Estimation Of Serum S100b Levels In Vitiligo To Determine Whether Increased Levels Are A Marker Of Disease Activity; A Prospective Case-Control Study

Abstract

Introduction: Vitiligo is an autoimmune disorder which is characterized by progressive destruction of melanocytes and clinically presents as hypopigmented or depigmented lesions. The exact mechanism remains unclear but there is a definitive part that cell mediated immunity plays in the pathogenesis of vitiligo A member of the family of S100 proteins, S100B protein is a damage-associated molecular pattern protein that is expressed in melanocytes and has been proposed as a potential marker of melanocyte cytotoxicity. Aim: To measure serum levels of S100B in cases of vitiligo and to correlate those levels with the activity and extent of the disease and to those of controls. Materials and methods: It is a hospital-based prospective case control study. Patients with characteristic clinical features of vitiligo irrespective of age, gender and on-going or previous treatment were included, whereas patients with any other co-existing chronic inflammatory disorders, any active cutaneous or systemic infections, co-morbidities, history of smoking, history of recent head injury, malignant melanoma, congenital and acquired causes of depigmentation disorders were excluded. After taking a complete history and performing physical examination, the severity of vitiligo was assessed with Vitiligo Disease Activity Score and the extent was calculated using Vitiligo Area Severity Index. Serum S100B levels were measured Results: A moderate, statistically significant correlation was found between VIDA and S100B levels (p=0.001), There was an absolute absence of correlation between VASI and S100B levels (p=0.0708) There was a statistically significant correlation between active disease (disease activity in past 6 months) and S100B levels (p=0.001) when compared to stable disease. Patients who were subjected to immunosuppressive therapy had lower serum S100B levels relative to patients who received no therapy (p=0.0027). S100B values in healthy control subjects were not significantly different compared with stable vitiligo patients (p=0.2752), While patients with active disease showed significantly high mean values of S100B compared to controls (p=0.0052). The patients not on immunosuppressive therapy showed higher mean S100B levels when compared with controls, (p=0.0046), while those on immunosuppressive therapy did not show higher mean S100B levels when compared to controls (p=0.1192). Conclusion: The moderate correlation between VIDA and S100B highlights that S100B levels are elevated during the active depigmenting phase and the findings of increased S100B levels amongst patients not on immunosuppressive therapy highlights that not just disease activity but also treatment status of patients should be considered while evaluating S100B levels in such conditions.