HLA haplotypes in Koreans based on 107 families

Abstract: There are marked differences in the distribution of HLA haplotypes among different populations, and multilocus HLA haplotypes can best be studied by family analysis. In the present study, 107 Korean families were analyzed for HLA-A, B, C, DR, and DQ antigens and haplotypes. Allele frequencies of more than 10% for class I antigens were A2, A24, A33, B44, B62, Cw1, Cw7, Cw9, Cw10, and C blank (CBL) and those for class II antigens were DR4, DR8, DR13, DR15, DQ1, DQ3, DQ4 and DQ7. In the analysis of HLA haplotypes, 18 kinds of A-B-DR and 11 kinds of A-C-B-DR-DQ haplotypes occurred at frequencies of more than 1%, comprising 34% and 24% of the total theoretical haplotypes, respectively. The five most common A-B-DR haplotypes were exclusively related with the five most common A-C-B-DR-DQ haplotypes (frequency>2%). These remarkably conserved five-locus haplotypes in Koreans were A33-CBL-B44-DR13-DQ1 (5.4%), A24-Cw7-B7-DR1-DQ1 (3.5%), A33-Cw7-B44-DR7-DQ2 (3.0%), A33-Cw10-B58-DR13-DQ1 (2.3%), and A30-Cw6-B13-DR7-DQ2 (2.3%). Comparison of the distribution of A-B-DR haplotypes among East Asian populations revealed that Koreans are closest to Japanese, but show a higher degree of polymorphism in the distribution of HLA haplotypes compared to Japanese. The results obtained in this study will be useful as basic data on Koreans for anthropology and organ transplantation.     

中国汉族白血病患者及其相关人群罕见的HLA-DR/DQ连锁不平衡研究

 目的 研究中国汉族白血病患者及其相关人群罕见的HLA-DR/DQ连锁不平衡单倍型。方法 对2000－2005年在我院进行异基因造血干细胞移植前HLA配型的白血病患者及与患者有血缘关系的家系供者共1500例的血液标本，采用低分辨序列特异性引物聚合酶链反应（PCR-SSP）方法进行HLA-DR/DQ基因分型，并对两位点间连锁不平衡参数进行统计学分析。1500例中患者650例，平均年龄25岁；家系供者850例，平均年龄42岁。结果 在41例的血液标本中发现13种罕见的连锁不平衡单倍型，主要为HLA-DQ8 或HLA-DQ9与不同DR位点的连锁。其中DR14/DQ4、DR4/DQ5、DR9/DQ6、DR9/DQ7、DR8/DQ8、DR9/DQ8、DR12/DQ8、DR13/DQ8和DR14/DQ9共9种单倍型尚未见报道。650例白血病患者中有20例存在12种罕见的连锁不平衡单倍型，850例家系供者中有21例存在8种罕见的连锁不平衡单倍型。DR8/DQ8单倍型只见于家系供者，而DR14/DQ4、DR12/DQ6、DR11/DQ8、DR13/DQ8和DR14/DQ9单倍型则只见于白血病患者。41例HLA-DR/DQ基因分型结果显示，连锁不平衡单倍型与DR52（DRB3）宽抗原相关联者占58.5%（24/41），与DR53（DRB4）宽抗原相关联者占36.6%（15/41），而与DR51（DRB4）宽抗原相关联者仅占4.9%（2/41）。所发现单倍型频率最高的为DR12/DQ8（0.0023）和DR9/DQ8（0.0023），其次为DR11/DQ9（0.0020）和DR12/DQ9（0.0017）。13种连锁不平衡单倍型的绝对及相对连锁不平衡参数均为负值，说明它们在中国汉族人群中较为罕见，并处于连锁不稳定状态。结论 发现了罕见的DR/DQ连锁不平衡单倍型，对补充中国汉族人群HLA-DR/DQ基因的连锁不平衡类型，提高HLA分型结果的准确性具有一定意义；同时，DR/DQ连锁不平衡单倍型在不同人群中的差异为疾病关联研究提供了思路。     

Additional association of intra-MHC genes,MICA and D6S273, with Addison's disease

Intra-MHC sequences including MHC class I chain-related genes (MICAs), D6S273 and D6S2223 are associated with autoimmune diseases in addition to HLA class II. In the current study, we ascertained the haplotypes of 57 Caucasian patients with Addison's disease composed of these genetic markers and compared them either with 72 general population controls or with 105 child controls carrying Addison's disease high-risk DR3-DQ2/DR4-DQ8 genotypes. The MICA-A5.1/A5.1 genotype as well as HLA DR3/4 especially with DRB1*0404 were the main susceptibility markers. The homozygous MICA-A5.1/A5.1 genotype was significantly more frequent in the patients with Addison's disease (61%) than in the healthy controls (6%). The MICA-A5.1 allele was increased on both the DR3 and DR4 haplotypes, independent of DQ and DRB1 subtyping, in the patients with Addison's disease compared with the controls. Furthermore, the D6S273*140 allele on the DR3 haplotype and the D6S273*134 allele on the DR4 haplotype in the DR3/4 heterozygotes influenced susceptibility relative to the DR3/4 controls. The risk for Addison's disease was increased for the DR3-D6S273*140-MICA-A5.1/DRB1*0404-D6S273*134-MICA-A5.1 genotypes compared with that conferred by the DR3/4 controls. Susceptibility to Addison's disease is influenced by the genes around MICA and D6S273 for both the HLA DR3-DQ2 and DR4-DQ8 haplotypes.     

The HLA-DRB1*0405 haplotype is most strongly associated with IDDM in Algerians.

Insulin-dependent diabetes mellitus (IDDM) in Caucasians is strongly associated with HLA-DR3-DQ2 and DR4-DQ8. In order to investigate the HLA class II associations with IDDM in Algerians, we have used polymerase chain reaction (PCR) and sequence specific oligonucleotide analysis (SSO) to identify DQA1, DQB1, and DRB1 alleles, haplotypes and genotypes in 50 unrelated IDDM patients and 46 controls from a homogeneous population in Western Algeria. Both DRB1*0301-DQA1*0501-DQB1*0201 (DR3-DQ2) and DRB1*04-DQA1*0301-DQB1*0302 (DR4-DQ8) haplotypes were found at increased frequencies among the patients compared to controls (45% vs. 13%, RR = 5.5, Pc < 10(-5) and 37% vs. 4%, RR = 12.9, Pc < 10(-4), respectively). Among the latter, in contrast to other Caucasian populations, only DRB1*0405-DQA1*0301-DQB1*0302 was significantly increased in the Algerian patients (25% vs. 1% in controls, RR = 30.3, Pc < 10(-3). Accordingly, the highest risk of disease was observed in DRB1*0301-DQA1*0501-DQB1*0201/DRB1*0405-DQA1+ ++*0301-DQB1*0302 heterozygotes (34% in patients vs. 0% in controls; RR = 49; Pc < 10(-3). This observation and its comparison with DR-DQ haplotypes in other ethnic groups suggest that the DRB1*0405 allele which encodes an Asp57-negative beta chain may contribute to IDDM susceptibility in a similar way as Asp57-negative DQ beta chains.     

Linkage disequilibrium between TAP2 variants and HLA class II alleles; no primary association between TAP2 variants and insulin-dependent diabetes mellitus

The TAP1 and TAP2 genes, located in the HLA class II region, encode subunits of a peptide transporter. Both genes display limited genetic variability; four different nucleotide substitutions have been found in theTAP2 gene. Here studies on linkage disequilibrium between TAP2 variants and HLA class II alleles are reported, in an attempt to evaluate whether TAP2 variants are associated with insulin-dependent diabetes mellitus (IDDM). As reported previously, a significant decrease of homozygosity for TAP2 alleles encoding alanine at residue 665 (665 Ala) and glut amine at 687 (687 Gin) paralleled by an increase in homozygosity for TAP2 alleles encoding threonine at residue 665 (665 Thr) and a stop codon at 687 (687 Stop), was found in both Finnish and Norwegian IDDM patients compared to random controls. However, a strong linkage disequilibrium between these TAP2 polymorphisms and given HLA-DR and -DQ genes was observed among healthy controls. The frequent 665 Thr and 687 Stop variants were in linkage disequilibrium both with the DR4-DQ8 and the DR3-DQ2 haplotypes, haplotypes which are strongly associated with IDDM. In contrast, the DR1-DQ5 and DR13-DQ6 (e.g. DQB1*0603) haplotypes, which are decreased among IDDM patients, were associated with the 665 Ala and 687 Gin variants. Thus, when DR- and DQ-matched patients and controls were compared, associations of the investigated TAP2 variants and IDDM were no longer detectable. These data, therefore, indicate that the associations previously found between certain TAP2 variants and IDDM are secondary to a primary association between this disease and particular DQαβ heterodimers.     

Tri-SNP polymorphism in the intron of HLA-DRA1 affects type 1 diabetes susceptibility in the Finnish population

Genes in the HLA class II region include the most important inherited risk factors for type 1 diabetes (T1D) although also polymorphisms outside the HLA region modulate the predisposition to T1D. This study set out to confirm a recent observation in which a novel expression quantitative trait locus was formed by three single nucleotide polymorphisms (SNP) in the intron of HLA-DRA1 in DR3-DQ2 haplotypes. The SNPs significantly increased the risk for T1D in DR3-DQ2 homozygous individuals and we intended to further explore this association, in the Finnish population, by comparing two DR3-DQ2 positive genotypes. Cohorts with DR3-DQ2/DR3-DQ2 (N = 570) and DR3-DQ2/DR1-DQ5 (N = 1035) genotypes were studied using TaqMan analysis that typed for rs3135394, rs9268645 and rs3129877. The tri-SNP haplotype was significantly more common in cases than controls in the DR3-DQ2/DR3-DQ2 cohort (OR = 1.70 CI 95% = 1.15–2.51P = 0.007). However, no significant associations could be observed in the DR3-DQ2/DR1-DQ5 cohort.     

Role of HLA class II genes in susceptibility and resistance to multiple sclerosis: studies using HLA transgenic mice

Multiple sclerosis (MS), an inflammatory and demyelinating autoimmune disease of CNS has both, a genetic and an environmental predisposition. Among all the genetic factors associated with MS susceptibility, HLA class II haplotypes such as DR2/DQ6, DR3/DQ2, and DR4/DQ8 show the strongest association. Although a direct role of HLA-DR alleles in MS have been confirmed, it has been difficult to understand the contribution of HLA-DQ alleles in disease pathogenesis, due to strong linkage disequilibrium. Population studies have indicated that DQ alleles may play a modulatory role in the progression of MS. To better understand the mechanism by which HLA-DR and -DQ genes contribute to susceptibility and resistance to MS, we utilized single and double transgenic mice expressing HLA class II gene(s) lacking endogenous mouse class II genes. HLA class II transgenic mice have helped us in identifying immunodominant epitopes of PLP in context of various HLA-DR and -DQ molecules. We have shown that HLA-DR3 transgenic mice were susceptible to PLP_91–110 induced experimental autoimmune encephalomyelitis (EAE), while DQ6 (DQB1*0601) and DQ8 (DQB1*0302) transgenic mice were resistant. Surprisingly DQ6/DR3 double transgenic mice were resistant while DQ8/DR3 mice showed higher disease incidence and severity than DR3 mice. The protective effect of DQ6 in DQ6/DR3 mice was mediated by IFNγ, while the disease exacerbating effect of DQ8 molecule was mediated by IL-17. Further, we have observed that myelin-specific antibodies play an important role in PLP_91–110 induced EAE in HLA-DR3DQ8 transgenic mice. Based on these observations, we hypothesize that epistatic interaction between HLA-DR and -DQ genes play an important role in predisposition to MS and our HLA transgenic mouse model provides a novel tool to study the effect of linkage disequilibrium in MS.     

HLA-A, -B, -DR and -DQ allele and haplotype frequencies in the Moroccan population: a general population study

PURPOSE OF STUDY: The aim of this general population study is to extend our knowledge about the HLA-A, -B, -DR and -DQ genes distribution and their diversity among the Moroccan population. PATIENTS AND METHODS: One hundred and ten unrelated healthy Moroccans from diverse regions of the country were included in the study. HLA typing was done either by serological (standard complement dependent microlymphocytotoxicity) and/or molecular (sequence-specific primer amplification) techniques. RESULTS: The most frequent alleles observed were: HLA-A2 (19.1%), -A1 (10%), -A3 (10%), -B44 (9.6%), -DR3 (17.1%), -DR4 (15.3%), -DQ2 (30.6%), -DQ6 (26.4%) and -DQ3 (25%). No predominant haplotype was observed for HLA A-B while high frequency was observed for some HLA DR-DQ associations (DR3-DQ2, DR15-DQ6, DR7-DQ2, DR4-DQ3, DR13-DQ6). Comparison with neighbouring populations, on the basis of alleles, haplotypes and genetic distances, showed that Moroccan population is close to the Algerians, the Tunisians, the Spaniards and the French. The haplotype frequencies revealed also relationships with Italians, Sardinians, Basques, Portuguese and Moroccan Jews populations. CONCLUSION: Our results confirm and extend the current knowledge about the Moroccan genetic pattern and reflect all the ethnic diversity of the country. This study will be helpful in the future for clinical analysis like transplantation and HLA-associated diseases in Moroccan population.     

Polymorphisms of TNF microsatellite marker a and HLA-DR-DQ in diabetes mellitus-a study in 609 Swedish subjects

We explored the importance of the genetic markers microsatellite TNFa, HLA-DR3-DQ2, and DR4-DQ8 in diabetes mellitus. The studied groups comprised autoimmune type 1 (n = 63), nonautoimmune type 1 (n = 35), latent autoimmune diabetes in adults (LADA; n = 54), and nonautoimmune type 2 (n = 340) and these patients were compared to 117 healthy controls. HLA genotyping was done with polymerase chain reaction and sequence-specific oligonucleotides. TNFa microsatellites were determined with polymerase chain reaction and fragment size determination. Univariate analysis of these genetic risk factors demonstrated that homozygosity for TNFa2/2 was a significant risk factor for autoimmune type 1 diabetes (odds ratio (OR) = 5.82; 95% confidence interval (95%CI) 1.97-17.2), for autoimmune negative type 1 diabetes (OR = 4.63; 95%CI 1.32-16.2), and for LADA (OR = 3.90; 95%CI 1.21-12.5). Moreover, heterozygosity for HLA-DR3-DQ2/DR4-DQ8 was an important risk factor for autoimmune type 1 diabetes (OR = 16.4; 95%CI 3.60-75) as was DR4-DQ8/x (OR = 2.52; 95%CI 1.27-4.98). Heterozygosity for HLA-DR3-DQ2/DR4-DQ8 was a risk factor also for LADA (OR = 10.0; 95%CI 2.05-48.9). Neither HLA-DR3-DQ2 nor DR4-DQ8 were risk factors for nonautoimmune type 1 or type 2 diabetes. We concluded that heterozygosity for DR3-DQ2/DR4-DQ8 and to some extent homozygosity for TNFa2/2 were risk factors for autoimmune diabetes irrespective of the clinical classification.     

Response to hepatitis B vaccine: multiple HLA genes are involved

Abstract: The mechanism underlying the impaired immune response to hepatitis B vaccines in up to 10% of healthy subjects is not known. An increased incidence of poor responsiveness in subjects with HLA- DR3 ⁺ or - DR7 ⁺ haplotypes has been documented, suggesting that HLA-DR-linked genes may regulate the human response to hepatitis B surface antigen. However, not all BLA-DR3 ⁺ and/or - DR7 ⁺ individuals are poor responders, and subjects with identical HLA-DR haplotypes sometimes display totally divergent antibody responses to vaccination. HLA class II DNA typing was performed in well and poorly responding hepatitis B vaccine recipients and we analyzed the role of the single HLA-DR, -DP, and -DQ molecules and of their associated (interaction) haplotypes in the response to hepatitis B vaccination. Statistical analysis revealed that HLA-DRBl*010*, - DR5 , -DPBl*040*, -DQBl*0301, and -DQBl*0501 were more abundant in good responders, whereas HLA-DRB1*07, -DPBl*1101, and -DQBl*020* were associated with poor response, with DQBl*020* showing the strongest association with poor responsiveness. We further investigated whether there were interactions between the HLA factors contributing to poor responsiveness. We show here that HLA-DPB1*02 was negatively associated with responsiveness when it occurred in association with haplotype DRBl*0701/ DRB4*0101-DQBl*020*, and DRB4*0101 was negatively associated with responsiveness when it occurred in association with haplotype DRB1*0301/ DRB3*0101-DQBl*020*. Our results indicate that the immune response to hepatitis B vaccine is largely determined by HLA-DR, -DP, and -DQ genes and that interaction between HLA molecules that are not in linkage disequilibrium contributes to poor responsiveness.     

HLA-DRB1-DQA1-DQB1 genotype and frequency of enterovirus in longitudinal monthly fecal samples from healthy infants

Enterovirus infections may be involved in the etiology of type 1 diabetes (T1D), which is strongly associated with certain human leukocyte antigen (HLA) class II haplotypes. Our aim was to assess whether HLA genotypes conferring varying degrees of risk for T1D were associated with enterovirus gut infections. From the general Norwegian population, 190 healthy infants at high-risk for T1D (DR4-DQ8/DR3-DQ2), and 383 infants without this genotype were identified. Non-DR4-DQ8/DR3-DQ2 genotypes were further categorized as conferring either an increased-to-moderate risk (DR4-DQ8 or DR3-DQ2), were protective (DQB1*06:02), or were neutral (all other genotypes). A total of 4626 monthly fecal samples taken between age 3 and 12?mo were tested for enterovirus RNA using real-time PCR. Enterovirus prevalence was 11.5% among high-risk children, and 12.2% in other children (adjusted odds ratio: 1.23, p=0.12). The prevalence was 11.3% in those with increased-to-moderate risk, 13.0% in the protective group, and 12.6% in the neutral group (likelihood ratio test, 3 d.f.: p=0.37). In conclusion, there was no statistically significant association between HLA genotype and the occurrence of human enterovirus gut infections.     

Study of cis and trans interactions between extended HLA-haplotypes in insulin-dependent diabetes

From the study of HLA, A, B, C, DR, Bf and C4A, C4B alleles in 287 insulin-dependent diabetes mellitus patients and 108 controls, comparisons were made between 424 diabetic and 216 normal extended haplotypes. In the "cis" situation (haplotype), the highest relative risks (RR) for IDDM were borne by multiloci allelic associations, mainly DR/complement alleles, rather than by DR3 or DR4 considered alone. Susceptibility was strongly associated with two extended haplotypes (Aw30, Cw5, B18, C4BQ0, C4A3, BfF1, DR3 and A2, Cw3, B15, C4Bx, C4A3, BfS, DR4) or their smaller segments. Two haplotypes, S31 associated with DR2 or DR5 and F31 associated with DRw6 or DR7 had a protective effect.
In the "trans" situation (opposite haplotype) the large excess of DR3/DR4 hetero-zygotes was not the only distortion observed. An excess of DR1 (57%) and of C4BQ0 (40%) was noted among non DR3, non DR4 haplotypes in diabetics compared to normal individuals (26% and 23%, respectively, p<0.01, 0.05). Homozygotes for DR3 or DR4 were not increased, and other homozygotes were decreased compared to controls. The protective antigens HLA DR2, DR5 and DR7 seemed not to be distributed randomly: their putative protective effect was not observed in the case of combination with DR1 or a B18, DR3 haplotype. DR2 was never found homozygous or combined with DR5.
These results suggest that susceptibility to IDDM is generated by both cis and trans interactions between genes or gene products of the HLA region.     

HLA associations in type 1 diabetes among patients not carrying high-risk DR3-DQ2 or DR4-DQ8 haplotypes

Type 1 diabetes is a complex disease where numerous genes are involved in the pathogenesis. Genes that account for approximately 50% of the familial clustering of the disease are located within or in the vicinity of the HLA complex on chromosome 6. Some DRB1, DQA1 and DQB1 genes are known to be involved, in addition to as yet unidentified HLA-linked genes. The DR4-DQ8 and DR3-DQ2 haplotypes are known to confer high risk for developing the disease, particularly when occurring together. Approximately 10% of patients, however, do not carry any of these high-risk HLA class II haplotypes. We have performed genotyping of DRB1, DQA1 and DQB1 alleles in non-DR3-DQ2/non-DR4-DQ8 patients and controls from Sweden and Norway to test if any HLA associations were observed in these patients. Our results clearly demonstrate several statistically significant differences in the frequency of HLA haplotypes between patients and controls. Case-control analysis including the relative predispositional effect test, and transmission disequilibrium test (TDT) analysis in Norwegian type 1 diabetes families revealed that the DQA1*03-DQB1*0301, DQA1*0401-DQB1*0402, DQA1*0101-DQB1*0501, DQA1*03-DQB1*0303 and DQA1*0102-DQB1*0604 haplotypes may also confer risk. Our analyses also supported independent risks of certain DRB1 alleles. The study clearly demonstrates that HLA associations in type 1 diabetes extends far beyond the well-known associations with the DR4-DQ8 and DR3-DQ2 haplotypes. Our data suggest that there is a hierarchy of HLA class II haplotypes conferring risk to develop type 1 diabetes.     

Different HLA-DR-DQ and MHC class I chain-related gene A (MICA) genotypes in autoimmune and nonautoimmune gestational diabetes in a Swedish population

The genetic susceptibility for gestational diabetes (GDM) was estimated by comparisons of genotypes within human leukocyte antigen (HLA) and major histocompatibility complex class I chain-related gene A (MICA) in 199 women with GDM and 213 healthy women. At least one of ICA, glutamic acid decarboxylase antibodies, or islet cell antigen-2 antibodies/tyrosine phosphatase antibodies was found in 6.0% (12/199) of women with GDM and were considered as autoimmune GDM, whereas the remaining 187 were considered as nonautoimmune GDM. HLA genotyping was done with polymerase chain reaction and sequence-specific oligonucleotides. MICA polymorphism was determined with polymerase chain reaction and fragment size determination. HLA-DR3-DQ2/x or DR4-DQ8/x and MICA5.0/5.1 were more frequent in autoimmune GDM compared with controls; 92% versus 46% and 42% versus 13% and conferred increased risk (odds ratio [OR] = 13; 95% confidence interval [CI] 1.7–104) and (OR = 4.7; 95%CI 1.4–16). Four other genotypes were more frequent in nonautoimmune GDM compared with controls: HLA-DR7-DQ2/y, 24% versus 14%; DR9-DQ9/y, 9.6% versus 1.9%; DR14-DQ5/y, 7.5% versus 0.94%; and MICA5.0/z, 24% versus 13% and gave increased risk: OR = 2.0; 95%CI 1.2–3.4, OR = 5.6; 95%CI 1.8–17, OR = 8.5; 95%CI 1.9–38, and OR = 2.0; 95%CI 1.2–3.4, respectively. We concluded that autoimmune diabetes with onset during pregnancy is associated with the type 1 diabetes–associated genotypes and also with MICA5.0/5.1, whereas DR7-DQ2/y, DR9-DQ9/y, DR14-DQ5/y, and MICA5.0/z are risk factors for nonautoimmune GDM.     

HLA class II associations with Type 1 diabetes mellitus: a multivariate approach

The association of HLA class II phenotype with the development of insulin-dependent (Type 1) diabetes mellitus (IDDM) is well established but the contribution of the various HLA-DR and -DQ alleles and haplotypes to disease predisposition is not fully understood. We have determined haplotype and genotype odds ratios, and further employed multivariate tree analysis to explore the contribution of individual HLA-DRDQ haplotypes to the genetic risk for developing IDDM in the Dutch population. Next to haplotype and genotype odds ratios, multivariate tree analysis techniques provide overall risk calculations for each modeled parameter, and offer insight in the interaction of the model parameters via tree-shaped reports, in which subsequent stratifications on the data can easily be followed. We compared 206 Dutch IDDM patients with 840 serologically typed random healthy unrelated Dutch Caucasoid controls. The multivariate tree analysis showed that the HLA-DR7DQ9 and DR15DQ6 haplotype were strongly associated with disease protection (OR = 0.04, P = 0.0003, and OR = 0.07, P < or = 0.0001, respectively). The highest ORs were found for the DR4DQ8/DR8DQ4 genotype (OR = 21.04, P = 0.001), followed by DR4DQ8/DR17DQ2 (OR = 12.45, P < 0.0001) and DR9DQ9/DR17DQ2 (OR = 10.87, P = 0.02). DR4DQ8 homozygous and DR17DQ2 homozygous individuals have a disease OR of 9.0 and 3.0 (P = 0.01 and 0.03), respectively. In conclusion, the results from haplotype, genotype, and tree analyses provide insight into the disease associations for combinations of HLA-DRDQ haplotypes. We confirm that the DR9DQ9/DR17DQ2 genotype is associated with susceptibility in the Dutch population, which has previously been noticed as a HLA risk genotypes in Asian populations only.     

Maternal HLA Class II Alleles Predispose to Pregnancy Losses in Danish Women With Recurrent Spontaneous Abortions and Their Female Relatives

PROBLEM: If damage to the trophoblast mediated through autoimmune mechanisms is responsible for recurrent spontaneous abortions (RSA), maternal class II HLA antigens might be expected to be involved. We wanted to evaluate the impact of these antigens on pregnancy outcome in RSA women and their relatives. METHOD: HLA-DR and -DQ typing using RFLP and PCR-SSP methods was carried out in 234 Danish women with unexplained RSA and 360 controls. The HLA-DR types were correlated to outcome of the next pregnancy in 94 patients. Sisters, brothers, and wives of brothers of 146 consecutive patients were HLA typed and their pregnancy outcomes were correlated to the HLA-DR types. RESULTS: HLA-DR1/Br and -DR3 were each significantly increased in women with at least four previous pregnancy losses (both P-values < 0.05 after correction for multiple comparisons). In the prospective study, 62% of the HLA-DR1/Br and/or -DR3 positive patients miscarried the next pregnancy compared with only 29% of those negative for both allogenotypes (P ? 0.025). The family studies indicated that female relatives of RSA patients had a greater risk (odds ratio ? 5.0, 95% CI = 2.0–11.0) of pregnancy losses when positive for HLA-DR1/Br and/or -DR3 than those negative for the allogenotypes. CONCLUSIONS: Maternal HLA-DR allogenotypes DR1/Br and -DR3 or closely linked genes seem to predispose to pregnancy losses in RSA patients and their first degree relatives.     

Hetero- and homozygosity of MHC class II gene products in systemic lupus erythematosus. The Members of the Deutsche Multizentrische SLE-Studie.

An analysis of HLA class II antigens in 356 white patients with systemic lupus erythematosus (SLE) showed that all HLA-DR and -DQ homozygous and heterozygous combinations appear with frequencies expected from the observed gene frequencies. HLA-DR2 and HLA-DR3 gene frequencies were both increased in SLE, as were the odds ratios of all DR2 and DR3 hetero- and homozygous combinations. HLA-DR2/C4AQ0 heterozygotes were also not increased over expected values. Therefore, gene complementation at MHC loci does not contribute to susceptibility to SLE, but rather one or two MHC allele(s) in linkage with HLA-DR2 and HLA-DR3.     

HLA-DR, DQ genotypes of celiac disease patients and healthy subjects from the West of Ireland

Celiac disease (CD) has one of the strongest class II HLA associations of any human illness. We used DNA-RFLP typing to study the class II HLA genotypes of celiac disease patients from the West of Ireland, the geographic area with the highest rate of celiac disease in the world. We confirmed the high frequency of HLA-DR3 in this population, and we were also able to demonstrate the additional risk of developing celiac disease imparted by HLA-DR7. This was done by clearly distinguishing DR7, DQ2 haplotypes from DR7, DQ9 haplotypes, and by "subtraction analysis" of haplotype frequencies. As reported in other populations, most of the patients without DR3 were heterozygous for DR7 and DR11 or 12 (DR5), or had DR4. We used PCR-RFLP and direct sequencing of amplified DNA to examine HLA-DR4 subtypes. The frequency of HLA-DR4 was markedly decreased in patients compared with controls (p=0.000001) and there was a significant alteration of DR4 subtypes of the patients compared with controls (p=0.0227). Moreover, all of the CD patients (5 of 5) with DR4 had a haplotype associated with the DQB1*0302 allele compared with only 11 of 23 control subjects with DR4. Our results in this population with exceptionally high risk of CD strongly support the DQ heterodimer hypothesis and suggest that the recently described sequence difference between the DQB1*02 alleles of DR3 and DR7 may contribute to a synergistic increased risk when these haplotypes are inherited together. In addition, our findings suggest a role for HLA-DQ in DR4-associated CD.     

Family studies of the HLA system in acute post-streptococcal glomerulonephritis

Eighteen families (67 siblings) of index cases with acute post-streptococcal glomerulonephritis (APSGN) were typed for HLA-A,B,C,DR antigens. Twenty cases of clinical nephritis and 10 cases of asymptomatic disease were detected among the sibships. In eight families with more than one affected individual comprising 18 sib pairs random segregation of paternal and maternal HLA haplotypes was found (0.5 < p < 0.6), but some antigens (CW1, DR3) showed deviation from the expected 1:1 ratio in affected and nonaffected siblings in backcross families. We had previously noticed the existence of Mendelian recessive ratios in APSGN but in the absence of clear evidence for a dominant or recessive mode of inheritance for a putative APSGN susceptibility gene(s), pedigree data were analyzed twice for linkage with HLA using the two genetic models. The data obtained, although not sufficient to reject the hypothesis of linkage, provide no support for it. Comparison of the frequency of 61 HLA antigens among 42 unrelated APSGN patients and 109 controls, showed that HLA-DRW4 is more frequent among the former (p_c = 0.0500).     

HLA-DR and -DQ gene polymorphism in Latvian patients with insulin-dependent diabetes mellitus

Abstract: Latvian insulin-dependent diabetes mellitus (IDDM) patients ( n =101) and healthy controls ( n = 111) were analyzed for HLA-DR and DQ polymorphism. DR3-DQ2 and DR4-DQ8 were positively associated and DR15-DQ6, DR13-DQ6, DR1-DQ5 and DQ7 negatively associated with the disease. The incidence of LDDM in Latvia is very low (6.5 per 100,000) compared to Sweden (24.4 per 100,000), even though Latvia is close to Sweden. The reasons for the decreased incidence are not clear. When the negatively associated DQ were taken together in the healthy controls, more than 75% of the healthy controls were positive for one of the four negatively associated DQ molecules. The excess frequency of the negatively associated DQ molecules in the general population could explain the lower incidence of IDDM in Latvia. Association of HLA-DR and DQ genes with autoantibody markers shows DR3, but not DQ2, to be increased in GAD65 antibody-positive compared to antibody-negative patients. This association was not observed with ICA512 antibodies.