Correlation between Interleukin-17A Gene Polymorphism and Psoriasis Disease Susceptibility and Severity: A Case–Control Study

Background: Psoriasis is a polygenic and multifactorial papulosquamous disorder where certain environmental factors interact in genetically susceptible hosts to cause immune imbalance and development of characteristic cutaneous lesions. The exact pathophysiology of this complicated disease is still not well understood. Elevated serum and lesional interleukin (IL)-17 family of cytokines lead to more exploration of Th17 pathway in the disease pathogenesis and development of newer targeted therapies. Although the importance of Th17 pathway is being extensively investigated in the recent era, the genetic susceptibility and genetic variations of IL-17 have rarely been explored. Aims: We aimed to study the association of single-nucleotide polymorphism (SNP) of IL-17A with psoriasis and to correlate the gene polymorphism with the disease severity in an East Indian population. Methods: Fifty patients of psoriasis with variable severity and 50 healthy controls were genotyped for IL-17A SNP (rs10484879) by amplification refractory mutation system–polymerase chain reaction method, followed by gel electrophoresis and estimated visualization in gel documentation system. Results: TT genotype was found more frequently in psoriatic patients (18%) than in healthy people (10%). Conversely, GG genotype was present more in controls (56%) than in cases (42%). Homozygous TT genotype prevailed more in patients with moderate (23.07%) to severe (22.72%) form of psoriasis than milder form (6.67%). T allele dominated in the genomic pool of psoriatic patients with nail and joint involvement. However, none of our findings showed statistically significant values ( P > 0.05). Limitation: The limitation of this study was small sample size. Conclusion: IL-17A gene polymorphism may contribute in psoriasis disease pathogenesis, susceptibility, and severity in East Indian population, but as the sample size is limited in this study to get significant results and to arrive in a decisive conclusion, this study should be replicated in large cohorts in different population.