Quantification of antiribosomal P0 protein antibodies by ELISA with recombinant P0 fusion protein and their association with central nervous system disease in systemic lupus erythematosus.

OBJECTIVE

Using solid phase ELISA with recombinant P0 fusion protein as the antigen for detecting antiribosomal P0 protein antibody, we analyzed the association of this antibody and anticardiolipin antibody (aCL) with central nervous system (CNS) disease in patients with active systemic lupus erythematosus (SLE).

METHODS

Sera from 70 randomly selected Japanese patients with active SLE were assayed for IgG and IgM antiribosomal P0 protein antibody titers and IgG aCL.

RESULTS

IgG and IgM antiribosomal P0 protein antibodies were present in 29 and 12 (41.4 and 17.1%) of the 70 patients, respectively. The incidence of CNS disease, excluding lupus psychosis, was significantly higher in patients with IgG and IgM antiribosomal P0 protein antibodies than in those who lacked them (IgG antiribosomal P0 protein antibody 11/29 vs 3/41; IgM antiribosomal P0 protein antibody 7/12 vs 7/58). In addition, both IgG and IgM antiribosomal P0 protein antibody titers were significantly higher in patients with CNS disease, excluding lupus psychosis, than those without. No significant association was observed between antiribosomal P0 protein antibodies and lupus psychosis. No significant association was observed between IgG aCL and CNS disease. Serial studies of antiribosomal P0 protein antibodies and aCL in patients with transverse myelopathy also showed that IgG and IgM antiribosomal P0 protein antibodies, but not IgG aCL, were associated with CNS disease, excluding lupus psychosis.

CONCLUSION

These data suggest a strong association of IgG and IgM antiribosomal P0 protein antibodies with CNS disease, excluding lupus psychosis, in SLE.