GCSF

GCSF stands for granulocyte colony-stimulating factor, a cytokine that promotes the production, maturation, and function of neutrophils. Endogenously, G-CSF is produced by cells such as macrophages, endothelial cells, and fibroblasts in response to infection or inflammation. It acts through the G-CSF receptor (CD114) on hematopoietic progenitors and mature neutrophils, triggering signaling pathways (including JAK/STAT) that enhance neutrophil proliferation, differentiation, survival, and function. G-CSF also mobilizes hematopoietic stem cells into the peripheral blood and can modify the bone marrow microenvironment to facilitate release of CD34+ cells.

Medical uses include reducing the duration and severity of chemotherapy-induced neutropenia and its associated infection risk, shortening hospital stays, and enabling higher-dose or more frequent chemotherapy regimens in some cancers. It is also used to treat severe chronic neutropenia and to mobilize stem cells for autologous or allogeneic peripheral blood transplantation. Pegylated formulations provide longer-lasting activity and are often given as a single dose per chemotherapy cycle, while nonpegylated forms are typically administered daily until neutrophil recovery.

Administration and agents: G-CSF products are given by subcutaneous injection. Common agents include filgrastim (short-acting), pegfilgrastim (long-acting), and lenograstim. Dosing depends on indication, regimen, and patient factors.

Safety and adverse effects: The most frequent side effects are bone pain, injection-site reactions, and leukocytosis. Other risks include splenomegaly and, rarely, splenic rupture; fever and edema can occur. G-CSF should be used cautiously in patients with myeloid malignancies or a history of hypersensitivity to the product. It is not used to treat established infection.