Human castor bean allergy and HLA-A, B, C, DR.

Abstract

Our results in 27 castor bean-allergic patients typed for HLA-A, B, C, DR antigens show (although the observed difference did not reach a statistical significance after correction for the number of tested specificities) an increase of A2 cross-reacting group antigens and, on the other hand, of HLA-A29, B39, CW2, B12, DR2, and especially DR5 (48.1% vs. 26.9% - chi 2 = 5.579; uncorrected p: 0.01 less than p less than 0.02), which possibly participate in haplotypic combinations. The facts that the markers of the haplotype segments involved are more frequent in northern European populations (e.g., A3,B7--Scandinavian; A29,B12--English) and that regional haplotypes are decreased (e.g., A11,B35) suggest that the allergics could in some geographical areas be less genetically adapted to their environment. In the same way, the fact that although the global number of assigned HLA antigens was increased, the percentage of only some alleles (among these those belonging to the A2-CREG) was increased suggests not only a recessive model but a diminution of the polymorphism in allergics. This is in agreement with the physiological role of the HLA system, the polymorphism of which, according to the numerous restriction phenomena allowed at the cellular level, represents broad possibilities of adapted immune response in man. In any event, these findings clearly suggest that HLA-DR5 and B39 may be the markers of castor bean allergy in the Mediterranean area, to which are superimposed the HLA alleles linked to the general atopic susceptibility.