TNF and vitiligo: Since we know systemic tetracyclines can reduce production of proinflammatory cytokines such as TNF-alpha and IL-1 [10], and these cytokines are high in the epidermis of vitiliginous skin [3], may cause damage to melanocytes, inhibit melanocyte stem cells differentiation, and induce various apoptotic pathways [13], we decided to test topical tetracycline that might be beneficial against vitiligo and has less side effects than systemic agents.