Prevalence of autoantibodies to ribosomal P proteins in juvenile-onset systemic lupus erythematosus compared with the adult disease

Abstract

Objective. To determine the prevalence of anti-ribosomal P (anti-P) proteins in several groups of patients with juvenile-onset systemic lupus erythemato-sus (SLE) in comparison with the prevalence in adult SLE. Methods. Serum samples were pooled together from 3 cohorts of patients with juvenile-onset SLE in 3 different medical centers and from a miscellaneous group of juvenile-onset SLE patients whose samples were sent by regional physicians. Sera were studied for the presence of anti-P using 2 assays: Western blot with ribosomes as antigen, and an enzyme-linked immu-nosorbent assay with the COOH-terminal 22 amino acids of the ribosomal P protein in a multiantigenic peptide format as antigen. Sera found positive by both tests were considered positive for anti-P antibodies. Findings from similar studies involving a large cohort of patients with adult-onset SLE from Oklahoma City were used for comparison. Results. The prevalence of anti-P antibodies in the pooled sample of juvenile-onset SLE sera was 45 of 108, or 42%, while in the adult cohort from Oklahoma City, 20 of 260, or 7.7%, were positive for anti-P (odds ratio [OR] 9.6, P < 10 8 by Fisher's exact test). In addition, it was shown that 12 of 13 patients with both anti-P and anti-double-stranded DNA (anti-dsDNA) in the juvenile SLE cohort had nephritis, while only 8 of 22 patients without both antibodies were nephritic (OR 21.0, P < 10 8). It was also shown that in 9 illustrative cases, the levels of anti-P and anti-dsDNA antibodies usually varied together and in concordance with the clinical activity as measured by the SLE Disease Activity Index (SLEDAI). Finally, anti-P-positive and anti-P-negative patients had a similar prevalence of anti-dsDNA, anti-Ro/SSA, and anti-La/SSB antibodies, but patients with anti-P had a higher prevalence of anti-U1 RNP and anti-Sm (P 0.041 and P 0.0385, respectively , by Fisher's exact test). Conclusion. Antibodies to ribosomal P protein are more prevalent in juvenile-onset SLE than in adult-onset SLE. Levels of antibodies to ribosomal P protein vary with the clinical disease activity as measured by the SLEDAI, often in concordance with the levels of anti-dsDNA. The presence of both anti-P and anti-dsDNA antibodies was powerfully associated with nephritis in the cohort of patients for whom comprehensive clinical and serologic data were available.

An Anti-nuclear Antibody-negative Patient with Systemic Lupus Erythematosus (SLE) Accompanied with Anti-ribosomal P Antibody (anti-P).

“…Recurrent fetal loss due to thrombosis of the placenta is one of the most prominent symptoms ofAPS (8). Anti-ribosomal P antibodies (anti-P), one of the anti-cytoplasmic antibodies, have also been found in patients, with a prevalence of 5 to 42% (9)(10)(11)(12)(13)(14). Anti-P is believed to be associated with neuropsychiatric disorders (12,15,16), as well as liver and kidney lesions in patients with SLE (17, 18).…”

International Multicenter Evaluation of Autoantibodies to Ribosomal P Proteins

“…Moreover, it was suggested that anti-Rib-P antibodies are more prevalent in juvenile-onset SLE than in adult-onset SLE (27). An association of anti-Rib-P with neuropsychiatric manifestations of SLE (NPSLE) has been more controversial (1,4,5,11,12,15,19,25,29,31).…”

Pathogenesis of neurocognitive and neuropsychiatric manifestations in childhood-onset lupus: an overview

“…[72][73][74][75][76] The few pediatric NPSLE studies so far have only demonstrated a higher prevalence of these and anti-dsDNA and anti-Sm antibodies, in childhood than adult onset SLE without any clear causal or pathogenic association yet elucidated. 4,77,78 Our group at University College London (UCL), recently described the observation that serum anti-Sm antibodies levels correlate positively with higher levels of nitrated nucleosomes, a serum marker of nitrosative stress, as measured by a novel capture ELISA. From our small number of patients with SLE from the UCL Hospital Lupus Cohort, we also made an observation that nitrated nucleosome levels significantly correlated with SLE disease activity and also significantly correlated with NPSLE involvement as per validated BILAG and ACR classification evaluation.…”