HLA-B14 subtyping by semi-nested PCR-SSP and haplotype distribution in a Spanish population.

HLA-B14 serological subtyping is very limited probably due to the internal position of the unique amino acid residue that differentiates B64 and B65 molecules. In order to carry out an accurate B14 subtyping we have designed a semi-nested PCR-SSP procedure that can differentiate B1401 and B1402 in any HLA-A, -B or -C antigen combination. A panel of 133 B14-positive and 31 B14-negative healthy and unrelated Spanish individuals were studied. Additionally, 45 B14-bearing haplotypes (-A,-B,-C,-DRB1,-DRB3/DRB4/DRB5,-DQA1,- DQB1) were available through family studies. The relative frequencies of HLA-B14 subtypes were 74% for B1402 and 26% for B1401, in agreement with those found in other Central European populations, but differing from those in Wales, where the relative presence of B64 goes to 41%. A total of 11/17 and 18/28 different haplotypes for B1401 and B1402, respectively, were identified. Both alleles showed the strongest association to Cw8 (43/45), indicating a primary ancestral B14-Cw8 association. However, B14 subtypes evidenced very distinguishable haplotype distributions. B1401 is strongly associated with the common HLA class II haplotype DRB10701-DQA10201-DQB102 (13/17), while B1402 is mainly associated to DRB10102 (16/28). Three major haplotypes were identified: A32-Cw8-B1401-DR7-DQ2 (5/17), A33-Cw8-B1402-DRB10102-DQ5 (5/28) and A2-Cw8-B1402-DRB1*0102-DQ5 (5/28).