Insight into the Possible Association between Gene Polymorphism of IFN-γ and IL-22 with Psoriasis in Punjab, India

Abstract

Introduction: IFN-γ and IL-22 are Th1/Th17 cytokine which have been shown to play important role in the development of autoimmune disorder like psoriasis. Aim: To identify the possible association of IFN-γ and IL-22 Single Nucleotide Polymorphisms (SNPs) with psoriasis as well as to find correlation between serum level of IL-22 and IFN-γ with severity of psoriasis. Materials and Methods: A total of 168 psoriasis patients and 152 healthy controls were included in the study. A 3 ml of blood sample was collected from each psoriasis patients and healthy control for further analysis of SNP and serum level of cytokine. A part of blood sample was used for isolation of DNA for gene polymorphism study in psoriasis patients. Gene polymorphism of IL-22 (rs1179251 and rs2227513) and IFN-γ (rs2430561, rs2069709) were studied by ARMS PCR method whereas serum level of IL-22 and IFN-γ was analysed using commercially available ELISA kits. Odds Ratio (OR) with 95% Confidence Interval (95% CI) was calculated to assess the relative risk of psoriasis for various genetic variants. Results: Serum level of IL-22 and IFN-γ was found to be (74.4±24.1 and 96.7±31.7 pg/ml respectively) significantly high (p<0.001), and associated with PASI score in psoriasis patients. In genotype analysis, a significant association was found between gene polymorphism of IFN-γ (rs2430561 and rs2069709) and IL-22 (rs1179251 and rs2227513) with psoriasis. Conclusion: These results suggest that polymorphism of IFN-γ and IL-22 genes can be responsible for elevated serum level of IFN-γ and IL-22 cytokines. As these cytokines play key role in pathogenesis of psoriasis thus in conclusion gene polymorphism of IFN-γ and IL-22 may be responsible factor for increased susceptibility to psoriasis in north Indian population, Punjab, India.

Keywords

• cytokines
• inflammatory
• interleukin
• polymorphism
• psoriasis