HLAⅠ类抗原的基因芯片分型技术研究

目的：采用DNA芯片技术进行汉族人群HLAⅠ类抗原A、B位点的DNA分型研究，并实现将A、B位点的DNA分型集中于一张芯片上，同时完成。方法：根据HLAⅠ类抗原A、B位点不同基因亚型的独特序列设计探针，制成分型芯片；待检测样品经PER反应标记上荧光之后，与探针在芯片上进行杂交，通过对杂交产生的荧光信号值进行分析，确定样品的HLA-A、B基因亚型。将这一方法应用于220份样本的HLAⅠ类DNA分型并将部分样品进行基因测序。结果：所有样本的HLAⅠ类基因芯片分型均获得成功，无假阳性和假阴性出现，80份样本的重复率为100％，总耗时2．5h。分型结果经双盲验证完全符合。可准确分辨出A位点等位基因20个，B位点等位基因41个，实际检出汉族人群A抗原特异性13个、B抗原特异性32个。结论：基因芯片用于HLAⅠ类A、B分型技术可行，其分辨率高、特异性强、重复性好、操作简便快速、结果直观，可以在一张芯片上同时检测HLA-A、B位点，并实现一张芯片多人份，适合于临床应用。     

顺序特异性引物聚合酶链反应技术对HLA-DR DNA的分型

目的：应用顺序特异性引物聚合酶链反应技术(PCR—SSP)进行临床肾移植供受者HLA—DR位点DNA的分型。方法：设计并合成HLA—DR位点16对特异性引物和1对阳性对照引物，建立PCR—SSP法，对52份临床肾移植供受者的外周血淋巴细胞样本进行DR位点基因的分型。结果与微量PCR—SSP基因分型试剂盒分型方法比较。结果：所有临床样本的PCR—SSP基因分型均获得成功，结果与微量PCR—SSP基因分型试剂盒分型方法完全相同，分型时间3h，特异性和重复性100％。结论：应用合成引物为临床肾移植供受者进行HLA—DR位点PCR—SSP基因分型简便快捷，重复性好，适合于临床应用。     

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.     

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。     

基因芯片法特异性检测丙型肝炎病毒的基因分型

目的：采用基因芯片特异性检测血清中丙型肝炎病毒（HCV）并进行基因分型。方法：设计HCV基因型特异探针，将其固定在玻璃片上制成微阵列芯片。阳性组血清60份，阴性组血清15份，乙型肝炎血清5份（抗HCV阴性）。经核酸提取，多聚酶链式反应（PCR）扩增，与芯片上的探针杂交，最后分析结果并与测序分型结果比较。结果：阳性组血清全部检测到HCV-RNA，均有基因芯片分型结果。基因芯片分型结果与测序分型结果一致者56例。阴性组血清HCV-RNA全部阴性。乙型肝炎血清全部阴性。结论：基因芯片可准确对HCV感染血清做定性检测并同时检测HCV基因型，简便快捷，特异性好，并且不需荧光标记和昂贵的荧光扫描仪器，与乙型肝炎血清无交叉反应。可替代基因测序分型，适于临床大量样品的检测。     

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。     

微量DNA体外扩增及顺序特异的寡聚核苷酸探针作HLA-DQA基因分型

本文用人的微量DNA作PCR体外扩增,将PCR产物用5种特异的寡聚核苷酸探针进行分子杂交及HLA-DQA基因分型。实验结果与血清学检测的DR抗原结果完全一致,从而表明HLA-DQ基因与DR基因之间存在着较强的相关性。该方法具有敏感度高、技术稳定和样品微量等特点,是目前用于分子水平检测HLA基因的一项先进技术。     

基因芯片技术在乙型肝炎病毒基因分型检测中的应用探讨

目的：探讨利用基因芯片技术建立乙型肝炎病毒基因分型诊断方法的可能性。方法：查阅国际上主要的乙型肝炎病毒(HBV)基因分型诊断标准和现行技术，通过将基因芯片技术与目前用于HBV基因分型的技术方法进行对比，探讨利用基因芯片技术建立乙型肝炎病毒基因分型诊断方法的可能性。结果：HBV的基因分型，既可通过全基因序列比对，也可通过片段基因序列比对，片段基因序列比对是实际工作中HBV基因分型的主要方法，现有报道的技术主要为型特异引物(SSP)PCR扩增法和PCR扩增型特异探针(SSO)杂交法。基因芯片技术具有高敏感、高通量和能够平行检测DNA类型等特点，技术类型属于PCR扩增型特异探针(SSO)杂交法。尚未见有应用基因芯片技术进行HBV基因分型检测的报道。结论：借鉴现有的PCR扩增型特异探针（SSO)杂交法，如微板核酸杂交一ELISA显色技术，理论上利用基因芯片技术建立乙型肝炎病毒基因分型诊断的方法是完全可能的，并且具有高效、快速和廉价等特点。     

使用PCR—SSP方法检测HLA—DR抗原

目的　采用顺序特异引物聚合酶链反应 (PCR -SSP)建立人类白细胞抗原DR位点的DNA分型方法 .方法　合成 2 9个特异性引物和 1对阳性对照引物 ,组成 2 0个PCR反应用于DR位点 ,建立一步法PCR -SSP .结果　所有样本PCR -SSP基因分型获得成功 ,分型结果经标准DNA ,限制性核酸内切酶分析证实符合 ,特异性和重复性 10 0 % .结论　PCR -SSP检测HLA -DR的方法具有快速、准确、特异性高等优点 ,适合临床应用 .     

PCR基因芯片上荧光PCR反应的研究

目的探讨能否在基因芯片上进行不同的荧光掺入PCR反应并根据基因芯片上荧光的变化判断基因的变异.方法利用健康外周血,正常脐血DNA,X连锁遗传性铁粒幼细胞贫血(XLSA)家系成员6人外周血DNA做PCR-SSCP,并测序确定.设计检测此点突变的Taqman探针进行荧光PCR反应,在芯片上进行同样的反应,与上述反应结果进行对照.利用4步位点特异PCR结合SYBR荧光染料初筛HLAA2,并在芯片上进行同样的反应,与上述反应结果进行对照.结果PCR-SSCP分析与测序确定X连锁遗传性铁幼粒细胞贫血家系两患者的ALAS2基因第5外显子有G514A点突变,母亲、外祖母为杂合子携带者.设计Taqman探针时此家系中六位成员DNA与二份正常男性脐血DNA检测与预期结果相符.将上述结果中同样的样本移入芯片进行PCR反应,结果与常规荧光PCR反应的结果一致.SYBR荧光染料PCR反应与芯片上SYBR荧光染料PCR反应的结果与预期完全相符.结论利用TaqMan探针与SYBR Green荧光染料可以在PCR基因芯片上顺利进行PCR反应,根据基因芯片上荧光的变化检测出点突变与单核苷酸多态性.为基因芯片的临床应用打下了基础.     

Reduced PCR-generated errors from a hybrid capture-based NGS assay for HLA typing

Next generation sequencing (NGS) assays are state of the art for HLA genotyping. To sequence on an Illumina sequencer, the DNA of interest must be enriched, fragmented, and bookended with known oligonucleotide sequences, a process known as library construction. Many HLA genotyping assays enrich the target loci by long-range PCR (LR-PCR), prior to fragmentation. This PCR step has been reported to introduce errors in the DNA to be sequenced, including inaccurate replication of repeated sequences, and the in vitro recombination of alleles encoded on separate chromosomes. An alternative library construction method involves fragmentation of genomic DNA, followed by hybrid-capture (HC) enrichment of target HLA loci. This HC-based method involves PCR, but with far fewer cycles. Consequently, the HC method had significantly fewer PCR-induced errors, including more faithful replication of repeated sequences, and the near elimination of recombinant sequences. These improvements likely produce more accurate NGS sequencing data of HLA loci.     

HLA-A位点PCR-SSP基因分型和血清学分型的比较

目的：建立优化ＨＬＡ－Ａ位点ＰＣＲ－ＳＰ分型方法。方法：采用普通扩增仪和Ｅｐｐｅｎｄｏｒｆ管对细胞系ＤＮＡ和３７个健康正常人进行基因分型,血清学检测采用标准淋巴细胞毒试验方法。结果：发现引物浓度和浓度比、ＤＮＡ的纯度及酶的选用,是影响ＨＬＡ－Ａ位点ＰＣＲ－ＳＳＰ分型准确性的重要因素。该方法对３７个标本的基因分型结果与血清学结果相符合。结论：ＰＣＲ－ＳＳＰ方法具有简便准确的优点,可以作为ＨＬＡ－Ａ位     

Nested polymerase chain reaction-based HLA class II typing for the unique identification of formalin-fixed and paraffin-embedded tissue

Human leukocyte antigen (HLA) genotyping is routinely performed prior to organ transplantation using peripheral blood leukocyte-derived DNA. In addition, polymerase chain reaction (PCR)-based methods have permitted HLA genotyping using DNA extracted from formalin-fixed and paraffin-embedded tissue, with proven applications in HLA–disease association studies and surgical biopsy identification. The utility of current techniques may be limited by the poor yield of intact DNA from such paraffin biopsies. This paper describes a new nested PCR-based HLA class II genotyping method which reliably detects HLA DRB alleles within DNA extracted from even extremely small paraffin biopsies. This method comprises initial PCR amplification of exon II sequences of the HLA DRB1, 3, 4, and 5 genes using generic PCR primers. Identification of the HLA DRB1 alleles and detection of the DRB3, 4, and 5 genes is then performed using a series of separate individual second-round PCR reactions, each of which contains PCR primer pairs detecting a single HLA DRB allele or group of alleles (PCR-SSP). The ability of this method to detect 19 individual HLA DRB1 alleles or groups of alleles, covering all common DRB1 specificities, was confirmed via concordant results when compared with ‘direct’ (single amplification step) PCR-SSP analysis of one cell line-derived and nine peripheral blood DNA samples, and with five DNA samples extracted from paraffin biopsies. The technique was then successfully applied to 11 further paraffin biopsy-derived DNA samples, of which ten were untypable by ‘direct’ PCR-SSP analysis, from five cases in which doubt existed as to the individual origin of the tissues. © 1997 John Wiley & Sons, Ltd.     

HLA-DRB1 genotyping by modified PCR-RFLP method combined with group-specific primers

We previously introduced HLA-DQA1, -DPB1 and DQB1 genotyping with the modified PCR-RFLP method using some informative restriction enzymes which have either a single cleavage site or alternatively no cleavage site in the amplified DNA region, depending on the HLA alleles, making reading of RFLP band patterns much easier. In this study, 43 HLA-DRB1 alleles, excluding DRB1*1103 and *1104 for which no restriction enzymes are available to distinguish each from the other, could be defined by this modified PCR-RFLP method combined with 7 pairs of group-specific primers. It is impossible to distinguish DRB1*0701 and DRB1*0702 as they are identical for the second exon of DRB1. For DR1-DRB1, DR2-DRB1, DR4-DRB1, DR7-DR1, DR9-DRB1, DRw10-DRB1 or DRw52 associated antigens (DR3, w11, w12, w13, w14, and DRw8)-DRB1 gene amplification, the second exon of the DRB1 gene was selectively amplified using each group-specific primer from genomic DNAs of 70 HLA-homozygous B-cell lines and healthy Japanese by PCR. Amplified DNAs were digested with restriction endonucleases and then subjected to electrophoresis assaying simply for cutting, or no cutting, of the DNA, although some alleles can be distinguished only after examination of RFLP band patterns generated and in some cases using double digestion technique with two restriction enzymes. This modified PCR-RFLP method can be successfully applied to all possible DRB1 heterozygotes, despite the fact that 15 pairs of heterozygotes among them cannot be distinguished theoretically by the PCR-SSO method, because the PCR-RFLP method can tell whether two polymorphic sites are linked to each other (cis position) or located on a different chromosome (trans position) by checking the length of RFLP bands generated with double digestion. Thus, the PCR-RFLP method is technically simple, practical and inexpensive for determination of the HLA-DRB1 alleles for routine HLA typing work.     

Clinical utility of next generation sequencing based HLA typing for disease association and pharmacogenetic testing

HLA associations have been linked to many diseases and are important for risk assessment of drug hypersensitivity reactions. The increasing number of HLA alleles discovered generated a list of ambiguities that cannot be resolved with the current clinical assays, which commonly include sequence-specific oligonucleotide probe (SSOP) genotyping, and real-time PCR with melting curve analysis. HLA typing by next-generation sequencing (NGS) has recently been adopted by clinical laboratories for transplantation testing, as it provides unambiguous and cost-effective HLA typing. The goal of this study was to evaluate the feasibility of using NGS-based HLA-B and DQ genotyping for clinical HLA disease association testing, and provide direct comparison with the currently used clinical tests, including SSOP genotyping, and real-time PCR with melting curve analysis. While the real-time PCR method is easy and inexpensive to perform, ambiguities are rapidly increasing as more and more HLA alleles are discovered. SSOP genotyping identifies the alleles present but limitations include ambiguities and underreporting less common alleles. Our data show that HLA typing by NGS is superior to the existing clinical methods for identifying HLA alleles associated with disease or drug hypersensitivity, and offers a viable approach for high volume clinical diagnostic laboratories.     

A strategy for high throughput HLA-DQ typing.

We have developed a high throughput HLA typing methodology that is a modification of the standard sequence-specific primer method. This approach is distinct from other methods using an automated DNA analyzer, as more than one gene is typed in a single lane. We have optimized the method for use on an ABI 373 automated genotyping machine. Primers were designed to preferentially amplify DNA fragments of the generic allelic groups of the DQA1 and DQB1 loci. PCR products representing alleles at the DQA1 locus were amplified using a different fluorescent dye than the PCR products from the DQB1 locus. Only three PCR reactions are required for low resolution typing of DQA1 and DQB1. Use of different labeled primers enables genotyping for both loci in a single gel lane, allowing for 64 samples to be typed at low resolution for both DQA1 and DQB1 on a single gel. Automated allele assignments were determined based on DNA migration distance through a polyacrylamide gel using a standard genotype allele-calling program. Accuracy of this method is greater than 98% for both loci. The strategy described here may be adapted to include more loci or to produce higher resolution typing of alleles encoded by these loci. It can be readily optimized for use on other slab gel or capillary electrophoresis systems.     

SEROLOGICAL AND MOLECULAR ANALYSIS OF HLA IN ISRAELI PRIMARY SCLEROSING CHOLANGITIS PATIENTS

HLA class I and class II were investigated in 15 Israeli primary sclerosing cholangitis patients and compared to healthy controls. None of the well established serological specificities were found to be associated with the disease. HLA-DR52 is serologically defined, but its subtypes DR52a, DR52b, and DR52c cannot be precisely defined by serological means. Therefore, we have used HLA-DNA typing in order to assign the DR52 splits in PSC patients. Genomic DNA was amplified by PCR, dot-blotted and hybridized with sequence specific oligonucleotide probes defining the known HLA-DR52 associated alleles. Only 4 out of the 15 PSC patients tested were found to express DRB3*0101 the allele that encodes DR52a. Of the remaining 11 patients, 9 expressed DRB3*0202 haplotypes, with 2 patients expressing both DRB3*0101 and DRB3*0202, and the remaining 2 patients expressed no DRB3 allele. Our data indicate that there is no apparent association between PSC and the HLA antigens and alleles studied including the alleles of the DRB3 locus in the Israeli population. Thus HLA pheno/genotyping of PSC patients in the Israelis will not be useful for early and/or differential diagnosis of this disease.     

Rapid HLA-DRB1 genotyping by nested PCR amplification

State of the art genotyping of HLA class II alleles with group-specific DNA amplification by the polymerase chain reaction (PCR) (1) and subsequent probing with sequence-specific oligonucleotides (2-4) is not suitable for typing cadaveric organ donors since the typing procedure takes far more than one working day. We designed specific oligonucleotide primer sets for nested PCR amplification which allowed typing for all serological HLA-DR specificities (DR1-DRw18) solely by the detection of amplified DNA in the reaction mixtures after agarose gel electrophoresis. Exon 2 of the DRB genes and a DRw52-group-specific part of DRB1 exon 2 was amplified directly from cell lysates without prior DNA extraction. The amplified DNA was subjected to a second round of amplification, which employed a set of 18 nested allele- or group-specific primer pairs. All alleles which have at least a single mismatched base at the terminal 3'-nucleotide of one primer were completely refractory to amplification. This assay is easy to perform and takes less than one working day to complete. Thus, this method may prove to be suitable for DNA typing of organ donors for prospective HLA-DR matching in renal transplantation.     

Serological and molecular analysis of HLA in Israeli primary sclerosing cholangitis patients.

HLA class I and class II were investigated in 15 Israeli primary sclerosing cholangitis patients and compared to healthy controls. None of the well established serological specificities were found to be associated with the disease. HLA-DR52 is serologically defined, but its subtypes DR52a, DR52b, and DR52c cannot be precisely defined by serological means. Therefore, we have used HLA-DNA typing in order to assign the DR52 splits in PSC patients. Genomic DNA was amplified by PCR, dot-blotted and hybridized with sequence specific oligonucleotide probes defining the known HLA-DR52 associated alleles. Only 4 out of the 15 PSC patients tested were found to express DRB3*0101 the allele that encodes DR52a. Of the remaining 11 patients, 9 expressed DRB3*0202 haplotypes, with 2 patients expressing both DRB3*0101 and DRB3*0202, and the remaining 2 patients expressed no DRB3 allele. Our data indicate that there is no apparent association between PSC and the HLA antigens and alleles studied including the alleles of the DRB3 locus in the Israeli population. Thus HLA pheno/genotyping of PSC patients in the Israelis will not be useful for early and/or differential diagnosis of this disease.