CD210, also known as the IL-10 receptor, is a 90-110 kD protein expressed on T cells, B cells, NK cells, monocytes and macrophages. CD210 belongs to the class II cytokine receptor family which includes the IFN-γ receptor (CDw119), the IFN-a/b receptor (CD118) and tissue factor (CD142). The IL-10 receptor is involved in signal transduction by inducing phosphorylation of STAT1a and STAT3 and by inducing activation of Jak1 and Tyk.