-occupancy","pmids":["38644556"],"confidence":"High","gaps":["Interplay of GATA1/KLF1 with other erythroid regulators not fully mapped"]},{"year":2017,"claim":"Defined the immune requirement for anti-KEL alloantibody formation, identifying Type 1 IFN signaling in B cells as essential.","evidence":"Murine transfusion model with IFNAR1 knockout and bone marrow chimeras with cell-specific deletion","pmids":["28836263"],"confidence":"High","gaps":["Source and trigger of Type 1 IFN in steady-state transfusion not identified"]},{"year":2016,"claim":"Explained how anti-KEL immunoprophylaxis works, attributing protection to FcγR- and complement-dependent antigen modulation.","evidence":"Murine transfusion model with FcγR/C3 knockouts, flow cytometry, Western blot, phagocytosis assay","pmids":["27688803"],"confidence":"High","gaps":["Relative contribution of phagocytic versus enzymatic antigen loss not separated"]},{"year":2025,"claim":"Identified a pathway to suppress anti-KEL alloimmunization, showing Nrf2 activation dampens IFN-stimulated responses and antibody production.","evidence":"Murine transfusion model with Nrf2 knockout and pharmacological CDDO-Im activation (preprint)","pmids":["40235992"],"confidence":"Medium","gaps":["Preprint not peer-reviewed","Mechanistic link between Nrf2 and IFN-stimulated gene suppression incomplete"]},{"year":null,"claim":"How Kell endothelin-3-converting enzyme activity mechanistically couples to Gardos channel regulation and what non-erythroid physiological roles Kell serves remain open.","evidence":"","pmids":[],"confidence":"Low","gaps":["No structural model of the Kell-XK complex","Physiological substrates beyond endothelin-3 uncharacterized","Non-erythroid functions only hinted at by tumor and motor phenotypes"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[0,1]},{"term_id":"GO:0016787","term_label":"hydrolase activity","supporting_discovery_ids":[0,1]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[0,8]}],"pathway":[{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[12,13]},{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[11]}],"complexes":["Kell-XK complex"],"partners":["XK","GATA1","KLF1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"P23276","full_name":"Kell blood group glycoprotein","aliases":[],"length_aa":732,"mass_kda":82.8,"function":"Zinc endopeptidase with endothelin-3-converting enzyme activity. Cleaves EDN1, EDN2 and EDN3, with a marked preference for EDN3","subcellular_location":"Cell membrane","url":"https://www.uniprot.org/uniprotkb/P23276/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/KEL","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/KEL","total_profiled":1310},"omim":[{"mim_id":"621391","title":"XK-RELATED PROTEIN 5; XKR5","url":"https://www.omim.org/entry/621391"},{"mim_id":"619926","title":"KELCH-LIKE FAMILY, MEMBER 18; KLHL18","url":"https://www.omim.org/entry/619926"},{"mim_id":"613883","title":"KELL BLOOD GROUP METALLOENDOPEPTIDASE; KEL","url":"https://www.omim.org/entry/613883"},{"mim_id":"613659","title":"GASTRIC CANCER","url":"https://www.omim.org/entry/613659"},{"mim_id":"612773","title":"BASAL CELL ADHESION MOLECULE; BCAM","url":"https://www.omim.org/entry/612773"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Golgi apparatus","reliability":"Approved"},{"location":"Plasma membrane","reliability":"Approved"},{"location":"Nucleoplasm","reliability":"Additional"},{"location":"Cytosol","reliability":"Additional"}],"tissue_specificity":"Group enriched","tissue_distribution":"Detected in some","driving_tissues":[{"tissue":"bone marrow","ntpm":53.1},{"tissue":"testis","ntpm":36.6}],"url":"https://www.proteinatlas.org/search/KEL"},"hgnc":{"alias_symbol":["ECE3","CD238"],"prev_symbol":[]},"alphafold":{"accession":"P23276","domains":[{"cath_id":"3.40.390.10","chopping":"85-115_431-482_531-714","consensus_level":"medium","plddt":89.8101,"start":85,"end":714},{"cath_id":"1.10.1380.10","chopping":"206-376","consensus_level":"high","plddt":93.055,"start":206,"end":376}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P23276","model_url":"https://alphafold.ebi.ac.uk/files/AF-P23276-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P23276-F1-predicted_aligned_error_v6.png","plddt_mean":87.44},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=KEL","jax_strain_url":"https://www.jax.org/strain/search?query=KEL"},"sequence":{"accession":"P23276","fasta_url":"https://rest.uniprot.org/uniprotkb/P23276.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P23276/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P23276"}},"corpus_meta":[{"pmid":"16394099","id":"PMC_16394099","title":"KEL-8 is a substrate receptor for CUL3-dependent ubiquitin ligase that regulates synaptic glutamate receptor turnover.","date":"2006","source":"Molecular biology of the cell","url":"https://pubmed.ncbi.nlm.nih.gov/16394099","citation_count":71,"is_preprint":false},{"pmid":"10960520","id":"PMC_10960520","title":"Differentiation of autologous ABO, RHD, RHCE, KEL, JK, and FY blood group genotypes by analysis of peripheral blood samples of patients who have recently received multiple transfusions.","date":"2000","source":"Transfusion","url":"https://pubmed.ncbi.nlm.nih.gov/10960520","citation_count":59,"is_preprint":false},{"pmid":"23621760","id":"PMC_23621760","title":"Transfusion of murine red blood cells expressing the human KEL glycoprotein induces clinically significant alloantibodies.","date":"2013","source":"Transfusion","url":"https://pubmed.ncbi.nlm.nih.gov/23621760","citation_count":49,"is_preprint":false},{"pmid":"23801629","id":"PMC_23801629","title":"Alloantibodies to a paternally derived RBC KEL antigen lead to hemolytic disease of the fetus/newborn in a murine model.","date":"2013","source":"Blood","url":"https://pubmed.ncbi.nlm.nih.gov/23801629","citation_count":41,"is_preprint":false},{"pmid":"27688803","id":"PMC_27688803","title":"Antigen modulation as a potential mechanism of anti-KEL immunoprophylaxis in mice.","date":"2016","source":"Blood","url":"https://pubmed.ncbi.nlm.nih.gov/27688803","citation_count":38,"is_preprint":false},{"pmid":"11134029","id":"PMC_11134029","title":"Molecular basis of the Kell-null phenotype: a mutation at the splice site of human KEL gene abolishes the expression of Kell blood group antigens.","date":"2000","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11134029","citation_count":37,"is_preprint":false},{"pmid":"28836263","id":"PMC_28836263","title":"B cells require Type 1 interferon to produce alloantibodies to transfused KEL-expressing red blood cells in mice.","date":"2017","source":"Transfusion","url":"https://pubmed.ncbi.nlm.nih.gov/28836263","citation_count":32,"is_preprint":false},{"pmid":"1683210","id":"PMC_1683210","title":"Genetic linkage between the Kell blood group system and prolactin-inducible protein loci: provisional assignment of KEL to chromosome 7.","date":"1991","source":"Annals of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/1683210","citation_count":26,"is_preprint":false},{"pmid":"461189","id":"PMC_461189","title":"Reverse-phase HPLC of DNA restriction fragments and ribooligonucleotides on uncoated Kel-F powder.","date":"1979","source":"Nucleic acids research","url":"https://pubmed.ncbi.nlm.nih.gov/461189","citation_count":24,"is_preprint":false},{"pmid":"21623766","id":"PMC_21623766","title":"Identification of RHCE and KEL alleles in large cohorts of Afro-Caribbean and Comorian donors by multiplex SNaPshot and fragment assays: a transfusion support for sickle cell disease patients.","date":"2011","source":"British journal of haematology","url":"https://pubmed.ncbi.nlm.nih.gov/21623766","citation_count":23,"is_preprint":false},{"pmid":"8916972","id":"PMC_8916972","title":"A combination of the effects of rare genotypes at the XK and KEL blood group loci results in absence of Kell system antigens from the red blood cells.","date":"1996","source":"Blood","url":"https://pubmed.ncbi.nlm.nih.gov/8916972","citation_count":23,"is_preprint":false},{"pmid":"31403208","id":"PMC_31403208","title":"Type 1 IFN signaling critically regulates influenza-induced alloimmunization to transfused KEL RBCs in a murine model.","date":"2019","source":"Transfusion","url":"https://pubmed.ncbi.nlm.nih.gov/31403208","citation_count":18,"is_preprint":false},{"pmid":"8809961","id":"PMC_8809961","title":"Development of a PCR-based diagnostic assay for the determination of KEL genotype in donor blood samples.","date":"1996","source":"Transfusion medicine (Oxford, England)","url":"https://pubmed.ncbi.nlm.nih.gov/8809961","citation_count":18,"is_preprint":false},{"pmid":"17076841","id":"PMC_17076841","title":"A KEL gene encoding serine at position 193 of the Kell glycoprotein results in expression of KEL1 antigen.","date":"2006","source":"Transfusion","url":"https://pubmed.ncbi.nlm.nih.gov/17076841","citation_count":17,"is_preprint":false},{"pmid":"11918559","id":"PMC_11918559","title":"Heterozygosity for two novel null alleles of the KEL gene causes the Kell-null phenotype in a Japanese woman.","date":"2002","source":"British journal of haematology","url":"https://pubmed.ncbi.nlm.nih.gov/11918559","citation_count":15,"is_preprint":false},{"pmid":"10421842","id":"PMC_10421842","title":"kel-1, a novel Kelch-related gene in Caenorhabditis elegans, is expressed in pharyngeal gland cells and is required for the feeding process.","date":"1999","source":"Genes to cells : devoted to molecular & cellular mechanisms","url":"https://pubmed.ncbi.nlm.nih.gov/10421842","citation_count":14,"is_preprint":false},{"pmid":"11132157","id":"PMC_11132157","title":"The mouse Kell blood group gene (Kel): cDNA sequence, genomic organization, expression, and enzymatic function.","date":"2000","source":"Immunogenetics","url":"https://pubmed.ncbi.nlm.nih.gov/11132157","citation_count":12,"is_preprint":false},{"pmid":"19747286","id":"PMC_19747286","title":"Two novel null alleles of the KEL gene detected in two Chinese women with the K(null) phenotype.","date":"2009","source":"Transfusion medicine (Oxford, England)","url":"https://pubmed.ncbi.nlm.nih.gov/19747286","citation_count":12,"is_preprint":false},{"pmid":"23741186","id":"PMC_23741186","title":"An easy and efficient strategy for KEL genotyping in a multiethnic population.","date":"2013","source":"Revista brasileira de hematologia e hemoterapia","url":"https://pubmed.ncbi.nlm.nih.gov/23741186","citation_count":10,"is_preprint":false},{"pmid":"19544475","id":"PMC_19544475","title":"Changes in red cell ion transport, reduced intratumoral neovascularization, and some mild motor function abnormalities accompany targeted disruption of the Mouse Kell gene (Kel).","date":"2009","source":"American journal of hematology","url":"https://pubmed.ncbi.nlm.nih.gov/19544475","citation_count":9,"is_preprint":false},{"pmid":"19347978","id":"PMC_19347978","title":"A novel KEL*1,3 allele with weak Kell antigen expression confirming the cis-modifier effect of KEL3.","date":"2009","source":"Transfusion","url":"https://pubmed.ncbi.nlm.nih.gov/19347978","citation_count":9,"is_preprint":false},{"pmid":"21707797","id":"PMC_21707797","title":"Genetic and functional analyses describe a novel 730delG mutation in the KEL gene causing K0 phenotype in a Taiwanese blood donor.","date":"2011","source":"Transfusion medicine (Oxford, England)","url":"https://pubmed.ncbi.nlm.nih.gov/21707797","citation_count":9,"is_preprint":false},{"pmid":"32266378","id":"PMC_32266378","title":"Poly(I:C) causes failure of immunoprophylaxis to red blood cells expressing the KEL glycoprotein in mice.","date":"2020","source":"Blood","url":"https://pubmed.ncbi.nlm.nih.gov/32266378","citation_count":8,"is_preprint":false},{"pmid":"33910309","id":"PMC_33910309","title":"[Expression of circ-KEL in acute myeloid leukemia and its regulatory mechanisms in leukemic cells].","date":"2021","source":"Zhonghua xue ye xue za zhi = Zhonghua xueyexue zazhi","url":"https://pubmed.ncbi.nlm.nih.gov/33910309","citation_count":7,"is_preprint":false},{"pmid":"198354","id":"PMC_198354","title":"Enzyme polymorphisms of Ideles populations (Ahaggar, Algeria) and the Iwellemeden Kel Kummer Twaregs (Menaka, Mali).","date":"1977","source":"Human heredity","url":"https://pubmed.ncbi.nlm.nih.gov/198354","citation_count":7,"is_preprint":false},{"pmid":"24795954","id":"PMC_24795954","title":"Three uncommon KEL alleles in one family with unusual Kell phenotypes explain a 35-year old conundrum.","date":"2014","source":"Vox sanguinis","url":"https://pubmed.ncbi.nlm.nih.gov/24795954","citation_count":7,"is_preprint":false},{"pmid":"8340113","id":"PMC_8340113","title":"Regional chromosomal assignment of the Kell blood group locus (KEL) to chromosome 7q33-q35 by fluorescence in situ hybridization: evidence for the polypeptide nature of antigenic variation.","date":"1993","source":"Human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/8340113","citation_count":7,"is_preprint":false},{"pmid":"23581578","id":"PMC_23581578","title":"Identification of novel silent KEL alleles causing KEL:-5 (Ko) phenotype or discordance between KEL:1,-2 phenotype/KEL*01/02 genotype.","date":"2013","source":"Transfusion","url":"https://pubmed.ncbi.nlm.nih.gov/23581578","citation_count":6,"is_preprint":false},{"pmid":"29280152","id":"PMC_29280152","title":"Silent KEL alleles identified from Japanese individuals with the Ko phenotype.","date":"2017","source":"Vox sanguinis","url":"https://pubmed.ncbi.nlm.nih.gov/29280152","citation_count":6,"is_preprint":false},{"pmid":"35140839","id":"PMC_35140839","title":"Functional Evaluation of KEL as an Oncogenic Gene in the Progression of Acute Erythroleukemia.","date":"2022","source":"Oxidative medicine and cellular longevity","url":"https://pubmed.ncbi.nlm.nih.gov/35140839","citation_count":5,"is_preprint":false},{"pmid":"20384970","id":"PMC_20384970","title":"KEL*02 alleles with alterations in and around exon 8 in individuals with apparent KEL:1,-2 phenotypes.","date":"2010","source":"Vox sanguinis","url":"https://pubmed.ncbi.nlm.nih.gov/20384970","citation_count":5,"is_preprint":false},{"pmid":"38644556","id":"PMC_38644556","title":"Epigenetic dissection of human blood group genes reveals regulatory elements and detailed characteristics of KEL and four other loci.","date":"2024","source":"Transfusion","url":"https://pubmed.ncbi.nlm.nih.gov/38644556","citation_count":5,"is_preprint":false},{"pmid":"35191535","id":"PMC_35191535","title":"Noninvasive diagnostics of fetal KEL*01.01 allele from maternal plasma of immunized women using digital PCR protocols.","date":"2022","source":"Transfusion","url":"https://pubmed.ncbi.nlm.nih.gov/35191535","citation_count":5,"is_preprint":false},{"pmid":"30418129","id":"PMC_30418129","title":"Transfused platelets enhance alloimmune responses to transfused KEL-expressing red blood cells in a murine model.","date":"2018","source":"Blood transfusion = Trasfusione del sangue","url":"https://pubmed.ncbi.nlm.nih.gov/30418129","citation_count":5,"is_preprint":false},{"pmid":"25041236","id":"PMC_25041236","title":"Three missense mutations found in the KEL gene lead to K(mod) or K0 red blood cell phenotypes.","date":"2014","source":"Transfusion","url":"https://pubmed.ncbi.nlm.nih.gov/25041236","citation_count":5,"is_preprint":false},{"pmid":"26024631","id":"PMC_26024631","title":"454-Sequencing™ for the KEL, JR, and LAN Blood Groups.","date":"2015","source":"Methods in molecular biology (Clifton, N.J.)","url":"https://pubmed.ncbi.nlm.nih.gov/26024631","citation_count":5,"is_preprint":false},{"pmid":"11904003","id":"PMC_11904003","title":"Point mutations in KEL exon 8 determine a high-incidence (RAZ) and a low-incidence (KEL25, VLAN) antigen of the Kell blood group system.","date":"2001","source":"Vox sanguinis","url":"https://pubmed.ncbi.nlm.nih.gov/11904003","citation_count":5,"is_preprint":false},{"pmid":"32565058","id":"PMC_32565058","title":"Genomic analyses of KEL alleles in alloimmunized thalassemia patients from Iran.","date":"2020","source":"Transfusion and apheresis science : official journal of the World Apheresis Association : official journal of the European Society for Haemapheresis","url":"https://pubmed.ncbi.nlm.nih.gov/32565058","citation_count":4,"is_preprint":false},{"pmid":"33562967","id":"PMC_33562967","title":"The effectiveness of KEL and RHCE fetal genotype assessment in alloimmunized women by minisequencing.","date":"2020","source":"Ceska gynekologie","url":"https://pubmed.ncbi.nlm.nih.gov/33562967","citation_count":4,"is_preprint":false},{"pmid":"39308969","id":"PMC_39308969","title":"The Incidences of KEL Blood Group Antigens and Phenotypes in Southwestern Saudi Arabia.","date":"2024","source":"International journal of general medicine","url":"https://pubmed.ncbi.nlm.nih.gov/39308969","citation_count":3,"is_preprint":false},{"pmid":"33925253","id":"PMC_33925253","title":"Risk Minimization of Hemolytic Disease of the Fetus and Newborn Using Droplet Digital PCR Method for Accurate Fetal Genotype Assessment of RHD, KEL, and RHCE from Cell-Free Fetal DNA of Maternal Plasma.","date":"2021","source":"Diagnostics (Basel, Switzerland)","url":"https://pubmed.ncbi.nlm.nih.gov/33925253","citation_count":3,"is_preprint":false},{"pmid":"26996808","id":"PMC_26996808","title":"New KEL*01M and KEL*02M alleles: structural modeling to assess the impact of amino acid changes.","date":"2016","source":"Transfusion","url":"https://pubmed.ncbi.nlm.nih.gov/26996808","citation_count":2,"is_preprint":false},{"pmid":"35356589","id":"PMC_35356589","title":"A paleoecological context to assess the development of oak forest in Colombia: A comment on Zorilla-Azcué, S., Gonzalez-Rodríguez, A., Oyama, K., González, M.A., & Rodríguez-Correa, H., The DNA history of a lonely oak: Quercus humboldtii phylogeography in the Colombian Andes. Ecology and Evolution 2021, doi: 10.100-2/ece3.7529.","date":"2022","source":"Ecology and evolution","url":"https://pubmed.ncbi.nlm.nih.gov/35356589","citation_count":2,"is_preprint":false},{"pmid":"31625357","id":"PMC_31625357","title":"Establishment of KEL*01 and KEL*02 Genotyping to Recruit Uncommon, Kell-positive, Reagent Red Cells Among Thai Blood Donors.","date":"2019","source":"Clinical laboratory","url":"https://pubmed.ncbi.nlm.nih.gov/31625357","citation_count":1,"is_preprint":false},{"pmid":"35852066","id":"PMC_35852066","title":"Novel KEL allele associated with loss of Kpb identified in a white blood donor.","date":"2022","source":"Immunohematology","url":"https://pubmed.ncbi.nlm.nih.gov/35852066","citation_count":1,"is_preprint":false},{"pmid":"32313639","id":"PMC_32313639","title":"A forest-specialist carnivore in the middle of the desert?Comments on https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.5230.","date":"2020","source":"Ecology and evolution","url":"https://pubmed.ncbi.nlm.nih.gov/32313639","citation_count":1,"is_preprint":false},{"pmid":"41241849","id":"PMC_41241849","title":"A novel homozygous KEL variant causing K0 phenotype in a Chinese woman and therapeutic plasma exchange for anti-Ku removal in preoperative management.","date":"2025","source":"Transfusion","url":"https://pubmed.ncbi.nlm.nih.gov/41241849","citation_count":1,"is_preprint":false},{"pmid":"1138437","id":"PMC_1138437","title":"The HL-A gene structure of Twareg populations. II. The Kel Dinig.","date":"1975","source":"Tissue antigens","url":"https://pubmed.ncbi.nlm.nih.gov/1138437","citation_count":1,"is_preprint":false},{"pmid":"417847","id":"PMC_417847","title":"[The hypothesis of the genetic transmission (autosomal recessive) of subtypes of HBs Ag. The example of Kel Kummer].","date":"1978","source":"Comptes rendus hebdomadaires des seances de l'Academie des sciences. Serie D: Sciences naturelles","url":"https://pubmed.ncbi.nlm.nih.gov/417847","citation_count":1,"is_preprint":false},{"pmid":"38629087","id":"PMC_38629087","title":"Genomic analysis of KEL*03 and KEL*04 alleles among Thai blood donors.","date":"2024","source":"African journal of laboratory medicine","url":"https://pubmed.ncbi.nlm.nih.gov/38629087","citation_count":0,"is_preprint":false},{"pmid":"18841563","id":"PMC_18841563","title":"[Different KEL gene mRNA transcripts in reticulocyte and non-reticulocyte cells].","date":"2008","source":"Zhonghua yi xue yi chuan xue za zhi = Zhonghua yixue yichuanxue zazhi = Chinese journal of medical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/18841563","citation_count":0,"is_preprint":false},{"pmid":"40235992","id":"PMC_40235992","title":"CDDO-Imidazole regulates RBC alloimmunization to the KEL antigen by activating Nrf2.","date":"2025","source":"bioRxiv : the preprint server for biology","url":"https://pubmed.ncbi.nlm.nih.gov/40235992","citation_count":0,"is_preprint":false},{"pmid":"41692422","id":"PMC_41692422","title":"Anti-Ku alloimmunization due to a KEL*02N.19 allele causing Kell-null phenotype despite KEL*02 genotype prediction.","date":"2026","source":"Vox sanguinis","url":"https://pubmed.ncbi.nlm.nih.gov/41692422","citation_count":0,"is_preprint":false},{"pmid":"36110879","id":"PMC_36110879","title":"Response to: A paleoecological context to assess the development of oak forest in Colombia: A comment on Zorrilla-Azcué, S., González-Rodríguez, A., Oyama, K., González, M.A. & Rodríguez-Correa, H., The DNA history of a lonely oak: Quercus humboldtii phylogeography in the Colombian Andes. Ecology and Evolution 2021, doi:10.1002/ece3.7529.","date":"2022","source":"Ecology and evolution","url":"https://pubmed.ncbi.nlm.nih.gov/36110879","citation_count":0,"is_preprint":false},{"pmid":"23727116","id":"PMC_23727116","title":"[A KEL*02mod allele responsible for an apparent maternity exclusion].","date":"2013","source":"Transfusion clinique et biologique : journal de la Societe francaise de transfusion sanguine","url":"https://pubmed.ncbi.nlm.nih.gov/23727116","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.11.24.689921","title":"Inorganic pyrophosphate disrupts amorphous hydrated bone mineral interfaces in hypophosphatasia","date":"2025-11-27","source":"bioRxiv","url":"https://doi.org/10.1101/2025.11.24.689921","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2025.06.20.25329990","title":"Rapid and long-lasting remodelling of the blood transcriptome following bariatric surgery","date":"2025-06-22","source":"bioRxiv","url":"https://doi.org/10.1101/2025.06.20.25329990","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":29810,"output_tokens":4064,"usd":0.075195,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":11964,"output_tokens":2830,"usd":0.065285,"stage2_stop_reason":"end_turn"},"total_usd":0.14048,"stage1_batch_id":"msgbatch_01BbTCMyrRPyhtEq6b1MdwCN","stage2_batch_id":"msgbatch_011dEed5bbxYvTAaQWKJevxu","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2000,\n      \"finding\": \"The mouse Kell glycoprotein (ortholog of human KEL) is a type II membrane glycoprotein with endothelin-3-converting enzyme (ECE-3) activity, disulfide-linked to the integral membrane protein XK on red blood cells.\",\n      \"method\": \"Western blot, enzymatic activity assay, Northern blot, cDNA sequencing, genomic organization analysis\",\n      \"journal\": \"Immunogenetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — direct enzymatic activity assay and biochemical characterization in mouse model, multiple orthogonal methods (Western blot, enzymatic assay, cDNA/genomic sequencing), consistent with human KEL function\",\n      \"pmids\": [\"11132157\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Targeted disruption of the murine Kel gene abolishes endothelin-3-converting enzyme activity on RBCs, reduces XK protein levels (without affecting XK mRNA), increases RBC Gardos channel activity, blunts the normal endothelin-3-mediated enhancement of Gardos channel activity, reduces intratumoral neovascularization, and mildly affects some motor activities.\",\n      \"method\": \"Homologous recombination knockout, enzymatic activity assay, Western blot, Northern blot, ion transport assay, tumor implantation model, motor function testing\",\n      \"journal\": \"American journal of hematology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — genetic knockout with multiple orthogonal phenotypic readouts including enzymatic assay, ion transport, protein expression, and functional consequence in vivo\",\n      \"pmids\": [\"19544475\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"A G-to-C mutation at the splice donor site of intron 3 in the KEL gene causes the Kell-null (Ko) phenotype by abolishing normal splicing; the resulting major transcript skips exon 3 (which encodes the transmembrane domain), introducing a premature stop codon that prevents translation of the C-terminal segment bearing all known Kell antigen positions.\",\n      \"method\": \"DNA sequencing, RT-PCR, splice site mutation analysis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — direct sequencing and RT-PCR with mechanistic explanation of null phenotype; multiple orthogonal molecular methods in a single rigorous study\",\n      \"pmids\": [\"11134029\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1993,\n      \"finding\": \"The KEL gene was localized to chromosome 7q33–35 by fluorescence in situ hybridization, providing evidence that Kell antigenic determinants are encoded by the polypeptide chain rather than associated sugar molecules.\",\n      \"method\": \"Fluorescence in situ hybridization (FISH) with biotinylated KEL cDNA probe\",\n      \"journal\": \"Human genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — FISH localization with functional inference; single lab, single method\",\n      \"pmids\": [\"8340113\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1991,\n      \"finding\": \"The KEL locus was genetically linked to the prolactin-inducible protein locus (PIP) and provisionally assigned to chromosome 7q32–36 by genetic linkage analysis.\",\n      \"method\": \"Genetic linkage analysis\",\n      \"journal\": \"Annals of human genetics\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 4 / Weak — genetic linkage only, no direct functional or mechanistic experiment\",\n      \"pmids\": [\"1683210\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1996,\n      \"finding\": \"Near-total absence of Kell antigens can result from a combination of homozygosity for Kpa (KEL3) and a splice-site mutation in XK (intron 2), demonstrating that Kell antigen expression is partially governed by XK protein and that both loci act together to regulate surface Kell antigen levels.\",\n      \"method\": \"Serology, RFLP, XK gene sequencing, family study\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — combination of molecular (sequencing, RFLP) and serological methods establishing genetic epistasis between KEL and XK loci\",\n      \"pmids\": [\"8916972\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"Point mutations G865A (Glu249Lys) and G863A (Arg248Gln) in adjacent codons of KEL exon 8 cause amino acid substitutions that define the RAZ and VLAN Kell blood group phenotypes, respectively.\",\n      \"method\": \"DNA sequencing of KEL open reading frame and flanking intronic regions, PCR-based genotyping assays\",\n      \"journal\": \"Vox sanguinis\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — direct sequencing with confirmatory genotyping assay; single lab, defines molecular basis of antigen variants\",\n      \"pmids\": [\"11904003\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"A serine at position 193 of the Kell glycoprotein (encoded by a 577A>T transversion, Ser193), distinct from the canonical Thr193Met KEL1/KEL2 polymorphism, results in expression of an abnormal KEL1 antigen in addition to KEL2, demonstrating that residue 193 is critical for KEL1 antigen expression.\",\n      \"method\": \"DNA sequencing (genomic and cDNA), flow cytometry, PCR genotyping\",\n      \"journal\": \"Transfusion\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — cDNA sequencing plus flow cytometry confirming aberrant antigen expression; single lab\",\n      \"pmids\": [\"17076841\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"Alternative splicing of KEL gene transcripts occurs in non-reticulocyte cells (total RNA), while reticulocytes express only one normal transcript; Kell glycoprotein is strongly expressed on RBCs but absent or very low on leukocytes.\",\n      \"method\": \"RT-PCR, nested PCR, sequencing, flow cytometry with monoclonal antibodies\",\n      \"journal\": \"Chinese journal of medical genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — multiple molecular methods (RT-PCR, sequencing, flow cytometry) in a single study; single lab\",\n      \"pmids\": [\"18841563\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"A novel KEL*1,3 allele (KEL1 and KEL3 on the same chromosome) causes approximately 80% reduction in KEL1 surface antigen expression, demonstrating a cis-modifier effect of KEL3 on KEL1 expression.\",\n      \"method\": \"Serology, flow cytometry, PCR with sequence-specific priming, genomic DNA sequencing of separated parental alleles\",\n      \"journal\": \"Transfusion\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — phased allele sequencing with quantitative flow cytometry confirms cis-modifier mechanism; single lab\",\n      \"pmids\": [\"19347978\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"A synonymous mutation (c.1719C>T) in KEL exon 16 causes complete exon 16 skipping despite being located 16 bases downstream of the 3′ splice site, resulting in a null (silent) KEL allele and contributing to Kmod phenotype when combined with another mod allele.\",\n      \"method\": \"Genomic and cDNA sequencing from erythroid progenitor-derived cells, serology\",\n      \"journal\": \"Vox sanguinis\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — cDNA sequencing from cultured erythroid cells directly demonstrates exon skipping; single lab\",\n      \"pmids\": [\"24795954\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"GATA1 and KLF1 co-occupy the KEL promoter and are functionally required for KEL transcription; naturally occurring variants in their binding motifs reduce GATA1 and KLF1 binding affinity and KEL transcriptional activity.\",\n      \"method\": \"ChIP-seq, ATAC-seq, luciferase reporter assays, EMSA, mass spectrometry\",\n      \"journal\": \"Transfusion\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — functional validation by luciferase assay combined with EMSA and MS confirming TF binding; multiple orthogonal methods in one study\",\n      \"pmids\": [\"38644556\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Anti-KEL immunoprophylaxis prevents alloimmunization through antigen modulation (rapid removal of detectable KEL antigen from circulating RBCs), and this process requires redundant pathways involving both Fcγ receptors and complement (C3); absence of both abolishes immunoprophylaxis efficacy and KEL antigen modulation.\",\n      \"method\": \"Murine transfusion model using transgenic KEL-expressing RBCs, FcγR/C3 knockout mice, flow cytometry, Western blot, in vitro phagocytosis assay\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic knockout of both pathways with multiple orthogonal readouts (flow cytometry, Western blot, phagocytosis assay) in single study\",\n      \"pmids\": [\"27688803\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"B cells require Type 1 interferon (IFN-α/β) signaling through IFNAR1 to produce alloantibodies against the KEL glycoprotein after transfusion; IFNAR1-deficient B cells fail to differentiate into germinal center B cells and plasma cells in response to KEL-expressing RBCs.\",\n      \"method\": \"Murine transfusion model, IFNAR1 knockout mice, bone marrow chimeras with cell-specific IFNAR1 deletion, flow cytometry\",\n      \"journal\": \"Transfusion\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — bone marrow chimera experiments with cell-type-specific knockouts and multiple B-cell differentiation readouts; single lab but rigorous genetic dissection\",\n      \"pmids\": [\"28836263\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Influenza infection promotes alloimmunization to transfused KEL-expressing RBCs through a mechanism dependent on recipient Type 1 IFN production; blocking or genetic deletion of Type 1 IFN signaling significantly reduces influenza-induced anti-KEL alloantibody formation.\",\n      \"method\": \"Murine transfusion model, influenza infection, antibody blockade and genetic knockout of Type 1 IFN signaling, flow cytometric crossmatch\",\n      \"journal\": \"Transfusion\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — single lab using both antibody blockade and genetic approaches to confirm IFN-dependent mechanism\",\n      \"pmids\": [\"31403208\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Poly(I:C)-induced antiviral responses cause breakthrough anti-KEL alloimmunization despite immunoprophylaxis; this is associated with increased RBC consumption by inflammatory monocytes and elevated MCP-1 and IL-6; poly(I:C) can induce breakthrough alloimmunization even in recipients lacking Type 1 IFN receptors, suggesting additional IFN-independent pathways.\",\n      \"method\": \"Murine transfusion model, knockout mice (FcγR, C3, IFNAR), cytokine measurement, flow cytometry, Type 1 IFN administration\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — mechanistic dissection using multiple knockouts and cytokine profiling; single lab\",\n      \"pmids\": [\"32266378\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"KEL promotes cell proliferation in acute erythroleukemia cells, and its downregulation reverses drug resistance to JQ1; KEL expression is associated with gain of H3K27 acetylation and is regulated by cotranscription factors GATA1 and TAL1.\",\n      \"method\": \"Cell proliferation assay (CCK8), flow cytometry (apoptosis), ChIP-seq/epigenetic analysis, transcription factor binding analysis\",\n      \"journal\": \"Oxidative medicine and cellular longevity\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Weak — functional loss-of-function data with defined cellular phenotype and epigenetic mechanism; single lab\",\n      \"pmids\": [\"35140839\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"The Nrf2 activator CDDO-Im suppresses poly(I:C)-induced Type 1 IFN-stimulated gene expression and inhibits anti-KEL IgG alloantibody production after transfusion of KEL-expressing RBCs, in an Nrf2-dependent manner (no effect in Nrf2−/− mice).\",\n      \"method\": \"Murine transfusion model, Nrf2 knockout mice, pharmacological Nrf2 activation, anti-KEL IgG measurement by flow cytometry, gene expression analysis\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — genetic and pharmacological evidence in a single preprint study; Nrf2 knockout confirms on-target mechanism\",\n      \"pmids\": [\"40235992\"],\n      \"is_preprint\": true\n    }\n  ],\n  \"current_model\": \"KEL encodes a type II transmembrane glycoprotein (Kell) that functions as an endothelin-3-converting enzyme (ECE-3/CD238) on red blood cells, where it forms a disulfide-linked complex with XK; XK protein levels depend on Kell expression, and Kell enzymatic activity modulates RBC ion transport (Gardos channel) via endothelin-3 signaling; KEL transcription is driven by GATA1 and KLF1 co-occupying its promoter, and surface antigen expression is modulated in cis by adjacent Kell alleles and in trans by XK; loss-of-function mutations (splice-site, nonsense, frameshift, missense) in KEL cause the Kell-null (Ko) or Kmod phenotypes; in the immune system, alloantibody responses to KEL-expressing RBCs require Type 1 IFN signaling in B cells and are regulated by FcγR/complement-dependent antigen modulation and by the Nrf2 antioxidant pathway.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"KEL encodes the Kell glycoprotein, a type II transmembrane red-cell protein that functions as an endothelin-3-converting enzyme (ECE-3) and forms a disulfide-linked complex with the integral membrane protein XK [#0]. Genetic disruption of Kell abolishes this enzymatic activity, reduces XK protein levels without altering XK mRNA, and increases Gardos channel activity while blunting the normal endothelin-3-mediated enhancement of that channel, linking Kell catalytic function to red-cell ion transport [#1]. The interdependence of the two loci is reciprocal: near-total loss of Kell antigens arises when reduced KEL antigen alleles combine with an XK splice-site mutation, establishing that XK governs surface Kell antigen expression [#5]. KEL transcription is driven by GATA1 and KLF1, which co-occupy its promoter and are required for KEL expression, with natural variants in their binding motifs reducing transcription factor occupancy and KEL activity [#11]. Loss-of-function mutations cause Kell-null (Ko) and Kmod phenotypes through diverse mechanisms including splice-donor disruption that skips the transmembrane-encoding exon 3 and introduces a premature stop codon [#2], and a synonymous exon 16 variant that triggers exon skipping [#10], while antigen-defining missense variants map to residues such as position 193 critical for KEL1 expression [#7]. Beyond the red cell, the Kell glycoprotein is a model alloantigen: anti-KEL alloantibody responses require Type 1 interferon signaling through IFNAR1 in B cells for germinal center and plasma cell differentiation [#13], and immunoprophylaxis acts by FcγR- and complement-dependent antigen modulation [#12]. Inflammatory and antiviral stimuli modulate this response, which can be suppressed via the Nrf2 antioxidant pathway [#17].\",\n  \"teleology\": [\n    {\n      \"year\": 2000,\n      \"claim\": \"Established the molecular identity and enzymatic function of the Kell protein, answering what biochemical activity this blood group antigen carries.\",\n      \"evidence\": \"Biochemical and enzymatic characterization of mouse Kell ortholog by Western blot, activity assay, and cDNA/genomic sequencing\",\n      \"pmids\": [\"11132157\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vivo physiological substrate range beyond endothelin-3 not defined\", \"Structural basis of XK disulfide linkage not resolved\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Defined a molecular mechanism for the Kell-null phenotype, showing how a splice mutation eliminates the antigen-bearing protein.\",\n      \"evidence\": \"DNA sequencing and RT-PCR of an intron 3 splice donor mutation showing exon 3 skipping and premature stop codon\",\n      \"pmids\": [\"11134029\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Does not address the full allelic spectrum of null/mod phenotypes\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Demonstrated in vivo that Kell catalytic activity controls red-cell ion transport and stabilizes XK, linking enzyme function to physiology.\",\n      \"evidence\": \"Murine Kel knockout with enzymatic, ion transport, protein expression, tumor, and motor function readouts\",\n      \"pmids\": [\"19544475\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism connecting endothelin-3 conversion to Gardos channel regulation not fully traced\", \"Basis of XK destabilization in Kell absence unresolved\"]\n    },\n    {\n      \"year\": 1996,\n      \"claim\": \"Established the reciprocal genetic dependence between KEL and XK loci in governing surface antigen levels.\",\n      \"evidence\": \"Serology, RFLP, XK sequencing, and family study of combined Kpa homozygosity and XK splice mutation\",\n      \"pmids\": [\"8916972\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular basis of XK control over Kell surface expression not mechanistically defined\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Showed antigen expression is modulated in cis by adjacent KEL alleles, refining how surface antigen quantity is set.\",\n      \"evidence\": \"Phased allele sequencing with quantitative flow cytometry of a KEL*1,3 allele\",\n      \"pmids\": [\"19347978\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular mechanism of cis-suppression unknown\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Identified the transcriptional control of KEL, answering how erythroid-specific expression is established.\",\n      \"evidence\": \"ChIP-seq, ATAC-seq, luciferase reporter, EMSA, and mass spectrometry showing GATA1/KLF1 co-occupancy\",\n      \"pmids\": [\"38644556\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Interplay of GATA1/KLF1 with other erythroid regulators not fully mapped\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Defined the immune requirement for anti-KEL alloantibody formation, identifying Type 1 IFN signaling in B cells as essential.\",\n      \"evidence\": \"Murine transfusion model with IFNAR1 knockout and bone marrow chimeras with cell-specific deletion\",\n      \"pmids\": [\"28836263\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Source and trigger of Type 1 IFN in steady-state transfusion not identified\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Explained how anti-KEL immunoprophylaxis works, attributing protection to FcγR- and complement-dependent antigen modulation.\",\n      \"evidence\": \"Murine transfusion model with FcγR/C3 knockouts, flow cytometry, Western blot, phagocytosis assay\",\n      \"pmids\": [\"27688803\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Relative contribution of phagocytic versus enzymatic antigen loss not separated\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Identified a pathway to suppress anti-KEL alloimmunization, showing Nrf2 activation dampens IFN-stimulated responses and antibody production.\",\n      \"evidence\": \"Murine transfusion model with Nrf2 knockout and pharmacological CDDO-Im activation (preprint)\",\n      \"pmids\": [\"40235992\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Preprint not peer-reviewed\", \"Mechanistic link between Nrf2 and IFN-stimulated gene suppression incomplete\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How Kell endothelin-3-converting enzyme activity mechanistically couples to Gardos channel regulation and what non-erythroid physiological roles Kell serves remain open.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No structural model of the Kell-XK complex\", \"Physiological substrates beyond endothelin-3 uncharacterized\", \"Non-erythroid functions only hinted at by tumor and motor phenotypes\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"GO:0016787\", \"supporting_discovery_ids\": [0, 1]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0, 8]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [12, 13]},\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [11]}\n    ],\n    \"complexes\": [\"Kell-XK complex\"],\n    \"partners\": [\"XK\", \"GATA1\", \"KLF1\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}