The evaluation of the changes of lymphocytes: T(CD3), B (CD19), subpopulations CD4, CD8, active lymphocytes CD3+HLA-DR+, lymphocytes with the receptor for IL2(CD3+CD25+), NK cells as well as the CD4/CD8 ratio in 30 patients with the early localized (group I n=7) and early disseminated (group II n=23) type of Lyme disease, before (examination 1) and after the antibiotic therapy (examination 2) was performed. Group III was composed of 90 healthy people. Measurements were carried out in an COULTER EPIC XL cytoflowmeter, using Becton Dickinson antibodies. Statistical analysis was performed using AnStat software. In the examined groups, a decrease of the subpopulations of CD4, CD8 lymphocytes in comparison with healthy subjects was revealed, as well as a decrease of the CD4/CD8 ratio after treatment. A considerably lower percentage value of active lymphocytes CD3+HLA-DR+ in both groups and the reduction of the NK subpopulation before and after treatment of early disseminated Lyme disease in comparison with healthy people was observed. The higher percentage values of the lymphocytes with IL-2 receptor were not statistically significant. The indicated essential changes in the subpopulations of T lymphocytes, characterized by a decrease before the antibiotic therapy and by the tendency towards an increase after that therapy of the percentage of CD4, CD8, NK and CD3+HLA-DR+ lymphocytes in peripheral blood, point out their role in the immunopathogenesis of the Lyme disease. The absence of the complete normalization of the examined parameters after the treatment, on the one hand, may provide evidence for some inertia of the elements of the immune system, on the other hand can also result from too short antibiotic therapy and maintenance of the antigenic stimulation.
key words: Lyme disease, lymphocyte subpopulations, pathogenesis

Keywords: pathogenesis, lymphocyte subpopulations, Lyme Disease