Polymorphisms in IL12A and cockroach allergy in children with asthma

BackgroundIL12A has been implicated in T-cell development and may thus influence the development of atopy and allergic diseases.MethodsWe tested for association between four linkage disequilibrium (LD)-tagging SNPs (rs2243123, rs2243151, rs668998, and rs17826053) inIL12Aand asthma and allergy-related (serum total and allergen-specific IgE, and skin test reactivity [STR] to two common allergens) phenotypes in two samples: 417 Costa Rican children with asthma and their parents, and 470 families of 503 white children in the Childhood Asthma Management Program (CAMP). The analysis was conducted using the family-based association test (FBAT) statistic implemented in the PBAT program.ResultsAmong Costa Rican children with asthma, homozygosity for the minor allele of each of two SNPs inIL12A(rs2243123 and rs2243151) was associated with increased risks of STR to American cockroach (P ≤ 0.03 for both SNPs), STR to German cockroach (P ≤ 0.01 for both SNPs), and having a positive IgE to German cockroach (P < 0.05 for both SNPs). Among children in CAMP, homozygosity for the minor allele of SNP rs2243151 inIL12Awas inversely associated with STR to German cockroach (P = 0.03) and homozygosity for the minor allele of SNP rs17826053 inIL12Awas associated with increased risks of STR to American cockroach (P = 0.01) and STR to German cockroach (P = 0.007). There was no significant association between any SNP inIL12Aand asthma, STR to dust mite, or total IgE in Costa Rica or CAMP.ConclusionOur findings suggest that variants inIL12Ainfluence cockroach allergy among children with asthma.