Study On NK Cell Number, Subsets, Receptors And Immune Effector Molecules In Children With Hand-food-mouth Disease Caused By Enterovirus71

Background：Hand-foot-mouth disease (HFMD) is a common oneof the global pandemic diseases caused by a variety of enterovirus. In recentyears, EV71is concerned as the main pathogen of HFMD in some regions ofChina because of its complications of nervous system. A lot of researchshows that EV71infection may led to children immune disorders.Congenital immune is the first line of defence in antiviral infection, NK cells,as its key cells, plays a very important role in the process of intestinal virus.Research reports that the decrease or defects of NK cells function can causeserious intestinal virus infection.Objective：To investigate the function of NK cells and its probablerole in the pathogenesis in Hand-foot-mouth disease (HFMD) caused by EV71.Methods：There were three groups,20cases in severe group,20casesin usual group, and30healthy children control group. All children were1-3years old. The percentage, the subsets, the surface receptors (NKp30, NKp 46, NKG2D, CD94, NKG2A and CD107a) and effector molecules (PF, GrBand GNLY) were detected by flow cytometry.Results：The percentage of NK cell in severe group was significantlyreduced than that in control group (P<0.01). Although the number of NKcell in the usual group was higher than that in the severe group, there was nosignificant difference (P>0.05). CD16~+%NK cell subset ratio in usual groupwas increased than that in control group (P<0.05). Although CD16+%NKcell subset ratio in severe group was decreased than that in usual group, therewas no significant difference (P>0.05). The percentage of NKG2D positivecells in severe group or usual group was lower than that in control group (P<0.01). The percentage of CD94, NKG2A, CD107a, PF, GrB or GNLYpositive cells in severe group or usual group was higher than that in controls(P<0.01or P<0.05), but there was no significant difference between severegroup and usual group (P>0.05). No significant difference in the percentageof positive cells for NKp30and NKp46among the three groups (P>0.05).Conclusion：EV71could reduce NK cells and CD16~+NK cell subsetsin children. It also could up-regulate the expression of inhibitory receptorCD94or NK G2A, and could down-regulate the expression of activatereceptor NKG2D. The secretions of PF, GrB and GNLY were reduced. Thefunction of NK cells could be inhibited in children with HFMD caused byEV71.