The Role of Foxp3, CD4+CD25+ Regulatory T Cells on the Pathogenesis of Infectious Mononucleosis in Children

Abstract

Objective To investigate the role of CD4+CD25+ regulatory T cells(Treg) and transcription factor Foxp3 on the pathogenesis of infectious mononucleosis(IM) in children. Methods From April 2010 to January 2011, 70 blood samples from 35 IM children(2 samples each person) were included into this study, and divided into IM acute stage group(n=35) and IM recovery stage group(n=35) according to the different disease periods.Meanwhile, 35 blood samples which taken from health children (1 sample each person) were chosen as control group(n=35). The expression of T lymphocyte subsets CD3+, CD3+CD4+, CD3+CD8+, CD4+CD25+ Treg and Foxp3 mRNA were compared among three groups. There was no significant difference in age and sex distribution between IM patients and health chirdren (P>0.05). The study protocol was approved by the Ethical Review Board of Investigation in Human Being of Sichuan Province People's Hospital.Informed consent was obtained from each parents. Results There had significant differences among three groups in relative expression levels of CD3+, CD3+CD4+, CD3+CD8+, CD4+CD25+ Treg (P 0.05). A significant positive correlation was found between CD4+CD25+ Treg and expression of Foxp3 mRNA in IM acute stage group(r=0.823, P<0.05). Conclusions There is functional disorder of T lymphocyte subsets at acute stage of IM in children. The relative expression levels of CD4+CD25+ Treg were reduced, and their special transcription factor Foxp3 mRNA were decreased, which led to the insufficient immunosuppressive effects that may be one of the important reasons of the immune imbalance. Key words: Foxp3; CD4+CD25+ regulatory T cell; infectious mononucleosis; child