Elevated levels of CXCL7 have been reported in the serum, synovial fluid and synovial tissue of patients with RA.27, 28 While CXCL7 promotes angiogenesis, CXCL4 has an antiangiogenic effect.29 The elevated expression of the angiostatic chemokine CXCL4 during the early phase of disease may reflect an attempt to prevent or minimise the first signs of angiogenesis that takes place in the RA synovium. Here, PPBP is linked to rheumatoid arthritis.