The cytokine receptors have come to demand the attention of more investigators than cytokines themselves, partly because of their remarkable characteristics, and partly because a deficiency of cytokine receptors have now been directly linked to certain debilitating immunodeficiency states.
The redundancy and pleiomorphism of cytokines are in fact a consequence of their homologous receptors, we therefore have chosen a classification of cytokines according to their cytokine receptors.