HLA-DQ-restricted CD4+ T cells specific to streptococcal antigen present in low but not in high responders.

We have found that the low immune response to streptococcal cell wall Ag (SCW) was inherited as a dominant trait and was linked to HLA, as deduced from family analysis. In the present report, HLA class II alleles of healthy donors were determined by serology and DNA typing to identify the HLA alleles controlling low or high immune responses to SCW. HLA-DR2-DQA1*0102-DQB1*0602(DQw6)-Dw2 haplotype or HLA-DR2-DQA1*0103-DQB1*0601(DQw6)-DW12 haplotype was increased in frequency in the low responders and the frequency of HLA-DR4-DRw53-DQA1*0301-DQB1*0401(DQw4)-Dw15 haplotype or HLA-DR9-DRw53-DQA1*0301-DQB1*0303(DQw3)-Dw23 haplotype was increased in the high responders to SCW. Homozygotes of either DQA1*0102 or DQA1*0103 exhibited a low responsiveness to SCW and those of DQA1*0301 were high responders. The heterozygotes of DQA1*0102 or 0103 and DQA1*0301 showed a low response to SCW, thereby confirming that the HLA-linked gene controls the low response to SCW, as a dominant trait. Using mouse L cell transfectants expressing a single class II molecule as the APC, we found that DQw6(DQA1*0103 DQB1*0601) from the low responder haplotype (DR2-DQA1*0103-DQB1*0601(DQw6)-Dw12) activated SCW-specific T cell lines whereas DQw4(DQA1*0301 DQB1*0401) from the high responder haplotype (DR4-DRw53-DQA1*0301-DQB1*0401(DQw4)-Dw15) did not activate T cell lines specific to SCW. However, DR4 and DR2 presented SCW to CD4+ T cells in both the high and low responders to SCW, hence the DR molecule even from the low responder haplotype functions as an restriction molecule in the low responders. Putative mechanisms linked to the association between the existence of DQ-restricted CD4+ T cells specific to SCW, and low responsiveness to SCW are discussed.     

T lymphocyte recognition of a celiac disease-associated cis- or trans-encoded HLA-DQ alpha/beta-heterodimer

The HLA-associated susceptibility to develop celiac disease may to a large extent be attributed to the combination of particular DQA1 and DQB1 genes, i.e., the DQA1*0501 and DBQB1*0201 alleles, located either in cis position (on the DR3DQw2 haplotype) or in trans position (DR5DQw7/DR7DQw2 heterozygous individuals). We report three alloreactive T lymphocyte clones that recognize an HLA-DQ alpha/beta heterodimer both when the DQA1*0501 and DQB1*0201 alleles are located in cis or in trans position. Thus, the celiac disease associated DQA1 and DQB1 genes encode a functionally expressed DQ alpha/beta heterodimer.     

用PCR-RFLP方法研究藏族HLA-DQA1和-DQB1基因多态性

应用目前HLA研究领域中成熟的,有效的PCR-RFLP基因分型技术,从DNA水平对藏族健康群体进行了HLA-DQA1(49人)和-DQB1(49人)基因分型,这在国内外属首次。所采用的PCR-RFLP基因分型技术是在HLA-DQA1和-DQB1各等位基因全部序列已知的情况下,对其第2个外显子碱基序列扩增进而进行RFLP分析的方法。这种方法得到的RFLP的所有片段都是已知序列,因而精确度很高,同时为发现新的等位基因提供了成熟而有效的分析方法。研究结果表明,在藏族DQA1的8个等位基因,DQA1*0301的基因频率最高(36.74％)。DQA1*0601(4.08％)、*0103(4.08％)和*0401(5.10％)最低。在DQB1的16个等位基因中,OQB1*0302(16.33％)、*0303(15.31％)和*0602(15.31％)为最常见,没有观察到*0504。统计分析表明,在DQA1各等位基因分布上,藏族与新疆汉族、北方汉族、上海汉族十分相近;与维吾尔族和哈萨克族也没有明显差异。在OQB1各等位基因的分布上,藏族与汉族、维族、哈族之间略有差异,而汉族、维族、哈族之间也存在一些差异。     

安徽汉族免疫性不育症与HLA-DQA1基因的相关性研究

目的:探讨抗精子抗体阳性的免疫性不育症患者与HLA-DQA1基因的相关性。方法:采用聚合酶链反应-序列特异性引物(PCR-SSP)技术,对50例抗精子抗体阳性的免疫性不育症患者和60例正常健康者的HLA-DQA1基因进行分型研究。结果:2组均未发现DQA1I0104和DQA1I0302两种基因型。免疫性不育症组DQA1I0401等位基因频率明显高于正常对照组(RR=5.5,P<0.05)。结论:DQA1I0401可能是安徽汉族免疫性不育症的易感基因。     

Analysis ofHLA-DR and -DQ gene polymorphisms in sudanese patients with type 1 (insulin-dependent) diabetes

In this study we report for the first time, the molecular analysis of HLA-DR and -DQ gene frequencies in a large cohort of well charaterized type 1 (insulin-dependent) diabetes mellitus (IDDM) patients (n=72), and ethnically matched controls (n=59) collected in subSaharan Africa. High molecular mass DNA was prepared and analyzed in Southern blots with DRBI, DQA1, and DQB1 probes. By identifying DR and DQ allele-specific restriction fragment length polymorphisms (RFLPs), we have shown a strong positive association between IDDM and the Asp 57^– DQB1 allele *0201 (DQw2). A rare DR4, DQw2 haplotype was also identified at high frequency in the IDDM cohort. We can now confirm that the association between Asp 57^–DQB1 alleles and IDDM, previously reported in ethnically diverse cohorts collected in Western Europe, North America, and South Asia, is also present in an IDDM cohort collected in Africa.     

HLA—DQ分子遗传结构与中国人重症肌无力的相关性

重症肌无力与ＨＬＡⅡ类基因关联性在不同人种和民族中具有不同遗传易感性,为探讨中国人重症肌无力（ＭＧ）与ＨＬＡ０ＤＱ分子关联性,采用聚合酶链式反应－限制性片段长度多态性（ＰＣＲ－ＲＦＬＰ）方法,分析了５０例中国正常人及４９例重症肌无力患者的ＨＬＡ－ＤＱＡ１和－ＤＱＢ１座位的基因型,结果：共检出正常人ＤＱＡ１等位基因８种,ＤＱＢ１等位基因１０种,重症肌无力患者ＤＱＡ１等位基因８种,ＤＱＢ１等位基因９种     

HLA DOA1 and DOB1 loci in Honduran women with cervical dysplasia and invasive cervical carcinoma and their relationship to human papillomavirus infection.

Molecular and epidemiological studies have demonstrated that certain types of human papillomavirus (HPV), mainly HPV-16 and HPV-18, are the primary causes of cervical cancer and its precursor lesions; there is now evidence for a clear association with specific HLA class I and class II loci contributing independently to the expression of cervical cancer. Among Honduran women carcinoma of the cervix is the most common type of cancer, and infections with high-risk HPV types are highly prevalent. To study the interactive role of viral-host genetics, we performed PCR amplification of DNA and sequence-specific oligonucleotide probe typing on cervical scrapes from 49 women [24 with cervical intraepithelial neoplasia stage III or cervical cancer (severe cases) and 25 with stage I or II cervical intraepithelial neoplasia (mild cases)] and 75 control subjects to look for possible associations between HPV and HLA class II DQA1 and DQB1 alleles in the development of dysplasias and invasive cancer. This analysis revealed a predominance of HLA-DQA1*0301 among severe-case patients [relative risk (RR) = 3.45, p = 0.008), whereas DQA1*0501 was negatively associated (RR = 0.30, p = 0.03), suggesting a protective effect of this allele. HPV typing showed a decreased relative risk among the HPV-16 or HPV-18 carrying patients and other HPV-related positive patients in the presence of DQB1*0602 compared with positive control subjects (p = 0.04). No statistically significant allele frequency difference was observed between mild dysplasia cases and control subjects. The results suggest that DQA1*03011, which is in linkage desequilibrium with all HLA-DR4 alleles, confers an increased risk for severe cervical dysplasia and invasive cancer, whereas DQA1*0501, which is in several DR52 haplotypes, has a protective effect. Furthermore, specific HLA-DQB1 sequences may be important in determining the immune response to HPV peptides and may affect the risk for cervical cancer after HPV infection in mestizo Honduran women.     

Complex HLA-DR and -DQ interactions confer risk of narcolepsy-cataplexy in three ethnic groups

Human narcolepsy-cataplexy, a sleep disorder associated with a centrally mediated hypocretin (orexin) deficiency, is tightly associated with HLA-DQB1*0602. Few studies have investigated the influence that additional HLA class II alleles have on susceptibility to this disease. In this work, 1,087 control subjects and 420 narcoleptic subjects with cataplexy, from three ethnic groups, were HLA typed, and the effects of HLA-DRB1, -DQA1, and -DQB1 were analyzed. As reported elsewhere, almost all narcoleptic subjects were positive for both HLA-DQA1*0102 and -DQB1*0602. A strong predisposing effect was observed in DQB1*0602 homozygotes, across all ethnic groups. Relative risks for narcolepsy were next calculated for heterozygous DQB1*0602/other HLA class II allelic combinations. Nine HLA class II alleles carried in trans with DQB1*0602 were found to influence disease predisposition. Significantly higher relative risks were observed for heterozygote combinations including DQB1*0301, DQA1*06, DRB1*04, DRB1*08, DRB1*11, and DRB1*12. Three alleles-DQB1*0601, DQB1*0501, and DQA1*01 (non-DQA1*0102)-were found to be protective. The genetic contribution of HLA-DQ to narcolepsy susceptibility was also estimated by use of lambda statistics. Results indicate that complex HLA-DR and -DQ interactions contribute to the genetic predisposition to human narcolepsy but that additional susceptibility loci are also most likely involved. Together with the recent hypocretin discoveries, these findings are consistent with an immunologically mediated destruction of hypocretin-containing cells in human narcolepsy-cataplexy.     

新疆维吾尔族、哈萨克族人群HLA-DQA1、-DQB1两基因座多态性的研究及与25个种族或民族的比较分析

应用ＰＣＲ－ＲＦＬＰ基因分型技术,首次对我国新疆地区维吾尔族和哈萨克族２个少数民族群体的ＨＬＡ－ＤＱＡ１、－ＤＱＢ１两个基因座的多态性进行了研究。结果显示,在ＤＱＡ１８个等位基因中,维族和哈族均表现为ＤＱＡ１＊０３０１最常见。最少见的ＤＱＡ１等位基因,在维族中为ＤＱＡ１＊０４０１和＊０６０１,而在哈族中为ＤＱＡ１＊０６０１;在ＤＱＢ１１６个等位基因中,ＤＱＢ１＊０２０１和＊０３０１在维族和哈族中均表现为最常见。在维族中未观察到ＤＱＢ１＊０５０２、＊０５０３２和＊０５０４,在哈族中未观察到ＤＱＢ１＊０５０３２、＊０５０４和＊０６０５等位基因。统计分析表明,维族和哈族ＤＱＡ１、ＤＱＢ１各等位基因的分布无显著性差异,说明维、哈族间具有较密切的亲缘关系。在以２７个种族或民族的ＨＬＡ－ＤＱＡ１、－ＤＱＢ１两基因座基因频率构建的分子系统树上,维族和哈族独立于其他群体而聚类,独处一支。维族和哈族接近蒙古人种,而离高加索人种较远。     

HLA-DQA1*0301-associated susceptibility for autoimmune polyglandular syndrome type II and III.

No significant differences were reported for the frequency of DR3-DQ2 and DR4-DQ8 haplotypes in a recent study of one of the largest cohorts worldwide of patients with isolated Addison's disease compared to patients with APS II. However, previous studies had suggested that the HLA-DQ genes, especially DQA1*0102, may be a genetic marker for resistance to autoimmune thyroid disease, which is the most frequent disease in APS II or III. Until now, HLA-DQA1 alleles have not been systematically investigated in APS. We determined the HLA-DR and HLA-DQA1 association in 112 unrelated patients with APS II (n = 29), APS III (n = 83) and 184 unrelated patients with single-component diseases without further manifestations of APS: Graves' disease (n = 70), Hashimoto's thyroiditis (n = 53), autoimmune Addison's disease (n = 15), vitiligo (n = 16) and alopecia (n = 30), and 72 healthy controls - German Caucasians - to identify possible predisposing and protective HLA class II alleles in APS. In agreement with previous studies, we detected a significantly higher frequency of DR 3 and/or DR 4 in patients with APS II and III compared to controls. In patients with APS II, we detected a significantly higher frequency of DQA1*0301 and *0501 compared to controls confirming the increased frequency of an extended HLA DRB1-*04-DQA1-*03-DQB-*03 haplotype as previously described. In contrast, only DQA1*0301 was increased in our patients with APS III compared to controls. Moreover, we detected an increased frequency of DQA1*0301 in patients with APS, whereas DQA1*0301 was only significantly elevated in alopecia in patients with single-component diseases without APS. Therefore, our results indicate an association between DQA1*0301 and APS II or III since this allele was otherwise not significantly associated with any of its component diseases except alopecia. Moreover, our data imply that the allele DQA1*0301 is a marker of increased risk for further APS manifestations in patients who suffer from an organ-specific autoimmune disease.     

Polymorphism of the DQA1 promoter region (QAP) and DRB1, QAP,DQA1, DQB1 haplotypes in systemic lupus erythematosus

We have investigated the DNA polymorphism for the DQA1 promoter region (QAP) and HLA-class II DRB1, DQA1, and DQB1 genes in 178 central European patients with Systemic lupus erythematosus (SLE) using polymerase chain reaction and Dig-ddUTP labeled oligonucleotides. Increased frequencies of DRB1*02 and *03 are confirmed by DNA typing. In addition, the frequencies of DQA1*0501, *0102 and DQB1*0201, *0602 alleles are increased in the patients as compared to controls. The strongest association to SLE is found with DRB1*03 and DQB1*0201 alleles (p<10^–7, p corr. <10^–5 and p<10^–6, p corr. <10^–4, respectively). By investigating the DQA1 promoter region in the SLE patients we have detected nine different QAP variants. Increased frequencies of QAP1.2 and QAP4.1 are observed in patients as compared to controls (p <0.05, p corr. = n. s.). Analysis of linkage disquilibria demonstrates a very strong association between QAP variants and DQA1, DRB1 alleles. Certain QAP variants are completely associated with DQA1 and DRB1 alleles, whereas others can combine with different DQA1 and DRB1 alleles. All DRB1*02-positive patients and controls carry QAP1.2, and all DRB1*03-positive patients and controls carry QAP4.1. Conversely, the QAP1.2 variant appears only in DRB1*02 haplotypes, while the QAP4.1 variant can be observed in DRB1*03, *11, and *1303 haplotypes. Based on the strong linkage disequilibria between DRB1-DQA1-DQB1 genes and between DRB1-QAP-DQA1, we have deduced the four-point haplotypes for DRB1-QAP-DQA1-DQB1 in patients and controls. Two haplotypes DRB1*02-QAP1.2-DQA1*0102-DQB1*0602-and DRB1*03-QAP4.1-DQA1*0501-DQB1*0201 are significantly increased in patient as compared to controls (p<0.01, p corr. = n.s., RR = 1.8 and p <10^–7, p corr. <10^–5, RR = 3.1, respectively). The analysis of relative risks attributed to the various alleles of QAP, DQA1, and DQB1 as well as the investigation of the deduced DRB1-QAP-DQA1-DQB1 haplotypes leads to the conclusion that QAP4.1 and DQA1*0501 on the DR3 haplotypes are probably not involved in SLE susceptibility. There is no evidence for the involvement of DQ2 / dimers coded in transposition. Thus, susceptibility to SLE is on the DR3 haplotype most probably localized at DRB1 or telomeric of DRB1, while for the DR2 haplotype such orientation cannot be given. SLE study group members: M. Baur, A. Corvetta, H. Ehrfeld, J. Frey, J. R. Kalden, F. Krapf, B. Lang, G. G. Lange, K. Pirner, C. Rittner, E. Röther, P. Schneider, H. P. Seelig, S. Seuchter, W. Stangel, C. Specker, P. Späth, H. Deicher. Correspondence to: Z. Yao.     

The importance of HLA DQB1*0602 typing in Slovene patients with narcolepsy

The HLA class II region genes DQB1*0602 and DQA1*0102 are currently the best genetic predictors for narcolepsy in humans (1(. The aim of this study was to identify the HLA DQ alleles (DQB1*0602 and DQA1*0102) in Slovene sporadic narcoleptic patients. 11 patients who fulfilled ICSD criteria for narcolepsy entered the study. DRB1*1501 DQB1*0602 was present in all the patients while DQA1*0102 was absent in 2 patients. We propose that DQB1*0602 typing is important in diagnosing narcolepsy in Slovene patients     

HLA-DQ primarily confers protection and HLA-DR susceptibility in type I (insulin-dependent) diabetes studied in population-based affected families and controls.

The association between HLA-DR and -DQ and insulin-dependent diabetes mellitus (IDDM) in a defined high-incidence area was analyzed in a total of 58 population-based patients, representing 77% of IDDM patients with age at onset below 16 years, and in 92 unrelated parents in control families without IDDM. HLA haplotypes were confirmed by analyzing first-degree relatives in both groups. Seven different methods were used to analyze risk: (1) odds ratio, (2) absolute risk, (3) haplotype relative risk, (4) transcomplementation relative risk, (5) relative predisposing effects, (6) stratification analysis, and (7) test of predisposing allele on haplotype. DQB1*0302 indicated somewhat higher risk than did DR4, while DR3 had a higher risk than DQB1*0201; however, the 95% confidence intervals of the risk estimates overlapped. The positive association between IDDM and the DQB1*0201-DQA1*0501-DR3 haplotype seems to be due to DR3 or to an unknown linked gene. More important, DQA1*0301 was present among 93% of the patients, and this allele in various transcomplementation combinations with DQB1 alleles showed closer association to IDDM than did any other alleles. The strong negative association of the DQB1*0602 allele also in the presence of either DR4 or DQB1*0302 or both suggests that, in a high-risk population for IDDM, HLA-DQ primarily confers protection, perhaps by induction of tolerance. Consistent with known functions, HLA-DR may primarily confer susceptibility, perhaps by induction of autoreactive T lymphocytes.     

Analysis of HLA DR2&;DQ6 (DRB1*1501, DQA1*0102, DQB1*0602) Haplotypes in Iranian Patients with Multiple Sclerosis

Multiple sclerosis (MS) is prototype of inflammatory demyelinating disease of the central nervous system .The etiology of MS remains unclear, but according to current data the disease develops in genetically susceptible individuals and may require additional environmental triggers. The human leukocyte antigen (HLA) class II alleles (DRB1*1501, DQA1*0102, DQB1*0602) may have the strongest genetic effect in MS. In this study, the role of these alleles were investigated in 183 Iranian patients with multiple sclerosis and compared with 100 healthy individuals. HLA typing for DRB1*1501, DQA1*0102, DQB1*0602 was performed by polymerase chain reaction (PCR) amplification with sequence-specific primers (PCR-SSP) method. The results show that, HLA DR B1*1501 was significantly more frequent among MS patients (46% vs. 20%, PV = 0.0006) but DQA1*0102 haplotype was negatively associated with MS (30% vs. 50%, PV = 0.0049) and no significant association was found with DQB1*0602 and MS patients in comparison with control group (24% and 30%, PV = 0.43). No significant correlation was observed among these alleles with sex, type of disease; initial symptoms, expanded disability status scale (EDSS), as well as age at onset and familial MS. This study therefore indicates that there is no association of above HLA haplotypes with clinical presentation, disease duration, and disability in Iranian patients with MS which is in line with other previous studies in different ethnic groups.     

A distinct HLA-DRw8 haplotype characterizes patients with juvenile rheumatoid arthritis

We studied the first domain of the HLA-DRB1, HLA-DQA1, and HLA-DQB1 loci of 67 HLA-DRw8-positive Caucasians including 43 with early-onset pauciarticular juvenile rheumatoid arthritis (EOPA-JRA, alternatively known as early-onset pauciarticular juvenile chronic arthritis). Serology, restriction fragment length polymorphism (RFLP), and polymerase chain reaction (PCR) oligotyping revealed that 62, including all the EOPA-JRA patients, carried the HLA-DRB1*0801, DQA1*0401, DQB1*0402 genotype. Approximately onefifth of the controls carried atypical HLA-DRB1, HLA-DQA1, and/or HLA-DQB1 loci on their HLA-DRw8 haplotype confirmed by family studies. DNA sequences of HLA-DRB1, DQA1, and DQB1 alleles in patients and controls were identical to those previously reported. Disease association studies in 113 EOPA-JRA patients and 207 controls unselected for HLA-DRw8 revealed that the HLA-DRB1*0801, DQA1*0401, DQB1*0402 genotype was associated with a higher relative risk (RR) for disease (RR = 12.8, ² = 48.8, P < 10^–4) than was the serologically defined presence of HLA-DRw8 (RR = 8, ² = 39, P < 10^–4). Further analysis suggested that the DQ genes on HLA-DRw8 haplotypes are as likely as the DR genes to contribute to the pathogenesis of EOPA-JRA. This study increases to five the number of HLA-DR/DQ haplotypes identified in HLA-DRw8 Caucasians.The nucleotide sequence data reported in this paper have been submitted to the GenBank nucleotide sequence database and have been assigned the accession number M34308.     

HLA class II influences the immune response and antibody diversification to Ro60/Sjögren's syndrome-A: heightened antibody responses and epitope spreading in mice expressing HLA-DR molecules

Abs to Ro/SSA Ags in the sera of patients with systemic lupus erythematosus and Sj?gren's syndrome are influenced by the HLA class II genes. To investigate the role of individual HLA class II genes in immune responses to human Ro60 (hRo60), mice lacking murine class II molecules and carrying either HLA genes DR2(DRB1*1502), DR3(DRB1*0301), DQ6(DQA1*0103/DQB1*0601), or DQ8(DQA1*0301/DQB1*0302), were immunized with rhRo60. The results show that hRo60 induces strong T and B cell responses in DR2, DR3, and DQ8 mice in comparison to weaker responses in DQ6 mice. In all mice, the majority of the dominant T cell epitopes were located in the amino portion (aa 61-185) and the carboxy portion (aa 381-525) of the hRo60 molecules. In contrast, the early dominant B cell epitopes were located in the middle and carboxy portion of the hRo60 molecule (aa 281-315 and 401-538). In DR2, DR3, and DQ8 mice, the B cell epitopes subsequently spread to the amino and carboxy portion of the hRo60 molecule but were limited to the middle and carboxy portion in DQ6 mice. The DR2 and DR3 mice produced the highest titers of immunoprecipitating Abs against hRo60 and native mouse Ro60. In addition, only DR2 mice exclusively produced immunoprecipitating Abs to native mouse Ro52 and Abs to mouse La by slot blot analysis, whereas in other strains of mice Abs to mouse La were cross-reactive with the immunogen. The results of the present study demonstrate the importance of HLA class II in controlling the immune responses to the Ro-ribonucleoprotein.     

Role of a Novel Human Leukocyte Antigen-DQA1*01:02;DRB1*15:01 Mixed Isotype Heterodimer in the Pathogenesis of “Humanized” Multiple Sclerosis-like Disease

Gene-wide association and candidate gene studies indicate that the greatest effect on multiple sclerosis (MS) risk is driven by the HLA-DRB1*15:01 allele within the HLA-DR15 haplotype (HLA-DRB1*15:01-DQA1*01:02-DQB1*0602-DRB5*01:01). Nevertheless, linkage disequilibrium makes it difficult to define, without functional studies, whether the functionally relevant effect derives from DRB1*15:01 only, from its neighboring DQA1*01:02-DQB1*06:02 or DRB5*01:01 genes of HLA-DR15 haplotype, or from their combinations or epistatic interactions. Here, we analyzed the impact of the different HLA-DR15 haplotype alleles on disease susceptibility in a new “humanized” model of MS induced in HLA-transgenic (Tg) mice by human oligodendrocyte-specific protein (OSP)/claudin-11 (hOSP), one of the bona fide potential primary target antigens in MS. We show that the hOSP-associated MS-like disease is dominated by the DRB1*15:01 allele not only as the DRA1*01:01;DRB1*15:01 isotypic heterodimer but also, unexpectedly, as a functional DQA1*01:02;DRB1*15:01 mixed isotype heterodimer. The contribution of HLA-DQA1/DRB1 mixed isotype heterodimer to OSP pathogenesis was revealed in (DRB1*1501xDQB1*0602)F1 double-Tg mice immunized with hOSP(142–161) peptide, where the encephalitogenic potential of prevalent DRB1*1501/hOSP(142–161)-reactive Th1/Th17 cells is hindered due to a single amino acid difference in the OSP(142–161) region between humans and mice; this impedes binding of DRB1*1501 to the mouse OSP(142–161) epitope in the mouse CNS while exposing functional binding of mouse OSP(142–161) to DQA1*01:02;DRB1*15:01 mixed isotype heterodimer. This study, which shows for the first time a functional HLA-DQA1/DRB1 mixed isotype heterodimer and its potential association with disease susceptibility, provides a rationale for a potential effect on MS risk from DQA1*01:02 through functional DQA1*01:02;DRB1*15:01 antigen presentation. Furthermore, it highlights a potential contribution to MS risk also from interisotypic combination between products of neighboring HLA-DR15 haplotype alleles, in this case the DQA1/DRB1 combination.     

HLA class II DR and DQ genotypes and haplotypes associated with rheumatic fever among a clinically homogeneous patient population of Latvian children

The HLA system is being paid more and more attention because it is very significant in polymorphous immunological reactions. Several studies have suggested that genetic susceptibility to rheumatic fever (RF) and rheumatic heart disease (RHD) is linked to HLA class II alleles. We hypothesized that HLA class II associations within RHD may be more consistent if analysed amongst patients with a relatively homogeneous clinical outcome. A total of 70 RF patients under the age of 18 years were surveyed and analysed in Latvia. HLA genotyping of DQA1, DQB1 and DRB1 was performed using PCR with amplification with sequence-specific primers. We also used results from a previous study of DQB1 and DRB1 genotyping. In the RF patients, HLA class II DQA1*0401 was found more frequently compared to DQA1*0102. In the RF homogeneous patient groups, DQA1*0402 has the highest odds ratio. This is also the case in the multivalvular lesion (MVL) group, together with DQA1*0501 and DQA1*0301. In the chorea minor patients, DQA1*0201 was often found. Significant HLA DQA1 protective genotypes were not detected, although DQA1 genotypes *0103/*0201 and *0301/*0501 were found significantly and frequently. In the distribution of HLA DRB1/DQA1 genotypes, *07/*0201 and *01/*0501 were frequently detected; these also occurred significantly often in the MVL group. The genotype *07/*0201 was frequently found in Sydenhamn's chorea patients that had also acquired RHD, but DRB1*04/DQA1*0401 was often apparent in RF patients without RHD. In the distribution of HLA DQA1/DQB1 genotypes, both in RF patients and in the homogeneous patient groups, the least frequent were *0102/*0602-8. The genotype DQA1*0501 with the DQB1 risk allele *0301 was often found in the MVL group. The genotype *0301/*0401-2 was frequently found in the RF and Sydenhamn's chorea patient groups. The haplotype *07-*0201-*0302 was frequently found in RF and homogeneous patient groups, including the MVL group. In addition, haplotypes *04-*0401-*0301 and *04-*0301-*0401-2 were frequent amongst patients with Sydenhamn's chorea. The protective alleles DQA1*0102 and DQB1*0602-8 in the haplotype DRB1*15 were less frequently found in RF patients. The results of the present study support our hypothesis and indicate that certain HLA class II haplotypes are associated with risk for or protection against RHD and that these associations are more evident in patients in clinically homogeneous groups.     

Polymorphism of the tumor necrosis factor beta gene in systemic lupus erythematosus: TNFB-MHC haplotypes

We investigated the Nco I restriction fragment length polymorphism (RFLP) of the tumor necrosis factor beta (TNFB) gene in 173 patients with systemic lupus erythematosus (SLE), 192 unrelated healthy controls, and eleven panel families, all of German origin. The phenotype frequency of the TNFB*1 allele was significantly increased in patients compared to controls (63.6% vs 47.1%, RR = 1.96, p <0.002). The results of a two-point haplotype statistical analysis between TNFB and HLA alleles show that there is linkage disequilibrium between TNFB*1 and HLA-A1, Cw7, B8, DR3, DQ2, and C4A DE. The frequency of TNFB*1 was compared in SLE patients and controls in the presence or absence of each of these alleles. TNFB*1 is increased in patients over controls only in the presence of the mentioned alleles. Therefore, the whole haplotype A1, Cw7, B8, TNFB*1, C4A DE, DR3, DQ2 is increased in patients and it cannot be determined which of the genes carried by this haplotype is responsible for the susceptibility to SLE. In addition, two-locus associations were analyzed in 192 unrelated healthy controls for TNFB and class I alleles typed by serology, and for TNFB and class II alleles typed by polymerase chain reaction/oligonucleotide probes. We found positive linkage disequilibrium between TNFB*1 and the following alleles: HLA-A24, HLA-B8, DRB1*0301, DRB1*1104, DRB1*1302, DQA1*0501, DQB1*0201, DQB1*0604, and DPB1*0101. TNFB*2 is associated with HLA-B7, DRB1*1501, and DQB1*0602.This study was supported by grants from the Federal Ministry of Research and Technology (BMFT/DFVLR, 01 VM 8608/9), the German Academic Exchange Service (DAAD, 322/501/014/0), and SFB (217).This work is part of the doctoral thesis of M. P. Bettinotti.     

The HLA-DRB4 gene is present in half of the Spanish HLA-DQ2-negative celiac patients

We studied nine consecutive DQ2-negative celiacs [from a group of 186 consecutive celiac disease (CD) patients] for the presence of the HLA-DQB1, DRB1, and DRBx alleles. HLA-DR53 was present in only 5 out of 9 (55%) of DQ2-negative patients. DRB4 (DR53) positivity -39% of chromosomes--among Spanish DQ2-negative CD patients is due to both DR4- and DR7-positive cases. Spanish DQ2-positive patients show a high frequency of DR7/DR11 heterozygous carriers of DRB4 (DR53). One-third of our DQ2-negative celiac patients have DRB1*04 (DR4). Six patients are DR4 negative: at least one of the DQ2 alleles (DQA1*0501/DQB1*02) is present in four cases, but none of the alleles of risk, including DR53, were found in the remaining two cases, both of whom carry DQB1*06 alleles (*0602/3 and 0604). The fact that half of our DQ2-negative patients lack DRB4 (DR53) leads us to believe that this gene is not an essential factor to confer CD susceptibility.