Table 1.

IL-1 family antagonist expression, activity, and signaling.

Cytokine	Producing cell	Target cell	Receptor	Effect
IL-1Ra	Keratinocytes (89, 90, 94, 98–101) Infiltrating myeloid cells (89, 94)	Keratinocytes Fibroblasts Myeloid cells	IL-1R1	Inhibition of IL-1 activity (94, 102, 111)
IL-36Ra	Keratinocytes (103, 114–118) Myeloid cells (114, 115, 119, 120)	Keratinocytes Myeloid cells CD4+ T cells	IL-36R	Inhibition of IL-36 activity (121–124)
IL-37	Keratinocytes (103, 125–127)	Myeloid cells	IL-18Rα	Broad inhibition of pro-inflammatory signaling (128–132)
			IL-18RAP	Inhibition of IL-18 activity (133)
IL-38	Keratinocytes (103, 117, 118, 124, 134–136)	γδ T cells	TIGIRR-2	Inhibition of IL-17A production (135)
		Myeloid cells	TIGIRR-2 IL-36R?	Broad anti-inflammatory activity (50, 137)
		Keratinocytes	IL-36R?	Inhibition of IL-36γ activity (124)

For each antagonist, the main producing cell type(s), target cells, receptors, and effects relevant to skin biology are listed. A comprehensive description of biological effects reported for each cytokine can be found in the text.