Lack of clinical association with antibodies to ribosomal P proteins in Indian patients with systemic lupus erythematosus

Abstract

Objective: We examined the prevalence and clinical association of the antiribosomal antibodies in our cohort of patients with systemic lupus erythematosus (SLE). Methods: IgG antiribosomal P protein (anti-P) antibodies were detected in 202 consecutive patients with SLE and 212 age and sex matched healthy subjects by an in-house ELISA, using the 22-mer C-terminal peptide. In 13 patients, IgG anti-P antibodies were also tested in paired cerebrospinal fluid (CSF) and sera samples. Clinical variables were compared in the antibody-positive and negative groups using appropriate statistical tests. Results: Of the 202 patients, 15 were male. Their median age was 30 years and the median disease duration was 36 months. Thirty-one patients (15.35%) were positive for IgG anti-P antibodies, of which 24 were also positive by Western blot. No association with SLE Disease Activity Index, nervous system disease, nephritis, hepatitis, skin disease, arthritis, and juvenile onset disease could be demonstrated. Levels of IgG anti-P antibodies in CSF were 100-fold less compared to levels in serum, and correlated well with the latter (r = 0.86; p < 0.01). Conclusion: The prevalence of IgG anti-P antibodies is similar in Indian and Caucasian patients with SLE. No association with specific organ involvement or age at onset could be demonstrated.