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The total number of T-lymphocytes (CD3) in the blood
Last reviewed: 18.10.2021
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Normally, the relative total number of T-lymphocytes in the blood in adults is 58-76%, the absolute amount is 1.1-1.7 × 10 9 / l.
Mature T-lymphocytes are responsible for the reactions of cellular immunity and carry out immunological surveillance of antigenic homeostasis in the body. They are formed in the bone marrow and differentiate in the thymus, where they are divided into effector (T-lymphocyte-killers, delayed-type hypersensitivity T-lymphocytes) and regulatory (T-lymphocytes-helper cells, suppressor T-lymphocytes) cells. In accordance with this, T-lymphocytes perform two important functions in the body: effector and regulatory. The effector function of T-lymphocytes is a specific cytotoxicity with respect to foreign cells. Regulatory function (T-helper-T-suppressor system) consists in monitoring the intensity of the development of a specific immune system response to foreign antigens. Regulatory effects of T-lymphocytes on the cells of the monocytic-macrophagal series are diverse. The ability of T-lymphocytes to synthesize and produce cytokines will enable them to participate not only in the regulation of immunity functions, but also in many vital processes. At the heart of many diseases is the pathology of T-lymphocytes, which in some cases is directly related to their defeat, and in others is mediated through impaired immunoregulation.