IGG AUTOANTIBODIES AGAINST C1Q ARE CORRELATED WITH NEPHRITIS, HYPOCOMPLEMENTEMIA, AND DSDNA ANTIBODIES IN SYSTEMIC LUPUS-ERYTHEMATOSUS

We investigated the association between serum titers of IgG antibodies against Clq (ClqAb) and clinical and laboratory variables of disease activity in systemic lupus erythematosus (SLE). ClqAb were measured by ELISA in serum samples of 88 patients. Thirty patients (34%) had increased ClqAb titers. No correlation between ClqAb titers and a score for general disease activity was found. However, significant positive correlations were found between ClqAb titers and the presence of several clinical and laboratory variables of disease activity. These included nephritis, dermatitis, hypocomplementemia, antibodies against dsDNA, and circulating immune complexes. A negative correlation was found with neurological disease manifestations. The correlations between ClqAb titers and clinical features indicate that the pathogenetic role for ClqAb in certain disease manifestations of SLE deserves further study.