Терапевтический архив (May 2013)
Anti-C1q antibodies in patients with systemic lupus erythematosus treated by rituximab
Abstract
AIM: To determine the time course of changes in the blood levels of antibodies (Ab) to complement component C1q (a-C1q) in patients with systemic lupus erythematosus (SLE) during rituximab (RTM) therapy and the association with organ injuries in SLE/MATERIAL AND METHODS: The study involved 41 patients (3 men and 38 women; their median age was 27.5 (range 22-36) years) with definite SLE. Their blood a-C1q levels were determined by enzyme immunoassay. The levels and detection rates of a-C1q were estimated in relation to organ injuries, the time course of RTM therapy-induced changes in a-C1q levels were determined. High-positive (>30 U/ml), low-positive (10-30 U/ml), and negative (≤10 U/ml) a-C1q levels were found/RESULTS: A-C1q was detected in 19 (46.3%) patients with different clinical manifestations of SLE. The patients with renal diseases had high-positive levels of a-C1q statistically significantly more frequently than those without renal involvement (p=0.04). Low-positive and negative a-C1q levels were found in 15 of 16 without nephritis. There was a statistically significant positive correlation of the concentration of a-Clq with Ab to double-stranded DNA (a-dsDNA), Ab to nucleosomes, the SLE Disease Activity Index 2000 (SLEDAI-2K), erythrocyturia, hematuria and a negative correlation between a-C1q and complement components C3 and C4. Just after one month of RTM therapy, the patients with nephritis were observed to have a statistically significant decrease in the levels of a-C1q (p=0.002), which persisted 1 year after the treatment (p=0.006). Nineteen patients with the higher baseline concentrations of a-C1q after RTM treatment showed a statistically significant decrease in the levels of a-C1q at 1-, 3-, 6-, and 12-month follow-up (p=0.016, 0.02, 0.035, and 0.04, respectively) which was accompanied by the decreased SLEDAI-2K (p
