Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025
Definition
A granuloma is an organized collection of immune cells formed in response to chronic inflammation, often due to persistent pathogens or foreign substances. It serves to isolate the offending agent but can also contribute to tissue damage.
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Granulomas are typically made up of macrophages, which can transform into epitheloid cells and multinucleated giant cells.
They are commonly associated with diseases like tuberculosis, sarcoidosis, and certain fungal infections.
Granulomas form when the immune system attempts to wall off substances it perceives as foreign but cannot eliminate.
Cytokines like TNF-alpha and Interferon-gamma play crucial roles in granuloma formation.
Despite their protective role, chronic granulomas can lead to tissue scarring and organ dysfunction.
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Related terms
Macrophage: A type of white blood cell that engulfs and digests cellular debris, foreign substances, and pathogens.
Cytokine: Signaling proteins that mediate and regulate immunity, inflammation, and hematopoiesis.
Chronic inflammation: Prolonged inflammatory response that involves a progressive change in the type of cells present at the site of inflammation.