Table 3. Major eosinophil products and their potential role in the development of hypereosinophilia.
| Eosinophil product | Effects potentially relevant to HE-related organ damage |
|---|---|
| Basic proteins | |
| MBP | Direct toxic effect, cytostimulatory |
| ECP | Direct toxic effect, mucus secretion, fibrosis |
| EDN | Direct toxic effect, TLR2 ligand effects, RNase |
| EPO | Direct toxic effect, cytostimulatory |
| Enzymes | |
| Lysophospholipase | Direct toxic effect |
| Phospholipase D | LFA-dependent adhesion |
| Arylsulphatase B | Lysosomal hydrolase |
| Histaminase | Histamine degradation |
| Catalase | Direct toxic effect |
| Acid phosphatase | Direct toxic effect |
| Nonspecific esterases | Direct toxic effect |
| Hexosaminidase | Direct toxic effect |
| Cytokines | |
| IL-1α | Endothelial activation, inflammation |
| IL-2 | Activation of T lymphocytes |
| IL-3 | Amplification of eosinophilia |
| IL-4 | B-cell maturation and mast cell activation |
| IL-5 | Amplification of eosinophilia |
| IL-6 | Lymphocyte maturation |
| IL-8 | Leukocyte recruitment and activation |
| IL-13 | Bronchial hyper-reactivity, mucus production, B-cell maturation |
| GM-CSF | Leukocyte/eosinophil activation |
| TGF-α | Fibrosis, growth inhibition |
| TGF-β | Fibrosis, growth inhibition |
| TNF-α | Endothelial activation, inflammation, cachexia |
| OSM | Fibrosis, angiogenesis |
| Chemokines | |
| MIP-1α (CCL3) | Leukocyte recruitment and activation |
| RANTES (CCL5) | Leukocyte recruitment and activation |
| Eotaxin (CCL11) | Further eosinophil recruitment |
| Membrane-derived mediators | |
| LTC4 | Mucus secretion |
| PAF | Bronchoconstriction, edema formation |
| 15-HETE | Diverse effects on blood and tissue cells |
| PGE1 and PGE2 | Diverse effects on platelets, endothelial cells, fibroblasts and other tissue cells |
| TXB2 | Platelet aggregation |
| Antifibrinolytic mediators | |
| PAI-2 | Antifibrinolytic and prothrombotic |
| Extracellular DNA traps | Direct toxic effect (on bacteria) |
ECP: Eosinophil cationic protein; EDN: Eosinophil-derived neurotoxin; EPO: Eosinophil peroxidase; GM-CSF: Granulocyte/macrophage colony-stimulating factor; HE: Hypereosinophilia; LFA: Leukocyte function antigen-1; LTC4: leukotriene C4; MBP: Eosinophil major basic protein; OSM: Oncostatin M; PAF: Platelet-activating factor; PAI: Plasminogen-activator inhibitor; PGE: Prostaglandin E; TLR: Toll-like receptor; TX: Thromboxan.