ANTIBODIES TO HEAT-SHOCK PROTEINS IN PATIENTS WITH PULMONARY SARCOIDOSIS

Serum concentrations of IgG, IgA, and IgM antibodies to three heat sho ck proteins (HSPs) - ubiquitin, HSP70, and HSP90 - were measured using ELISA in 37 patients with pulmonary sarcoidosis. When compared to hea lthy controls (n=44), increased concentrations of IgA and IgG antibodi es to ubiquitin were found in 13 (35.1%, p<0.002) and 7 (18.9%, p<0.05 ) patients, respectively. In 10 patients (27.0%) elevated concentratio ns of Ige antibodies to HSP70 were detected (p<0.02), whereas IgA anti bodies to this protein were found in 7 cases (18.9%, p<0.05), IgM anti bodies to ubiquitin and HSP70, and antibodies to HSP90 were not detect ed in patients' sera. The levels of antibodies to ubiquitin and HSP70 correlated well with each other within the given immunoglobulin class (r=0.7391, p<1E-5 and r=0.9854, p<1E-5 for Ige and IgA class, respecti vely). There was also a weak correlation between the level of IgC anti bodies to HSP70 and both serum activity of angiotensin converting enzy me (SACE; r=0.4668, p<0.005) and serum level of soluble receptor for i nterleukin 2 (sIL-2-R; r=0.4142), p<0.02). A similar tendency was seen with IgG antibodies to ubiquitin. Furthermore, there was an associati on between the increased concentration of C-reactive protein (CRP) and increased levels of IgG antibodies to ubiquitin and HSP70 (p<0.005 an d p<0.05, respectively). Our results suggest that antibodies to variou s HSPs are present in a subset of patients with sarcoidosis. The humor al immune response to HSPs relates probably to the immune activation a nd/or infection.