The humoral immunity to epidermal and dermal antigens in psoriasis: a downstream rather than an upstream event

Excerpt

The presence of immunoglobulin G (IgG) and complement in upper epidermis of psoriatic skin lesions has been reported for more than 40 years [1, 2]. Recently, a number of antigenic proteins have been observed in psoriatic skin lesions, in association with IgG and complement deposition [3]. Some of them have increased levels in both skin and serum samples of psoriatic patients [4, 5]. However, functional validation and systematic analysis of epidermal antigens that immunoreact to IgG from psoriatic serum are very scarce. Moreover, it is still unclear whether antigen-autoantibody interaction in psoriatic skin lesions is an upstream event (i.e., an early or primary mechanism that subsequently causes disease pathogenesis) or only a downstream phenomenon (i.e., a secondary effect or consequence of psoriatic plaque formation, which can induce secondary humoral immunity to the exposed epidermal antigens). Hence, this hazy mechanism of antigen recognition in psoriatic skin should be elucidated. …