In lupus, serial evaluation of dsDNA antibody titers and complement (C3 and C4) in blood samples have been useful in assessing disease activity in patients. High levels of C3a, a split product of C3, are particularly sensitive and reflective of lupus flares. Our study looks at whether elevations in C3a can predict lupus flares and how C3a compares with other conventional blood indicators such as dsDNA antibody, C3, C4, and CH50. The utility of serial anti-dsDNA antibodies and complement measurements in clinical decision-making for people with systemic lupus erythematosus (SLE) remains controversial. This study has two specific parts designed to address these issues.

In the first, we will take advantage of a unique opportunity to collaborate with a large, multicenter NIH-sponsored protocol, the Safety of Estrogens in Systemic Lupus National Assessment (SELENA) trial. We will perform an observational study of approximately 1,000 women enrolled in the SELENA trial to assess the sensitivity, specificity, and predictive value of anti-dsDNA antibodies, C3, C4, CH50, and C3a desArg. Using samples from patients enrolled in the SELENA study, we will perform subgroup analyses in diverse ethnic groups, patients treated with exogenous estrogen, and patients with chronically depressed CH50.

In the second-an interventional study-we will evaluate the effectiveness of short-term corticosteroid treatment in averting flares when elevations of plasma C3a are accompanied by rising anti-dsDNA antibody. We will determine whether corticosteroid treatment reduces the frequency of clinical flare, serological abnormalities, or disease activity in inactive or stable patients. We will explore whether steroids disproportionately exacerbate or initiate comorbid medical conditions (e.g., hypertension, diabetes) that may be more prevalent among minority patients. The studies should result in observations that lead to rational, cost-effective, and evidence-based guidelines that improve the treatment of patients with SLE and-by decreasing the morbidity of disease-result in significant improvement of their quality of life.