HLA CLASS-II DRB1, DQB1 AND DPB1 GENOTYPIC ASSOCIATIONS WITH PEANUT ALLERGY - EVIDENCE FROM A FAMILY-BASED AND CASE-CONTROL STUDY

Background Peanut is one of most common foods provoking allergic react ions and is the most frequent cause of fatal and near-fatal food-induc ed anaphylaxis. However, as yet, little is known of the genetic and im munological mechanisms which underly peanut allergy. Objective Based o n findings in other allergic diseases, we have investigated whether pa rticular human leucocyte antigen (HLA) class II genetic polymorphisms contribute to the development of peanut allergy. Methods All individua ls from 37 families each containing one or more peanut allergic indivi duals, plus nine unrelated patients (161 individuals in total, defined as the study group) were typed for the HLA class II DRB1, DQB1 and DP B1 loci, by PCR-based techniques. Genotype frequencies were compared w ith those found in 293 unrelated controls. Results Four class II genot ypes (DRB108 (13.7% vs 4.8%; P-c = 0.026), DRB1*08/12, tyr 16 (22.4% vs 8.2%; P-c = 0.021), DQB104 (12.2% vs 2.7%; P-c = 0.0026) and DPB1* 0301 (49.1 vs 22.5%; P-c = 0.00062)) were present at a significantly h igher frequency in the study group compared with controls. Three of th ese genotypes (DRB108 (18.0%; P-c = 0.027), DRB1*08/12 tyr16 (24.0%; P-c = 0.029) and DQB104 (16.7%; P-c = 0.0029)) were also significantl y increased in peanut allergic individuals compared with controls, In addition, two genotypes (DPB10101 and 0201) were significantly decrea sed in frequency in the overall study group, but not specifically in p eanut allergic individuals, Conclusion While other genetic factors may be important, results from this study indicate that HLA class II gene tic polymorphism may play a role in determining susceptibility to pean ut allergy.