QUANTIFICATION OF ANTIRIBOSOMAL PO PROTEIN ANTIBODIES BY ELISA WITH RECOMBINANT PO FUSION PROTEIN AND THEIR ASSOCIATION WITH CENTRAL-NERVOUS-SYSTEM DISEASE IN SYSTEMIC LUPUS-ERYTHEMATOSUS

Objective. Using solid phase ELISA with recombinant PO fusion protein as the antigen for detecting antiribosomal PO protein antibody, we ana lyzed the association of this antibody and anticardiolipin antibody (a CL) with central nervous system (CNS) disease in patients with active systemic lupus erythematosus (SLE). Methods. Sera from 70 randomly sel ected Japanese patients with active SLE were assayed for IgG and IgM a ntiribosomal PO protein antibody titers and IgG aCL.Results. IgG and I gM antiribosomal PO protein antibodies were present in 29 and 12 (41.4 and 17.1%) of the 70 patients, respectively. The incidence of CNS dis ease, excluding lupus psychosis, was sig significantly higher in patie nts with Ige and IgM antiribosomal PO protein antibodies than in those who lacked them (IgG antiribosomal PO protein antibody 11/29 vs 3/41; IgM antiribosomal PO protein antibody 7/12 vs 7/58). In addition, bot h IgG and IgM antiribosomal PO protein antibody titers were significan tly higher in patients with CNS disease, excluding lupus psychosis, th an those without. No significant association was observed between anti ribosomal PO protein antibodies and lupus psychosis. No significant as sociation was observed between IgG aCL and CNS disease. Serial studies of antiribosomal PO protein antibodies and aCL in patients with trans verse myelopathy also showed that IgG and IgM antiribosomal PO protein antibodies, but not IgG aCL, were associated with CNS disease, exclud ing lupus psychosis. Conclusion. These data suggest a strong associati on of IgG and IgM antiribosomal PO protein antibodies with CNS disease , excluding lupus psychosis, in SLE.