TNFSF15 and rheumatoid arthritis: It has been shown that TL1A (TNF-like cytokine) synergizes with IL-12 plus IL-18 in inducing IFN-γ by CD4+ T cells [21], [22], and TL1A production by immune complex-stimulated monocytes may be involved in the pathogenesis of rheumatoid arthritis [23].