TNF and rheumatoid arthritis: We observed an aberrant downregulation of SIGIRR and enhanced TNF-α production in memory CD4 T cells from the peripheral blood of RA patients and found that SIGIRR deficiency promoted the progression of AIA mediated by elevated TNF-α expression, thus establishing a closer association between SIGIRR and TNF-α production in memory CD4 T cells in RA for the first time.