Collagen Vascular Disease

Abstract

Collagen vascular diseases (CVDs) are a heterogeneous group of multisystem autoimmune disorders characterized by the presence of autoantibodies. It is generally accepted that the initiation and progression of CVDs, including lupus erythematosus, systemic sclerosis, and dermatomyositis, are caused by the complex interplay between environmental and intrinsic factors. The presence of autoantibodies and autoantigens derived from dying cells, such as keratinocytes in cutaneous lupus erythematosus and dermatomyositis and endothelial cells in systemic sclerosis, is a common pathological feature shared among these diseases, which leads to the activation of interferon-dependent signalings because immune complexes consisting of autoantibodies and autoantigens promote type I interferon production especially from plasmacytoid dendritic cells. Type I interferon potentially induces autoimmunity by activating innate and adaptive immunity. In addition, interferon directly induces apoptosis as well as vascular damage, two histologic hallmarks of CVDs in the skin. Note that recent progress provides new insights into the better understanding of the disease-specific pathological process connecting the initial events, cell death of keratinocytes or endothelial cells, with the progressive tissue damage via innate and adaptive immune responses. In this chapter, the role of skin immunology in the pathogenesis of cutaneous lupus erythematosus, scleroderma, and dermatomyositis is overviewed.