Monocytes are white blood cells that belong to the mononuclear phagocyte system. They
derive from precursors in bone marrow, from there they go into blood, where they have a half-
life of 1–2 days, and then they migrate into the various tissues. Monocyte subsets were
discovered by means of flow cytometry in human blood some 20 years ago and their
phenotype and function has been characterized in detail in health and disease. The subset
classification as classical, intermediate and non-classical monocytes appears to apply to …