PTX3 and rheumatoid arthritis: In addition, Weitoft and colleagues reported that the level of PTX3 in synovial fluid from RA patients is higher in seropositive patients (anti-cyclic citrullinated protein -CCP- antibody or rheumatoid factor -RF-) when compared to seronegative patients, and correlates with disease activity and local expression of markers of inflammation such as IL-6 or vascular endothelial growth factor (VEGF) (21).