Autoantibodies in lupus nephritis useful in distinguishing proliferative nephritis from membranous nephritis.

OBJECTIVES
This study was conducted to determine autoantibodies associated with lupus nephritis, especially those useful in diagnosing proliferative and membranous nephritis.


METHODS
106 patients with lupus nephritis and 63 patients with SLE but no nephritis were enrolled. 55 patients were selected from the lupus nephritis group and were divided into two groups: proliferative nephritis patients (n=36) and membranous nephritis patients (n=19). The autoantibody profiles of patients' sera were evaluated using the EUROLINE ANA profile 3 (IgG) kit.


RESULTS
A higher positivity rate of anti-dsDNA antibody and anti-histone antibody were seen in lupus nephritis patients compared to non-renal SLE patients. In comparing between proliferative and membranous nephritis, positivity of anti-nucleosome antibody was higher in proliferative nephritis compared to membranous nephritis, although it was not statistically significant. However, anti-nucleosome antibody-positive patients with lupus nephritis had higher prevalence of hematuria and pyuria, which are strong indications of proliferative nephritis. Also, a significantly higher positivity rate of anti-RNP70 antibody was seen in membranous nephritis compared to proliferative nephritis.


CONCLUSIONS
Our results showed anti-nucleosome antibody and anti-RNP70 antibodies may be predictive non-histological factors for discriminating between proliferative and membranous lupus nephritis.