Immune Features Of Childhood And Adulthood Tuberculosis Patients

Tuberculosis is a serious threat to human life and health worldwide.Despite the joint efforts,there are still estimated 10 million new cases each year,including 1 million children who are vulnerable to severe threat.Immune response was known to has a dominant role against M.tuberculosis infection.However,it is still seriously lack of in-depth analysis concerning tuberculosis pathogenesis and protective immunity,especially among children.This study mainly adopts the strategy of exploring systemic immunology,based on multiparametric flow cytometry to intricately analyze the immune status of children and adults with tuberculosis.On the same time,we establish a comparative immune-profiling of adults with tuberculosis before and after the treatment,hoping to identify tuberculosis-specific immune alterations and to provide substantial scopes for the novel diagnosis and treatment.This study includes two parts:childhood and adulthood tuberculosis research.The objectives,methods,the main results and conclusions of two studies are presented separately as below.1.Childhood tuberculosis researchObjectives:Infants are highly susceptible to Mycobacterium tuberculosis,which may be related to their specific immune status.However,there is a lack of understanding of children's immune status.A systematic dissection of the global immune status of childhood TB?cTB?is urgently needed.The purpose of this part is to comprehensively profile the peripheral immune cells and soluble immune factors in cTB patients and healthy controls and to identify disease-specific immune changes.Methods:Whole blood was collected from two groups of clinically diagnosed cTB patients below and above 5-year-old?Pt<5,n=23 and Pt>5,n=22?,and corresponding healthy controls?HC<5,n=25,and HC>5,n=20?.Flow cytometry was used to measure the frequency of circulating immune cells and the T cells specific IFN-?response after the stimulation of mycobacterial antigens.Plasma cytokines were detected by Luminex xMAP Technology.Main Results:Common abnormality was observed in cTB patients for decreased frequency of IgM⁺memory B cells,V?2??T cell and central memory regulatory T cells?Tregs?and increased frequency of effector memory Tregs.Furthermore,CD56^lo NK cells were strongly decreased in Pt>5 group.There were higher CD4 T cell IFN-?responses to ESAT-6 and CFP-10 antigens in both cTB groups;strikingly,only the Pt>5group had an increased CD8 T cell IFN-?response to CFP-10 antigens.Plasma cytokine profiling indicated a systemic Th1 response in both cTB groups.Conclusions:Immune profiling indicated that even cTB patients exhibited a Th1-dominant response and immune activation,strong defects in cytotoxic lymphocyte compartment were observed.This study could provide new immunological clues for the prevention and treatment of cTB.2.Adulthood tuberculosis researchObjectives:At present,there is no clear understanding of tuberculosis immunity.In this part,we showed the disease-specific immune cell changes by comparing the status of immune cells in peripheral blood between tuberculosis patients and healthy controls.Furthermore,a follow-up study of the immune cells in tuberculosis patients is planned to investigate the potential predictive immune markers.Methods:Flow cytometry was used to detect the immune cells from the blood of bacteriologically diagnosed tuberculosis patients?Pt-B,n=38?,clinically diagnosed tuberculosis patients?Pt-C,n=34?and corresponding healthy controls?HC,n=26?.In addition,blood samples from 22 tuberculosis patients were analyzed at three time points?month 0,3 and 6?.Main results:The immune status of tuberculosis patients was in a highly activated state,and the degree of activation decreased after treatment.The frequency of activated V?1??T cells decreased significantly after 3 months of treatment,but then increased significantly to the level of healthy control.The frequency of effective memory V?2??T cells decreased significantly after 6 months'treatment.The frequency of naive B cells in tuberculosis patients increased significantly,while the frequency of memory B cells,including IgM⁺Bm and class-switched memory B cells,decreased significantly.Conclusion:Immune profiling analysis showed that the immune status of tuberculosis patients was highly activated,and there were some differences between the immune status of bacteriologically diagnosed tuberculosis patients and clinically diagnosed tuberculosis patients.Effector memory V?2??T cells and V?1??T cells may play an important role in the rapid elimination of Mycobacterium tuberculosis.What's more,humoral immune response may play an important role in anti-tuberculosis immunity.In conclusion,T cells in tuberculosis patients showed a highly activated state,both in children and adults.Th1 response played an undeniable role in anti-tuberculosis immunity,but cytotoxic killer cells,including NK cell,MAIT and V?2??T cells,also play a crucial role in anti-tuberculosis immunity.Humoral immunity,which has been neglected for a long time,may also play an important role in anti-tuberculosis immunity.Defects in B cells,NK cells and MAIT cells may be a potential cause of high susceptibility of children to TB.The pathological and physiological mechanisms of CD8 T cells selectively response to CFP-10 in childhood tuberculosis needs further study.The immune parameters identified in this study could provide novel clues to the prevention,diagnosis and treatment of childhood and adulthood tuberculosis.