Influence of single gene variants of FOXP3 on allergic asthma predisposition

The role of FoxP3, a master regulator of T regulatory cells, in allergic diseases such as asthma is of immense importance yet the effect of its gene variants on the disease predisposition is not fully understood. We studied the association of FoxP3 polymorphisms (-2383C/T and -3279C/A) in allergic asthma patients and their correlation with serum IL-4, IL-13, Total IgE, and Vitamin D levels.

In this study 350 individuals were enrolled, 150 allergic asthma patients and 200 healthy controls. SNP analyses were performed by RFLP. IL-4, IL-13 vitamin D and Total IgE were measured by ELISA.

The AA homozygous mutant of -3279C/A posed a three-fold risk [P < 0.005; OR, 3.52] whereas the -2383C/T variants TT genotype carried a fourfold risk [P = 0.002; OR, 4.04]. Haplotype analysis exhibited predisposition to allergic asthmawith CC/TT [P = 0.01; OR 5.93 (95%CI)], AA/CC [P = 0.01; OR 3.29] and AA/TT haplotypes [P = 0; OR 11.86 (1.31-85.87)]. A negative correlation between IgE and Vitamin D was found [r = -0.30p-value 0.001] but a negative correlation betweenIgE and Vit D was established in the haplotype CC/TT [r = -0.45P = 0.002] and CC/CT [r = -0.52P = 0.04]. In allergic patients, the eosinophils count was high [p = 0.003] and the mean levels of pro-inflammatory cytokines IL-4 and IL-13 were elevated [P < 0.001] as well.

The study suggests SNP -3279 -AA genotype and, -2383-TT genotype in association with certain haplotypes pose a risk for allergy development. There was no correlation between different genotypes and serum levels of various cytokines.