As nouns the difference between cytokine and oncostatin
is that cytokine
is (protein|immunology) any of various small regulatory proteins that regulate the cells of the immune system while oncostatin
is (medicine) any of a group of pleitropic cytokines.
As an adjective pleitropic
is (genetics) describing a gene that has multiple, often unrelated effects.
As a noun oncostatin is
(medicine) any of a group of pleitropic cytokines.