The Correlation Between IL-21 Level And Immuno-inflammatory Responses In HFMD Children With EV71 Infectious

Objective: To study the correlation between interleukin 21(IL-21) levels and inflammatory indicators and cytokines in Enterovirus 71 infectious patients of Hand-Footand-Mouth Disease(HFMD).providing a theoretical basis for the diagnosis, treatment and prognosis of HFMD.Methods: 109 EV71 infectious HFMD patients according to the guidelines of HFMD diagnosis and treatment of 2010 version were divided into three groups: common group, severe group and critical group. Then peripheral blood samples were collected and separately packed in heparin, EDTA-K2 and common biochemical tube in the early phase of HFMD, and The clinical data and laboratory parameters of gender, age, CRP, SAA, NEUT, LYMPH and PLT were collected. The percentage of CD4+-IL-21+T cells, expression of IL-21 m RNA and levels of serum IL-21, IFN-? were tested separately by flow cytometry, quantitative PCR and enzyme-linked immunosorbent assay(ELISA), and the levels of serum cytokines TNF-?, IL-6, IL-8, IL-10 were tested by chemical luminescence immunity analyzer of IMMULITE1000. The correlation between serum IL-21 levels, inflammatory indicators and cytokines were analyzed to explore the immune-inflammatory responses of IL-21 in EV71 infectious HFMD patients.Results: The percentage of CD4+-IL-21+T cells, expression of IL-21 m RNA and levels of serum IL-21 were significantly increased in the common group and critical group groups of HFMD compared with the control group(P<0.01), and positive correlation with the severity of disease. Comparing with the control group, the inflammatory indicators CRP, SAA, NEUT, LYMPH, PLT, NLR, PLR rised significantly in which the level of CRP hold the highest level(P<0.01). The levels of SAA?LYMPH?PLT in the three groups of HFMD were significantly increased comparing with the common and control groups(P<0.01), and NEUT, NLR, PLR in the critical group increased comparing with other groups(P<0.001). The levels of serum cytokines(IFN-?, TNF-?, IL-6, IL-8, IL-10) increased with the progress of diseases.the levels of IFN-?, TNF-?, IL-10 in three groups and IL-6, IL-8 in the severe and critical groups were significantly increased(P<0.01). Finally, Positive correlation in CRP(r=0.32, P<0.001), PLT(r=0.25, P<0.05), IFN-?(r=0.54, P<0.001), TNF-?(r=0.36, P<0.001), IL-6(r=0.30, P<0.01), IL-8(r=0.33, P<0.001), negative correlation in IL-10(r=-0.23, P<0.05), and no correlation in SAA, NEUT, LYMPH, NLR, PLR(P>0.05) were observed accompanied with serum IL-21 levels.Conclusion: IL-21 might be a new type of inflammatory cytokines that involved in immune-inflammatory response of EV71 infectious HFMD patients, and closely related to development of HFMD.