The multifaceted role of mast cells in the pathogenesis of rheumatoid arthritis.

Mast cells (MC) are tissue duelling cells playing an active role in both innate and adaptive immune system. They act as first players in different microbial infections and exert a crucial role in allergy, chronic inflammation, fibrosis, and rheumatic diseases (RD), including rheumatoid arthritis (RA). MC are normally present in human synovia and they increase in the joints of RA patients, contributing to inflammatory and remodelling processes. Due to their great plasticity and multifunctionality, MC exert a wide range of roles in different stages of the disease. To date, the results obtained by in-vitro and in-vivo studies have contributed to better clarify the dynamic role of MC in local arthritis of RA and have improved our knowledge on different aspect of the disease. Although different mice models have been extensively used to investigate the contribution of MC in different stages of RA, those models often fail to reproduce the complexity and the heterogeneity of the human disease. Here, we provide an overview on different roles of MC in RA pathogenesis and how these cells might influence some clinical features of the disease.