Autoantibodies to ribosomal P proteins in systemic lupus erythematosus

Autoantilbodies to ribosomal P proteins (anti-P) are directed against three ribosomal phosphoproteins (P0, P1, and P2) and are believed to be specific markers for systemic lupus erythematosus (SLE), particularly with neuropsychiatric manifestations. The objective of this study was to determine the rate of occurrence and clinical significance of anti-P in Tunisian patients. Methods. We included 100 Tunisian patients with SLE whose sera were received between January 1998 and December 2000 by the immunology laboratory of the Charles Nicolle Teaching Hospital in Tunis, Tunisia, and were tested for anti-P. An immunodot technique based on a synthetic protein shared by all ribosomal phosphoproteins was used. Results. Sera from 22 (22%) patients were positive for anti-P. This rate is consistent with the literature. We found no statistically significant associations between anti-P and specific manifestations of SLE. Conclusion. We found that anti-P were significantly associated with anti-Sm and anti-RNP, as reported previously. The significance of these associations remains debatable.