Ribosomal P is located in the cytoplasm. The detection of antibodies is to the 60 kda fraction. Anti-ribosomal P antibodies are highly specific for systemic lupus erythematosus (SLE), and are detected at a 15–20% frequency according to the literature. Elevated anti-ribosomal P titers correlate with disease activity and are specifically associated with neuropsychiatric disease such as psychosis/depression. and coexist with anti-dsDNA antibodies. The aim of our study was to evaluate the frequency of anti-ribosomal P antibody titers and the correlation with manifestations in SLE patients.

Sera samples from 174 individuals were evaluated for titers of anti-ribosomal P antibodies: 77 samples from SLE patients, 22 patients with antiphospholipid syndrome (APS), 20 patients with familial Mediterranean fever, 12 patients with infections, and 43 healthy controls. Anti-ribosomal P antibody titers were tested by ELISA. Manifestations of SLE at the time of serum sampling were determined by the SLEDAI score.

Six SLE patients (11%) harbored elevated anti-ribosomal P antibody titers. Five SLE patients were females, mean age 44.3 years (range, 18–73 years old), and the mean SLEDAI mean score was 7 (range, 3–10) indicating moderate disease. Elevated titers of anti-dsDNA were detected in 50% of SLE patients with elevated anti-ribosomal P antibodies. One patient had secondary APS. One patient with elevated titers of anti-ribosomal had renal disease and psychosis. Three patients had a rash, while none of the patients had arthritis or leukopenia. Anti-ribosomal P titers were not elevated in patients with primary APS, familial Mediterranean fever, infections, or in healthy controls.

The prevalence of elevated titers of anti-ribosomal P antibodies was restricted to SLE patients. No correlation with a specific manifestation was found.