C3 and systemic lupus erythematosus: The expressions of Complement C5 (C5), Complement component C9 (C9), Complement C3 (C3), Complement component C7 (C7), Complement C4-B (C4B), Complement component C8 alpha chain (C8A) and Complement component C8 gamma chain (C8G) were up-regulated between SLE-A and SLE-S, while the expressions of Mannan-binding lectin serine protease 2 (MASP2), Complement component C6 (C6) and Complement factor D (CFD) are down-regulated.