AUTOANTIBODIES TO AUTOLOGOUS SKIN IN GUTTATE AND PLAQUE FORMS OF PSORIASIS AND CROSS-REACTION OF SKIN ANTIGENS WITH STREPTOCOCCAL ANTIGENS

Background Psoriasis is a chronic disease of the skin that appears to be of autoimmune nature. It has a strong association with throat strep tococcal infections, as well as with stressful events. Although many g roups consider psoriasis to be a T-cell-mediated autoimmune disease, a utoantibodies could also play a role in the development of this proces s. Methods In this work, we looked for autoantibodies to psoriatic ski n in 21 psoriatic patients and four healthy donors (controls). The imm unoperoxidase technique was used to look for autoantibodies in autolog ous sera in skin sections obtained from lesions or from healthy areas of the same patient, before and after immunoadsorption with a Streptoc occus pyogenes extract. The skin biopsies were also analyzed with a po ol of sera from mice immunized with the streptococcal extract. Results We found that all psoriatic patients bad autoantibodies to antigens p resent in keratinocytes, whereas healthy subjects did not. These antib odies did not recognize epitopes on healthy skin from the same psoriat ic patients or controls. Immunoadsorption of autologous sera removed t he reactivity to antigens in skin lesions in all cases. Mouse anti-str eptococcal sera recognized epidermal antigens present in lesional psor iatic skin, but not in healthy skin from psoriatic patients or control s. Deposits of immunoglobulin G (IgG) were not detected in the lesions . Conclusions It seems that autoantibodies, although they do not appea r to participate in the pathogenesis of psoriasis, are an important fe ature, and that skin antigens, which appear in lesional immature kerat inocytes, cross-react with S. pyogenes and contribute to the autoimmun e process in psoriasis.