Diabetes, Vol 44, Issue 9 1021-1028, Copyright © 1995 by American Diabetes Association
Human leukocyte antigen identity and DQ risk alleles in autoantibody-positive siblings of children with IDDM are associated with reduced early insulin response. Childhood Diabetes in Finland (DiMe) Study Group
R Veijola, P Vahasalo, E Tuomilehto-Wolf, H Reijonen, P Kulmala, J Ilonen, HK Akerblom and M Knip
Department of Pediatrics, University of Oulu, Finland.
To investigate the relationship between human leukocyte antigen
(HLA)-associated genetic factors and the development of beta-cell
dysfunction, we performed sequential intravenous glucose tolerance tests
(IVGTTs) on 81 islet cell antibody (ICA)-positive and/or insulin
autoantibody-positive healthy siblings of children with newly diagnosed
insulin-dependent diabetes mellitus (IDDM). A lower glucose disappearance
rate (Kg) (P < 0.5) and decreased first-phase insulin response (FPIR) (P
< 0.05) were observed on multiple occasions in HLA-identical siblings
compared with the haploidentical or nonidentical ones. Siblings carrying
the DQB1*0302/0201, -0302/x, or -0201/x genotype also had lower FPIRs (P
< or = 0.05) at several time points than those with no DQB1 risk
genotype. When all IVGTTs were taken into account, DQB1*0302/0201
heterozygous siblings had an abnormally low FPIR (< 45 mU/l; 3rd
percentile) in at least one test more often than did siblings with no DQB1
risk genotype (50.0% vs. 6.1%; P = 0.001). Siblings carrying either the
DQB1*0602 or the DQB1*0603 protective allele had lower serum peak ICA and
glutamic acid decarboxylase (GAD)65 antibody levels (P = 0.023 and 0.007,
respectively) and higher FPIRs on several occasions (P < 0.05) than
those with the DQB1 risk genotypes. Progression to IDDM was related to both
HLA identity and the presence of the DQB1*0302/0201 genotype. Normal Kg and
FPIR levels were observed in siblings who were positive for only insulin
autoantibody, and none of them developed IDDM.(ABSTRACT TRUNCATED AT 250
WORDS)