TNF and Arthritis: FLSs are considered tissue-resident cells involved in the initiation, maintenance, and resolution of chronic inflammation in arthritis, and their activation is a key step in the occurrence and development of arthritis.101,102 Smith et al.94 by analyzing the chromatin accessibility and gene expression profiles of FLSs, constructed a spatial atlas of FLS cell states influenced by local exposure to TNF, IFN-γ, and IL-1β during active RA.