ORM2 and rheumatoid arthritis: As shown in Fig. 1f, stimulation of synovial fluid mononuclear cells (SFMCs) from RA patients (RA-SFMCs) with LPS, IL-1β, or TNF-α resulted in a substantial increase in ORM2 mRNA expression levels—by 19.4-, 3.1-, and 5.2-fold, respectively—compared to treatment with medium alone.