IGG AUTOANTIBODIES TO COMPLEMENT C1Q IN PEDIATRIC-ONSET SYSTEMIC LUPUS-ERYTHEMATOSUS

Objective. Antibodies to C1q (aC1q) have been found in up to 50% of ad ult patients with systemic lupus erythematosus (SLE) and have been ass ociated with proliferative glomerulonephritis. We investigated the pre valence and clinical significance of aC1q in pediatric SLE. Methods. A ntibodies to C1q, measured by an ELISA method, were evaluated in 29 pa tients with childhood-onset SLE, 26 females and 3 males, aged 7.5 to 1 9.6 years. Results. Seventeen (59%) of the 29 patients were initially positive for aC1q. No correlation was found between either the presenc e or titer of aC1q and any of the clinical manifestations, including n ephritis. However, a significant correlation was observed between aC1q levels and anti-double-stranded DNA antibodies and C3 values. Serial determinations of aC1q in 23 patients showed a progressive decline in the titers with few significant fluctuations. Antibodies to C1q were n ot a reliable predictor of increased SLE activity, since they increase d or became detectable in only 50% of the pre-flare sera. Conclusion. Antibodies to C1q were frequently positive in our patients with pediat ric SLE and were correlated with laboratory variables of disease activ ity, However, unlike in adults with SLE, a high correlation between aC 1q and glomerulonephritis was not found in these pediatric patients.