Objectives The aim of the study was to assess the levels of the antibody to C1q complement component (anti-C1q) in the sera of patients (pts) with lupus nephritis (LN) in relation to the clinical activity of SLE during anti-B-cell therapy with Rituximab (RTM).
Methods The study involved 41 pts with definiteSLE (3 male, 38 female; mean age Me 27,5[22-36]).The concentration of anti-C1q in the blood were determined by immunoenzyme methods. Associations between levels of anti-C1q antibodies and parameters of LN were statistically analyzed. Patients were divided into 2 groups: those with LN (n=25) and without renal involvement (n=16).Marked highly positive (>30U/ml), low positive (10-30U/ml) and negative (≤10U/ml) levels of anti-C1q.
Results In pts with LN highly positive levels of anti-C1q occurred significantly more frequently than in pts without renal involvement (p=0.04). The majority of pts without LN had negative and low positive levels anti-C1q. In the group of 25 pts with nephritis in 7 were highly positive levels of anti-C1q, and in the rest of pts were found negative and low positive levels of anti-C1q. In pts without nephritis (n=16) in only one was detected highly positive anti-C1q.
In patients with nephritis in a month after treatment with RTM was observed a significant decrease of levels of anti-C1q (p=0.002), which persisted through a year after treatment with RTM (p=0.006). There was no association between SLE activity index SLEDAI 2K and the level of anti-C1q before initiating therapy.
Conclusions The results of recent studies suggest that there is a link between the presence of highly positive levels of anti-C1q Abs and kidney involvement in SLE. As a result of therapy with RTM revealed a significant decrease of levels of anti-C1q Abs.
Disclosure of Interest None Declared