Interleukin 17, Interleukin 22 and FoxP3 expression in tissue and serum of non-segmental vitiligo: A case- controlled study on eighty-four patients

Background: Skewing of responses towards T helper (Th) 17 and away from T regulatory cells (T-regs) has been suggested to be partially involved in autoimmune diseases like vitiligo. Aims: Clarify the possible role and relationship between Th17 and T-regs in vitiligo by measuring tissue, systemic levels of interleukin (IL)-17, IL-22 and Forkhead box P3. Patients and methods: 84 non-segmental vitiligo patients and 80 controls were included. Vitiligo Area Scoring Index, Vitiligo Disease Activity and stress score were determined. Skin biopsies underwent immunohistochemical staining for IL-17, IL-22 and FoxP3 and their systemic levels were determined by ELISA and quantitative real time PCR. Results: Mean area % of +ve immunostaining and serum levels of IL-17 (34.12 +/- 5.12, 23.62 +/- 8.17 pg/mL) and IL-22 (48.63 +/- 19.23, 43.53 +/- 11.95 pg/mL) were significantly higher in patients compared to controls (15.33 +/- 4.19, 12.83 +/- 3.29 pg/mL) (13.44 +/- 3.82, 9.92 +/- 4.7 pg/mL) (P < 0.001). Mean area % of +ve immunostaining and peripheral blood levels of FoxP3 were significantly lower in patients (2.67 +/- 0.54, 0.574 +/- 0.32) compared to controls (7.12 +/- 0.18, 1.48 +/- 0.49) (P < 0.001). In patients, a positive correlation between IL-17 and IL-22 was detected (r = 0.671, P < 0.001), each showing negative correlation with FoxP3 (r = -0.548, P < 0.001), (r = -0.382, P < 0.001). VASI, VIDA and stress score correlated positively with IL-17, IL-22 and negatively with FoxP3. Conclusion: Th17 and T-regs are intertwined in the complexity of vitiligo giving hope of treatment through adjuvant therapies controlling the delicate balance between them.