What is the action of Sargramostim (GM-CSF)?

• A. Suppresses immune response
• B. Stimulates neutrophil, monocyte, macrophage, and eosinophil production
• C. Reduces platelet production
• D. Decreases RBC count

Answer: (B)

GM-CSF acts on the bone marrow to stimulate the growth and differentiation of multiple myeloid cell lineages. Sargramostim increases production of neutrophils, monocytes, macrophages, and eosinophils, boosting the body's ability to fight infections, especially after chemotherapy or bone marrow transplantation. It enhances immune cells rather than suppressing them, and it does not primarily reduce platelets or red blood cells—those are governed by different growth factors. So the action described—stimulating neutrophil, monocyte, macrophage, and eosinophil production—best matches Sargramostim.