HLA-DRB4 GENE ENCODED HLA-DR53 SPECIFICITY SEGREGATING WITH THE HLA-DR7, HLA-DQ9 HAPLOTYPE - UNUSUAL ASSOCIATION

HLA phenotyping of a leukemia patient of Caucasoid origin revealed the presence of the serological HLA-DR53 specificity. Comprehensive pedig ree analysis demonstrated that the HLA-DR53 specificity segregated wit h the HLA-DR7, -DQ3 haplotype. High resolution PCR-SSP genotyping of t he HLA class IT genes revealed the presence of the HLA-DRB40101101 al lele segregating together with the HLA-DRB10701, -DQA1*0201 and DQB1* 03032 alleles. This finding is in contrast to known linkages in that t hus far, the HLA-DR7, -DQ9 haplotype has only been described in associ ation with the non-expressed HLA-DRB40103102N allele. The existence o f this ''novel'' haplotype may be explained by a homologous recombinat ional event that occured between the HLA-DR7, -DR53, -DQ2 and the HLA- DR7, -DQ9 haplotypes. (C) American Society for Histocompatibility and Immunogenetics, 1998. Published by Elsevier Science Inc.