Immunology. Arsonists in rheumatoid arthritis

Abstract

Inflammation associated with rheumatoid arthritis is stoked by platelets, expanding their roles into the immune system.

Figure. Perpetrators in a painful joint

In rheumatoid arthritis, the joint synovium becomes inflamed with dilated blood vessels and immune cells. Polymorphonuclear leukocytes (PMN), cytokines, chemokines, and other mediators of inflammation, accumulate in the synovial fluid. Local activation of platelets by collagen and synoviocytes may trigger the release of microparticles from platelets. These microparticles then enter the joint space and further amplify inflammation by producing interleukin-1. This then activates synoviocytes, thus supporting a cycle of inflammation.