TY - CHAP M1 - Book, Section TI - Monocytosis and Monocytopenia A1 - Lichtman, Marshall A. A1 - Kaushansky, Kenneth A1 - Prchal, Josef T. A1 - Levi, Marcel M. A1 - Burns, Linda J. A1 - Linch, David C. PY - 2022 T2 - Williams Manual of Hematology, 10e AB - Monocytes in the blood are in transit. They function in the tissues, where they mature into macrophages and participate in:— Inflammation, including granulomatous reactions, atheroma formation, and tissue repair— Immunologic reactions, including delayed hypersensitivity— Reactions to neoplasia and allograftsThe need for macrophages in tissues also can be met by local proliferation of macrophages, not requiring increased transit of blood monocytes.In normal subjects, a mean of 87% of blood monocytes intensely express CD14 (lipopolysaccharide receptor) but not CD16 (Fc receptor) (CD14++/CD16–), the classical subset, designated MO1.A mean of 4% of blood monocytes have weaker expression of CD14 and strongly express CD16 (CD14+CD16++), the intermediate subset, designated MO2.A third monocyte subset, at a mean of 9% of blood monocytes, have weak expression of CD14 and strong expression of CD16 (CD14low/CD16++), the nonclassical subset, designated MO3.Distinctions among monocyte subsets have been validated by gene expression profiling.Older persons have a striking decrease in the proportion of classical CD14++/CD16– monocytes to intermediate CD14+/CD16++ monocytes compared with younger persons.Disorders rarely produce abnormalities of monocytes alone in the absence of other blood cell abnormalities. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/04/25 UR - hemonc.mhmedical.com/content.aspx?aid=1189334014 ER -