IL1B and rheumatoid arthritis: Thus, specific pathogenic infiltrating immune cell subsets—such as IL-1β positive pro-inflammatory monocytes, autoimmune-associated B cells, and peripheral helper T (Tph) cells sharing similarities with Tfh cells, distinct subsets of CD8+ T cells, as well as mast cells—contribute to the inflammatory pattern of the RA synovial lining/sublining [26,27,28,29,30,31].