Antibodies against nuclear components in schistosomiasis. Results compared to values in patients with rheumatoid arthritis, systemic lupus erythematosus, and osteoarthrosis.

Occurrence of autoantibodies against nuclear material was compared in groups of patients with rheumatoid arthritis (RA n = 22), systemic lupus erythematosus (SLE n = 24), osteoarthrosis (OA n = 25), and chronic schistosomiasis mansoni (CSM n = 28). Anti-ds DNA antibody was detected by an ammonium sulphate precipitation radioimmunoassay antibodies against extractable nuclear antigen (ENA) were detected and differentiated in RNAse-resistant and RNAse-sensitive components (Sm and RNP antigens) with an ELISA technique. IgG organ-non-specific and granulocyte-specific antinuclear antibodies (ANA) were detected by immunofluorescence technique with quantitative titration of positive reactions and determination of complement-fixing properties. The results in groups of patients with SLE, RA and OA were of confirmative nature and supported that the different methods detect different systems of autoantibodies and nuclear autoantigens. In CSM it was demonstrated that 23 of 28 cases had positive reactions to the RNAse-resistant part of ENA (the Sm-antigen), a significant difference from the three other groups of patients (P less than 0.001). The antibody was in all cases of IgM class, in seven cases also of IgA class. Antibodies against nuclear material in CSM are probably a consequence of heavy disturbance of the immune system in this chronic infection with great permanent antigen load. It is a matter of discussion, whether production of these antibodies is induced by nuclear material from the host or from the parasite.