The purpose of the work was research and functional reserves immunity in participants in the Chernobyl with cardiovascular disease. A Clinical Lab 49 men aged 44 to 52 years with diseases of the cardiovascular system, participated in the Chernobyl nuclear power plant in 1986 to 1988. As control used data 33 patients with similar pathology, and 16 healthy men. Researched the total number of white blood cells, lymphocytes and transfusions, the absolute number and relative CD4+ and CD8+, CD 16, CD20+, CD95+ lymphocytes peripheral blood, number mononuclear, synthesizing IL-1beta, TNF-alpha, INF-alpha, IL-4, the content of lipids and proteins, the activity of alkaline phosphatase and mieloperoksidazy in neutrophils. To assess the functional reserve immune system blood samples studied people subjected to radiation doses 0.25, 50, 1.0 Gy of in vitro and studied the reaction cytochemical indicators neutrophils before and after the radiative forcing. The liquidators not detected significant changes in the absolute number of leucocytes, but compared with control groups noted significant reduction in the absolute number of CD8+ and CD20+ lymphocytes, increased the number of cells, expression of FAS-antigen, change the number of mononuclear spontaneously synthesizing and produce cytokines, decreased maintenance of cation proteins in neutrophils. Radiation samples peripheral blood liquidators caused the same reaction cytochemical indicators of neutrophils and control groups, the compensatory and adaptive nature of the changes in the immune system, developed in response to complex factors radiation accident.