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 < 0.05) with an odds ratio of 11.11 (CI95% of 4.33-28.49). The PP infected with S.pyogenes had higher titers of the antirHSP60Sp, high ASO, and high PASI. The PP patients did not significantly recognize the HSP60Ec or the HSP60Hu. The GP patients had a higher response to the rHSP60Sp than the healthy controls or ISp patients (P < 0.05) but showed no association with the disease. The response of the ISp patients to the HSP60Sp was similar to the healthy controls. The response to the rHSP70Sp was similar in the PP patients and the healthy controls. Conclusion. Results suggest that a high response to the HSP60Sp could be associated with the chronic form of psoriasis.