Association of genetic polymorphism of interleukin-17A & interleukin-17F with susceptibility of psoriasis

BACKGROUND & OBJECTIVES: Psoriasis is a chronic inflammatory skin disease with unknown aetiology. So far studies have confirmed that interleukins, pro-inflammatory factors and T-cell activation play major role in the development of disease. Interleukin-17 (IL-17) a T helper inflammatory cytokine, was found to be positively correlated with severity of psoriasis. However, the specific mechanism has not been clarified. IL-17A and IL-17F are group members of IL17 family cytokines and found to be located adjacent to one another on the same human chromosome, 6p12. The present study was designed to identify the association between IL-17A and IL-17F gene polymorphism with susceptibility of psoriasis in north Indian population. METHODS: A total of 166 psoriasis patients and 150 healthy controls were genotyped for IL-17A and IL-17F gene polymorphism by amplification refractory mutation system-polymerase chain reaction method. One single nucleotide polymorphism (SNP) was analysed in IL-17A (rs10484879) and one SNP in IL-17F (rs763780) to look for an association with psoriasis. RESULTS: Our study indicated decreased frequency of IL-17A (rs10484879) G allele (51.8 vs. 65.0%), and IL-17F (rs763780) C allele (36.5 vs. 45.7%) in psoriatic patients as compared to healthy controls. INTERPRETATION & CONCLUSIONS: The present findings suggest that IL-17A (rs10484879) G/T and IL-17F (rs763780) C/T gene polymorphisms may contribute in pathogenesis of psoriasis. Further studies need to be done to confirm these findings.