A case control study on the role of interleukin 17 in the pathogenesis of vitiligo

Abstract

Background: Interleukin 17 (IL-17) has recently been implicated in the pathogenesis of vitiligo by many studies but it is unclear whether it has any definitive role in causing depigmentation. IL-17 inhibitors have already been used in other inflammatory disorders with good results and may prove to be a valuable therapeutic modality in vitiligo. Thus, this study aims at adding to the existing data on the role of IL-17 in the pathogenesis of vitiligo. Objectives: (1) To determine the correlation between IL-17 and the extent of body surface area involvement. (2) To determine the correlation between IL-17 and the severity of disease activity. (3) To determine the correlation between IL-17 and serum vitamin D levels. Methodology: Thirty-two clinically diagnosed patients with vitiligo and 26 age- and sex-matched controls who fulfill the inclusion criteria were enrolled in the study. After obtaining a detailed history, a complete dermatologic examination was performed and vitiligo area severity index (VASI) and vitiligo disease activity score (VIDA) were assigned. The baseline serum IL-17 level was measured using Raybiotech serum IL-17 enzyme-linked immunosorbent assay kit. Serum vitamin D was measured for all cases and controls. Results: In our study, the mean VASI score of all the patients was 6.32 ± 10.14 and the mean VIDA score was 1.97 ± 0.999. The mean serum IL-17 levels were 155.72 ± 79.412 pg/mL in patients with vitiligo compared to 102.73 ± 56.478 pg/mL of the controls, with a mean difference of 52.99 pg/mL and the difference was statistically significant (P = 0.008). Although, there is no significant correlation between the serum IL-17 levels with the VASI score, our study noticed slightly higher levels of IL-17 in generalized vitiligo and lowest levels were noticed in localized vitiligo. Limitations: Our study was limited by the small sample size of 32. Conclusion: Although, serum IL-17 levels were significantly higher in the patient group than the controls, there was no correlation with the disease extent or activity. Thus, it is difficult to establish a causal role of serum IL-17 in vitiligo.