Distribution of the HLA‐A9 antigen family (A23, A24 and A2403)

Characterization of 50 local anti-HLA-A9 (A23 and/or A24) sera against the HLA-A2403 antigen allowed the retrospective assignment of A2403 and the verification of A23 and A24 specificities in a panel of 9196 volunteer bone marrow donors. The six A2403 positive subjects identified were confirmed by PCR using four sequence-specific primer mixtures. Population analysis showed the distribution and HLA-A/B linkage disequilibrium of HLA-A23 and A24 to be typical of a Northern European Caucasoid population. HLA-A2403 has a phenotype frequency of 0.00065 (gene frequency-0.00033) and is in linkage disequilibrium with HLA-B63 and possibly B35.