AUTOANTIBODIES AGAINST CALPASTATIN IN SERA FROM PATIENTS WITH SYSTEMIC-SCLEROSIS

Objective. To determine the prevalence and clinical correlation of ant i-calpastatin antibodies in patients with systemic sclerosis (SSc). Me thods. Serum samples from patients with limited cutaneous SSc (ISSc; n = 36), diffuse cutaneous SSc (dSSc; n = 27), and healthy control subj ects (n = 29) were examined by an ELISA using human recombinant calpas tatin as antigens. Results. IgG anti-calpastatin antibodies were posit ive in 15 (24%) of 63 patients with SSc, which was similar to the freq uency of IgM anti-calpastatin antibody positivity (14/63, 22%). The pr esence of anticentromere antibodies was associated with the presence o f IgG and/or IgM anti-calpastatin antibodies. The patients with SSc po sitive for IgG anti-calpastatin antibodies had significantly higher er ythrocyte sedimentation rates (ESR) compared with those negative for I gG anti-calpastatin antibodies. Furthermore, the levels of IgG anti-ca lpastatin antibodies correlated positively with the levels of ESR. The patients with dSSc positive for IgM anti-calpastatin antibodies had s ignificantly higher frequency of inflammatory joint and muscle involve ment compared with those negative for IgM anti-calpastatin antibodies. Four (80%) of 5 patients with dSSc with both joint and muscle involve ment produced IgM anti-calpastatin antibodies. Conclusion, The presenc e of anti-calpastatin antibodies may be a clue to mechanisms of the in flammatory change occurring in SSc. Furthermore, the presence of anti- calpastatin antibodies could be a novel and useful serologic tool for recognizing patients with dSSc with inflammatory joint and muscle invo lvement.