Role of Calreticulin Autoimmunity in the Pathogenesis of Photosensitive Cutaneous Lupus Erythematosus

Skin disease in lupus erythematosus (LE) patients can be divided into two categories: lesions that have a histopathology that is specific for LE (LE-specific skin disease), and lesions that have a histopathology that can be seen in disorders other than LE (LE nonspecific skin disease). Examples of LE-specific skin disease include acute cutaneous LE (e.g., butterfly rash), subacute cutaneous lupus erythematosus (SCLE), and chronic cutaneous LE (e.g., discoid LE). Cutaneous small-vessel leukocytoclastic vasculitis manifested clinically as dependent palpable purpura or urticarial vascultis would be an example of LE-nonspecific skin disease. The etiology and pathogenesis of LE-specific skin disease is thought to be a direct manifestation of the underlying systemic autoimmune process that is responsible for systemic LE (SLE). Comprehensive overviews of the etiopathogenesis of LE-specific skin disease have recently been presented elsewhere (1–3).