Characteristics Of Gut Microbiota And Potential Immune Regulation In Newly Retreated Pulmonary Tuberculosis Patients

Pulmonary Tuberculosis(PTB)is a major global infectious disease that seriously endangers human health and is also an immune disease.Its occurrence,development and prognosis are closely related to the level of immune function of the body.A large number of studies have confirmed that intestinal microorganisms not only affect local immunity,but also affect systemic immunity.It can regulate,optimize and inhibit host immune response.However,few studies can fully explain the interaction between intestinal microflora changes and immune response of PTB patients at different treatment stages.This study investigates the characteristics of gut microbiota in newly treated PTB patients,including changes in composition,screening of specific marker strains,and prediction of metabolic function;At the same time,comprehensive immune assessment will be conducted on newly treated and relapsed PTB patients,including combined detection of immune cells,cytokines,and other factors.Further research will be conducted on the correlation between the selected gut microbiota and the immune indicators of the body,to explore the potential mechanism of gut microbiota regulating the body’s anti-tuberculosis protective immune response under Mycobacterium tuberculosis(M.tb)infection,in order to provide some ideas for timely immune intervention,precision medicine,and personalized treatment for PTB patients.From December 2021 to November 2022,40 PTB patients and 20health controls(HC)were included in this study.According to the grouping criteria,they were divided into 20 patients in the first-treated PTB group(FT-PTB)and 20 patients in the re-treated PTB group(RT-PTB).The participants collected blood and fresh stool samples from the corresponding anticoagulant tubes within one week after admission.Fecal samples were sequenced with 16Sr RNA to study the characteristics and changes of intestinal flora in different groups of PTB patients.The ratio of Th1 cells to Th17 cells and the spectrum of Th1/Th2 cytokines(IL-2,IL-4,IL-6,IL-10,TNF-α,IFN-γ).And CD3~+T,CD4~+T,CD8~+T count,NK cell and B cell count.Supplement personal history data,blood routine,liver and kidney function,acid-fast staining of sputum smear,tuberculosis DNA test,Gene Xpert test and other tuberculosis-related tests,and conduct secondary grouping(lung affected range and whether there are cavities)analysis and research according to the clinical data and imaging CT examination of the two groups of PTB patients.(1)The abundance and species diversity of intestinal flora in PTB group were significantly lower than those in HC group.Comparison between two PTB groups,compared with FT-PTB group,the species diversity of intestinal microflora in RT-PTB group was significantly reduced.The distribution of bacteria in different groups has both similarity and significant unique enrichment.For example,compared with HC group,the abundance of B.adolescentis,B.thermophilum,P.copri,C.clostridioform,and B.obeum in the intestines of two PTB patients was significantly decreased;The abundance of B.ovatus and D.longicatena in FT-PTB group was higher than that in the other two groups;C.ramosum is a specific marker in RT-PTB group.(2)The proportion of white blood cells,basophils,neutrophils,Th1cells,IL-2,IL-4,IL-6,IL-10,TNF-α,and IFN-γin FT-PTB group were significantly higher than those in HC group.The lymphocyte of RT-PTB group was significantly lower than that of HC group,and the expression levels of IL-2,IL-4,IL-6 and IL-10 were significantly higher than those of HC group.The proportion of neutrophils,Th17 cells and CD4~+cell count were significantly lower than those of FT-PTB group.The ratio of neutrophils to lymphocytes(NLR)and CD4/CD8 in FT-PTB and RT-PTB groups were significantly higher than those in HC group,and the PTB hemoglobin in both groups was significantly lower than that in HC group.(3)The proportion of bilateral lung lesions and lung cavities in RT-PTB group was significantly higher than that in FT-PTB group.Lymphocytes,hemoglobin,CD4/CD8 in bilateral FT-PTB group were significantly lower than those in the unilateral FT-PTB group;Lymphocytes,hemoglobin,CD4/CD8 in bilateral RT-PTB group were significantly lower than those in unilateral RT-PTB group.The hemoglobin of FT-PTB group with cavity was significantly lower than that of FT-PTB group without cavity;NLR,total bilirubin and IL-6 were significantly higher than FT-PTB group without cavities.(4)There is a correlation between the specific bacterial strains in each group screened in the early stage and blood immune indicators.There was a significant negative correlation between F.praussnitzii and IL-2 in the HC group;C.clostridioforme form is negatively correlated with eosinophil count,monocyte count,and lymphocyte count.There is a correlation between two specific bacterial strains and blood immune indicators in the FT-PTB group.A.muciniphila showed a significant positive correlation with IL-4 and IL-6;B.ovatus is positively correlated with eosinophil count and significantly negatively correlated with IL-6.There was no statistically significant correlation between specific bacterial strains and immune indicators in the RT-PTB group.In summary,the gut microbiota of the body undergoes significant changes under M.tb infection,affecting the growth and colonization of various gut microbiota,especially in the RT-PTB group.Our results preliminarily proved that the intestinal flora may participate in the potential immune regulation mechanism of PTB,and screened two specific strains with significantly reduced abundance in PTB patients and significant correlation with body cellular immunity,and two differential marker strains with significant aggregation in FT-PTB patients and certain correlation with cytokine expression.In addition,we found that the decrease in hemoglobin in PTB patients is closely related to the decrease in the abundance of selected gut marker bacteria.Nutritional deficiency caused by anemia may damage the immune system function of the body,and the decrease or degree of immune status may directly depend on the severity of nutritional loss in the body.Correcting the imbalance of gut microbiota may have clinical significance for improving the nutritional status and immune level of PTB,It’s worth further research.This study lays the foundation for future research to verify whether specific bacterial preparations can be applied to PTB animal models to balance intestinal disorders and provide immune intervention.