Effect of Rituximab on Serum Levels of Anti-C1q and Antineutrophil Cytoplasmic Autoantibodies in Refractory Severe Lupus Nephritis

Abstract

The objective of this study was to analyze and compare the effects of rituximab (RTX) and cyclophosphamide (CTX) on the serum levels of anti-C1q antibodies and antineutrophil cytoplasmic autoantibodies (ANCA) in assessing the prognosis of severe and refractory lupus nephritis (LN). Eighty-four cases of severe and refractory LN were randomly divided into two groups of 42 cases each: CTX group and RTX group (CTX+RTX) during February 2010 to February 2014 in our hospital. Changes in serum levels of anti-C1q antibodies and ANCA in the two groups were examined, and efficacies of the drugs were compared. The total efficacy of RTX group was found to be 83.3 %, which was significantly higher than that of the CTX group, 57.1 % (p < 0.05). The serum anti-C1q antibodies and ANCA were decreased to 11.9 and 26.2 % in the RTX-treated group, which was significantly lower than those observed in the CTX-treated patients (21.4 and 69.0 % respectively) (p < 0.05). The clinical indices of LN were significantly improved in the two groups after the treatment. However, the urinary protein, albumin, complement C3, the percentage of CD19(+)B cells, and SLEDAI scores in the RTX group were significantly lower than those in the CTX group (p < 0.05). RTX plus with CTX showed a better therapeutic efficacy compared to CTX, and it significantly improved the prognosis of refractory and severe LN. The improvement in disease prognosis was directly related to the reduced serum levels of anti-C1q and ANCA measured during the course of treatment suggesting that they can serve to be valuable biomarkers of LN prognosis. Moreover, the measurement can assist in the judgment of RTX efficacy guiding the adjustment of the drug dose to improve the quality of life.

Keywords: Anti-C1q antibodies; Antineutrophil cytoplasmic autoantibodies; Rituximab; Severe lupus nephritis prognosis.