HLAⅠ、Ⅱ类抗原的组织配型基因芯片的建立及应用

目的应用基因芯片技术进行北方汉族人群HLAⅠ、Ⅱ类抗原中分辨度分型研究,建立稳定的HLA检测芯片。方法采用寡核苷酸芯片分型方法,选择了中国人群基因频率较高的等位基因,同时考虑遗传的连锁不平衡,根据HLA-A、HLA-B、HLA-DR、HLA-DQB、HLA-DQA不同基因亚型的独特序列,完成了探针的设计与筛选,共设计了213条探针(HLA-A 56条,HLA-B 66条,HLA-DQA 22条,HLA-DQB 38条,HLA-DR 31条)制成基因分型芯片。采用带荧光标记的引物,用合适的PCR方法扩增HLAⅠ、Ⅱ类抗原上的多态性区域,产物与芯片上探针杂交。杂交结果经荧光扫描并用特定软件分析判断,以此确定样品基因型。结果所有样本的HLAⅠ、Ⅱ类抗原基因分型均获成功。此中分辨度探针可分出598个Ⅰ类抗原等位基因,511个Ⅰ类抗原等位基因,可检出Ⅰ类抗原特异性57个,Ⅱ类抗原特异性30个。结论基因芯片用于HLAⅠ、Ⅱ类抗原分型可行。其分辨率高、特异性强,可用于HLA基因分型、骨髓移植、器官移植的HLA配型、与HLA有密切关系的遗传性疾病的人群筛查。     

HLA-Ⅰ类抗原的组织配型基因芯片的建立及应用

目的:应用基因芯片技术进行北方汉族人群HLA-Ⅰ类抗原中分辨度分型研究,建立稳定的HLA检测芯片.方法:采用寡核苷酸芯片分型方法,依据第十三届国际组织相容性工作会议报告及相关文献,同时考虑遗传的连锁不平衡,及强脊炎、幼年型糖尿病等与HLA密切相关的遗传病等因素,选择了中国人群基因频率较高的等位基因,根据HLA-Ⅰ类不同基因亚型的独特序列,完成了探针的设计与筛选,最后设计了122条探针(HLA-A56条,HLA-B66条)制成基因分型芯片.采用带荧光标记的引物,用合适的PCR方法扩增HLA-Ⅰ类抗原上的多态性区域,产物与芯片上探针杂交.杂交结果经荧光扫描并用特定软件分析判断阳性探针,以此确定样品基因型.结果:所有样本的HLA-Ⅰ类抗原基因分型均获成功.此中分辨度探针可分出598个Ⅰ类抗原等位基因,可检出Ⅰ类抗原特异性57个.结论:基因芯片用于HLA-Ⅰ类抗原分型可行.其分辨率高,特异性强,可用于HLA基因分型、骨髓移植、器官移植的HLA配型、与HLA有密切关系的遗传性疾病的人群筛查.     

HLA-DR位点的基因芯片分型与临床应用

目的：建立一种新型的HLA－DR位点的基因分型方法，为HLA－DR的基因分型提供一个较新的思路。方法：利用基因芯片技术HLA不同基因亚型的独特序列设计探讨，制成分型芯片；待检测样品经PCR反应标记上荧光之后，与芯片进行杂交，根据杂交产生的荧光信号值分析确定样品DR位点的基因亚型，将这一方法应用于70份标准DNA和200份医院移植供受者的HLA－DR基因分型并将部分样品进行基因测序。结果：检测结果表明HLA－DR基因分型芯片可准确分辨出DR位点等位基因30大类，耗时3h 。结论：基因芯片用HLA－DR的基因分型，分辨率高，特异性强，重复性好，操作简便，对比常规的PCR－SSP和PCR－SSO方法，HLA－DR基因芯片方法更为直观，并具有集成化优势。可以在一张芯片上同时检测HLAⅠ类的A、B位点，并实现一张芯片多人份，适合于临床应用和骨髓库，脐血库的建立。     

人类白细胞抗原-A基因芯片分型研究

目的 探索人类白细胞抗原-A（HLA-A）基因芯片分型，为器官移植临床配型服务。方法 根据中国汉族南方人常见的HLA-A位点基因及其多态性的独特序列，设计并合成48条特异性的寡核苷酸分型探针，将其点在玻片上，制成芯片。基因组DNA通过组间特异性引物扩增，并用荧光素Cy5标记。标记后的产物与结合在芯片上的探针进行杂交，通过荧光扫描仪获得杂交产生的荧光信号值，再经过计算机软件自动分析，确定样品的HLA-A基因亚型。用该方法对120份样本进行HLA-A基因分型。结果 120份待检样本，其中6份因PER无产物，不能分型。1份信号杂乱，不能分型。其余113份样本分型成功。实际检出A抗原特异性结果为A2（含A203）：56；A11（含A1101）：52；A24：33；Al：8；A30（含A3001）：7；A33：21；A26：1；A29：2；A31：3；A68：2；A3：9；A32：1。未检出A＊3002基因型。整个检测耗时约4．5h。芯片检测的重复率为100％。结论 HLA-A基因芯片是一种理想的分型方法，具有特异性高、重复性好、操作简便、所需样本量少、结果判读容易、一次可作多份样本的优点，适合临床器官移植配型应用。     

沈阳汉族群体HLAⅠ类基因座PCR-序列特异性寡核苷酸探针分型研究

目的检测和分析沈阳汉族HLA-A、-B、-Cw位点等位基因的多态性。方法采用聚合酶链反应．寡核苷酸探针杂交分型方法对108名沈阳籍健康献血员进行HLA-A、-B、-Cw等位基因分型。结果检出等位基因HLA-A位点21个，B位点43个，Cw位点23个；所有位点的等位基因频率分布符合Hardy—Weinberg平衡。结论从基因水平分析了HLA Ⅰ类基因的群体分布特征，提供了沈阳汉族群体HLA Ⅰ类基因座更准确的基因频率。     

HLA-B40组等位基因多态性和血清学分型不明确标本分析

目的：利用DNA分型技术调查上海汉族人群HLA－B40组等位基因多态性并比较配型标本中HLA－B40抗原血清学和DNA分型的结果：方法：采用反向PCR－SSOP技术进行DNA分型，可检出HLA－B＊4001－4011等11个等位基因，结果：所有标本DNA分型均获成功，无假阳性和假阴性结果出现，质控DNA分型结果与UCLA结果相符，上海地区汉族人群共检出B＊4001－4003，4005－4007，4011等等位基因，未检出B＊4004，4008－4010等等位基因，296名无关个体中HLA－B40＊组等位基因频率为0．1402，血清学方法检测HLA－B40组抗原错误率为12．82％（10／78），结论：该技术用于HLA－B40分型分辨率高，分型结果较血清学方法更加精确，可确保HLA分型的准确。     

脐血HLA-A位点PCR-SBT分型的研究

目的建立HLA—A位点等位基因的PCR-SBT高分辨分型方法，探讨DNA测序技术在脐血库样本HLA分型中的应用价值。方法利用PCR产物直接测序，对广州脐血库保存的547份脐血样本进行HLA—A位点2、3、4外显子的序列分析，由分型结果得出基因频率，与中华（上海）骨髓库北方人群、上海地区人群及德国白种人进行比较。结果采用PCR-SBT分型方法并结合分析软件确定了全部样本的HLA—A基因型，广州地区人群HLA-A等位基因以A＊110101（30．8％）最为常见，其后依次是A＊24020101／02L（16．18％）、A＊0207（11．88％）、A＊3303（9．42％）。A＊110101在广州汉族人群中出现的频率明显高于中华（上海）骨髓库北方人群，而A＊010101、A＊3001明显低于后者；在HLA-A2亚型人群中，A＊020101在广州、上海两地汉族人群中的频率明显低于德国白种人，而广州汉族人群中A＊020101与A＊0206均明显低于上海汉族人，但A＊0203明显高于后者。结论基于核酸序列测定的HLA分型技术能够直接、准确、快速地进行高分辨分型，将有助提高无亲缘关系供者脐血移植的临床效果。改进实验条件、升级分型软件，可以降低试剂成本和节约时间。     

人类白细胞抗原新等位基因HLA-A*3020的鉴定及确认

目的 鉴定及确认1名中国人的人类白细胞抗原(human leukocyte antigen,HLA)新等位基因.方法 应用聚合酶链式反应-序列特异性寡核苷酸探针(polymerase chain reaction-sequence specific oligonucleotide probes,PCR-SSOP)方法基因分型、PCR产物测序和基因克隆DNA测序方法,通过软件分析该基因序列及与最相近HLA等位基因序列的差异.结果 PCR-SSOP基因分型结果显示该样品HLA-A谱型为与已知HLA-A等位基因谱型不一致的新谱型;测序结果显示该样品HLA-A位点第2外显子序列与所有已知HLA-A等位基因序列不一致.软件分析表明该基因序列与序列最相近的等位基因A*300101,在所检测的第1～3外显子中的差异只是在第2外显子区域产生了nt 294 C→A一个碱基替代,并导致相应的密码子98由GAC(D)→GAA(E).结论 该基因为HLA新等位基因,被世界卫生组织HLA因子专用术语命名委员会正式命名为HLA-A*3020.     

人类白细胞抗原新等位基因HLA-A*31∶22的序列分析及确认

目的 序列分析及确认一例中国人群中的人类白细胞抗原(human leukocyte antigen,HLA)新等位基因.方法 应用基于Luminex平台的聚合酶链反应-序列特异性寡核苷酸探针(PCR-SSOP)基因分型法、PCR产物测序法和组特异性引物测序法,通过软件分析该样本DNA基因序列及与最相近HLA等位基因序列的差异.结果 PCR-SSOP结果显示该样本HLA-A基因座的反应格局与已知HLA-A等位基因均不一致;DNA序列分析显示,在所检测的第2～4外显子中,该样本HLA-A基因座序列与所有已知HLA-A等位基因序列均不一致,与同源性最高的等位基因A*31∶01∶02的差异只在外显子2区域中产生了nt 245 A—C一个碱基取代,并导致相应的82位密码子由GAG→GCG,编码的氨基酸由谷氨酸(Glu)变为丙氨酸(Ala).结论 该基因为HLA新等位基因,被世界卫生组织HLA因子命名委员会正式命名为HLA-A*31∶22.     

造血干细胞移植56例人类白细胞抗原基因和单倍型分析

背景：收集56例欲行造血干细胞移植的供受者,均为无血缘关系的江西省汉族人群。了解个体的人类白细胞抗原基因型和单倍型。 目的：分析56例造血干细胞移植供受者的人类白细胞抗原基因频率,单倍型频率。 方法：收集56例欲行造血干细胞移植的供受者,均无血缘关系的江西省汉族人群。应用PCR-SSP的方法进行人类白细胞抗原(HLA)-A、B、DRB1基因分型,计算出HLA-A、B、DRB1各位点的基因频率和单倍型频率。 结果与结论：56例供受者测出HLA-A位点等位基因8种,HLA-B位点等位基因19种,HLA-DRB1位点等位基因13种,呈现出丰富的基因多态性。56例供受者两位点共224条等位基因中,A﹡02-B﹡46、A﹡11-B﹡40、B﹡46-DRB1﹡09单倍型的频率高于0.10。有10种A-B单倍型,4种B-DRB1单倍型呈现出显著的连锁不平衡。提示江西省汉族人群人类白细胞抗原基因具有较丰富的基因多态性。     

Analysis of HLA-A and -B serologic typing of bone marrow registry donors using polymerasee chain reaction with sequence-specific oligonucleotide probes and DNA sequencing

Unrelated volunteer donors (69) recruited by the National Marrow Donor Program were HLA typed by DNA-based methods for both the HLA-A and -B loci. Each donor had been previously typed by serology by at least two independent laboratories. Of the 69 samples, all serologic laboratories were in concordance for HLA-A in 62 typed samples and for HLA-B in 48 typed samples. Of the serologically concordant samples, 5 samples typed for HLA-A and 7 samples typed for HLA-B received DNA and serology types differing in their level of resolution. One sample typed for HLA-A and 3 samples typed for HLA-B by DNA methods gave different results from their serologic assignments. Of the samples exhibiting disparities among the different serologic typing laboratories, the DNA-defined types of 7 samples typed for HLA-A and 18 samples typed for HLA-B were consistent with at least one of the serologic assignments. The DNA types for the remaining 3 HLA-B typed samples did not agree with the serologic assignments and their alleles were subsequently sequenced. One of these sequences was a previously undefined allele, B*1537. Sharing of polymorphic sequences among HLA allelic products creates difficulties for consistent serologic assignments of some types complicating the process of identifying potential donors from bone marrow registries. Thus, the use of DNA-based typing techniques for characterization of donor class I types should allow a more consistent definition of types and should speed the donor selection process.     

Allelic heterogeneity of HLA-B35 subtypes in different populations as assessed by DNA typing

Abstract: HLA-B35, a class I antigen differentially associated to several diseases in different ethnic groups, comprises at least eight alleles which differ among them by one to six amino acids. In the present work a rapid DNA typing procedure was used to investigate the distribution of the various HLA-B35 alleles in different populations. The approach is based on a group-specific PCR amplification of a set of closely related HLA-B alleles sharing a Thr in position 45 of the alpha-1 domain. The amplified DNA was then hybridized to a panel of sequence-specific oligonucleotide (SSO) probes designed to recognize the polymorphic residues in previously reported HLA-B35 subtypes. This methodology was successfully tested in 100 individuals of four different populations, previously typed by serology as HLA-B35, and in six reference panel cells of the 10th International Histocompatibility Workshop. HLA-B*3501 was the predominant subtype in all populations. B*3502, B*3503 and, to a lesser extent B*3508, were also found. Among Mexican Mestizos, thirteen individuals had patterns of SSO hybridization suggestive of new B35 alleles. The evolutionary considerations on the different B35 alleles and their extended B35, Cw4 haplotypes are discussed.     

Validation of DNA-based HLA-A and HLA-B testing of volunteers for a bone marrow registry through parallel testing with serology

A total of 42,160 individuals were typed for HLA-A and HLA-B by both serology and PCR-based typing. The HLA assignments included all of the known serological equivalents. The majority of the individuals (99.9%) were from U.S. minority population groups. The serologic typing was performed between 1993 and 1997 at the time of recruitment for the National Bone Marrow Program (NMDP) registry. The polymerase chain reaction (PCR)-based typing was carried out in two phases. In phase I, DNA typing was performed by PCR using sequence-specific oligonucleotide probes (PCR-SSOP) or PCR using sequence-specific primers (PCR-SSP) without knowledge of the serologic assignments. Discrepancies were identified between the serologic and DNA assignments in 24% of the volunteers (8% of volunteers differed for only HLA-A assignments, 13% for HLA-B, and 3% for both HLA-A and -B) and a potential explanation was assigned each discrepant serology/DNA pair. In phase II, a random sampling scheme was used to select a statistically significant number of individuals for repeat DNA typing from each of these categories. The categories included antigens missed by serology, nonexpressed (null) alleles, PCR amplification failures, misassignment of antigens and nomenclature issues. Only a single individual was found to carry a null allele. DNA-based testing correctly typed nearly 99% of the donors at HLA-A, more than 98% at HLA-B, and more than 97% at both HLA-A and -B validating this methodology for registry typing.     

Haplotype-specific extraction: a universal method to resolve ambiguous genotypes and detect new alleles - demonstrated on HLA-B

Haplotype-specific extraction (HSE) allows the collection of individual alleles by separating diploid samples into their haploid components. The separation step is performed using magnetic beads in conjunction with allele-group-specific probes. The haplo-separated DNA samples can be directly typed with downstream applications such as sequence-specific oligonucleotide (SSO) typing, sequence-specific primer (SSP) typing, and sequence-based (SB) typing. Here we show that HSE permits the direct sequencing of an allele in its individual, separated state, including previously unknown alleles. Allele pair combinations that cannot be resolved by SSP, SSO, or generic SB typings can be unambiguously typed after the alleles are separated by HSE, which allows for new alleles to be easily detected without cloning. We show how HSE was performed to separate samples with locus-specific ambiguities in human leukocyte antigen (HLA)-B, which could not be resolved by means of generic SB typing for either sample. After haplotype-specific separation of the respective allele pairs, novel polymorphisms in the HLA-B*56 and HLA-B*44 alleles were clearly detected by SB typing.     

Clarification of HLA-B serologically ambiguous types by automated DNA sequencing

Abstract: Assignment of HLA-B types can be hampered by ambiguous reactivity of the typing sera resulting in inaccurate HLA-B assignments. In this study, 19 Korean samples exhibiting ambiguous serologic reactivities were characterized by DNA sequencing. Alleles identified from 7 samples were previously undetected in this population (B*1517, B*4101, B*4701, B*5001, and B*5106) and from 9 samples were common alleles in this population (B*4002, B*4003, B*4006, B*1501, B*1401, B*67012, and B*5401). Three samples were putative HLA-B homozygotes. Three major factors causing serologic ambiguity were identified: weak or false negative reactivity of typing sera (52.4%); cross or false positive reactivity of the sera (38.1%); and absence of information on the reaction patterns due to the lack of appropriate sera in the typing kit (e.g. B*4101 encoded molecule) or to the presence of recently characterized molecules (e.g. B*5106 encoded molecule) (9.5%). Overall, sequencing was helpful in clarifying ambiguous serologic reaction patterns improving the HLA typing for the Korean population.     

HLA-B27 genotyping by fluorescent resonance emission transfer (FRET) probes in real-time PCR

Several polymerase chain reaction (PCR)-based human leukocyte antigen (HLA) genotyping methods are in use, but none is fully satisfactory. The introduction of real-time PCR (rt-PCR) with fluorescence resonance energy transfer (FRET) probes provides a powerful tool to overcome the drawbacks of current methods such as the long processing time and the requirement for post-PCR manual procedures. Here we present evidence that the FRET-fluorotyping principle may resolve HLA-B27 variants, providing a higher resolution in less time than the techniques currently in use. The protocol uses between one and three consecutive amplification reactions depending on the resolution required. The first reaction, aimed at detecting HLA-B27-positive samples, uses beta-globin coamplification as control. The second reaction, aimed at resolving most frequent B27 alleles, uses two hybridization probes whose melting temperatures curves allow the classification of HLA-B27 alleles into eight groups. By adding a third reaction, even the rarest alleles associated and not associated to ankylosing spondylitis (AS) may be discriminated. The technique was blindly tested on 60 samples from individuals previously typed and confirmed by standard PCR sequence-specific oligoprobes-PCR sequence and PCR-based typing PCR-SBT (30 B27+, 30 non-B27). There was a complete concordance rate, thus confirming the potential of this new technique for clinical HLA-B27 typing and for HLA typing in general.     

HLA class I and II typing of the patients with Behçet's disease in Saudi Arabia

Thirteen Saudi Arabian patients with Beh?et's disease (BD) were typed for HLA-A and -B alleles by the conventional serologic typing and for HLA-DRB1, -DQB1 and -DPB1 alleles by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. As a result, the phenotype frequency of the B51 antigen was significantly increased in the patient group as compared to the ethnically matched control group (76.9% in patients vs. 22.20% in controls), but no significant difference was observed in HLA-A, -DRB1, -DQB1 or -DPB1 alleles between the patients and controls, as previously observed in Japanese BD. Further, by HLA-B51 allelic genotyping performed by the polymerase chain reaction-sequence specific primers (PCR-SSP) method, all of the B51-positive patients and controls were found to carry one particular allele, B*5101, except one patient with B*5108.