Human platelets in synovial fluid. A focus on the effects of growth factors on the inflammatory responses in rheumatoid arthritis.

The alpha granules of platelets are a major storage site for peptide growth factors. The inflamed synovial fluid of rheumatoid arthritis contains a high number of platelets as well as platelet-derived growth factors. These platelets may apparently be acted upon to release their alpha granule-located substances. It can thus be suggested that platelets present in the synovial fluid express growth factors of significance to the local inflammatory responses of rheumatoid arthritis.