Development of systemic lupus erythematosus in a rheumatoid arthritis patient with anti-ribosomal P protein antibody

Abstract
We describe a patient with rheumatoid arthritis (RA) whose sera contained a high titre of an antibody targeting cytoplasmic ribosomal P proteins (anti-P). This association preceded by 6 years the development of serological and clinical manifestations of systemic lupus erythematosus (SLE). The clinical significance of anti-P for the diagnosis of SLE is discussed.