Role of CD4~+ CD_(25)~+ Regulator T Cell in Pathogenesis of Infectious Mononucleosis in Children

Objective To observe the dynamic changes of CD4 +CD 25 + regulator T cell and T lymphocyte subsets CD3 +,CD4 +,CD8 + in children with infectious mononucleosis(IM) and explore the role of CD4 +CD 25 + regulator T cell in pathogenesis of IM. Methods The peripheral blood of 30 patients with IM was collected in the acute phase and the convalescent phase(the 1 st,the 3 rd and the 6 th month),at the same time,the peripheral blood of 25 healthy children in control group was collected.The cells were stained by fluorochrome-labeled monoclonal antibodies [mouse anti-human CD3-phycoerythrin-anthocyanin 5(PC5),CD4-fluorescein-isothiocyanate(FITC),CD8-phy-coerythin(PE) and CD3-phycoerythrin texas red-x(ECD),CD4-PE,CD 25-FITC],then erythrocytes were lysed.The expressions of CD4 +CD 25 +,CD3 +,CD4 +,CD8 + on peripheral blood mononuclear cells were analyzed by flow cytometry. Results 1.The expressions of CD4 +CD 25 +[(4.42±1.70)%],CD4 +[(14.84 ±5.03)%]and CD4 +/CD8 +(0.25±0.13)were markedly decreased in the acute stage.One way analysis of variance among these groups were significant differences(P a0.001).The expressions of CD3 +[(82.55±5.49)%],CD8 +[(66.17±8.10)%]were obviously increased in the acute stage(P a0.001).2.Compared with the control group [(7.85± 1.97)%],the expression of CD4 +CD 25 + returned to normal in the 1 st month[(6.81±1.84)%](P 0.05).The expression of CD4 +CD 25 + in the 3 st month [(6.60±1.93)%] and the 6 th month [(8.02±2.52)%] was not significant difference(P a0.05).3.There was no significant difference on the expression of CD3 +,CD4 +,CD8 + and CD4/CD8 between the 6 th month[CD3 +(67.98±8.01)%,CD4 +(32.81± 6.79)%,CD8 +(33.96±7.37)%,CD4 +/CD8 +0.93±0.31]and control group[CD3 +:(65.04±6.50)%,CD4 +:(35.98± 4.19)%,CD8 +:(30.72±16.51)%,CD4 +/CD8 +:1.18±0.35](P a0.05). Conclusions There was markedly immunoresponsiveness unbalance in acute phase of IM.The large number of mononuclear cells consisted mainly of activated CD8 + T cells.The decrease of CD4 +CD 25 + regulator T cells might be involved in pathogenesis of IM,which provided one of the new ways to treat EBV-associated diseases.