Single anti-P ribosomal antibodies are not associated with lupus nephritis in patients suffering from active systemic lupus erythematosus

Background: In clinical practice, it is sometimes difficult to diagnose a relapse in patients suffering from systemic lupus erythematosus (SLE) and lupus nephritis (LN) having potential complications, including renal failure and death. Some immunological markers can help to determine their association with LN and, therefore, diagnose the early onset of complications.

Objectives: Evaluating the association between systemic and/or kidney activity and anti-P ribosomal and anti-dsDNA antibodies in patients suffering from active SLE.

Methods: 389 patients were evaluated, 140 of whom were subsequently included in the study. The patients were divided into two groups by means of case-control studies, including Colombian patients having American College of Rheumatology (ACR) classification criteria for SLE (1997). The SLE disease activity index (SLEDAI) was applied and all patients presenting an increase of 5 or more compared to their last evaluation, as well as presenting renal manifestations, were considered to be cases; all patients had an activity score. An ELISA kit and the indirect immunofluorescence method with Crithidia luciliae were used for determining the presence of anti-P ribosomal and anti-dsDNA antibodies, respectively.

Results: No association was found between anti-P ribosomal antibodies and LN (p=0.2971) but anti-P ribosomal antibodies showed association with a >5 SLEDAI score (OR=4.87; 1.32-17.98 95% CI; p=0.008). The coexistence of anti-P ribosomal and anti-dsDNA antibodies was associated with LN (OR=3.52; 1.07-13.42 95% CI; p=0.019) and anti-dsDNA was associated with LN (p=0.001).

Conclusion: There was no association between anti-P ribosomal antibodies and LN but anti-P ribosomal antibodies coexisting with anti-dsDNA antibodies was associated with LN, thereby suggesting that the coexistence of two antibodies is nephritogenic to a greater extent. Additional studies are needed to evaluate the coexistence of kidney-specific antibodies in SLE to determine the biological nature of LN.