IgG class antibodies from psoriasis patients recognize the 60-KDa heat-shock protein of Streptococcus pyogenes

Background We have previously found that psoriatic patients have IgG autoantibodies that recognize lesions but not autologous normal skin. The reactivity of the autoantibodies can be adsorbed with streptococcal antigens. Methods IgG antibodies were determined by immunoblot and ELISA to streptococcal antigens and by ELISA to the recombinants HSP60Sp, HSP70Sp, HSP60Ec and HSP60Hu, in plaque (PP) and guttate (GP) psoriasis patients, in healthy subjects (HC) and in individuals with streptococcal throat infections and high ASO titers, but without history of dermatological disease (ISp). Results We found by immunoblot that the IgG response to 71‐, 60‐, and 14‐kDa protein fractions of Streptococcus pyogenes is important in psoriasis. We also found by ELISA that the response to the rHSP60Sp in PP was higher than in all the other three groups studied (P