Expression Of Pattern Recognition Receptor In Patients Of EV71

Objective:To investigate the expression of pattern recognition receptor (PRR) of immune cells from the patients with enterovirus71(EV71) infection and the changes of cytokines.Methods:71patients and20age-matched healthy children were enrolled in the study. The patients were divided into three groups according to the critical degree:20mild patients,25severe patients and26critical patients. Real-time PCR were used to evaluate the levels of RlG-I(Retinoic acidinducible gene I)、 MDA5(Melanoma differentitation-associated gene5) and cytokines IL-12、 IFN-a mRNA expression in peripheral blood mononuclear cells(PBMC).The proportions of Toll like receptors(TLRs) on MC (monocytes/macrophages)、mDC(myloiddentritic cells) and pDC(plasmacytoiddentritic cells) were analyzed by flow cytometry. The concentrations of plasma cytokines(IL-12、 IFN-a) were measured by enzyme-linked immunosorbent assay (ELISA).Results:(1) The proportion of TLR7is the unique TLR which is increased in mild patients and it was significantly elevated in MC、mDC and pDC in severe group (P <0.05),TLR2、 TLR3and TLR4also had an enhanced expression in MC and mDC. The enhanced expression of TLRs mentioned above had a decreased trend in critical patients.(2)Transcription levels of RIG-I and MDA5was significantly elevated in EV71infected children.(3)The expression levels of DC-associated cytokines gene (IL-12and IFN-a) have an increased trend in mild cases and these cytokines were remarkably increased in severe patients (P<0.05),whereas decreased in critical cases (P<0.05).Conclusion:TLR7might be the main PRR recognizing EV71in immune cells and RIG-I/MDA5might also take part in the recognition of EV71. The exogenous or endogenous ligands released from bacterial infection and cell destruction could result in the activation of TLR2or TLR4, inducing the inflammatory response. The concentration of the cytokines (IL-12、IFN-a) increased in severe patients while decreased in critical patients.