Rh phenotype prediction by DNA typing and its application to practice

The complexity of the RHD and RHCE genes, which is the greatest of all blood group systems, confounds analysis at the molecular level. RH DNA typing was introduced in 1993 and has been applied to prenatal testing. PCR-SSP analysis covering multiple polymorphisms was recently introduced for the screening and initial characterization of partial D. Our objective is to summarize the accrued knowledge relevant to the approaches to Rh phenotype prediction by DNA typing, their possible applications beyond research laboratories and their limitations. The procedures, results and problems encountered are highly detailed. It is recommended that DNA typing comprises an analysis of more than one polymorphism. We discuss future directions and propose a piecemeal approach to improve reliability and cost-efficiency of blood group genotyping that may eventually replace the prevalent serology-based techniques even for many routine tasks. Transfusion medicine is in the unique position of being able to utilize the most extensive phenotype databases available to check and develop genotyping strategies.     

HLA-B44 subtyping in a Spanish population: further evidence of Caucasian population diversity

HLA-B44 is the most frequent HLA-B allele in Caucasian populations. Several B44 subtypes, B*4402-B*4406, have been identified in individuals with this ethnic origin. Mismatches among B44 subtypes have been described as major targets for allogeneic responses in bone marrow transplantation. We have developed a PCR-SSO method, based on a B12- specific DNA amplification of exon 2 through exon 3 and subsequent non radioactive hybridization with eight probes, which allow us to discriminate all B12 homozygous combinations. We applied this method to determine the frequency of B44 subtypes in a Spanish population, as well as their HLA-A.-C.-DRB1,-DRB3/DRB4/DRB5.-DQA1 and -DQB1 associated haplotypes. A total of 141 healthy unrelated Spanish individuals and 31 B44-bearing haplotypes were investigated. Four B44 alleles were identified, B*4402 (33%), B*4403 (66%), B*4404 (0.7%), and B*4405 (0.7%). Haplotype analysis showed a clear differentiated distribution pattern for the two major B44 subtypes. B*4402 is associated with Cw5 (11/13) and A2 antigens (10/13). In contrast, B*4403 is mainly found together with DRB1*0701 (14/16). An inverted B*4402/B*4403 frequency in comparison with other European and North American Caucasian populations, revealed the existence of an extended haplotype diversity between populations of the same ethnic origin. Apart from anthropological studies, high resolution typing for HLA class I antigens presenting molecular polymorphism will be of great relevance in unrelated bone marrow transplantation.     

HLAⅠ、Ⅱ类基因与肾综合征出血热重型与轻型的相关性研究

目的 探讨HLAⅠ、Ⅱ类基因多态性与肾综合征出血热（hemorrhagic fever with renal syndmme，HFRS）患者临床特征的相关性。方法 应用PCR-SSO（polymerase chain reaction using sequencespecific oligonucleotides）基因分型技术对中国北方地区56例汉族HFRS患者HLAⅠ、Ⅱ类基因频率分布进行了检测。结果 HFRS重型组HLA-B35携带率为20％，HLA-B62及HLA-DR11携带率皆为15％．与轻型组比较差异皆具有统计学意义（P〈0．05）。结论 HLAⅠ类基因中HLA-B35、HL4-B62及HLAⅡ类基因中HLA-DR11与中国北方地区汉族人群HFRS患者病情严重性密切相关。     

新等位基因人类白细胞抗原B*15:133的鉴定及其原核表达

背景:国际上至2010-04共报告人类白细胞抗原4 633个等位基因,中国自2000年至少发现200个新的等位基因,由于资金和时间有限,大部分新等位基因未作血清分型、家系研究以及进一步的功能性研究.目的:在健康志愿者人群中发现新等位基因,并对其进行家系研究,同时构建重链胞外区多肽的原核细胞表达载体,鉴定其在原核细胞中是否表达.方法:利用PCR-SSO和PCR-SBT技术,对人群的人类白细胞抗原进行筛选.使用血清学和SBT技术对拥有新等位基因的供者进行家系分析.用分子克隆的方法构建表达载体转染原核细胞,运用Western-blot鉴定是否表达.结果与结论:发现一个新等位基因与人类白细胞抗原B*15:18:01在第419位相差一个核苷酸,C->T, 即Codon116位 TCC->TTC,导致氨基酸由丝氨酸改变成苯丙氨酸.最终确定命名为人类白细胞抗原B*15:133.血清学表达B71(70)抗原.发现此供者的新等位基因来自于母亲.表达载体pET30a(+)- B*15:133在原核细胞中表达的多肽可被抗HIS标签单克隆抗体特异性识别.结果表明,使用分子生物学技术在大样本的筛查下发现了新等位基因人类白细胞抗原B*15:133,利用分子克隆的方法成功构建表达载体pET30a(+)- B*15:133,并在原核细胞中有大量高纯度蛋白表达.     

Identification of a new allele, HLA-DRB1*1360, on a DRB5 haplotype in a Brazilian individual

The application of DNA-based methods for human leukocyte antigen (HLA) genotyping has revealed an ever-increasing degree of polymorphism within the HLA-DRB loci and has resulted in the discovery of new alleles. We have identified a new DRB1 allele that was subsequently named DRB1*1360 by the WHO Nomenclature Committee. This allele is unusual for a DRB1*13 allele, as it is present on a DRB5 haplotype rather than the normal DRB3 haplotype found in association with DRB1*13 alleles.     

新等位基因HLA-A~*1127的确认和序列分析

目的识别确认临床样本中一个新的HLA等位基因。方法应用PCR-SSO,PCR-SSP基因分型技术对HLA分型,对可能的HLA新等位基因进行分子克隆和DNA测序,分析与最同源的A*1104的差异。结果该序列与已知的所有HLA-A等位基因序列不一致,与A*1104的差异表现在第3外显子区域中的核苷酸570 G→C,571 T→G导致氨基酸分别由谷氨酸→天冬氨酸,色氨酸→甘氨酸。结论该基因为HLA-A位点的一个新等位基因,已被WHO HLA因子命名委员会于2007年8月正式命名为HLA-A*1127。     

消化性溃疡与HLA-DRB1基因位点相关性的研究

目的 探讨人类HLA-DRB1等位基因与消化性溃疡的病因与发病机制的相关性.方法 采用聚合酶链反应-序列特异性寡核苷酸探针(PCR-SSO)杂交的方法,对101例消化性溃疡和305例正常对照无偿献血者的血液标本进行HLA-DRB1等位基因的检测.结果 消化性溃疡组的HLA-DRBl*09基因频率明显低于正常对照组(7.43%vs 12.95%,RR=0.539159).结论 HLA-DRB1*09基因对消化性溃疡可能具有重要的抵抗作用.     

蒙古族儿童过敏性紫癜与HLA—A基因的关联性

目的探索内蒙地区蒙古族儿童过敏性紫癜（AP）与HLA-A基因的关联性。可望找出相关基因,以探寻其部分发病机理及防治前景。方法采用病例对照研究策略,引入PCR—SSO技术,在祖籍三代居住内蒙地区,无血缘关系,无与异族通婚史及其他免疫性疾病史和家族史的蒙古族人群中,选择儿童AP病例组56例和健康儿童对照组66名,作HEA-A等位基因的型别分析。基因频率比较在单因素四格表X。或Fisher检验的基础上,作以Logistic多因素回归。结果病例组HLA-A$11基因频率为16．1％,与对照组的9．1％比较,Wald为3．954,P为0．047,差异有统计学意义。B为0．844〉0,OR为2．325〉1,促进发病,其95％可信区间为1．012—5．340,其内不包含1,与P意义相符,有统计学意义。EF为0．342〉0。结论HLA-A＊11等位基因可能是内蒙地区蒙古族儿童AP发病单体型中的一个遗传易感基因。     

Molecular analysis of HLA class II polymorphism in Croatians

Abstract: HLA-class II polymorphisms have been studied in a population of 141 unrelated healthy Croatians using PCR amplification, followed by non-radioactive oligonucleotide hybridization. Thirty one DRB1, 8 DQA1, 13 DQB1 and 16 DPB1 alleles were found in the tested population. DRB1*1601, 0701, 1501, 0101 and 1104 are the most frequent alleles at the DRB1 locus. At the DQA1 locus two alleles predominate: DQA1*0501 and 0102, while the most frequent DQB1 allele is *0301. Analysis of HLA-DPB1 polymorphism showed that, as in other Europeans, DPB1* 0401 is the most frequent allele. Four different two locus haplotypic associations (DRB1-DRB3, DRB1-DRB5, DRB1-DQB1 and DQA1-DQB1) as well as three locus DRB1-DQA1-DQB1 haplotypic associations were assigned on the basis of known linkage disequilibria. Several unusual two-locus associations have been observed: DRB1*0301-DRB3* 0202, DRB1*1501-DRB5*02, DRB1*1601-DRB5*0101, DRB1*1502-DRB5*0101, DQA1*0103-DQB1*0503 and DQA1*0501-DQB1*0302. Among 236 examined DRB1-DQA1-DQB1 haplotypic combinations, the most frequent was DRB1*1601-DQA1*0102-DQB1*0502 that was found with statistically significant higher frequency than in other Europeans. Twenty-eight distinct probable haplotypes were observed just once, suggesting that the main characteristic of Croatian population is great heterogeneity of haplotypes. This study will serve as a reference for further anthropology studies, HLA and disease associations studies and for donor/recipient matching in organ and bone marrow transplantation.     

Comparison of HLA-DRB1 typing by DNA-RFLP, PCR-SSO and PCR-SSP methods and their application in providing matched unrelated donors for bone marrow transplantation

Abstract: The aim of the study was to devise a strategy for large batch analysis to determine HLA Class II alleles exhibited by candidate bone marrow transplant donors and prospective recipients using previously published DNA-based typing techniques. Special attention was directed towards the technical aspects of procedures, the level of typing resolution and the speed of data analysis. 200 blood samples from volunteer bone marrow transplant donors typed serologically for HLA-DR and DQ were further investigated using three DNA-based typing methods: (i) restriction fragment length polymorphism (RFLP) analysis, (ii) polymerase chain reaction (PCR) amplification and subsequent hybridisation with sequence specific oligonucleotide probes (PCR-SSO), and (iii) PCR amplification with sequence specific primers (PCR-SSP) to resolve the DRB1* specificity of each individual. In general, the HLA-DR results obtained using PCR-SSO and PCR-SSP correlated well with each other. However, discordant results were obtained between PCR and RFLP based typing in 21 cases, especially in relation to DRB3* alleles associated with the DRB1 gene. These differences were due to three problems pertaining to RFLP analysis: i) alleles with identical DRB, DQA and DQB fragment sizes, ii) reliance on DQA and DQB results to assign the DRB genotype, and iii) a "new polymorphism" of DR7, in a DR7 homozygous, exhibiting a fragment similar in size to DR8. Our findings suggested a strategy requiring PCR-SSO analysis for initial low resolution class II typing involving large numbers of samples, while the use of PCR-SSP is reserved for small numbers of samples, for urgent samples or for situations where higher resolution is required. As the PCR-based methods are relatively quick, precise, simple and inexpensive, they have replaced RFLP analysis and become the routine approach for DR' typing in our laboratory.