[Comparative characteristics of clinical and immunologic indicators of various groups of opisthorchiasis patients in a focus. Aboriginal population].

Clinical and immunological observations of people belonging to two population groups--aborigens (khanty, mansi, komi) and 40 immigrants--were performed in opisthorchiasis foci of the Tyumen region. Rapid clinical reinvasion of unimmune immigrants (in a 3-4 year period) was established; the aborigens featured subclinical invasion pattern. T-system immunity in immigrants was suppressed, while in the aboriginal group insignificant reduction of the number of T-helpers and significant increase in the number of T-suppressors, lack of apparent mobilization of humoral immunity factors--reduction of the absolute B-lymphocytes number, normal A, G immunoglobulines and CIC levels-were observed. Such T--B immune systems' ratio may indicate immune tolerance of a suppressor type. The observed indicators of aborigens' tolerance to helminths' antigens point to the necessity of differentiated approach to chemotherapy prescription (especially of the repeated courses) in the endemic invasion foci.