Role of monocytes in immunopathogenesis of infectious and inflammatory diseases: from theory to practice

Monocytes are circulating blood cells derived from bone marrow. They are the body’s first line of defense against pathogens and are involved in immune responses against viruses, bacteria, fungi and parasites invasion. For a long time, monocytes were considered a homogeneous group of cells, but then by means of flow cytometry development it was shown that they can be divided into three subpopulations according to surface molecules CD14 and CD16 expression: classical (CD14++CD16–), proinflammatory (CD14+CD16++) and intermediate (CD14++CD16+). This review focuses on various mechanisms of an implementation of the functional activity of various monocytes subpopulations and their impairment in various viral diseases, bacterial infections and sepsis.