Cooperative effects of human recombinant granulocyte-macrophage colony stimulating factor and human recombinant erythropoietin in inducing erythroid differentiation of the human erythroleukaemia cell line K 562 clonogenic cells.

Human acute erythroleukaemia arises from the inability of the haemopoietic stem cell to differentiate. K 562 cell line provides a homogeneous population of primitive erythroleukaemic cells that are at the same point of differentiation. The effect of human recombinant granulocyte-macrophage colony-stimulating factor and human recombinant erythropoietin on the differentiation of K 562 clonogenic cells was studied. Cells were cultured in methylcellulose culture for 5 days at 37 degrees C in humidified atmosphere containing 5% CO2 in air and scored for erythroid differentiation by benzidine staining. A combination of both growth factors induced erythroid differentiation in more than 80% of K 562 clonogenic cells. This combination may be useful in the treatment of patients with erythroleukaemia.