Recent evidence indicates that HLA-C molecules are biologically relevant by eliciting T-cell responses and exerting control over NK cell function. In addition, HLA-C is associated with susceptibility to various diseases, notably psoriasis vulgaris. Clarification of the full biological roles for HLA-C has however proved difficult because detection of HLA-C antigens by complement mediated cytotoxicity using alloantisera is inefficient. Up to 50% of individuals in every race have serologically undetectable HLA-C locus antigens due to a combination of relatively low expression, lack of serological reagents and a lack of information about the distribution of the HLA-C blank alleles. Recently, amplification of DNA using sequence-specific primers (PCR-SSP) has proved a reliable, accurate and rapid method for medium resolution HLA-C typing. We have now developed high resolution HLA-C typing by PCR-SSP utilizing allele and group-specific PCR-SSP reactions which can identify all HLA-C alleles (except non-coding change alleles) in most heterozygous combinations. Using this system we have typed 604 unrelated United Kingdom Caucasoids to generate accurate frequency and linkage disequilibrium data. To assess the validity of serology for HLA-C, PCR-SSP typings for 527 out of the 604 individuals were compared to serology. We find that the frequency of many HLA-C antigens has been underestimated by serology and some antigens such as Cw6 are consistently assigned incorrectly by serology. The overall discrepancy rate between serology and SSP was high at 37% (195/527). High-resolution HLA-C typing of 112 International Histocompatibility Workshop cell lines has also been performed.

High resolution HLA-C typing by PCR-SSP: identification of allelic frequencies and linkage disequilibria in 604 unrelated random UK Caucasoids and a comparison with serology

Cotransplantation of third-party mesenchymal stromal cells can alleviate single-donor predominance and increase engraftment from double cord transplantation.

We present here the analysis of 86 individuals who were true antibody nonresponders to a vaccine containing hepatitis B surface antigen. The HLA type of these individuals and of 248 controls were determined by serology for HLA class I and by molecular typing for the HLA class II loci DRB1 and DQB1. Subsequent analysis of the results revealed that HLA-DRBI*0701 and HLA-DQB*02 were significantly associated with antibody non-response to the “S” -containing vaccine compared with the HLA control population. Further, we found that the antibody non-response was also significantly associated with the above antigens when found in linkage disequilibrium on the HLA haplotype DRB*0701; DQB1*0202. The hepatitis B surface antigen vaccine antibody nonresponder group, compriing 86 individuals, were revaccinated with a noval vaccine Hep B-3, containing both preS1- and preS2- derived proteins in a addition to hapatitis B surface antigen, to circumvent their previous nonresponsiveness. The hepatitis B surface antigen antibody results from this group of patients show that 30 of the 86 individuals remained antibody results from this group of patients show that 30 of the 86 individuals remained antibody non-responders and that 24 individuals (80%) expressed the HLA-DQB1* and that 21 individuals (70%) expressed HLA-DRB1*0701. Our results indicate that antibody nonresponse to the Hep B-3 vaccine is significantly associated with an extended HLA haplotype B44; DRB1*0701; DQB1*0202. A possible indication of these results is that antibody nonresponse to Hep B-3 vaccine is linked with the HLA allele DQB1*0202. These findings may have an important impact on future vaccine design.

Contribution of human leukocyte antigens to the antibody response to hepatitis B vaccination

The use of unrelated donors for bone marrow transplantation (BMT) is associated with an increased morbidity and mortality when compared with HLA-identical donors, primarily due to an increased rate of graft-versus-host disease, but also to increased susceptibility to infections and graft failure. HLA matching for donors and recipients is the single most important factor influencing the outcome of BMT. However, unrelated donor selection generally relies on matching only for HLA-A, -B and -DR antigens without considering potential incompatibility for other HLA loci, such as HLA-C, -DQ and -DP. In addition, other factors that affect the outcome of BMT need to be taken into consideration in selecting the best unrelated donor. In this review, we will focus on the effects of HLA-associated factors in determining the result of a transplant procedure. We will also mention other relevant factors, drawing on our experience of laboratory studies performed at The Anthony Nolan Research Institute and clinical studies at the Hammersmith Hospital in London.

Factors influencing the outcome of bone marrow transplants using unrelated donors

Molecular Typing Shows a High Level of HLA Class I Incompatibility in Serologically Well Matched Donor/Patient Pairs: Implications for Unrelated Bone Marrow Donor Selection

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.

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

J. M. Goldman

Papers

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

A new HLA Cw6 split -Cw6.2- detected in three ethnic groups that is inherited in families.

A short variant of A9 that is identical to A9V2