A strong association between HLA-DR9 and gelatin allergy in the Japanese population

The frequency of HLA class I and II phenotypes was determined among 23 pati ents with positive gelatin IgE, eight of whom developed anaphylaxis. 18 pat ients who did not have gelatin IgE but who experienced non-immediate reacti ons after exposure to gelatin. HLA-DR9. which is unique to Orientals, was p resent in 56.5% of the gelatin IgE positive patients. as compared to contro l population frequency of 24%:, (P < 0.002). In the non-immediate reaction group, who did not generate IgE, phenotype distribution resembled controls. HLA-DR9 positive individuals have a relative risk of 4.1 for developing ge latin allergy with positive IgE. (C) 2001 Elsevier Science Ltd. All rights reserved.