Additional inflammatory cells and subsidence of acute inflammation
THE CONTEXT
Besides neutrophils and macrophages, several immune cell types contribute to inflammatory defense and allergic reactions.
Th17-mediated defense
•
Th17 cells are T cells that secrete cytokines such as IL-17, which recruit neutrophils and stimulate production of antimicrobial peptides that directly kill microbes.
•
Ineffective Th17 responses increase susceptibility to fungal and bacterial infections.
•
Skin abscesses arising in the absence of effective Th17 responses lack classic acute inflammatory features such as warmth and redness.
Other participating cells
•
Eosinophils are especially important in reactions to helminthic parasites and in some allergic disorders.
•
Mast cells and basophils are critical participants in allergic reactions.
Why the acute response subsides
•
After elimination of the offending stimulus, further leukocyte recruitment ceases.
•
Inflammatory mediators are short lived and decline when production stops; neutrophils also have short life spans. Together, these changes allow the reaction to subside.