Convergence Theory
The convergence theory attempts to link together the potential causal mechanisms of vitiligo [210]. It suggests multiple sequential stages in pathogenesis beginning with an elicitation stage perhaps due to mechanical friction and skin trauma, emotional stresses, chemical exposure or imbalances in endogenous neural factors, metabolites, cytokines or hormones [5, 206, 211-214]. Such factors, in an individual whose genetic make-up predisposes to immune activation and melanocyte destruction, it is proposed result in oxidative stress within melanocytes which subsequently express HSP70 and chaperoned melanocyte antigens, presented by dendritic cells to T cells in regional lymph nodes, resulting in proliferation of melanocyte-specific cytotoxic T cells and melanocyte destruction — the stage of immune activation [54, 135, 166].
Absent or reduced fully-functional skin-infiltrating Tregs contribute to the on-going immune response and disease spread [86]. Antibodies against melanocyte-specific proteins such as tyrosinase, generated in response to melanocyte destruction, damage pigment cells by activating complement or by antibody-dependent cellular cytotoxicity [122, 133].