granulocyte-macrophage colony-stimulating factor (GM-CSF)

A substance that stimulates the bone marrow to develop white blood cells (especially granulocytes and macrophages). These white blood cells help defend the body against bacteria, viruses and types of fungus.

GM-CSF is a cytokine found naturally in the body. It can also be made in a lab.

GM-CSF is a type of biological therapy used in cancer treatment to stimulate the immune system. It may also be given after chemotherapy to help increase white blood cell counts and to lower the risk of infection.