Immunophenotyping is the characterization of cells using monoclonal antibodies or any other probes, which make it possible to judge their type and functional state by the presence of one or another set of cellular markers.
Immunophenotyping of leukocytes involves the detection of differentiation markers or CD antigens on their surface. Leukocytes express a number of surface and cytoplasmic antigens that are unique to their subpopulations and stages of development. CD antigens ( English cluster of differentiation antigens ) are antigens on the surface of cells, markers that distinguish one type of cell from another. Differentiations of these antigens are studied and standardized, they are assigned certain numbers. CDs can be recognized using appropriate monoclonal antibodies. Using fluorescently labeled monoclonal antibodies that bind to specific CDs, one can use the flow cytometry method to calculate the content of lymphocytes belonging to subpopulations of different function or stage of development. This makes it possible to understand the nature of certain diseases, assess the condition of the patient, predict its further development, and follow the course of the disease.