Assessment of tissue expression of matrix metalloproteinase-9 level in patients with vitiligo and its relation to disease pattern, activity, and severity

Background Vitiligo is a common acquired depigmentary disorder characterized by milky-white cutaneous macules devoid of identifiable functional melanocytes of unknown origin. Several hypotheses have been advanced to explain the link between matrix metalloproteinase-9 (MMP-9) and vitiligo. Aim We aimed to compare the tissue expression of MMP-9 in vitiligo lesions with that of healthy controls. Patients and methods A case–control study was performed to evaluate MMP-9 levels by punch biopsies using an immunohistochemistry technique in lesional and nonlesional tissues of the same patient with vitiligo and in comparison with healthy controls. The study included 20 patients (10 patients with vitiligo and 10 healthy controls). Patients included were 18 years of age and older of both sexes, any duration, and any subtype. Results MMP-9 expression was found to be lower in the lesional skin of patients with vitiligo at the basal cell layer, follicular epithelium, and stromal cell layer when compared with nonlesional skin of the same patient with vitiligo and matched control individuals. Conclusion Tissue MMP-9 imbalance has a role in the etiopathogenesis of vitiligo. The low MMP-9 tissue expression may not facilitate the migration of melanoblasts. Tissue MMP-9 is a significant predictor of severity of vitiligo.