A phase I/II study to evaluate the effect of fractionated hemibody irradiation in the treatment of osseous metastases--RTOG 88-22

Previous studies have indicated that certain alleles of HLA-DR and -DQ genes were strongly associated with susceptibility and resistance to insulin-dependent diabetes mellitus (IDDM), and the role of DQ molecule in IDDM has been suggested. To further clarify the association of DQ alleles with IDDM, we determined the nucleotide sequences of full-length cDNA from 13 DQA1 alleles and 14 DQB1 alleles. The sequencing analysis revealed sequence polymorphisms outside the hypervariable region of DQ genes. We then analyzed the DQA1 and DQB1 polymorphisms along with that of DRB genes in 86 B-lymphoblastoid cell lines (B-LCLs) from various ethnic groups and in healthy unrelated Japanese and Norwegian individuals. The allelic and haplotypic distributions in each population revealed the characteristic haplotypic formation in the HLA class II region. HLA genes in 139 Japanese and 100 Norwegian IDDM patients were analyzed. DQB1*0301 was negatively associated with IDDM in both ethnic groups, irrespective of associated DRB1 and DQA1 alleles. In DQB1*0302 positive populations, which represented a positive association with IDDM in both ethnic groups, DRB1*0401, *0404, *0802 haplotypes increased in the patients, whereas DRB1*0406 haplotype decreased. Considering about the hierarchy in DRB1 alleles with IDDM susceptibility (DRB1*0401>*0404>*0403 in Norwegian and DRB1*0802>*0403>*0406 in Japanese), the genetic predisposition to IDDM is suggested to be defined by the combination of DR-associated susceptibility and DQ-associated susceptibility and by the DQ-associated resistance which is a dominant genetic trait.     

Time to conception after orchidopexy: evidence for subfertility?

A variety of malignancies have been linked to major histocompatibility complex genes, including the DRB1 alleles. The association of certain DRB1 antigens with renal cell carcinoma (RCC) has been both claimed and disclaimed. To determine whether HLA-DRB1 genotypes are associated with RCC, we used the modified PCR-RFLP method for the high-resolution HLA-DRB1 genotyping of 96 Japanese RCC patients. There were no significantly frequent HLA-DRB1 alleles, whereas the DRB1*0101 and *0405 alleles had significantly lower frequencies [P = 0.004, relative risk (RR) = 0.2 and P = 0.002, RR = 0.4) in the RCC patients than in the healthy Japanese controls (n = 1216). Moreover, patients with the HLA-DRB1 *0101 or *0405 allele tended to be in earlier stages and to have less aggressive tumors than patients with neither of these alleles. The corresponding serotyping subclassification, however, showed a significantly lower frequency only for DRB1-DR1 (P = 0.01, RR = 0.3). High-resolution genotyping is essential because the polymorphism of the peptide-binding domain of major histocompatibility complex class II molecules is more precisely determined by genotypes than serotypes. In addition, inherent technical difficulties and potential typing errors render serotyping inefficient. Our data suggest that HLA-DRB1*0101 and *0405 are protective alleles for both RCC development and tumor progression.     

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Ethnic comparisons are extremely important and useful for studying the HLA component involved in insulin-dependent diabetes mellitus (IDDM) predisposition. To date there have been only a few reports on the association of HLA loci and IDDM in Chinese. We report here a study on DQA1*Arg52, DQB1*nonAsp57, and DRB1*04 in IDDM children and control adults among Han Chinese living in Taiwan. One hundred and fourteen unrelated children (62 boys) with IDDM were studied. Their ages at diagnosis were between 0.3 and 15.0 years (6.8 +/- 3.6 years). The control population consisted of 120 randomly selected normal adults. DQA1*Arg52(+/+), DQB1*nonAsp57(+/+), and DRB1*04(+/-) were associated with IDDM (RR = 11.50, 2.21, and 2.82; p = 1.11 x 10(-15), 2.84 x 10(-3), and 1.98 x 10(-4), respectively). DQA1*Arg52, DQB1*nonAsp57, and DRB1*04 conferred risks for IDDM (RR = 12.79, 7.11, and 2.83; pc = 8.22 x 10(-4), 5.35 x 10(-3), and 5.68 x 10(-4), respectively). Combinations of DQA1*Arg52 and DRB1*04 conferred the highest risk for IDDM (RR = 19.64, pc = 5.4 x 10(-5)). DQA1*Arg52 was associated with IDDM in subjects with DQB1*nonAsp57+ (RR = 14.87, pc = 2.41 x 10(-4)) and DQB1*nonAsp57 was also associated with IDDM in subjects with DQA1*Arg52+ (RR = 8.41, pc = 1.54 x 10(-3)), suggesting that DQA1*Arg52 and DQB1*nonAsp57 are interacting. This study demonstrates that DQA1*Arg52, DQB1*nonAsp57, and DRB1*04 confer susceptibility for IDDM to Chinese children. A combination of DQA1*Arg52 and DRB1*04 confers the highest risk and it is suggested that a susceptibility gene might be situated between DQA1*Arg52 and DRB1*04 or both are synergistic. There is an interaction between DQA1*Arg52 and DQB1*nonAsp57 and homozygosity for DQA1*Arg52/DQB1*nonAsp57, which encodes four susceptibility DQ heterodimers, confers a high risk.     

Pancreatic beta cell function and antibodies to glutamic acid decarboxylase (anti-GAD) in Chinese patients with clinical diagnosis of insulin-dependent diabetes mellitus

Antibodies to glutamic acid decarboxylase (anti-GAD) and pancreatic beta cell secretory function were measured in 39 consecutive Chinese patients with a clinical diagnosis of insulin-dependent diabetes mellitus (IDDM) (19 males, mean +/- SD age. 37 +/- 15 years; body mass index (BMI), 22 +/- 4 kg/m2; mean duration of disease, 6.7 +/- 5.6 years). IDDM was defined on the basis of acute symptoms with heavy ketonuria (> 3+) or ketoacidosis at diagnosis, or requirement for continuous insulin treatment within one year of diagnosis. Insulin deficiency was defined as a post-glucagon stimulated plasma C-peptide concentration < or = 0.6 nmol/l. Overall, anti-GAD antibodies were positive (> 18 units) in 23% (n = 9) of these patients. Of the 39 patients, 29 (74%) were insulin deficient and 10 (26%) were non-insulin deficient. Anti-GAD antibodies were positive in 31% of the insulin-deficient patients but in none of the non-insulin-deficient group. Insulin deficiency and anti-GAD positivity were associated with younger age, earlier age of clinical onset and lower BMI. There were independent negative relationships between levels of anti-GAD antibodies and blood pressure and a positive relationship between insulin dosage and albuminuria. This study emphasises the difficulty in differentiating clinically between IDDM and NIDDM in Chinese patients. Despite the acute presentation, these patients had variable pancreatic beta cell secretory function. The varying duration of disease may partly explain the low prevalence of positive anti-GAD antibodies in these patients, but seems unlikely to explain fully the difference from Caucasian IDDM patients.     

Characteristics of the innervation of the head and neck

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 DQB*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-DQB*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.     

Glomerular filtration rate and kidney size after six years disease duration in non-insulin-dependent diabetic subjects

To evaluate the association of TNFB NcoI polymorphism with SLE in the Korean population, we investigated the frequencies of the TNFB and HLADRB1 alleles in 281 controls and 97 SLE patients, including 56 patients with nephritis and 41 patients without nephritis. The frequency of the TNFB*2 homozygote in SLE was significantly increased over controls (43.3% vs 28.5%, RR = 1.9,p < 0.01). In SLE with nephritis, the TNFB*2 homozygote was more significantly increased (57.1% vs 28.5%, RR = 3.4,p < 0.0001), whereas there was no significant difference between SLE without nephritis and controls. The study of HLA-DRB 1 alleles revealed the increased frequencies of DRB1*02 and *03 (30.9% vs 18.2%, RR = 2.0,p < 0.01; 8.2% vs 2.1%, RR = 4.1,p < 0.05). There was no significantly different distribution of HLA-DRB1 alleles between SLE patients with nephritis and without nephritis. We found positive LD between TNFB*1 and HLA-DR1B1*13, and between TNFB*2 and the particular DRB1 allele: *15, *04, and *07 in controls and/or in SLE patients. After stratification for each HLADRB1 allele, SLE with nephritis showed a higher frequency of TNFB*2 homozygote compared with the corresponding controls in DRB1*15, *08, and *09 positives. Our results suggest that the TNFB*2 homozygote may be a strong susceptibility gene of SLE with nephritis in the Korean population.     

Insulin-dependent diabetes mellitus in Santiago, Chile: the role of immunogenetic and environmental factors

The role of HLA class II alleles in the genetic susceptibility to develop insulin-dependent diabetes mellitus (IDDM) was examined by means of PCR and oligospecific probes in 63 IDDM children and 74 controls subjects. In diabetic patients we found a significant increase in the alleles frequency DR3, DR4, DQB1*0302 and DQA1*0301 compared to the control group, where the most prevalent alleles were DR2, DR14 (DRB1*1402), DQA1*0101 and DQA1*0201. All the risk genotypes in the diabetic group were similar than in other caucasian groups: DR3/DR4-DQB1*0201/0302-DQA1*0301/0501 and DR4/DR4-DQB1*0302/0302-DQA1*0301/0301. The homozygote character no asp57 conferred an absolute risk (AR) of 3.87 and the marker Arg52 an AR of 5.78/100.000 bab year. The homozygosis for both markers (no Asp57 + Arg52) had an AR of 7.56/100.000 bab year. Regarding environmental factors associated with IDDM, our population under study showed a low prevalence of infectious agents (mainly mumps and rubella, specifically associated with IDDM) and a high prevalence of effective breast-feeding (over 3 months). These factors could be exercising a protector role in the development of IDDM. The factors that appear to be important in the low incidence of IDDM in Santiago de Chile are: the low prevalence of infectious agents related to IDDM, the high percentage of breast-feeding children in the population, the reduced frequency of susceptible molecules as DR3, DQB1*0201 (compared to other caucasian groups) and the presence of protective genotypes related to DR13 and DR14 observed in the non diabetic children.     

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HLA-DQ genes are the main inherited factors predisposing to IDDM. This gene region harbors long terminal repeat (DQ LTR) elements of the human endogenous retrovirus HER V-K, which we analyzed for a possible association with disease. We first investigated whether LTR segregate with DQ alleles in families. Members (n = 110) of 29 families with at least one diabetic child, unrelated patients with IDDM (n = 159), and healthy controls (n = 173) were analyzed. Genomic DNA was amplified for DQ LTR3 by a nested primer approach as well as for DQA1 and DQB1 second exons, to assign DQA1 and DQB1 alleles. DQ LTR segregated in 24 families along with DQ alleles. Of the 29 families, 20 index patients were positive for DQ LTR. The DQ LTR was in all patients on the haplotype carrying the DQA1 *0301 and DQB1 *0302 alleles. A majority of patients had DQ LTR (62%) compared with controls (38%) (p < 1.3 x 10(-5)), even after matching for the high-risk alleles DQA1 *0501, DQB1 *0201-DQA1 *0301, and DQB1 *0302 (79% of patients and 48% of controls; p < 0.02). Subtyping for DRB1 *04 alleles in all DQB1 *0302+ individuals showed 56% DRB1 *0401, DQB1 *0302 [LTR' patients vs. 29% controls with the same haplotype (p < 0.002)]. In conclusion, these data demonstrate the segregation of DQ LTR with DQA1, DQB1 alleles on HLA haplotypes. Furthermore their presence on DRB1 *0401-, DQA1 *0301-, and DQB1 *0302-positive haplotypes suggest that they contribute to DQ-related susceptibility for IDDM.     

Exocrine pancreatic ductograms in insulin-dependent diabetes mellitus

OBJECTIVES: To examine the prevalence of abnormal pancreatic ductograms in patients with insulin-dependent diabetes mellitus (IDDM) and to determine the clinical characteristics of those patients. METHODS: Pancreatic exocrine morphology was studied by endoscopic retrograde pancreatography (ERP) in 43 patients with IDDM, 12 patients with islet cell antibody (ICA)-positive non-insulin-dependent diabetes mellitus (NIDDM), and 22 patients with ICA-negative NIDDM. RESULTS: ERP revealed a significantly higher prevalence of abnormal pancreatic ducts (dilation and stenosis, tortuosity, obstruction, and intraductal calculi) in the patients with IDDM (17/43, 40%) than in the patients with ICA-negative NIDDM (2/22, 9%, p = 0.018). IDDM patients who slowly progressed to insulin dependency more than 13 months after the onset of diabetes had a higher frequency of abnormal pancreatic ducts (13/22, 59%) than those who needed insulin therapy within 12 months after the onset (4/21, 19%, p = 0.016). There was no difference in duration of diabetes between the two groups. ICA-positive NIDDM patients also had a higher frequency of abnormal pancreatic ducts (7/12, 58%) than ICA-negative NIDDM patients (2/22, 9%, p = 0.0074). CONCLUSIONS: These results indicate that a high proportion of IDDM patients who have prolonged histories of non-insulin dependency with ICA suffer pancreatic exocrine impairment. A similarity between IDDM with a slowly progressive clinical course and fibrocalculous pancreatic diabetes seen in tropical countries also was suggested.     

Characterization of self-glutamic acid decarboxylase 65-reactive CD4+ T-cell clones established from Japanese patients with insulin-dependent diabetes mellitus

To investigate autoimmunity to glutamic acid decarboxylase (GAD) 65 in Japanese patients with insulin-dependent diabetes mellitus (IDDM, type I diabetes), we established seven CD4+ T-cell clones, by stimulating peripheral blood mononuclear cells (PBMC) of six IDDM patients, using a mixture of overlapping human GAD65 peptides. No GAD65 autoreactive T-cell clones were evidenced in four healthy controls. Specificities of T-cell clones were as follows: (a) two clones specific to GAD65 p111-131 (residue 111 to 131) + DR53 (DRB4*0103); (b) one clone specific to GAD65 p413-433 + DR1 (DRB1*0101); (c) two clones specific to GAD65 p200-217 + either DR9 (DRB1*0901) or DR8 (DRB1*0802); and (d) two clones specific to GAD65 p368-388 + DP2 (DPA1*01 or 0201-DPB1*0201). Two DR53-restricted and one DR1-restricted T-cell clones, responded to a recombinant human GAD65 protein, and showed cytotoxicity against B lymphoblastoid cell lines pre-pulsed with the peptides. Six T-cell clones exhibited the Th1-like phenotype. Interestingly, two DR53-restricted T-cell clones killed a Fas-deficient B lymphoblastoid cell line, thereby indicating that cytotoxicity was not completely dependent on a Fas-Fas ligand interaction. Thus, the T-cell epitopes were mapped in a limited portion of GAD65 protein, with a tendency to be restricted by disease-associated HLA-DR, but not DQ molecules.     

T cell epitopes of insulin defined in HLA-DR4 transgenic mice are derived from preproinsulin and proinsulin

Approximately one-half of Caucasians with newly diagnosed insulin-dependent diabetes mellitus (IDDM) have autoantibodies to insulin, and the majority of those express the HLA-DR4 genotype [Ziegler, R., Alper, C. A., Awdeh, Z. L., Castano, L., Brink, S. J., Soeldner, J. S., Jackson, R. A. & Eisenbarth, G. S. (1991) Diabetes 40, 709-714]. However, it has been difficult to demonstrate T cell proliferative responses to human insulin in IDDM patients [Durinovic-Bello, I., Hummel, M. & Ziegler, A. G. (1996) Diabetes 45, 795-800]. We have immunized transgenic mice expressing the susceptible HLA-DR (alpha1*0101,beta1*0401) (hereafter called DRB1*0401) and human CD4 molecules on a murine major histocompatibility complex class II null background, with human preproinsulin (PPI), proinsulin (PI), and insulin and derived large panels of T cell hybridomas to determine the immunogenic epitopes of these proteins. These results show that the prohormones PI or PPI carry the major immunogenic T cell epitope in the DRB1*0401 transgenic mice. The PPI/PI immunodominant epitope LALEGSLQK was localized at the C-peptide/A-chain junction. This T cell epitope PPI/PI LALEGSLQK is unusual because, normally, it is proteolytically destroyed during the maturation of the insulin molecule. Additionally, this T cell epitope is both processed and presented by human DRB1*0401-positive Epstein-Barr virus transformed B cells, and it can also stimulate T cells from the peripheral blood of HLA-DR4-positive patients with type 1 diabetes. These findings may partly explain why susceptibility to type 1 diabetes is associated with HLA-DR4-positive individuals and why T cell responses to the mature insulin protein are rarely detected in IDDM patients.     

Contents of glycogen in neutrophils in patients with diabetes]

Glycogen neutrophils level was evaluated in 54 patients with non-insulin dependent diabetes mellitus (NIDDM) and 10 patients with insulin dependent diabetes mellitus (IDDM). Glycogen concentration estimated by histochemical method was lower in diabetics than in control group. Patients with NIDDM were divided in the groups according to: sex, duration of disease, a kind of complications and a way of treatment. The glycogen contents in neutrophils, defined in "score"-unit was not different in isolated groups. There was found significant correlation between glycogen contents in neutrophils and the metabolic control in patients with IDDM (r = 0.72) and less significant in patients with NIDDM (r = 0.29).     

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Autoantibodies against heat shock protein (hsp) 60 have been reported to be detected in sera of non-obese diabetic mice, in an experimental model of IDDM. However, there are only a few studies which have examined IDDM patients for antibodies against mammalian hsp60. We produced murine hsp60 derived from pancreatic beta cells which has high homology to human hsp60 and examined antibodies against the hsp60 in IDDM patients using an enzyme-linked immunosorbent assay. We extended the analysis to patients with other immune-mediated diseases and non-insulin-dependent diabetes mellitus (NIDDM). Positive sera for hsp60 antibody were more frequently detected in 13 out of 84 IDDM (15.5%) and 5 out of 25 rheumatoid arthritis patients (20%), when compared to healthy subjects (1/85; 1.2%, P < 0.001 and P < 0.01, respectively). The levels of hsp60 antibodies of IDDM (0.218 +/- 0.227) and rheumatoid arthritis patients (0.259 +/- 0.191) were significantly higher than those of healthy subjects (0.076 +/- 0.131, P < 0.001, P < 0.01, respectively). Patients with slowly progressive IDDM (n = 26), autoimmune thyroid disease (n = 42), or NIDDM (n = 40) had levels of hsp60 antibodies similar to those in healthy subjects. We found no relationship between the levels of hsp60 antibodies and islet cell antibodies (ICA) or antibodies to glutamic acid decarboxylase (GAD65) in IDDM patients. In conclusion, hsp60 antibodies were detected in Japanese IDDM as well as in rheumatoid arthritis patients. Although the positivity was low, the detection of hsp60 antibodies may be helpful for diagnosis of IDDM especially in GAD65 Ab- or JCA-negative Japanese patients.     

Contribution of DRB1*04 variants to predisposition to or protection from insulin dependent diabetes mellitus is independent of dq

Certain DQ alpha/beta dimeric molecules have been shown to play a major role in determining susceptibility or resistance to IDDM. Whether or not predisposition associated with DR4 haplotypes is exclusively due to linkage to DQB1*0302 and DQA1*0301 alleles is still a controversial issue. A modifying effect of certain DRB1*04 subtypes on the susceptibility encoded by DQ alleles is possible, since not all DRB1*04-DQB1*0302 haplotypes are associated with the disease. The distribution of DRB1*04 subtypes was analysed in 240 DR4-positive Caucasian IDDM patients and 110 DR4-positive healthy controls using allele-specific hybridization after genomic amplification. Although an important contribution to IDDM predisposition was encoded by the DQB1*0302 allele which was found in the majority of patients (94.2% vs 64.7% in controls, Odd's ratio OR = 8.8, P < 0.0001), differences between DRB1*04 variants persisted after the effect of the DQB1 locus was removed by matching patients and controls for DQB1*0302. Thus, the DRB1*0402 allele conferred a strong IDDM-predisposing effect (OR = 3.1, P < 0.02) which was highly significant in the absence of DR3 on the second haplotype (OR = 5.6, P < 0.0001) but was not visible among DR3/4 heterozygote individuals. Conversely, the DRB1*0404 allele conferred a strong protective effect (OR = 0.26, P < 0.0001) which was dominant even in the presence of the associated high risk DR3 haplotype (OR = 0.21, P < 0.03). These data indicate that DQ molecules are not the sole contributors to the DR4-associated IDDM predisposition, and that peculiar DR4 subtypes play a significant role in susceptibility to or protection from the disease. DRB1*0402 differs from DRB1*0404 by only two acidic residues at positions 70 and 71 within the peptide binding groove, instead of amide and basic amino acids. This might induce changes of peptide binding specificity that correlate with the genetic linkage of IDDM predisposition.     

HLA-C genes and susceptibility to type 1 autoimmune hepatitis

Susceptibility to autoimmune hepatitis (AIH) is associated with the HLA A1-B8-DR3 haplotype, DR4 antigen, and, more specifically, the HLA DRB3*0101, DRB1*0301, and DRB1*0401 alleles. Few investigators, however, have examined the HLA C locus in AIH, which warrants detailed study in view of its recently described roles in immunoregulation. Eighty-seven adult, white patients with well-characterized type 1 AIH and 100 controls were studied. HLA C and HLA DRB1 alleles were assigned by polymerase chain reaction (PCR)-based genotyping. HLA A and B antigens were determined by standard microlymphocytotoxicity assay. Extended haplotypes were constructed according to known patterns of linkage disequilibrium. Only one HLA C locus allele, Cw*0701, which was present in 54% of patients versus 34% of controls (P = .006; relative risk [RR] = 1.54) was associated with AIH. The overall increase in the frequency of the Cw*07 gene (70.1% of patients vs. 54% of controls; P = .024; RR = 1.3) was due entirely to inheritance of the Cw*0701 allele rather than the other Cw*07 alleles, Cw*0702, *0703, and *0704. The RR for Cw*0701 (RR = 1.54) is greater than that for HLA A1 (RR = 1.33) and DRB1*0301 (RR = 1.49), but less than that for HLA-B8 (RR = 1.75). The present findings suggest that the gene or genes conferring susceptibility to AIH lie in the region centromeric to the HLA A locus between HLA C and DRB1. Although linkage disequilibrium with both B8 and DRB1*0301 may account for our finding of an increased frequency of Cw*0701, it is also possible that this allele contributes to disease susceptibility, perhaps by interaction with natural killer cells or cytotoxic T lymphocytes.     

Fibrosis and inflammatory cells in human chronic chagasic myocarditis: scanning electron microscopy and immunohistochemical observations

Several publications have shown that certain alleles at the HLA-DRB1, -DQA1, and -DQB1 loci are associated with insulin-dependent diabetes mellitus (IDDM). Many of these studies have claimed that HLA-DQalpha1Arg52 and DQbeta1Asp57 showed the strongest association with IDDM, but these results could not be confirmed in different populations. We have recently found that DRbeta1Lys71+ provided major susceptibility to IDDM and that DQbeta1Asp57- had an additive effect to DRbeta1Lys71+ [Zamani et al., 1994a: Eur J Hum Genet 2:177-184]. This was confirmed with haplotype analysis in multiplex IDDM families [Zamani et al., 1996a: J Med Genet 33:899-905]. Therefore, we have reanalyzed the data from the literature on the association of the human leucocyte antigen (HLA) DRB1, DQB1, and DQA1 with IDDM in different ethnic groups to determine whether different amino acids in the antigen binding cleft of HLA class II molecules play a preponderant role in the development of IDDM. The results showed that the DRbeta1Lys71+ allele provided the highest relative risk for IDDM in the Belgian, Danish, Greek Taiwanese, and Chinese population while this was not the case in Norwegians, Sardinians, and Algerians. Indeed, in the Sardinian and Algerian population the DRB1*0401 allele encoding Lys71+ is very rare. Nevertheless, the few positive cases were always in the patient group. We also measured the clinical relevance of the testing for DRbeta1Lys71, DQbeta1Asp57, and DQalpha1Arg52 by calculating a prevalence-corrected positive predictive value (PcPPV), a prevalence corrected negative predictive value (PcNPV), the sensitivity and specificity of these tests. The results indicated that the sensitivity of the test for DRbeta1Lys71+ was lower than for DQalpha1Ag52+ and DQbeta1Asp57-, while testing for DRbeta1Lys71+ was more specific than testing for DQbeta1Asp57- and DQalpha1Arg52+ and that the DRbeta1Lys71+ allele had a higher PcPPV than DQalpha1Arg52+ and DQbeta1Asp57- in all studied populations. These results also showed that testing for DRbeta1LyS71+/+ can be useful in IDDM risk assessment particularly in populations with a high prevalence (P) of IDDM such as the Danish (P[IDDM] = 0.65%). PcPPV for DRbeta1Lys71+/+ was 0.2313 in the Danish, indicating a 23.13% risk for an individual who is homozygous for the genotype DRbeta1Lys71+/+ to develop IDDM. Some mechanisms which might explain the role of these HLA class II alleles in susceptibility to IDDM are discussed.     

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Insulin promoter factor 1 (IPF1) is a key factor both for the regulation of insulin gene expression and for the development of the pancreas. In this study 88 patients with non-insulin-dependent diabetes mellitus (NIDDM) who were diagnosed as diabetic at less than 40 years of age, 55 patients with insulin-dependent-diabetes (IDDM), and 67 normal control subjects were analysed for variants in the upstream region of the IPF1 gene by direct sequencing. A novel single nucleotide insertion polymorphism was found in a guanine triplet at 108 bp upstream of the translation start site. The G insertion allele (G4 allele) was found to be common in the Japanese population, at a frequency of 0.50. The prevalence of G3 homozygotes was higher in IDDM patients (35%) and lower in NIDDM patients (17%) than in normal control subjects (28%, p=0.049). In the NIDDM group, the ratio of insulin treatment tended to be higher in subjects homozygous for the G3 allele, although the genotype was not significantly associated with basal C-peptide levels. The polymorphism is unlikely to be a major contributor to the insulin deficiency of diabetes. However, the polymorphic locus, or an unknown mutation which is in linkage disequilibrium with the polymorphism, could be involved in the pathophysiology of diabetes. The high heterozygosity may be useful for genetic linkage studies of other mutations within and near the IPF1 gene.     

MHC class II alleles and haplotypes in patients with pemphigus vulgaris from India

Pemphigus vulgaris (PV) is a blistering disease of the skin and mucous membranes characterized by an autoantibody response against a keratinocyte adhesion molecule, desmoglein 3, causing acantholysis and blister formation. We compared high resolution MHC class II alleles and haplotype frequencies (HLA-DRB, DQA1 and DQB1) in 37 patients with PV to 89 haplotypes of normal relatives from New Delhi and Ahmedabad. We found that PV patients had significantly increased frequencies of DRB1*1404 (P < 0.0001), DQA1*0101 (P = 0.001), and DQB1*0503 (P < 0.0001). These associations were due to the increased frequencies of the haplotype HLA-DRB1*1404, DRB3*0202, DQA1*0101, DQB1*0503 in patients compared to control haplotypes (p < 0.0001). Also, patients from Ahmedabad had a significant increase in HLA-DQB1*0302 (p = 0.03). An identical amino acid sequence (Leu-Leu-Glu-Arg-Arg-Arg-Ala-Glu), in positions 67-74 of the beta domain of DRB alleles is restricted to some DR14 alleles. Therefore, there are three possible explanations for class II allele involvement in autoantibody in PV patients with class II haplotypes marked by HLA-DR14. First, the class II alleles could be markers for an unidentified susceptibility gene in linkage disequilibrium with them. Second, the primary association could be with DQB1*0503 and the association with HLA-DR14 alleles would be the result of linkage disequilibrium. Third, the HLA-DRB1 locus susceptibility could involve a specific amino acid sequence in the third hypervariable region shared by several HLA-DR14 alleles.     

HLA-DRB1*04 and DRB1*14 alleles are associated with susceptibility to pemphigus among Japanese

It has previously been demonstrated that susceptibility to pemphigus vulgaris is associated with human leukocyte antigen (HLA)-DR4 serologic specificity among Ashkenase Jews, and with DR4 as well as DR6 (DR14) in other ethnic groups. We genotyped HLA-DRB1, DQA1, DQB1, and DPB1 alleles in 16 patients with pemphigus by polymerase chain reaction-restriction fragment length polymorphism, to find evidence of potential HLA class II allele associations with pemphigus in Japanese patients who have a relatively homogeneous ethnic background. All nine patients with pemphigus vulgaris and five of seven patients with pemphigus foliaceus carried one or two alleles of HLA-DRB1*04 (*0403, *0406) and HLA-DRB1*14 (*1401, *1405, *1406) subtypes. Sequence analysis of these DRB1*04 and DRB1*14 alleles revealed the amino acid homology of phenylalanine at position 26 and valine at position 86 with the DRB1*0402 allele that reportedly confers a strong susceptibility to pemphigus vulgaris in Ashkenazi Jews. Thus our findings, together with previous HLA studies on pemphigus vulgaris patients of different ethnic groups, suggest that HLA-DRB1*04 and DRB1*14 alleles are commonly associated with pemphigus vulgaris across racial barriers. These HLA-DRB1 alleles are likely to be also associated with pemphigus foliaceus. Further studies on more diverse ethnic populations will be helpful in determining the significance of the association between certain amino acid residues of the class II molecules and disease susceptibility to pemphigus vulgaris as well as pemphigus foliaceus.