Clinical manifestation of systemic lupus erythematosus in patients with antiribosomal P protein antibodies

INTRODUCTION: Antibodies against ribosomal P protein (anti‑P) are detected predominantly in patients with systemic lupus erythematosus (SLE). However, the data on their frequency and clinical relevance remain inconclusive. OBJECTIVES: The aim of the study was to assess the frequency as well as clinical and serological relevance of anti‑P autoantibodies in Polish patients with SLE and to determine the significance of these antibodies in the diagnosis of SLE. PATIENTS AND METHODS: Anti‑P antibody levels were measured in the sera of 100 SLE patients using an enzyme‑linked immunosorbent assay and Western blotting. All patients underwent a routine clinical and laboratory evaluation. Disease activity was assessed using the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) score. RESULTS: Anti‑P antibodies were detected in 14 of 100 patients. When compared to anti‑P‑negative patients, this group was characterized by earlier onset of SLE, higher disease activity, more frequent occurrence of fever and facial erythema, decreased serum levels of complement, and elevated levels of alanine and aspartate aminotransferases. In 2 cases, anti‑P antibodies were the only serological marker of SLE detected in these patients. CONCLUSIONS: SLE with the presence of anti‑P antibodies is characterized by an early onset and high disease activity.