Association Of Serum 25-(OH) D Level And The Severity Of Enterovirus 71 Type HFMD In Children

BACKGROUND:EV71 hand-foot-mouth disease(HFMD)has a high fatality rate and a poor prognosis for severe and critically ill patients.It is necessary to identify the risk factors that leading to the seriousness of EV71 HFMD and providing timely intervention.In recent years,serum 25-(OH)D levels have a certain correlation with various infectious diseases in children,but there have been few studies on serum 25-(OH)D and EV71 HFMD in published literature at home and abroad.Therefore,this study used the clinical data of EV71 HFMD to comprehensively evaluate the epidemic characteristics and critical risk factors of EV71 HFMD,and explore the risk factors of severe hand-foot-mouth disease,revealing the serum 25-(OH)D level and the severity of EV71 type HFMD,the correlation between serum 25-(OH)D level and immune function in children with EV71 type HFMD was further evaluated,to verify the reliability of the research of this subject.METHODS:A total of 402 children with EV71 HFMD who were admitted to hospital from January 2017 to December 2019 in the Xi'an Children's Hospital were selected as the case group,including 252 in the general group and 150 in the severe group.At the same time,100 healthy children were selected as the control group.The serum 25-(OH)D levels and T lymphocyte subsets of the study subjects were detected,and the clinical data of the children in the case group were collected to record the factors that may affect the severity of EV71 HFMD.Compare the relationship between serum 25-(OH)D levels in each group,and use ROC curves to calculate the cut-off value of serum 25-(OH)D levels in the case group,and study the association between serum 25-(OH)D levels and the severity of EV71 HFMD.In addition,the cellular immune function of the case group was examined,and the correlation between serum 25-(OH)D level and cellular immune function was analyzed to further confirm the correlation between the severity of EV71 type HFMD and serum 25-(OH)D level.RESULTS:(1)Compared with the control group,the serum 25-(OH)D level of the case group was significantly reduced(P<0.05).Compared with the case group,the severe group was lower than the ordinary group,and the ordinary group was lower than the control group.The differences were statistically significant(P<0.05).(2)Compared with the severe group of EV71 HFMD,there were significant differences in serum 25-(OH)D levels,WBC>15×10~9/L,and blood glucose>8.3mmol/L(P<0.05).ROC curve analysis showed that the serum 25-(OH)D concentration was 30.31ng/ml.The Jordan index was the largest,with a specificity of 65%and a sensitivity of 72%.According to the 25-(OH)D cut-off value of 30.31 ng/ml,402 patients were divided into two groups.The risk of 25-(OH)D<30.31 ng/ml was significantly higher than that of25-(OH)D>30.31 ng/ml group(P<0.05).(3)Multivariate Logistic regression analysis found that WBC>15×10~9/L,blood glucose>8.3mmol/L,25-(OH)D<30.31ng/ml were statistically significant(P<0.05),and concluded 25(OH)D<30.31ng/ml is a risk factor for severe disease in children with EV71type HFMD.(4)Compared with the control group,the levels of T lymphocyte subsets(CD3~+,CD4~+,CD8~+percentage,CD4~+/CD8~+ratio)of the children in the case group were all reduced,and the case group was significantly lower than the normal group.The serum 25-(OH)D level in the case group was positively correlated with the level of T lymphocyte subsets,and the differences were statistically significant(P<0.05).CONCLUSIONS:(1)The serum 25-(OH)D level of children with EV71 type HFMD is related to the degree of illness.The more severe the illness,the lower the serum 25-(OH)D level.When serum 25-(OH)D<30.31ng/ml has important predictive value,it may be an early warning factor for the severity of EV71 HFMD.(2)The cellular immune function of children with EV71 type HFMD is positively correlated with serum 25-(OH)D levels.When serum 25-(OH)D is deficient or insufficient,the antiviral immune function of children with EV71 type HFMD is reduced.It is suggested that monitoring serum 25-(OH)D level has important clinical significance for evaluating the severity,early intervention,and prognosis of children with EV71 type HFMD.