Purpose of the research is to determine the reaction of regulatory T cells after chemoradiation therapy of Hodgkin lymphoma.

29 samples of peripheral blood of patients with Hodgkin lymphoma (before treatment – 10; after chemotherapy – 9; after consolidation radiotherapy – 10). Chemotherapy was carried out according to the following schemes: ABVD, BEACOPP with the addition of 1-2 courses of СVРР or СОРР. The subsequent consolidation of radiation therapy was accomplished to a dose of 20-24 Gy. Тreg-cells were identified by phenotype CD45+CD4+CD25+CD127-. Control group consisted of 40 practically healthy people. The group data were compared using the Mann-Whitney U test.

At the onset of Hodgkin lymphoma the percentage and absolute count of regulatory T cells corresponded to normal values (5.19%/0.036*109 cells/l - Hodgkin lymphoma vs 3.69%/0.031*109 cells/l - control level, p>0.05). After chemotherapy the percentage of regulatory T cells increased to 9.09%, p<0.05; the absolute count remained at the same level (0.037*109 cells/l, p>0.05). After consolidation of radiation therapy the percentage of regulatory T cells was determined at the level of 9.19%, p>0.05. The decrease of absolute count of regulatory T cells was statistically significant difference and was near 0.019*109 cells/l.

There is a relative redistribution of cells within a subpopulation of activated CD4+CD25+T cells towards an increase in the level of regulatory T cells after chemotherapy of Hodgkin lymphoma. The subsequent radiotherapy consolidation at a dose of 20-24 Gy continued to increase the sensitivity of regulatory T cells to the radiation component of chemoradiation therapy.