Subpopulations of B- And T-Lymphocytes and NK (Natural Killer) Cells (LGL – Large Granular Lymlphocytes) in Patients With Infectious Mononucleosis

In a group of 54 patients with verified diagnoses of infectious mononucleosis values of leukocytes, lymphocytes and atypical mononuclear cells (AMNC) in the peripheral blood were measured and the number of B-lymphocytes, T11 T4, T8-lymphocytes and large granular lymphocytes (LGL) and NK (natural killer) cells respectively identified and determined by appropriate immunological tests. Maximal leukocyte values in the peripheral blood did not exceed 14 x 109/1 and were recorded in the first three weeks of the disease. Lymphocytes and AMNC were predominating cells in the differential leukocyte formula. Their maximal values amounted up to 88 percent and were largest in the first three weeks of the disease. The values of antibodies to VCA (viral capsid antigen) and of antibodies to EBNA (Epstein-Barr nuclear antigen) were in accord with data reported in the literature. In direct immunofluorescence tests (polyvalent and monovalent anti-immunoglobulin antibodies) we found increased values of B-lymphocytes, which culminated in the first week of the disease. In most cases we recorded elevated values of B-lymphocytes which carried on their membranes IgG 4 + IgM + IgA or IgG + IgM. The rise B-lymphocyte values was most likely due to the action of EB virus as polyclonal activator of B-cells resulting in their proliferation and differentiation. In indirect immunofluorescence tests with use of anti-TH, anti-T4 and anti-T8 monoclonal antibodies we found increased Tll-lymphocytes values and marked rise in the values of suppressor-cytotoxic T-lymphocytes (T8) throughout the entire duration of the disease. There was also a mild upward trend in the values of T-helper lymphocytes (T4). Infection of B-lymphocytes with EB virus was accompanied by intensive immune stimulation and the activation of, and increase in the values of, T-lymphocytes, in the first place of those with a cytotoxic and suppressor function (T8), which also seemed to have been primarily activated. The tendency of a light increase in T-helper lymphocytes (T4) values might have been the result of the activation of this subspecies of T-lymphocytes in acute infectious mononucleosis. In the smears of whole blood and in the smears of separated lymphocytes, and with the use of monoclonal NKH’ antibodies, we found increased values of large granular lymphocytes (LGL) and NK (natural killer) cells, respectively, which tallies with the results reported by other researchers. The increase in the mean values of NK cells was greatest between the fifteenth and thirtieth days of the disease. An intact function of NK cells is a precondition for normal protection against herpes simplex virus, so that these cells would behave in a similar way also against Epstein-Barr (EB) virus. NK cells alone could directly act on EB virus-infected B-cells, thus immediately taking part in defence processes, and could together with activated cytotoxic T-cells act on the plasma cells whose appearance is the result of virus-induced transformation of B-lymphocytes and could eliminate them. T-suppressor lymphocytes would restrict the growth of EB virus-infected B-cells by acting antiproliferously.