Interferon-gamma and interleukin-4 single nucleotide gene polymorphisms in Paracoccidioidomycosis

The gene polymorphisms interferon-gamma (IFN-γ) +874 T/A and interleukin (IL)-4 −590 C/T have been associated with the altered production of cytokines. Therefore, they might be indicative of the occurrence of Paracoccidioidomycosis (PCM) caused by Paracoccidioides brasiliensis. The analysis of single nucleotide polymorphism (SNP) at position +874 IFN-γ showed an increase occurrence of A/T genotype in both PCM patients and healthy individuals as control (HIC) (56% and 45%, respectively), while the allelic distribution showed 82% of A allele in the patients and 80% in the controls. The SNP of −590 IL-4 showed that C/T genotype was significantly (p < 0.05) more prevalent (39%) in PCM group compared to the HIC group (19%), while IL-4 C/C genotype was significantly less frequent (59%) in the patient group compared to the control group (81%). Otherwise, 41% of PCM patients and 19% of HIC individuals carried the IL-4 T allele. Stimulation of peripheral blood mononuclear cells (PBMC) from PCM patients with cell extract antigenic preparations (PbAg) as well as secreted and surface antigens (MEXO) of P. brasiliensis evidenced that there is no difference in the IFN-γ production related to A and T alleles between PCM and HIC individuals. However, with IL-4 production, PCM patients classified as C phenotype showed two times more IL-4 production than PCM patients classified as T phenotype and HIC controls. In conclusion, our results suggest that functional genetic variants in the IL-4 promoter could influence the production of IL-4 in PCM.