Restricted specificity of anti-ribosomal P antibodies ot SLE patients in Israel

Objective. Anti-ribosomal P antibodies (aRib-P Ab) are highly specific for systemic lupus erythematosus (SLE), but their correlatation with disease activity and manifestations including renal, hepatic and central nervous system (CNS) involvement is still controversial. The aim of our study was to evaluate the prevalence of aRib-P Ab and their correlation with clinical manifestations and anti-dsDNA antibodies in SLE patients from Israel. Methods. Elevated titers of aRib-P Ab utilizing the ELISA method were analyzed in 141 sera samples from 44 SLE patients, 20 Familial Mediterranean Fever (FMF) patients, 22 primary anti-phospholipid syndrome (PAPS) patients, 12 patients with infections, and 43 healthy individuals. The SLEDAI score was utilized for assessing SLE disease activity. Results. Elevated titers of aRib-P Ab were present in 11% of SLE patients (n = 6). The mean SLEDAI was 7 (range: 3-10). No statistically significant association was observed between the presence of aRib-P Ab and disease manifestations present in the SLEDAI. The 6 SLE patients had renal disease (n = 1), leucopenia (n = 1), rash (n = 3), and CNS involvement manifested as psychosis (n = 1) or depression (n = 1). Elevated titers of anti-dsDNA antibodies were found in 50% of patients with elevated titers of aRib-P Ab. Patients with PAPS, FMF, infections or healthy controls did not harbor elevated titers of aRib-P Ab. Conclusion. Elevated titers of aRib-P Ab were restricted to SLE patients. We confirm previously reported associations of aRib-P Ab reactivity with disease activity and elevated anti-dsDNA Ab titers. No significant correlation with a specific manifestation described on the SLEDAI score was established in this small cohort of patients.