C3 and polycystic ovary syndrome: Constantly updated comparative studies (PCOS women vs. PCOS-free age- and BMI-matched controls) have revealed typical components of the inflammatory background in PCOS that include C-reactive protein (CRP) and high-sensitivity CRP (hs-CRP), interleukin 18 (IL-18), tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), white blood cell count (WBC), monocyte chemoattractant protein-1 (MCP-1), complement element 3 (C3), and macrophage inflammatory protein-1α (MIP-1α) [14,16].