Radiation sensitivity of lymphocytes from human blood and from the thoracic duct

Peripheral blood and thoracic duct lymphocytes are sensitive to irradiation. However, a distinct population of resistant lymphocytes exists, which is characterized by reactivity to a very low dose of lymphocyte-stimulating lectins in vitro. Blood lymphocytes are rapidly eliminated from the circulation after radiation damage. An analysis of the function of blood lymphocytes is thus of little or no use in assessing the therapeutic effect of extracorporeal irradiation. Lymphocyte activation must accordingly also be unsuitable for use as a biologic dosimeter after accidental total body irradiation.