Abstract:We have established a DNA typing system for the HLA‐B5 serologically cross‐reactive group (CREG) by means of a two‐step PCR amplification with nested sequence‐specific primers (nPCR‐SSP). The present study provides a low resolution definition of the HLA‐B5 CREG, i.e. identifying polymorphism equivalent to serology. Two different primer combinations allow group‐specific amplification of all HLA‐B5 CREG alleles and other related HLA class I alleles from genomic DNA. The amplified DNA is subjected to a second amplification step using eleven nested primer pairs. This assay permits the detection of the HLA‐B5 CREG specificities B35, B51, B52, B53, and B7801 in all homozygous and heterozygous combinations. Sensitivity and specificity as judged by a blind quality control study investigating a reference panel (n=50) is 100%. Extension of this approach should allow rapid DNA typing of all serologically defined HLA‐B specif