C3 and rheumatoid arthritis: Measurements of CICs along with complement products such as C1q, C3b, C3d, C3dg, and MASPs levels in the serum and synovial fluid of RA patients along with rheumatoid factor (RF), anti-citrullinated protein antibodies (ACPA), and anti-carbamylated protein (anti-CarP) antibodies can provide a better picture of the local production and their role in the RA pathogenesis.