The IL-6 receptor complex is composed of two membrane glycoproteins: the low affinity receptor and the signaltransducing component. The soluble form of IL6R is found in the urine of healthy adult humans and the serum of HIV positive individuals, as well as in the cell culture supernatants of stimulated PBMCa€(TM)s. This soluble form of IL6R results from either proteolytic cleavage from the membrane, or an isoform derived splice variant.
