What is happening
Key players
| Mast cells | the main source of histamine, which starts it all |
| Neutrophils | the first cell to arrive at the site |
| Macrophages | swallow antigens tagged by opsonization |
| Cytokines | carry messages between WBCs and other cells |
| Prostaglandins | drive fever and pain through the brain |
| Leukotrienes | a chemical that speeds up the response |
Systemic phase: inflammation can go whole-body. Prostaglandins, cytokines, and leukotrienes drive it. You then see fever, a ↑ WBC count, and changes in vital signs. A short-term trigger is usually infection. Long-term triggers include asthma, lupus, and RA.