Focal bone erosion in CIA is attributed to cells expressing definitive features of osteoclasts, including CTR. The expression of RANKL by cells within inflamed synovium suggests a mechanism for osteoclast differentiation and activation at sites of bone erosion. Inhibitors of RANKL may represent a novel approach to treatment of bone loss in rheumatoid arthritis.

Changes in ILN and PLN PTHrP mRNA expression suggest that elevated levels of the cytokine are associated with aggravation of the inflammatory immune response. Changes in PTHrP in DIP joints indicate its involvement in late rather than early pathogenic events in CIA joints.

Mast cells represent a unique cell population, which is involved in a number of immune responses in our body. Mast cells (MCs) release an array of potent pro-inflammatory mediators and cytokines upon activation that are either pre-stored in the granules or synthesised de novo. These mediators can make a substantial contribution to the initiation and perpetuation of the inflammatory processes. This review provides an insight for the potential role of MCs in rheumatoid arthritis (RA). The data on mast cell distribution in the rheumatoid joint along with the information obtained from in vitro experiments and observations in animal models suggest that these cells may be involved in RA. The encouraging results of MC inactivating therapy in animal models of arthritis indicate that MC stabilizers may prove beneficial as a supplementary therapy in RA.

No abstract