HLA distribution in Korean patients with insulin-dependent diabetes mellitus

Polymorphisms of HLA class II predispose children and adolescents with type 1 diabetes mellitus to autoimmune thyroid disease

To determine the prevalence of autoimmune thyroid disease (AITD) in children and adolescents with type 1 diabetes mellitus (DM), and assess whether the development of AITD is correlated with specific DQ-A and DQ-B loci of the HLA class II antigens, we analyzed thyroid function using anti-thyroid antibodies and HLA-DQ-A and -DQ-B polymorphisms in 69 patients with type 1 DM, in 75 normal healthy controls, and in 21 patients with AITD but without type 1 DM. Eighteen patients (26%) in the diabetic patients had AITD. In the diabetic patients, DQA1*0301 and DQB1*0302 occurred more frequently than in controls [DQA1*0301: OR = 1.939, 95% CI = 1.210-3.109 (P = 0.008, P(c) (corrected P) < 0.05); DQB1*0302: OR = 2.558, 95% CI = 1.354-4.832 (P = 0.005, P(c), > 0.05)]. Compared with controls, non-diabetic subjects with AITD showed higher frequency of DQA1*0301 (P(c), < 0.05) and DQB1*0601 (P(c) > 0.05), but these alleles were not contributing factors in the development of AITD in diabetic patients. In diabetic patients, DQB1*0201, known as susceptible allele of type 1 DM was not a contributing factor in the development of AITD in diabetic patients. Unlike DQB1*0201, DQB1*0401 was more frequently found in diabetic patients with AITD than in controls [OR = 4.053, 95% CI = 1.607-10.221 (P = 0.0017, P(c) < 0.05)] or than in non-diabetic AITD patients [OR = 15.769, 95% CI = 1.905-130.530(P = 0.002, P(c) < 0.05)]. In non-diabetic subjects, DQB1*0401 did not provide susceptibility for AITD. Our results suggest that HLA DQB1*0401 is a predisposing genetic marker for the development of AITD in patients with type 1 DM in Korea.

Role of HLA class II alleles in Korean patients with IDDM

MHC associations with IDDM in the Korean population were studied to investigate genetic susceptibility to this disorder. The frequencies of HLA-DR3, -DR4 and -DR9 were significantly higher in diabetic patients. However, the frequency of DR2 was significantly decreased in diabetic patients. DQA1*0301 and DQA1*0501 were positively and DQA1*0102 and DQA1*0201 negatively associated with IDDM. DQB1*0301 and DQB1*0601 were negatively associated with IDDM. Heterodimers DQA1*0301-DQB1*0201, DQA1*0501-DQB1*0201 and DQA1*0501-DQB1*0302 were positively associated with DQA1*0102-DQB1*0601 negatively associated with IDDM. The frequencies of DR3-DQA1*0301-DQB1*0201 and -DQA1*0501-DQB1*0201 were significantly higher in diabetic patients. The frequencies of DR4-DQA1*0301-DQB1*0201 and DR9-DQA1*0301-DQB1*0303 were significantly higher in diabetic patients. The presence of non-aspartic acid at position 57 of the DQ beta-chain was not associated with susceptibility to IDDM. However, the frequency of Arg 52 homozygotes was significantly higher in diabetic patients. These results suggest a role of the MHC molecule and also suggest racial differences in susceptibility to IDDM even within the Asian populations.

Immunogenetic and nutritional profile in insulin-using youth-onset diabetics in Korea

There are few reports on the genetic, immunological and nutritional characteristics of insulin-using youth-onset diabetes mellitus, insulin-dependent diabetes mellitus (IDDM) and malnutrition-related diabetes mellitus (MRDM) in Korea. Among 1266 hospitalized Korean diabetics, 29 (2.3%) were IDDM and 84 (6.6%) were MRDM. A diabetes history of first-relatives (28.6%) was more frequently found in the MRDM group than in the IDDM (14.8) and non-insulin-dependent diabetes mellitus (NIDDM) (19.0%) groups. HLA-DR4 was more common among IDDM (54.2%) and MRDM (52.4%) patients than controls (26.3%), and HLA-DR3 was more common among only IDDM patients (29.2%) than controls (10.9%). Conventional islet-cell antibodies were detected in 8 of 15 IDDM patients tested (53.3%) and in 11 of 22 MRDM patients (50.0%). MRDM patients had higher serum basal (1.02 +/- 0.51 ng/ml) and peak (1.44 +/- 0.76 ng/ml) C-peptide concentrations than IDDM patients, but lower concentrations than NIDDM patients. Before the onset of diabetes, the calorie intake of 21 MRDM patients assessed was 63.1% of the daily requirement and the intake of carbohydrate, protein and fat was 71.7%, 55.9% and 39.8%, respectively. In summary, our data suggest that IDDM in Korea is associated with HLA-DR3 or HLA-DR4, indicating a risk for IDDM in Western societies; furthermore, MRDM has a history of undernutrition at the preonset period and is also associated with HLA-DR4. It might be also concluded that MRDM in Korea is another expression of IDDM caused by the shortage of some nutrients for the structural and/or functional maintenance of pancreatic beta-cells.

Speculation on the evolution of insulin-dependent diabetes genes

A hypothesis about the evolution of insulin-dependent diabetes mellitus (IDDM)-susceptibility alleles is proposed. IDDM is known to be associated with two HLA-DR alleles, DR3 and DR4. DR3 is associated with IDDM in all ethnoracial groups including populations in which IDDM is rare, such as African and Asian populations, as well as whites in whom IDDM is common. However, in general, DR4 is associated with IDDM only in populations with white ancestry with high rates of IDDM. IDDM in American blacks illustrates the evolutionary patterns of the two diabetes alleles. The frequency of IDDM in American blacks relative to that in American whites (20% to 30%) approximates the frequency of the American black gene pool that is white-derived (also 20% to 30%), and DR4 is associated with IDDM in American blacks but not in African blacks. These data are consistent with the infusion of a dominant white-derived DR4-associated diabetes allele into the black gene pool. Recent studies of mitochondrial DNA suggest that modern humans evolved in Africa 200,000 to 300,000 years ago and that repeated migrations populated the world. The DR-population:IDDM-frequency relationships suggest that the DR3-associated diabetes allele evolved early (greater than or equal to 100,000 years ago) in Africa, whereas the DR4-associated diabetes allele evolved later (less than 15,000 years ago) in northern Europe. Recent data from studies of IDDM in families and populations which suggest that the DR4-associated allele has dominant characteristics and the DR3-associated allele has recessivelike characteristics fit into this hypothesis.

Human leukocyte antigen (HLA) in Korean patients with autoimmune thyroid diseases

In previous studies, there has been evidence of different allelic associations with a particular disease among various ethnic groups. The present study was done to investigate the associations between HLA and autoimmune thyroid diseases in the Korean. We found no association between Graves’ disease and HLA-B8 or -B35. However, increased frequencies of HLA-A11 and -DRw8, and the decreased frequencies of HLA-A10 and B12 were found in patients with Graves’ disease. In the cases of Hashimoto’s disease, the frequencies of HLA-A2 and -DRw8 were found to be significantly increased and the frequency of HLA-DRw6y decreased. These data indicate that the association between autoimmune thyroid disease and HLA in the Korean would appear to be different from that in most other racial groups, including Caucasians, Japanese and Chinese.