Intestinal Bifidobacterium In Infants With RLRTI And Immune Function Analysis And Correlation Study

Objective:In order to analyze the relationship between intestinal bifidobacterium and immune function,so as to explore the pathogenesis of recurrent respiratory tract infection in infants and young children and then provide new ideas and methods for the prevention and treatment of recurrent lower respiratory tract infection in infants,by comparing the concentration of intestinal Bifidobacterium in infants with recurrent lower respiratory tract infection(RLRTI) and non-recurrent lower respiratory tract infection(non-RLRTI),Methods: A case-control study was conducted to randomly select 73 infants and young children with pneumonia or bronchitis who were hospitalized in the Department of Pediatrics of our hospital from June 2021 to December 2020.The concentrations of intestinal bifidobacterium,serum levels of IL-2,IL-4,IL-6,IL-10,TNF-α and IFN-γ,and serum levels of Ig A,Ig G and Ig M were detected by PCR fluorescence quantitative method.According to the diagnostic criteria of recurrent lower respiratory tract infection,they were divided into recurrent lower respiratory tract infection group(30 cases)and non-recurrent lower respiratory tract infection group(43 cases).The concentration of intestinal bifidobacterium,the levels of IL-2,IL-4,IL-6,IL-10,TNF-α,IFN-γ,Ig A,Ig G and Ig M were compared between the two groups.The correlation between the concentration of intestinal bifidobacterium and meaningful cytokines and immunoglobulin was analyzed.Results:1.The content of fecal bifidobacterium in RLRTL group was lower than that in non-RLRTL group,and the difference was statistically significant(P=0.01);The serum IL-2 level of RLRTL group was lower than that of RLRTL group,and the difference was statistically significant(P=0.043);The serum level of IL-10 in RLRTL group was lower than that in nonRLRTL group,and the difference was statistically significant(P=0.035);The level of Ig A in RLRTL group was lower than that in non-RLRTL group,and the difference was statistically significant(P=0.035,P=0.012).2.Correlation analysis:(1)There was a positive correlation between intestinal bifidobacterium and Ig A by Sperman correlation analysis(r=0.275,P=0.019).(2)There was a positive correlation between intestinal bifidobacterium and IL-4 by Sperman correlation analysis(r=0.241,P=0.040).(3)There was a correlation between IL-2 and IL-4 by Sperman correlation analysis(r=0.649,P < 0.001),and between IL-10 and IL-6 by Sperman correlation analysis(r=0.382,P=0.005).IL-6 and IL-4 were correlated by Sperman correlation analysis(r=-0.261,P=0.026),IL-6 and INF-γ were correlated by Sperman correlation analysis(r=-0.269,P=0.022),IL-6 and INF-γwere correlated by Sperman correlation analysis.Spearman correlation analysis showed that there was a correlation between IL-6 and TNF-α(r=-0.728,P < 0.001).3.Area under ROC curve:(1)The ROC curve analysis of serum IL-2 in the diagnosis of RRTI showed that the area under the curve was 0.640,P=0.043,with statistical difference.(2)ROC curve analysis of serum IL-10 in the diagnosis of RLRTI showed that the area under the curve was 0.646,P=0.035,with statistical difference.(3)The ROC curve analysis of peripheral blood Ig A in the diagnosis of RLRTI showed that the area under the curve was0.674(P=0.012).Conclusions: 1.The content of intestinal bifidobacterium in infants is closely related to the occurrence of recurrent lower respiratory tract infection in infants,and the content of intestinal bifidobacterium in infants affects the level of Ig A in peripheral blood.2.The decrease of serum IL-2 and IL-10 levels is involved in the mechanism of recurrent lower respiratory tract infection in infants,and the immune dysfunction of Ig A is related to recurrent lower respiratory tract infection in infants.