C3 and systemic lupus erythematosus: Serum levels of IL-1b in SLE patients were positively correlated with anti-dsDNA, anti-AnuA, ESR, and SLEDAI, and were inversely associated with C3 (r = 0.584, 0.504, 0.566, 0.624 and p = 0.002, 0.010, 0.003, 0.001, respectively).