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

Arthritis Rheum. 1999 Jan;42(1):69-75. doi: 10.1002/1529-0131(199901)42:1<69::AID-ANR9>3.0.CO;2-J.


Objective: To determine the prevalence of anti-ribosomal P (anti-P) proteins in several groups of patients with juvenile-onset systemic lupus erythematosus (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 immunosorbent 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.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Age of Onset
  • Autoantibodies / blood
  • Child
  • Cohort Studies
  • Humans
  • Lupus Erythematosus, Systemic / epidemiology*
  • Lupus Erythematosus, Systemic / immunology*
  • Lupus Nephritis / immunology
  • Prevalence
  • Ribosomal Proteins / immunology*
  • Severity of Illness Index


  • Autoantibodies
  • Ribosomal Proteins