人类白细胞抗原群体遗传学研究

人类白细胞抗原(human leukocyte antigen,HLA)系统是人类最复杂的遗传多态性系统。HLA群体遗传学的研究,一方面可揭示不同地区、不同民族的人群HLA分布情况,进行人群遗传学分析;另一方面有助于HLA与疾病相关性的研究以及为寻找HLA相合造血干细胞供者提供基础性资料。本文就HLA分子遗传基础、HLA群体遗传的内容及研究方法进展作一综述。     

Structure of HLA Molecules and Immunosuppressive Effects of HLA Derived Peptides

Elucidation of the structure of MHC molecules has provided profound new insights into their function in antigen presentation. In addition, structural studies have implicated certain regions of MHC molecules in specific functions. Although much of MHC biology has concentrated on the extensive polymorphism among these molecules, there is also evolutionary pressure to maintain the relatively monomorphic portions of these molecules. Drs. Krensky and Clayberger have found that synthetic peptides corresponding to linear sequences of HLA molecules have immunomodulatory effects both in vitro and in vivo. In this paper, they review the structure of HLA molecules and their studies of HLA derived peptides as novel immunotherapeutics. Members of the heat shock protein 70 family are implicated in the HLA derived peptide immunosuppressive pathway.     

A bioinformatics approach to ascertaining the rarity of HLA alleles

A project of the 15th International Histocompatibility Workshop examined the rarity of human leukocyte antigen (HLA) alleles. A section was constructed in the website, www.allelefrequencies.net to contain this data from different sources. A mechanism to search the data was implemented for use by any individual.     

HLA profile and Reiter's syndrome

The analysis of the clinical and HLA profiles of 99 patients with Reiter's syndrome is reported. Antigen HLA-B27, which has previously been firmly associated with Reiter's syndrome, predisposes patients to develop disease features which reflect articular involvement. The HLA haplotype A2, B27 was found to be at an elevated frequency in our Reiter's syndrome sample, and the latter two antigens are also associated with a general increase in disease severity. Conversely, antigen BW35 appears to be protective against certain features of the syndrome. Patients with certain antigenic profiles (namely A2 and A3 together with B27) tend to develop certain syndrome manifestations earlier in the course of the disease than those with other antigens.     

Correlations between Terasaki's HLA class II epitopes and HLAMatchmaker-defined eplets on HLA-DR and -DQ antigens

Human leukocyte antigen (HLA) class II-specific antibodies increase the risk of transplant failure, and their characterization must consider epitopes rather than antigens. There are two strategies to determine HLA epitope structure. Terasaki's group has analyzed antibody reactivity patterns with single antigen panels with a computer program based on shared amino acid residues of reactive alleles. HLAMatchmaker is a theoretical algorithm that predicts HLA epitopes on the HLA molecular surface from stereochemical modeling of epitope–paratope interfaces of antigen–antibody complexes. Our epitope repertoire is based on so-called 'eplets' representing 3-Å patches of at least one polymorphic residue on the molecular surface. This report describes how 49 of 53 Terasaki's HLA-DR epitopes correspond to HLAMatchmaker-defined eplets. Most of them are equivalent to single eplets ( n  = 33) or two or more possible eplets ( n  = 10), but six had corresponding eplet pairs. There were 10 cases whereby eplets have permissible residue combinations, and in 5 cases, we found that eplet specificity might be influenced by nearby hidden residues. We could assign corresponding eplets to 17 of 18 Terasaki's HLA-DQ epitopes. This study demonstrates how the HLAMatchmaker interpretation of amino acid residues shared between antibody-reactive antigens can increase our understanding of the structural basis of HLA epitopes.     

Characterization of three novel HLA alleles, HLA-B*4613, HLA-B*4614 and HLA-B*4618, in Chinese individuals

Three novel alleles, human leukocyte antigen (HLA)-B*4613, HLA-B*4614 and HLA-B*4618, were identified in Chinese individuals. HLA-B*4613 shows four nucleotides difference from B*460101, resulting in two amino acids change from Glu to Val at codon 152 and Trp to Leu at codon 156. HLA-B*4614 has a single nucleotide difference at position 97 T→C compared with HLA-B*460101, with an amino acid change from Tyr to His at codon 9. HLA-B*4618 shares the sequence of exon 2 with B*4601 and sequences of exons 3 and 4 with B*55, B*54 or B*59, together resulting in eight amino acids change compared with HLA-B*460101.     

HLA新等位基因B*5618的序列分析

目的识别确认中国汉族人群中的HLA新等位基因。方法采用聚合酶链反应-序列特异性寡核苷酸探针(polymerase chain reaction-sequence specific oligonucleotide probes,PCR-SSOP)方法、聚合酶链反应-序列特异性引物(PCR-sequence specific primer,PCR-SSP)方法以及基因测序分型(sequence-based typing,SBT)技术,发现1个与HLA-B*5610等位基因相近的未知等位基因。以基因特异性引物单独扩增B*56基因并对第2、3、4外显子进行双向测序,序列经BLAST验证并分析该基因与B*5610基因的核苷酸序列差异。结果该基因为新的等位基因,其序列已被GenBank接受(编号为EF016753)。新等位基因与最接近的B*5610相比,在第3外显子上有4个核苷酸的不同,即第379位C→G(密码子127CTG→GTG,氨基酸127Leu→Val);第412位A→G(密码子138AAC→GAC,氨基酸138Asn→Asp);第419位T→C、第420位A→C(密码子140TTA→TCC,氨基酸140Leu→Ser)。结论该等位基因为新的HLA-B等位基因,2006年9月已被世界卫生组织HLA因子命名委员会正式命名为HLA-B*5618。     

Incidence of humoral sensitization in HLA partially mismatched hematopoietic stem cell transplantation

As part of the 15th International Histocompatibility and Immunogenetics Workshop (IHIWS), seven centers participated in a collaborative project to determine whether any significant humoral sensitization occurred post-transplant among recipients of HLA partially mismatched hematopoietic cell transplants (HCTs). A total of 140 donor/recipient pairs were enrolled with a total of 367 pre-and post-transplant sera analyzed. The majority of the samples (69.1%) were obtained within 30–90 days post-HCT. HLA-specific antibodies were defined using single antigen bead assays on a Luminex™ platform with a positive cutoff value of 1000 normalized median fluorescence intensity (MFI). There was an overall incidence of post-HCT sensitization toward donor HLA mismatches of 5.7%; however, all cases were among recipients of one HLA haplotype-mismatched grafts under nonmyeloablative, pre-transplant conditioning. Among the one haplotype-mismatched recipients, 15.7% (8/51) developed donor HLA-specific antibodies and 29.4% also had antibodies directed toward third party HLA antigens. Among the donor-specific antibodies, 9.8% were directed toward HLA class I antigens; 7.8% were against class II antigens; and 2.0% had both class I and II specificity. The relative strength of post-transplant antibodies was low with no significant difference in the mean maximum MFI values between third party and donor-specific antibodies. Because only a small number (10.2%) of the post-transplant samples were obtained 180 days or more post-HCT, longer term study is needed to evaluate any clinical relevance of these low-to-moderate levels of donor-specific antibody in one haplotype-mismatched recipients, as well as to determine whether any other antibodies occur at later times.     

HLA-B is the best candidate of susceptibility genes in HLA for Japanese ulcerative colitis

Recently, a genome-wide association study for ulcerative colitis (UC) in the UK population was reported, and several susceptibility loci including the human leukocyte antigen ( HLA ) region were identified. The strongest association in the HLA region was found at a 400 kb haplotype block containing HLA-DRB1 . In Japanese population, previous study suggested the association between UC and HLA-B*52 ; however, HLA typing was determined using serotyping with the small sample size. The purpose of this study was to perform an association study in HLA-B by genotyping. A total of 320 patients with UC and 322 healthy controls were recruited in this case–control study. All subjects were Japanese. Genotyping of HLA-B was performed by polymerase chain reaction using a sequence-specific primer. When the allele frequencies were compared, significant associations were found with B*52 [odds ratio (OR) = 3.65, P  = 1.6 × 10⁻¹⁷, P _c = 3.7 × 10⁻¹⁶] and B*4002 (OR = 0.52, P  = 0.00030, P _c = 0.0068). The allele frequency of B*52 was significantly higher in patients diagnosed before 40 years of age than in those diagnosed after 40 years (OR = 1.79, P  = 0.010, P _c = 0.020). A combination association map of Japanese UC using our current and previous studies showed two equal peaks of association on HLA-DRB1 and HLA-B , indicating the possible existence of two casual variants in the HLA region inside and outside the 400 kb block found in UK. We conclude that HLA-B contributes to the susceptibility to Japanese UC, especially cases with younger age of onset. The strength of association for HLA-B was equal to that for HLA-DRB1 in Japanese UC, in contrast to the UK population.     

Identification of a new HLA DRB1 allele (HLA-DRB1*1167) in a potential hematopoietic stem cell donor from Iraqi Kurdistan

High-resolution polymerase chain reaction sequence-specific primer typing and sequence-based typing of the human leukocyte antigen (HLA) gene DRB1 in a potential hematopoietic stem cell donor of Kurdish ethnicity revealed a new allelic variant of HLA-DRB1*11. The sequence was named DRB1*1167, and comparison with previously described DRB1 alleles demonstrated a mixed pattern shared with some DRB1*08 alleles.     

HLA-DQB1*0634, a novel DQB1 allele found by high-resolution HLA typing of a sibling pair for potential bone marrow transplantation

In this paper, we characterize the novel human leukocyte antigen (HLA)-DQB1*0634 allele we found in a sibling pair during high-resolution HLA typing in forecast of upcoming bone marrow transplantation. Both siblings, the female patient and her brother, were HLA identical, and therefore, both figured out the novel DQB1 allele characterized by a nucleotide exchange 'C' to 'T' at position 565, which is the last nucleotide of DQB1 exon 3. DQB1 exon 4 sequencing confirmed the exchange of codon 189-arginine (CGG), which is replaced by tryptophan (TGG) in the new allele DQB1*0634.     

云南汉族原发性高血压与HLA-DRB1等位基因的相关性

目的　探讨云南汉族人群 HL A- DRB1等位基因与高血压病的相关性。方法　应用病例 -对照相关分析方法 ,采用 PCR-序列特异性引物基因分型技术对云南汉族 91名健康个体和 83例高血压病患者 (均无血缘关系 )进行 HL A- DRB1位点 17个特异性的等位基因分型 ,并进行遗传相关分析。结果　原发性高血压患者中 DRB1* 15 0 1/ 2的频率为 ( 0 .2 19)显著高于对照组 ( 0 .0 6 0 ) ,χ2 =18.331,P<0 .0 1,相对危险率为 4 .4 6 ,病因分数为 0 .34。 DR9( DRB1* 0 90 1)的频率 ( 0 .0 81)显著低于对照组 ( 0 .192 ) ,χ2 =8.70 4 ,P<0 .0 5。相对危险率 RR为 0 .4 1,预防分数为 0 .19。结论　云南汉族 HL A- DRB1等位基因与高血压病的相关性与北方汉族存在差异 ,HL A- DRB1* 15 0 1/ 2可能与原发性高血压易感相关 ;DRB1* 0 90 1可能在发病中有保护作用。     

应用SBT直接测序分型法研究中国南方汉族人群HLA五个基因座单倍型

目的 研究中国南方汉族人群HLA-A、B、Cw、DRBl、DQBl等位基因多态性及单倍型的分布特征.方法 应用聚合酶链反应-直接测序分型(polymerase chain reaction sequence-based typing,PCR-SBT)法对186名中国南方汉族健康人群HLA-A、B、Cw、DRBl、DQBl进行基因分型.结果 检出的HLA-A、B、Cw、DRBl、DQBl等位基因分别有28、49、24、29、20种.经统计分析A*0207-B*4601(10.81%),A*3303-B*5801(6.14%),B*4601-DRBl*0901(6.22%),B*4001*DRBl*0901(3.78%),DRBl*0901-DQBl*0303(12.16%)和DRBl*1202-DQBl*0301(8.38%)单倍型呈强连锁不平衡单倍型(RLF≥0.5,X<'2>>3.84,P<0.05);A*0207-B*4601-Cw*0102(10.75%),A*3303-B*5801-Cw*0302(5.14%),A*0207-B*4601-DR*0901(5.07%),A*3303-B*5801-DRBl*0301(2.96%),A*0207-B*4601-Cw*0102-DRBl*0901-DQBl*0303(4.87%)和A*1101-B*1301-Cw*0304-DRBl*1501-DQBl*0601(2.43%)单倍型分别是中国南方汉族人群常见单倍型.结论 中国南方汉族人群HLA 5个基因座单倍型分布具有高度的遗传多态性且有其自身分布特点.本研究获得的较完整的HLA 5个基因座单倍型分布数据,将为人类学、HLA疾病相关性和器官移植等研究提供遗传学参考数据.     

新等位基因HLA-B*9526的确认和序列分析

目的 鉴定中国人群中人类白细胞抗原(human leukocyte antigen,HLA)新等位基因HLA-B*9526,并进行核苷酸序列分析.方法 使用序列特异性寡核苷酸PCR技术进行HLA基因分型,发现1个反应格局异常的等位基因,应用分子克隆和DNA双向测序技术测定新等位基因的核苷酸序列,并与已知等位基因进行序列比对分析.结果 检出反应格局异常的DNA样本,经过克隆测序得到两个等位基因,分型结果一个为B*5403,另一个的核苷酸序列与已知的HLA等位基因均不同,该基因序列与同源性最高的HLA-B*1507基因序列相比在第3外显子区域中425位碱基发生A→G突变,导致142位编码氨基酸由酪氨酸变成半胱氨酸.结论 一个新的HLA-B等位基因被确认,并被世界卫生组织HLA因子命名委员会正式命名为HLA-B*9526.     

HLA class II amino acid epitopes as susceptibility markers of sarcoidosis

Sarcoidosis is a multisystemic disorder of unknown etiology, affecting primarily the lung and characterized by epithelioid granulomas. Disease association studies showed human leukocyte antigen (HLA) class II to be related to sarcoidosis. Initially, we studied the association of sarcoidosis with DQB1, and in the present study, we evaluated all amino acid variants of the HLA-DPB1, -DQB1, -DRB1, -DRB3, -DRB4 and -DRB5 genes to identify possible polymorphisms associated with the disease. Patients and controls were typed for class II genes to the allele level by sequence-based typing. Multiple logistic regression models showed DRAla71 and DQPhe9 to be independently associated with the disease. Subdivision of patients according to their radiographic stage resulted in identification of DRArg74 as independent associated residue in the RS I group, whereas DRAla71 and DQTyr30 were associated with RS II-IV groups. Polymorphic residues specifically associated with sarcoidosis shed new light on the characteristics of sarcoidosis-triggered peptides. Overall, pocket 9 of DQ and pocket 4 of DR seem to be the most important areas involved in the association with sarcoidosis.     

Naming HLA diversity: A review of HLA nomenclature

The development of a standardized HLA nomenclature has been critical in our understanding of the HLA system and in facilitating the clinical applications of HLA. The Nomenclature Committee for Factors of the HLA System, established in 1968, has overseen the development and usage of nomenclature based on serologic specificities, cellular responses, and DNA sequences. Their decisions have been guided by community consensus reached through 17 international workshops beginning in 1964 and continuing today. Two websites provide a curated database of the sequences of over 26,000 HLA alleles and a reference site for the current nomenclature. This review covers the major steps in the development of the HLA nomenclature as well as the efforts of other groups to extend its usefulness for research and clinical applications.