A macrophage is a type of immune cell. It destroys foreign substances to protect the body from infection.
Macrophages do not travel through the blood. Instead, they remain in one part of the body.
Macrophages are found in many organs and tissues, including the:
- Breast tissue
- Lymph nodes
In people with a disease called Langerhans cell histiocytosis (previously called histiocytosis X), there is an excess of macrophages and other white blood cells in some bodily tissues.
Crow MK. The innate immune system. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 39.
Hall JE, Hall ME. Resistance of the body to infection: I. Leukocytes, granulocytes, the monocyte-macrophage system, and inflammation. In: Hall JE, Hall ME, eds. Guyton and Hall Textbook of Medical Physiology. 14th ed. Philadelphia, PA: Elsevier; 2021:chap 34.
Review Date 4/17/2022
Updated by: Stuart I. Henochowicz, MD, FACP, Clinical Professor of Medicine, Division of Allergy, Immunology, and Rheumatology, Georgetown University Medical School, Washington, DC. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.