TNF and psoriasis: While, to our knowledge, the role of dnTs and HSPCs in PSA has not been extensively investigated, dnT cells have been reported to infiltrate psoriatic skin as well as participate in IL-23/IL-17 signaling in mouse models of psoriasis (34) and spondyloarthritis (35), and the proliferation and differentiation of HSPCs is currently known to respond to systemic interferon and TNF signaling (36).