monocytosis

pathology

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

June 30, 2026

Quick Summary

Monocytosis is a condition characterized by an increase in the number of monocytes in the blood. Monocytes are a type of white blood cell that play a crucial role in the innate immune system, helping to combat infection and inflammation.123

These large cells are produced in the bone marrow and circulate in the bloodstream before migrating into tissues, where they differentiate into macrophages or dendritic cells. Monocytosis can occur during certain infectious processes, such as subacute bacterial endocarditis or malaria, and also when the bone marrow is recovering from injury. Excessive monocyte activity can contribute to chronic inflammatory conditions, autoimmune diseases, and cancer.2413

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

5 Britannica Sources

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

blood disease
Leukocytosis
Monocytosis, an increase in the number of monocytes in the blood, occurs in association with certain infectious processes, especially subacute bacterial endocarditis—inflammation of the lining of the heart—and malaria. Monocytosis also occurs when the bone marrow is recovering from a toxic injury.
Read More
Monocytosis, an increase in the number of monocytes in the blood, occurs in association with certain infectious processes, especially subacute bacterial endocarditis—inflammation of the lining of the heart—and malaria. Monocytosis also occurs when the bone marrow is recovering from a toxic injury.
Read More