HLA-DRB5 genotyping by PCR-RFLP

PCR-RFLP typing detects new HLA-DRB1 alleles: DRB1*13022, DRB1*1336 and DRB1*1435

It is difficult to resolve all heterozygous combinations of the HLA-DRB1*03, *08, *11, *12, *13 and *14 allele group in a one-step generic HLA-DRB1 typing system. Therefore, it is common to employ a secondary technique utilizing group-specific primers to amplify this group of alleles separately from the other HLA-DRB1, -DRB3, -DRB4 and -DRB5 alleles. This paper describes a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method for broad typing of the HLA-DRB1*03, *08, *11, *12, *13 and *14 alleles which, as well as being time-efficient and cost-effective, has so far allowed the detection of 10 new alleles. The new alleles were identified after following up unusual or novel PCR-RFLP patterns. Of the 10 novel alleles found so far with this method, seven have been described previously while three, DRB1*13022, DRB1*1336 and DRB1*1435, are presented here.

An integrated multiplex-PCR and PCR-RFLP typing system for markers associated with seronegative arthritides

The system was designed with emphasis on the identification HLA-B alleles and genotypes associated or potentially associated with seronegative arthritides. By using a combination of multiplex SSP and PCR-RFLPs, the assays can be economically performed on a large range of sample sizes in diagnosis and epidemiology. 24 HLA-B alleles and subtypes can be discriminated, including options for PCR-RFLP or sequence specific amplification of the allele groups B27 and B60 (B*4001 and B*4007). In addition, the internal control carries central MHC polymorphisms, which can help to identify HLA extended halplotypes. False negatives, caused by preferential amplification of the internal control under suboptimal PCR conditions, were prevented by employing new, optimized PCR buffer. Four of the HLA-B primers were pooled into a multiplex reaction whose products were subtyped by digestion with seven restriction endonucleases. Specificity and sensitivity were verified in a panel of 68 homozygous cell lines and 200 heterozygous samples. An HLA-B*27-B*40 hybrid allele was observed in 3 out of 95 B*27-positive individuals from Berlin, Germany. Such an allele could be mistyped by some published assays as a B*27/B*40 heterozygote, a genotype reported to confer an increased risk for ankylosing spondylitis.

HLA-DR2 haplotypic diversity in populations of South-East Asia, northern China, Melanesia and Australian aborigines using PCR-RFLP for DRB1, DRB5, DQA1 and DQB1. A novel DRB1 allele: DRB1*16022

The polymorphism of the human leucocyte antigen HLA-DR2 and the heterogeneity of HLA-DR2 class II-related haplotypes (HLA-DRB1-DRB5-DQA1-DQB1) were investigated in four populations of east and south-east Asia (SEA) and five Melanesian populations using TaqI restriction fragment length polymorphism (RFLP) analysis, and the polymerase chain reaction (PCR) amplification-based techniques PCR-RFLP and sequence-specific oligonucleotide (SSO) typing. The haplotype DRB1*1502-DRB5*0101-DQA1*0102-DQB1*0601 was common in Malaysians, Javanese, Thursday Islanders, Madang, Goroka and the Australian Aborigines, while DRB1*16021-DRB5*0101-DQA1*0102-DQB1*0502 was common in the Thai and Thursday Islanders. DRB1*1501-DRB5*0101-DQA1*0102-DQB1*0602 was present at a high frequency in Northern Chinese, Goroka, Watut and Australian Aborigines. The study describes four rare or unusual haplotypes: HLA-DRB1*1501-DRB5*0101-DQA1*0101-DQB1*0601, DRB1*1502-DRB5*0101-DQA1*0101-DQB1*0502, DRB1*1502-DRB5*0102-DQA1* 0102-DQB1*0502 and DRB1*1501-DRB5*0101-DQA1*0101/2-DQB1*0503; the latter two were confirmed by segregation in two Javanese families. A new DR2 allele, initially detected by PCR-RFLP and confirmed by DNA sequencing as DRB1*16022 (previously designated DRB1*16Madang), was seen in a Madang individual. A new HLA-DR2 TaqI RFLP subtype, locally designated as DR15U, is also described. This RFLP subtype segregated in a Javanese family and correlated with a typically SEA haplotype, DRB1*1502-DRB5*0102-DQA1*0101-DQB1*0501. The allele HLA-DR16Thai, determined by TaqI DRB RFLP, was found by PCR-RFLP and SSO typing to correlate with a unique SEA haplotype, HLA-DRB1*16021-DRB5*0101-DQA1*0102-DQB1*0502, and was observed in the Thai, Malaysian, Thursday Islander, Javanese and Northern Chinese populations.

The role of HLA class II antigens in the induction of cytotoxic T lymphocytes

Investigation of pairs of unrelated persons mismatched for a particular HLA-DQB1 or -DPB1 gene on the induction of cytotoxic T lymphocytes (CTL) revealed that HLA-DQ and HLA-DP antigens provided a slight proliferative stimulus which was, however, sufficient for the generation of CTL. Monomorphic anti-DQ and anti-DP monoclonal antibodies abrogated the induction of cytotoxic response. The results indicate that the HLA-DQ and HLA-DP antigens play a similar role to HLA-DR specificities in clinical bone marrow transplantation.