| Objective: Malaria is a worldwide public health problem.Plasmodium are the pathogen basis of disease.According to the world health organization’s malaria report in 2017,there are 21.6 million cases of malaria infection in 91 cities and more than 445,000 deaths,with malaria cases increasing by 5 million compared with previous years.In which Plasmodium vivax is widely distributed,mainly in Asia and the Pacific.At present,Plasmodium vivax is an important disease committed by malaria researchers worldwide.The analysis of immune response characteristics and its correlation with the clinical manifestations will be required to reveal the pathogenic mechanism of malaria parasites.The analysis of chemokine/cytokine changes in the host of Plasmodium infection will certainly provide a new direction for researchers.Invision of Plasmodium into the body causes an immune response involving a series of immune cells,and chemokines and cytokines are essential for the recruitment of immune cells and the regulation of their functions.Chemokine is a family of about 8-14 kD peptides that can signal through seven transmembrane G protein-coupled receptors(GPCRs).Depending on the degree of sequence homology of different chemokines,it is divided into CC,CXC,C and CX3 C subfamily.A large number of studies have shown that chemokines play important biological functions in the process of invasion of the human body by Plasmodium.Cytokines are a class of small molecule polypeptides/glycoproteins produced by cells that have a variety of biological functions.IL-2 is an important T cell proliferative factor that can induce Th0 to Th1 differentiation.IL-2,IFN-γ,and IL-12 mainly act on Th1 type cells and mediate the cellular immune response.Cytokines such as IL-4 and IL-10 mainly mediate Th2 type immune responses and promote the differentiation of B cells into plasma cells,producing antibodies.IL-1β,IL-6 and TNF-α are pro-inflammatory cytokines produced by macrophages and can cause clinical reactions such as fever and inflammation.The progress of studies in P.vivax is slower than that of Plasmodium falciparum,but this situation has changed after scientific and technological progress and our increased awareness of the malaria infection caused by P.vivax.Relative to the severe clinical manifestations and mortality of P.falciparum,P.vivax appears to be less important,but P.vivax has a dormant life cycle stage and it can reside in the liver of the infected host,making it difficult to be removed by the immune system and anti-malaria drugs.The presence of P.vivax asymptomatic infection is still present.It can be used as a carrier to spread malaria,which makes malaria work a great challenge.In China,high malaria-prone areas are mainly located in Yunnan,Hainan,and Guangxi,especially the malaria epidemic area at the national border between China and Myanmar.In recent years,China-Myanmar tourism has been developing vigorously,and the malaria infection on the China-Myanmar border is likely to affect the status of malaria infection in the country.The China-Myanmar border is a high-risk area of P.??vivax,studies in a large number of malaria patients and local asymptomatic infection will have great significance in the investigation of malaria.In 2015 we in yunnan and myanmar border epidemiological investigation,and collected a large number of local,analysis of the detection index and the correlation of basic data and the internal relation between each factor,will provide strong clues for the prevention and control of plasmodium vivax.Methods: In 2015,we conducted an epidemiological investigation of P.vivax in China and Myanmar border.(1)Sample collection: under the requirement of the ethical statments,and obtaining the participants’ right of informed consent,medical professionals collect blood samples from participants,record basic information,prepare blood smears,and microscopically determine the infection type and parasitemia.Plasma were separated and stored at-80℃.(2)Experimental grouping:Epidemic controls(EC): 30 cases Asymptomatic P.v infection(Asym): 38 cases Symptomatic P.v.infected patients(Symp): 92 Cases(3)Determine the expression of chemokines and cytokines in plasma samples using suspension chip technology: according to the kit’s instructions,magnetic beads were loaded into the 96-well plates.After washing,4-fold dilution of samples and standards were added into each well and incubated in the dark for 1 hour while shaking.After incubation,the plate was washed three times with the washing buffer,and then the detection antibody was added into each well.Then the plate was incubated in the dark for30 minutes while shaking.After washing the plate,PE staining buffer was loaded into the plate.15 minutes later,125 ul of assay buffer was added to each well.The plate was shaken for 30 seconds,and read by Luminex 200.(4)Statistical Analysis: Experimental data were processed by Bioplex Manager(Bio-Rad Version 4.0)software,and the concentration values ??of each detection index were converted according to the standard curve.Statistical analysis of sample data was performed using statistical software SPSS 13.0,R software,SPSS.11 and GraphPad prism 5.After verification,the experimental data does not follow the normal distribution and the variance is uneven.Therefore,non-parametric statistical methods are used for analysis.In the statistical method,two groups were compared using the Mann-Whitney U test,and multiple groups were compared using the one-way Kruskal-Wallis test.At the same time,the Spearman correlation analysis and the orthogonal correction of partial least squares analysis(OPLS)were used to further analyze the intrinsic relationship between mediators and diseases.Results: 1.In the china-myanmar border area,plasmodium vivax infection causes the levels of various chemokines/cytokines changed in the patients,and these chemokines/cytokines are highly correlated.2.IL-10,CCL27,CX3CL1,CXCL9,CXCL11,and CXCL13 can be used as key factors in identifying P.vivax infection.3.CCL23,CCL8,CXCL10,CXCL16,TNF-α and IL-6 can be used as biomarkers related to the symptoms of malaria infection.Their expressions are positively related to the levels of parasitemia and body temperature of the patients.4.The level of CCL22 acts as a key indicator for the screening of asymptomatic infection,its expression level is negatively correlated with the age of the participants.Conclusion: In 2015,the investigation of the host immune status of P.vivax infection was conducted in the malaria endemic region of China-Myanmar border.Tthe identification of the key chemokines/cytokines of P.vivax infection,and the biomarkers of asymptomatic infections will provide a new basis for the further development of prevention and control against malaria. |
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