The observation of the liquidators of the Chernobyl accident has shown that as time goes on, they have different pathological processes and chronic illnesses. Increased level of chromosome aberrations, immune and endocrine disorders, clastogene factors etc., requires active treatment and rehabilitation measures. We have studied the changes in the immune system of the liquidators in combination with the other vital systems of the organism activity and not in isolation. The condition of cell-mediated immunity was assessed based on the relative and absolute quantity of T- and B lymphocytes. The assessment of the humoral immunity condition was carried out by the estimation of Ig G, Ig A, Ig M class immunoglobulin concentration in the serum. Non-specific defense factors are the complement content in the serum and phagocytic activity of the neutrophils. Statistical analysis of the data was carried out with the help of such methods of system analysis as correlation, variance factor and cluster analysis. Making use of the method of the assessment of human immune system suggested by L.V. Kovalchuk and A. N. Cheredeev, based on the pathogenetic principle, we developed an algorithm of assessment of humoral component of immune system in case of immunodeficiency. In spite of the seemingly good condition of the immune system in the early post-accident period, which can be accounted for by adaptation mechanisms, in most cases (63.8%), a recurrence of inflammatory processes is observed, which is probably explained by the displacement of the immune system component provoked by radiation influence 20-25 years ago, with non-radiative factors connected with the way of life.

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