The interleukin-4 −34TT and −590TT genotype is correlated with increased expression and protein production in aggressive periodontitis

Aggressive periodontitis (AgP) is a severe periodontal disease characterized by rapid destruction of the tissues supporting the teeth in otherwise healthy individuals. The frequency of the interleukin-4 homozygous −34TT and −590TT genotype was increased in patients in comparison with controls. This study aimed to test the functional effect of this specific genotype in AgP patients by analyzing gene expression of IL-4 and STAT6, and protein concentration of IL-4, in activated CD4+ T cells. Results revealed an increased IL-4 and STAT6 expression and IL-4 production in the cells of the patients who were homozygous for the −34T and −590T alleles in comparison with the patients who were homozygous for the −34C and −590C alleles (p < 0.05). These findings demonstrate that the IL-4 −34TT and −590TT genotype has a functional effect on T helper (Th) cells of patients with AgP, inducing increased expression of IL-4 and STAT6, and increased production of IL-4.