| Factors | Cellular sources | [Ref.] |
| Growth factors/cytokines | ||
| PDGF | Platelets, monocyte-macrophage, BSMC, epithelium | 84 |
| FGF | Extracellular matrix, monocyte-macrophage, BSMC | 85 |
| EGF | Epithelium, platelets | 86 |
| TNF-α | BSMC, epithelium, T-lymphocytes, monocyte-macrophage | 87 |
| TGF-β (controversial) | BSMC, T-lymphocytes, epithelium | 88, 89 |
| Inflammatory mediators | ||
| Histamine | Mast cells, basophils | 90 |
| Endothelin-1 | Epithelium, monocyte-macrophage | 91 |
| Thromboxane A2 | Mast cells, monocyte-macrophage | 92 |
| Cysteinyl leukotriene | Monocyte-macrophage, eosinophils, mast cells, fibrocytes | 93 |
| Sphingosine 1-phosphate | Plasma, platelets | 94 |
| Enzymes | ||
| Tryptase | Mast cells | 95 |
| Thrombin | Plasma | 96 |
| Elastase | Neutrophils | 97 |
| Reactive oxygen species | Monocyte-macrophage, neutrophil, eosinophils, mast cells | 98 |
| Mechanical stress | 99 |
PDGF: platelet-derived growth factor; FGF: fibroblast growth factor; EGF: epidermal growth factor; TNF: tumour necrosis factor; TGF: transforming growth factor; BSMC: bronchial smooth muscle cells.