Table 2 Biological functions of the studied cytokines and some evidence on their expression related to radiation lung treatment.
Cytokine | Function | Prior evidence related to RT |
|---|---|---|
G-CSF | Induces the survival, proliferation, and differentiation of neutrophilic granulocyte precursor cells and functionally activates mature blood neutrophils | Pulmonary toxicity26 |
GM-CSF | Stimulates the production of neutrophilic granulocytes, macrophages, and mixed granulocyte-macrophage colonies from bone marrow cells and stimulates the formation of eosinophil colonies from fetal liver progenitor cells | Elevation induced by radiation24 |
IFN-γ | Coordinates a diverse array of cellular programs through transcriptional regulation of immunologically relevant genes, antiviral and antineoplastic activity | N/A |
IL-1α | Plays a role in various immune responses, inflammatory processes, and hematopoiesis. | Potential marker4,5; causes radiation lung toxicity6.16,28 |
IL-1β | Plays a role in immune defense against infection; induces fever, controls lymphocytes, increases the number of bone marrow cells and causes degeneration of bone joints | Uncertain correlation with RT toxicity6 |
IL-2 | Causes activation and differentiation of other T lymphocytes independently of antigen | N/A |
IL-4 | Promotes antibody production by causing proliferation and differentiation of B-cells | N/A |
IL-5 | Promotes eosinophil differentiation and activation in haematopoiesis and triggering activated B-cells for a terminal differentiation into Ig-secreting cells | N/A |
IL-6 | Stimulates the growth and differentiation of B-cells and T-cells | Potential marker4,5,29,30Cause radiation lung toxicity28 |
IL-7 | Promotes growth of B-cell precursors and activation of mature T-cell | N/A |
IL-9 | Stimulates the proliferation of erythroid precursor cells | N/A |
IL-10 | Co-regulates mast cell growth; inhibits synthesis of pro-inflammatory cytokines; suppresses the antigen presentation capacity of antigen presenting cells; stimulatory towards certain T cells, mast cells and B cells | Potential marker for lung toxicity27 |
IL-12p70 | Involved in the differentiation of naive T cells into Th1 cells, which is important in resistance against pathogens | N/A |
IL-13 | Plays a role in regulating inflammatory and immune responses and has anti-inflammatory activity | Maybe related to RT lung damage, no evidence yet |
IL-15 | Stimulates the proliferation of T-lymphocytes; induces B-lymphocyte proliferation and differentiation. | N/A |
IL-17 | Induces and mediates pro-inflammatory responses; induces the production of many other cytokines, chemokines and prostaglandins from many cell types | Maybe related to RT lung damage, no evidence yet |
IP-10 | Selectively chemoattracts Th1 lymphocytes and monocytes and inhibits cytokine stimulated hematopoietic progenitor cell proliferation | Fibrosis related14,32,18 |
KC | Activates neutrophils and attracts neutrophils and T-lymphocytes | Fibrosis related28, possible marker31 |
MCP-1 | Causes cellular activation of specific functions related to host defense | No correlation to RT4, fibrosis related14,18 |
MIP-1α | Attracts macrophages and monocytes; stimulates macrophages, and may play a role in regulating haematopoiesis | No significant correlation18 |
RANTES | Attract eosinophils, monocytes, and lymphocytes | Fibrosis sensitivity related14,18 |
TNF-α | Regulates immune cells; causes apoptotic cell death, cellular proliferation, differentiation, inflammation, tumorigenesis, and viral replication; induces necrosis (death) of tumor cells and possesses a wide range of proinflammatory actions | Causes radiation-induced lung toxicity22,28,37 |
MIP-1β | Attracts macrophages and monocytes; stimulates macrophages and acute lung inflammation | RT lung injury38 |