A novel HLA-haplotype containing a DRB5 gene not associated with DRB1*15 or DRB1*16 alleles.

In Caucasians, HLA-DR2 haplotypes usually express two DRB genes encoding the DR specificity. The DRB5 genes are in strong linkage disequilibrium with the respective DRB1*15 or DRB1*16 alleles. So far, no other DRB1 alleles have been found in association with DRB5 genes. Here, we report evidence for a probably recombinant DRB5 haplotype with a DRB1 allele not specific for DR2. From our results the haplotype DQB1*0501, DRB1*0101 and DRB5*0101 seems most likely.