title: HLA-DQB1*0602 is associated with dominant protection from diabetes even among islet cell antibody-positive first-degree relatives of patients with IDDM.
abstract: HLA-DQB1 alleles confer susceptibility and resistance to insulin-dependent diabetes mellitus (IDDM). We investigated whether the susceptibility alleles DQB1*0302 and DQB1*0201 affect progression to diabetes among islet cell antibody-positive (ICA+) first-degree relatives of IDDM patients and whether the protective allele DQB1*0602 can be found and is still protective among such relatives. We human leukocyte antigen-typed and periodically tested beta-cell function (first-phase insulin release [FPIR] during the intravenous glucose tolerance test) in 72 ICA+ relatives, of whom 30 became diabetic on follow-up (longest follow-up 12 years); 54 (75%) relatives carried DQB1*0302 and/or DQB1*0201. The frequency of DQB1*0302 and DQB1*0201 and of the high-risk genotype DQB1*0302/DQB1*0201 did not differ significantly between diabetic relatives and those remaining nondiabetic. On follow-up, progression to IDDM was not statistically different for relatives with or without the DQB1*0302/DQB1*0201 genotype. However, those relatives with the DQB1*0302/DQB1*0201 genotype had a tendency to develop diabetes at an earlier age (log-rank P = 0.02). We found DQB1*0602 in 8 of 72 (11.1%) ICA+ relatives. Relatives with DQB1*0602 did not develop diabetes or show any decline of FPIR versus 28 of 64 DQB1*0602- relatives who developed IDDM (log-rank P = 0.006; Wilcoxon's P = 0.02). The protective allele DQB1*0602 is found in ICA+ relatives who have minimal risk of progression to IDDM. Therefore, DQB1*0602 is associated with protection from IDDM both in population studies and among relatives with evidence of autoimmunity who should not enter prevention trials.
authors.affiliation: Barbara Davis Center for Childhood Diabetes, University of Colorado Health Sciences Center, Denver 80262.
authors.forename: A
authors.initials: A
authors.lastname: Pugliese
authors.forename: R
authors.initials: R
authors.lastname: Gianani
authors.forename: R
authors.initials: R
authors.lastname: Moromisato
authors.forename: Z L
authors.initials: ZL
authors.lastname: Awdeh
authors.forename: C A
authors.initials: CA
authors.lastname: Alper
authors.forename: H A
authors.initials: HA
authors.lastname: Erlich
authors.forename: R A
authors.initials: RA
authors.lastname: Jackson
authors.forename: G S
authors.initials: GS
authors.lastname: Eisenbarth
mesh_terms: D000293:Adolescent; D000328:Adult; D000483:Alleles; D001323:Autoantibodies / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics*; D005190:Family; D005260:Female; D005787:Gene Frequency; D005799:Genes, Dominant; D005838:Genotype; D006683:HLA-DQ Antigens / Q000235:genetics*; D059866:HLA-DQ beta-Chains; D006801:Humans; D007515:Islets of Langerhans / Q000276:immunology; D015993:Life Tables; D008297:Male; D008875:Middle Aged
chemical_list: D001323:Autoantibodies; D006683:HLA-DQ Antigens; D059866:HLA-DQ beta-Chains; C069051:HLA-DQB1 antigen; C024211:islet cell antibody