TNFRSF18 and Autoimmunity: Soluble forms of receptors and ligands of TNF and Ig superfamily molecules, namely CD30, OX40, OX40L, CD40, CD30, CD95, GITR, GITRL, CTLA4, Tim3, Nectin-2, Siglec-7, PDL-1, and PDL-2 [24,25,26,27,28,29,64] have been reported in plasma in autoimmunity and a variety of cancers.