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Inflammation

The body's coordinated response to injury, infection, or irritation. Acute inflammation is short-lived and supports healing. Chronic inflammation persists and is implicated in cardiovascular disease, metabolic disease, autoimmunity, and post-viral syndromes.

Edited by M. Callahan · Last reviewed 2026-05-10

How researchers study it

The molecular basis of inflammation involves pattern-recognition receptors on innate immune cells, cytokine cascades (IL-1, IL-6, TNF-alpha), recruitment of neutrophils and macrophages, complement activation, and tissue remodeling. Resolution requires specialized pro-resolving mediators (resolvins, lipoxins, protectins). When resolution fails, inflammation becomes chronic (Furman D et al., Nature Medicine, 2019).

Researchers measure inflammation with serum biomarkers — high-sensitivity C-reactive protein (hsCRP), interleukin-6, fibrinogen, ferritin. None is perfect; each captures a slice. Imaging (PET, MRI) can localize inflammation in specific tissues. Chronic low-grade inflammation has been associated with cardiovascular disease, insulin resistance, neurodegenerative disease, and aging in large prospective cohorts.

In COVID-19, inflammation features prominently both in the acute phase (where cytokine elevations correlate with severity) and in long COVID (where some patients show persistent elevation of inflammatory markers and immune-cell activation, though not uniformly). The NIH's health information portal and CDC publish overviews. The 2019 Nature Medicine review by Furman and colleagues is a useful primer on chronic inflammation across diseases (PubMed 31806905).

Common misconceptions

"All inflammation is bad."Acute inflammation is essential — wound healing, infection control, and tissue repair depend on it. The problem is unresolved or excessive inflammation.
"Anti-inflammatory diet will treat any condition."Whole-food, Mediterranean-style diets are associated with lower inflammatory markers in trials. The clinical magnitude varies and is not a substitute for treatment of specific diseases.
"You can measure inflammation reliably at home."Validated measurement requires laboratory biomarkers. Consumer "inflammation tests" vary widely in evidence base.
WHAT THIS DOES NOT MEAN This entry describes inflammation as a biological process. It is not a diagnosis or a treatment plan. Suspected chronic inflammation needs clinical evaluation — many treatable causes (infection, autoimmunity, metabolic disease) need to be considered.
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SOURCES
  1. Furman D et al. "Chronic inflammation in the etiology of disease across the life span." Nature Medicine, 2019. PubMed: 31806905
  2. NIH Health Information. nih.gov/health-information
  3. CDC. cdc.gov
Informational only · Not medical advice This entry describes a biological process. It does not diagnose, treat, cure, or prevent any disease. Persistent symptoms or elevated markers need clinical evaluation.