Study On The Level Of Cytokines In Serum Of Patients With Severe Fever With Thrombocytopenia Syndrome

ObjectivesSevere fever with thrombocytopenia syndrome(SFTS)is a novel infectious disease caused by severe fever with thrombocytopenia syndrome virus(SFTSV).Due to the high case-fatality rate and no targeted vaccine,it has become an important public health problem.The purposes of this study are to explore its clinical significance and an in-depth understanding of the pathogenesis of SFTSV.MethodsBased on previous investigation and research,the 990 Hospital of the joint service support force of the Chinese people's Liberation Army(Formerly known as 154 Hospital of the Chinese people's Liberation Army)in Xinyang City,Henan Province,was selected as the research site to collect the clinical case data and patient serum samples of SFTS in 2018-2019.The epidemiological survey of the infection of SFTSV in the natural population was carried out in 2016-2018 in Xinyang City through the Infectious Diseases Institute of Henan Center for Disease Control and Prevention,and a total of 100 subjects were included in the study.Cytokine levels were detected by ELISA kit and viral load was detected by micro drop digital PCR.For the continuous quantitative data conforming to normal distribution,t test or variance analysis was used.For the quantitative data not conforming to normal distribution,nonparametric test comparative analysis was used.For the correlation of continuous variables,pearson correlation analysis was used.For the analysis of qualitative data,x2 test was used.The mapping tool was the software of Graphpad prism 7(USA)and QuantaSoft(USA,BIO-RAD).The statistical analysis software was the SPSS 21.0(SPSS,Chicago,IL).All the tests were bilateral,P<0.05 was considered the difference had statistically significant.Results1.The levels of IL-6,IL-8,IL-10,IP-10,MCP-1,MIP-1?,IFN-(?),TGF-?1,and RANTES in serum were significantly different among the three groups(P<0.05),the levels of IL-6,IL-6,IL-10,IP-10,MCP-1,and IFN-(?)in SFTS patient group were significantly higher than that in the asymptomatic infection group and the healthy people group,but the levels of IL-8,TGF-?1,and RANTES were significantly lower(P<0.0167),the levels of IL-10,IP-10,MIP-1?,IFN-(?)TNF-? and RANTES in the healthy people group were not significantly different from those in the asymptomatic infection group,but there were significant differences in the levels of IL-6,IL-8,MCP-1,and TGF-?1.The level of RANTES in the asymptomatic infection group was higher than those in the patient group,but there was no significant difference between the asymptomatic infection group and the healthy group(P>0.0167).2.During the observation period,the levels of IL-8 and IL-10 gradually increased with the increase of course time,while the level of IP-10 gradually decreased;the level of MIP-1? did not fluctuate significantly after hospitalization.It should be noted that the serum levels of IL-6,MCP-1,TGF-?1 and RANTES had the tendency of first increasing and then decreasing or first decreasing and then increasing.3.The serum levels of IL-6,IL-10,IP-10 and MCP-1 in the severe group were significantly higher than those in the mild group(P<0.05),while the serum levels of IL-8,MIP-1?,TGF-?1 and RANTES were not significantly different between the severe group and the mild group(P>0.05).4.There was a significant difference in viral load between patients with mild and severe symptoms,and the viral load of patients with severe symptoms was higher than that of patients with mild symptoms(P<0.05).The correlation analysis showed that the viral load was positively correlated with the levels of IL-6 and IP-10,but negatively correlated with the levels of RANTES(P<0.05).Conclusions1.SFTSV could cause a cytokine change.The cytokine levels of patients had different degrees of fluctuation after the onset of the disease,suggesting that the levels of cytokines might be changing dynamically in this process,rather than simply increasing or decreasing.2.The levels of IL-6,IL-10,IP-10 and MCP-1 in serum could reflect the severity of the disease,and the levels of some cytokines(IL-6,IP-10,RANTES)were correlated with the viral load.3.The levels of serum cytokines(IL-6,IL-8)in the asymptomatic infection group were between the SFTS patients group and the healthy people group.Immune system of some infected people could clear SFTSV and no clinical symptoms.