C4A and systemic lupus erythematosus: We identified no significant difference between SLE patients with and those without anti-class A scavenger receptors antibodies (anti-SRCR or anti-SR-A) in the presence of arthritis, serositis, mucosal ulcer, neurological or hematological manifestations, lupus nephritis, and lower levels of C3 or C4 (all P > 0.05).