Recent single-cell RNA sequencing (scRNA-seq) analysis of synovial tissue biopsies from RA and PsA patients uncovered a synergic interaction between synovial macrophages and T cells, facilitated by IL-1β and TGF-β, which influence the gene expression profile of pro-inflammatory SFs specifically in RA, not in PsA [29]. This evidence concerns the gene IL1B and rheumatoid arthritis.