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

OBJECTIVES: This study was conducted to determine autoantibodies associated with lupus nephritis (LN), especially those useful in diagnosing proliferative and membranous nephritis. METHODS: A total of 106 patients with LN and 63 patients with systemic lupus erythematosus but no nephritis were enrolled; then, 55 patients were selected from the LN 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-double-stranded DNA antibody and anti-histone antibody was seen in LN patients compared to nonrenal systemic lupus erythematosus patients. In comparing between proliferative and membranous nephritis, the positivity of anti-nucleosome antibody was higher in proliferative nephritis, although it was not statistically significant. However, anti-nucleosome antibody-positive patients with LN had a higher prevalence of haematuria 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 that anti-nucleosome and anti-RNP70 antibodies may be predictive nonhistological factors for discriminating between proliferative and membranous LN.