Anti-C1q Autoantibodies in Lupus Nephritis: Prevalence and Clinical Significance

Recently, anti-C1q autoantibodies have been proposed as a useful marker in systemic lupus erythematosus (SLE) since their occurrence correlates with renal involvement and, possibly, with nephritic activity. We aimed to evaluate the prevalence of anti-C1q antibodies in patients with SLE, with and without renal involvement, and to correlate these markers' presence and levels with the activity of the disease and nephropathy. We studied 61 patients with SLE, 40 of whom had biopsy-proven lupus nephritis; 35 patients with other connective tissue diseases; and 54 healthy controls. In addition, 18 lupus nephritis patients were followed up during the disease time course. Anti-C1q antibodies were mea…