CD118 (LIFR alpha) is a type I transmembrane glycoprotein of the cytokine receptor family, which associates noncovalently with CD130 to form the functional high affinity LIF receptor, which also acts as an oncostatin M receptor. CD118 alone binds LIF with low affinity. A secreted form of CD118 results from alternative splicing, and may have inhibitory effect, as it also binds LIF, although with low affinity. CD118 is not expressed on lymphocytes, but it is widely expressed outside the immune system. Soluble CD118 level rises during pregnancy, in parallel with a drop in circulating LIF levels.
