[Roles of CD8+ CD28- T regulatory cells in acute infectious mononucleosis in children].
OBJECTIVE
To explore the role of CD(8)(+)CD(28)(-) T regulatory cells (Tr) in the immunological pathogenesis of acute infection with Epstein-Barr virus in children.


METHODS
The present study enrolled 25 children with infectious mononucleosis (IM) and 25 age-matched healthy children. Flow cytometric analysis was performed to detect the percentage of CD(3)(+), CD(3)(+)CD(4)(+), CD(3)(+)CD(8)(+), CD(8)(+)CD(28)(+) by determining the ratio of positive cells in lymphocytes. Reverse transcriptase-polymerase chain reaction (RT-PCR) and real-time PCR were used to analyze IL-6, IL-10, IFN-gamma expression in CD(8)(+)CD(28)(-) Tr cells and ILT-3, ILT-4 expression in monocytes/macrophages.


RESULTS
The proportions of CD(8)(+)CD(28)(-)T cells in children with acute-phase IM was significantly higher than those in the controls (P < 0.01). The expression level of IL-6, IL-10, IFN-gamma, ILT-3, ILT-4 mRNA significantly increased compared to those of the controls (P < 0.01).


CONCLUSIONS
The CD(28) expressed on CD(8)(+) T cells in vivo is gradually lost with age and CD(8)(+)CD(28)(-) cells increase up 50% to adult. EBV can directly infect B cells, trigger CD(8)(+) CTL response and destroy the target cells to cause serious immunopathological lesion. Therefore we speculate that the expansion of CD(8)(+)CD(28)(-) Tr cells in children with IM may be an adaptive immune response to avoid serious inflammation and autoimmune reactions.
Zu
Ying
Y
Shenzhen Institute of Pediatrics, Shenzhen Children's Hospital, Shenzhen 518026, China.
Li
Cheng-rong
CR
Ma
Zu-xiang
ZX
Li
De-fa
DF
Fu
Xiao-ling
XL
D018106:CD28 Antigens / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D016207:Cytokines / Q000276:immunology; D020031:Epstein-Barr Virus Infections / Q000276:immunology; D005260:Female; D005434:Flow Cytometry; D004854:Herpesvirus 4, Human; D006801:Humans; D007244:Infectious Mononucleosis / Q000276:immunology* / Q000821:virology; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism; D011971:Receptors, Immunologic / Q000378:metabolism; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
D018106:CD28 Antigens; D016207:Cytokines; C491341:LILRB2 protein, human; C107907:LILRB4 protein, human; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D011971:Receptors, Immunologic