Serum and Tissue CXCL9 Levels in Patients with Vitiligo Before and After Phototherapy: A Case-Control Study

Background: Vitiligo is a common pigmentation disease that affects 1–2% of the global population. It is a genetic disease that is triggered by an environmental factor resulting in an autoimmune disease. The predominance of the T-helper 1 (Th1) pattern favors the development of vitiligo. Interferon-gamma (IFN-γ) is the most important cytokine that is associated with the Th1 immune response. IFN-γ induces the release of chemokine which is called CXCL9. Objectives: Evaluation of the effects of narrow band ultraviolet B (nbUVB) phototherapy on the serum and tissue levels of CXCL9 among vitiligo patients. Patients and methods: We recruited in our study two groups; one group of twenty patients complaining of nonsegmental vitiligo and the other is a control group composed of another age and sex-matched twenty healthy controls, we assessed the serum level of CXCL9 in all subjects before the study and the patient group was reassessed after treatment with nbUVB for 12 weeks. We also determined tissue level of CXCL9 in patients before and after the phototherapy for 12 weeks from suction blister fluid. Results: We detected that serum levels of CXCL9 were higher in patients with vitiligo compared to healthy matched controls. nbUVB sessions for twelve weeks were done, and we found that serum and tissue levels of CXCL9 after treatment were decreased. Conclusion: Serum and tissue CXCL9 can be used as a marker for disease activity and potentiality for the response to treatment. Therefore, targeting the inhibition of the Interferon-γ-chemokine axis may help in treating the disease activity.