Organ-specific autoantibodies in HLA genotyped insulin-dependent diabetes mellitus families

The prevalence of cytoplasmic islet cell antibodies (ICA) and extrapancreatic antibodies (EPA), (stomach, adrenal and thyroid) was investigated in 132 juvenile onset diabetic patients, without personal or familial history of other autoimmune disease, and their 31 diabetic and 402 non-diabetic first degree relatives. The prevalence of ICA was 59% in index cases and 12% in the non-affected first degree relatives. The frequency of EPA was 23% and 16% respectively. There were no sex-related differences among the patients. However, among the non-affected relatives, an increased frequency of EPA was observed in females (23%) compared to males (8%) (P less than 10-4). There was a higher prevalence of ICA in healthy relatives bearing DR3 and/or DR4 antigen combinations compared to non-DR3 and non-DR4 individuals (14% versus 5%, P less than 0.05). Furthermore, ICA were more frequent in healthy siblings sharing two haplotypes compared with one or no haplotype (21% vs 10%, P less than 0.05). These results support the heterogeneity of the autoantibodies: ICA are related closely to diabetes, decline in frequency with the duration of the disease and show association with DR3 or DR4 and the number of HLA haplotypes shared with the proband; EPA are sex related, independent of the duration of diabetes, non-HLA linked, and clustered in families with parent-offspring overtransmission, reflecting an overlapping autoimmune background.     

HLA genotype distribution and genetic models of insulin-dependent diabetes mellitus

When comparing the odds ratios (OR's) obtained by contrasting various HLA-DR phenotypic classes in patients (e.g. diabetics) and controls, it is desirable to use the same reference phenotypes for all OR's. If this is done, it can be shown that the OR for, say, DR3/4 , heterozygotes cannot exceed the OR's for both of the two homozygotes (DR3/3 and DR4/4) , if there is one disease susceptibility locus with one normal allele and one susceptibility allele in linkage disequilibrium with two HLA-DR alleles {HLA-DR3 and 4) and if the action of the susceptibility gene is dominant, recessive or intermediate between dominant and recessive. In each of these cases, the OR for the heterozygotes will be intermediate between the OR's of the two homozygotes. If the two alleles at the susceptibility locus act in an overdominant way, the OR for the heterozygotes may in some cases exceed the OR's of both homozygotes. Comparison of the magnitude of two OR-values can be reduced to investigating whether the OR value generated by comparing one phenotypic class against the other (as reference group) differs from unity. There is suggestive but not conclusive evidence that the OR of developing insulin-dependent diabetes for the DR3/4 genotype is higher than the corresponding OR-values for both of the two homozygotes (DR3/3 and DR4/4) , indicating that the susceptibility to this disease may not be explained by a dominant, recessive or intermediate model.     

HLA microsatellite associations with insulin-dependent diabetes mellitus in Singaporean Chinese.

Singaporean Chinese with insulin-dependent diabetes mellitus (IDDM) have previously been shown to be associated with the DRB1*0301 haplotype and the joint occurrence of DRB1*0301/*0901 and DRB1*0301/*04. The present study extended previous HLA associations by investigating the HLA region using four microsatellites (TNFa, D6S273, TAP1, DQCARII). Seventy-five IDDM patients and 80 healthy controls were studied. TNFa*3 (RR = 2.26), TNFa*12 (RR = 3.30), TAP1*9 (RR = 2.55) showed increased frequencies while TNFa*11 (RR = 0.29), TAP1*4 (RR = 0.50) showed decreased frequencies in patients compared to controls. Linkage analysis suggested that the positive associations of TNFa*3 and TAP1*9 were secondary to that of DRB1*0301. However, TNFa*12 appeared to provide additional risks to IDDM besides the DRB1*0301 haplotype, whereas TNFa*11 and TAP1*4 conferred an independent protective effect against IDDM. Our findings reinforce the notion that susceptibility to and protection against IDDM may include TNF region. In the present study, TNFa*12 seemed to be the primary association in the DRB1*0405 haplotype and may play an independent role in the pathogenesis of IDDM through TNF-alpha function.     

HLA antigens of insulin-dependent diabetics

We describe three human proliferating T cell colonies, derived from mixed leukocyte culture with a non-diabetic individual (DR3 + 4) as the source of responding cells and an insulin-dependent diabetic patient (also DR3 + 4) as the source of stimulating cells. One colony detects HLA-Dw10 or a closely related antigen, and two detect an antigen that we call BO1 (Boston 1). BO1 is found so far on cells of all persons with DR5, about half of those with DRw6, and a particular subset of those with DR3. Among DR3-positive subjects, BO1 is positively correlated with HLA-B18 and BfF1, and negatively correlated with HLA-B8. These findings suggest that BO1 occurs in linkage disequilibrium with DR5, DRw6, and the haplotype B18, BfF1, DR3, the latter being common in southern Europe and reported previously to be a marker for insulin-dependent diabetes. In limited testing (21 subjects), BO1 was completely included in the supertypic specificity MT2, BO1 is a Class II HLA antigen, as demonstrated by blocking with monoclonal antibodies, but is distinct from all known antigens of the DR, MB(DC), MT, and SB series. It could be located on the same polypeptide chain as one or more of these antigen groups, however, particularly DR and/or MT.     

Extended HLA haplotypes in families with insulin-dependent diabetes mellitus in Northern Finland

Haplotypes including HLA, Bf and C4 loci were analyzed in a material comprising 55 families with diabetic children. One hundred and ten haplotypes found in IDDM patients were compared with 101 haplotypes present only in healthy family members. Two complotypes, BfSC4A3B3 and SC4A0B1 . were significantly more common (P <0.05) in the diabetic haplotypes, and these were in most cases found in haplotypic combinations with HLA-B15,Dw4,DR4 and HLA-B8.Dw3,DR3 genes, respectively. The B8/DR3 haplotype was better conserved, as 72% included the BfSC4A0B1 complotype as compared with only 35% of the B15/DR4 haplotypes with "high risk" C4A3B3 complement alleles (p <0.05). DR3 was found in 26% of the diabetic haplotypes and DR4 in 43%. DR4 associated with the Dw4 in 69% of cases and with D w14 in 26% of the diabetic haplotypes. Our results confirm that the two phenotypes found earlier to be associated with IDDM in Northern Finland, e.g. "B15, BfS, C4A3B3, Dw4, DR4" and "B8, BfS, C4A0B1, Dw3, DR3" are inherited as haplotypes.     

Lack of interaction of HLA and IgG heavy chain allotypes in insulin-dependent diabetes mellitus

Because of conflicting previous reports showing the presence or absence of Gm-HLA interaction in insulin-dependent diabetes mellitus (IDDM), we report results for a group of Wisconsin families having 2 or more siblings with IDDM. Although this study is very similar to one by Field et al., who found HLA-Gm interaction in IDDM, we find no evidence for such an interactive effect p = 0.33). We discuss published data on HLA-Gm interaction in IDDM, and conclude that overall there is little reason to postulate such an interaction.     

Immunotherapy of insulin-dependent diabetes mellitus

Type 1 diabetes mellitus is caused by the T cell mediated autoimmune destruction of insulin-producing beta cells of the islets of Langerhans within the pancreas. Current immunotherapy strategies are aimed at directly inactivating the autoreactive T cells and/or inducing T cells with regulatory capabilities. At the preclinical level, several strategies that employ TCR antagonists -- including monoclonal antibodies, autoantigen-specific peptides and soluble TCR ligands -- are showing promise and being developed for clinical application. Several of these approaches employing monoclonal antibodies against the TCR-CD3 complex or soluble peptide antigens are producing favorable results in the clinic.     

Combinations of HLA DR and DQ molecules determine the susceptibility to insulin-dependent diabetes mellitus in Koreans

The association of HLA-DRB1 and DQB1 genes with IDDM in Koreans was assessed using 115 IDDM patients and 140 nondiabetic controls. DQB1*0201 is the only DQB1 allele positively associated with IDDM while DQB1*0602, *0601 and *0301 are negatively associated. Three DRB1 alleles (DRB1*0301, DRB1*0407 and DRB1*0901) are positively associated while four DR allele groups (DRB1*15, DRB1*12, DRB1*10 and DRB1*14) are negatively associated. However, Haplotype analyses indicated that DQB1*0302, DRB1*0405 and DRB1*0401 may confer susceptibility because the DRB1*0405-DQB1*0302 and DRB1*0401-DQB1*0302 haplotypes are positively associated with the disease. The lack of association in Koreans with the DQB1*0302 allele, which appears predisposing in studies of non-Orientals, is due to its strong linkage disequilibrium (LD) with the protective DRB1*0403 and *0406 alleles, while the lack of association with DRB1*0405 is because of its strong LD with the protective DQB1*0401 allele. Nine DR/DQ genotypes confer significantly increased risk to IDDM. Seven of the nine genotypes (DR3/4s, DR1/4s, DR4s/13, DR4s/8, DR4s/7, DR9/13 and DR3/9) were also found to be at high risk to IDDM in other populations, while the two others (DR1/9 and DR9/9) are only found in Koreans. Surprisingly, DR4/4 homozygotes are not associated with high risk to IDDM in Koreans. This observation can be explained by the high frequency of protective DR4 subtypes and the protective DQ alleles (0301 and 0401) associated with the susceptible DR4 alleles. Our analyses indicate that the counterbalancing act between susceptible DRB1 and protective DQB1, and vice versa, that has already been observed in Chinese and Japanese, is the major factor responsible for the low incidence of diabetes in Koreans.     

An islet cell antibody negative form of insulin-dependent diabetes mellitus (IDD) associated with HLA antigens A9 and Bw16.

One hundred and sixty-six unrelated children and adolescents having growth-onset, insulin-dependent diabetes mellitus (IDD) were studied for pancreatic-cytoplasmic islet cell antibodies (ICA) at various times from the diagnosis of the disease. A strong association between HLA antigens A9 and Bw16 and an absence of ICA early in the course of disease was seen. On the other hand B8/Dw3 or B15/Dw4 antigens were not significantly associated with the occurrence of ICA although both these antigens are greatly increased among pediatric IDD patients in northern Finland. The finding of the association of the HLA antigens A9 and Bw16 with ICA-negativity contributes to the evidence for the heterogeneity in the genetic susceptibility to IDD.     

Immunogenetics of insulin-dependent diabetes mellitus in humans

Diabetes mellitus is the second most prevalent chronic disease in children in the U.S. It is associated with severe manifestations which include blindness and circulation deficiencies as well as markedly increased risk of death. The etiology of diabetes mellitus remains a mystery although both genetic and environmental factors have been implicated. The geneticist is confronted with a number of obstacles in his attempts to unravel this problem, including differences in the definition of affected individuals. This matter was certainly clarified by the separation of noninsulin-dependent diabetes (NIDDM) and insulin-dependent diabetes mellitus (IDDM) into two separate disease entities. Twin studies, however, show that IDDM cannot be entirely due to genetic causes as concordance is no more than about 50%. Although the disease is then clearly not inherited per se, the "susceptibility" to diabetes seems almost surely inherited and, provided this susceptibility, the disease can be brought on by environmental factors. Until the underlying mechanism causing IDDM is completely ascertained, we have to rely on genetic markers to approach the study of the inheritance thereof. Since, in the early 1970s, research by Nerup's and Cudworth's groups revealed associations between the HLA-B locus and IDDM, the HLA markers are considered the classical genetic markers for IDDM susceptibility. In this paper, we review the nature of the genetic susceptibility to IDDM and the possible environmental factors which can bring on the disease.     

Immunotherapy of insulin-dependent diabetes mellitus.

Immunotherapy of diabetes is now focusing on induction of tolerance to beta cell antigens using either soluble antigens or monoclonal anti-T-cell antibodies. These approaches have reached the clinical arena. At the experimental level, strategies are being developed that use or target cytokines (with gene therapy) or stimulate regulatory T cells.     

HLA-DP and susceptibility to insulin-dependent diabetes mellitus in Japanese

ABSTRACT: Human leukocyte antigen (HLA) genes are candidates for susceptibility genes in insulin-dependent diabetes mellitus (IDDM). Recently, the association of DR and DQ with IDDM has been reported, but the role of HLA-DP genes remains uncertain. To address the question, we analyzed the DPB1 gene of 20 Japanese IDDM patients and 30 control subjects using a combination of polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis (PCR-RFLP method). DPB1*0501 was the most frequent allele both in Japanese patients and control subjects. There was no appreciable association between IDDM and the DPB1 allele in Japanese. The absence of association between IDDM and DP, in spite of the known association between this disease and both DR and DQ, suggests that the HLA locus (loci) telomeric to DP encodes susceptibility to IDDM.     

Azathioprine associated T-cell mutations in insulin-dependent diabetes mellitus

Somatic mutations arise regularly in human T lymphocytes. As these events occur at increased frequencies in several autoimmune disorders, presumably because of increased T-cell proliferation, we investigated if this is also true for insulin-dependent diabetes mellitus (IDDM). Mutations of the hypoxanthine guanine phosphoribosyltransferase (hprt) gene measured by 6-thioguanine (TG) selection were studied in 28 patients (60 determinations) enrolled in a prospective double-blinded placebo-controlled study of azathioprine immunosuppression: 17 patients (34 determinations) were receiving azathioprine and 11 (26 determinations) placebo. Mean hprt T-cell mutant frequencies (MFs) were elevated in both patient groups, but only in the azathioprine group were elevations large and statistically correlated with the duration of the therapy. These results suggest that the organ-specific antigenic stimulus of the T-cell proliferation in IDDM does increase mutant cells in the peripheral blood, but this increase is relatively small. However, azathioprine, which is converted to 6-mercaptopurine in vivo, selects and amplifies the hprt mutants that do arise. Clinical azathioprine resistance may be explained by hprt mutations arising in T cells relevant to the underlying autoimmune process. Monitoring for these mutations should allow more effective use of this immunosuppressive agent.