Clinical features of anti-ribosomal P protein antibodies in systemic lupus erythematosus: A single-center retrospective study in China

ObjectivesTo investigate the clinical characteristics of patients with systemic lupus erythematosus (SLE) with positive anti-ribosomal P protein antibodies and the associated risk factors in a larger sample size.MethodsA single-center, retrospective study was conducted. Based on the medical records of in-patients from June 2009 to December 2022, patients with SLE were divided into anti-ribosomal P protein antibody-positive and negative groups according to a 1:3 gender and age match.ResultsThis study included 388 patients with SLE, of which 97 (25%) and 291 (75%) were positive and negative for anti-ribosomal P protein antibodies, respectively. The median age of all patients was 35.0 (27.0-48.0) years, and 89.9% were female. The result showed that compared with the patients with anti-ribosomal P protein antibody-negative SLE, those who were positive had lower C3 and C4 levels, more frequent comorbid rashes, and higher disease activity; in terms of autoantibodies, the anti-ribosomal P protein antibodies correlated with anti-Smith and anti-U1RNP antibodies. The result also showed that low C3 levels, anti-U1RNP antibody positivity, and rash are independent risk factors for anti-ribosomal P protein antibody positivity in patients with SLE.ConclusionAnti-ribosomal P protein antibody-positive SLE is characterized by high disease activity; low C3 levels, anti-U1RNP antibody positivity and rashes are independent risk factors for anti-P antibody positivity in SLE.