Shifts of T4/T8 T lymphocytes from BAL fluid and peripheral blood by clinical grade in patients with pulmonary tuberculosis

Characterization of Immune Cells From the Lungs of Patients With Chronic Non-Tuberculous Mycobacteria or Pseudomonas aeruginosa Infection

Little is known of the lung cellular immunophenotypes in patients with non-tuberculous mycobacterial lung disease (NTM-LD). Flow-cytometric analyses for the major myeloid and lymphoid cell subsets were performed in less- and more-diseased areas of surgically resected lungs from six patients with NTM-LD and two with Pseudomonas aeruginosa lung disease (PsA-LD). Lymphocytes, comprised mainly of NK cells, CD4⁺ and CD8⁺ T cells, and B cells, accounted for ~60% of all leukocytes, with greater prevalence of T and B cells in more-diseased areas. In contrast, fewer neutrophils were found with decreased number in more-diseased areas. Compared to NTM-LD, lung tissues from patients with PsA-LD demonstrated relatively lower numbers of T and B lymphocytes but similar numbers of NK cells. While this study demonstrated a large influx of lymphocytes into the lungs of patients with chronic NTM-LD, further analyses of their phenotypes are necessary to determine the significance of these findings.

Bronchoalveolar lavage as a diagnostic procedure: a review of known cellular and molecular findings in various lung diseases

Bronchoalveolar lavage (BAL) is a commonly used procedure in the evaluation of lung disease as it allows for sampling of the lower respiratory tract. In many circumstances, BAL differential cell counts have been reported to be typical of specific lung disorders. In addition, more specific diagnostic tests including molecular assays such as polymerase chain reaction (PCR) or enzyme-linked immunosorbent assay, special cytopathologic stains, or particular microscopic findings have been described as part of BAL fluid analysis. This review focuses on common cellular and molecular findings of BAL in a wide range of lung diseases. Since the performance of the first lung irrigation in 1927, BAL has become a common and important diagnostic tool. While some pulmonary disorders have a highly characteristic signature of BAL findings, BAL results alone often lack specificity and require interpretation along with other clinical and radiographic details. Development of new diagnostic assays is certain to reinforce the utility of BAL in the future. Our review of the BAL literature is intended to serve as a resource to assist clinicians in the care of patients with lung disorders.

Immunology of Mycobacterium tuberculosis Infections

Tuberculosis (TB) is a serious global public health challenge that results in significant morbidity and mortality worldwide. TB is caused by infection with the bacilli Mycobacterium tuberculosis (M. tuberculosis), which has evolved a wide variety of strategies in order to thrive within its host. Understanding the complex interactions between M. tuberculosis and host immunity can inform the rational design of better TB vaccines and therapeutics. This chapter covers innate and adaptive immunity against M. tuberculosis infection, including insights on bacterial immune evasion and subversion garnered from animal models of infection and human studies. In addition, this chapter discusses the immunology of the TB granuloma, TB diagnostics, and TB comorbidities. Finally, this chapter provides a broad overview of the current TB vaccine pipeline.

Immunological biomarkers of subclinical infection in household contacts of leprosy patients

Hansen's disease (or leprosy) still persists as a serious public health issue. Its diagnosis is based primarily on the detection of clinical signs that are characteristic of the disease. Studies have pointed to the selection of a set of serological and cellular biomarkers of subclinical infection that result in an efficient diagnosis. The aim of this study was compare index cases and their household contacts to identify differentially expressed biomarkers of immune response in leprosy that could provide reliable evidence of subclinical infection in household contacts. The study population consisted of index cases with multibacillary form (IC, n = 13) and their household contacts (HC, n = 14). Serum cytokines and chemokines were quantified using the cytometric beads array (CBA) system. The humoral response was assessed by ELISA test. Flow cytometry was used to characterize the cellular immune response. Monocyte and CD4 + T lymphocytes frequency was significantly higher in IC. Both CD4+ and CD8 + T lymphocytes had a reduced CD25 expression in HC. The immunoglobulin (Ig)M profile anti- NDO-HSA, LID-1, and NDOLID antigens was significantly higher in IC. This study points to the monocyte and CD4+ lymphocyte frequency, as well as specific IgM profile, as predictors of subclinical infection in the household contacts.

Increased Aqueous Humor CD4+/CD8+ Lymphocyte Ratio in Sarcoid Uveitis

Purpose: To determine aqueous humor CD4+/CD8+ T-lymphocyte ratio changes in sarcoid and non-sarcoid uveitis with anterior chamber involvement. Methods: The case-control study includes 61 patients with either anterior uveitis, intermediate uveitis with anterior spill, or panuveitis. A total of 21 of them were categorized as sarcoid uveitis and 40 as non-sarcoid uveitis according to diagnostic criteria. CD4+/CD8+ ratio in the aqueous humor was determined using flow cytometry. Results: Significantly higher CD4+/CD8+ ratio in the aqueous humor was observed in patients with sarcoid uveitis (6.3 ± 1.4; mean ± SEM) compared to non-sarcoid uveitis (1.6 ± 0.1; mean ± SEM). Whole blood CD4+/CD8+ ratio was not elevated in subjects with sarcoid and non-sarcoid uveitis. Aqueous humor CD4+/CD8+ ratio >3.5 was observed to be associated with sarcoid uveitis (OR 38, 95% CI 7.0-205.2). Conclusion: Increased aqueous humor CD4+/CD8+ ratio in sarcoid uveitis. Immunophenotyping of localized lymphocytosis in aqueous humor could be utilized as an additional confirmatory marker for ocular sarcoidosis.

Comparison of immune peripheral blood cells in tuberculin reactor cattle that are seropositive or seronegative for Mycobacterium bovis antigens

Bovine tuberculosis (bTB) is a major economic problem in animal husbandry and is a public health risk in nonindustrialized countries. It is generally accepted that protection against TB is generated through cell-mediated immunity. Previous investigations have shown that WC1(+) γδ, CD4(+) and CD8(+) T-cell subpopulations are important in the immune response to bTB. It is known that changes in the immune balance from a dominant T helper 1 (Th1)-type response toward a more prominent Th2 response may be observed during disease progression. In this study, we aimed to investigate immune peripheral blood cells in tuberculin reactor cattle that are seropositive or seronegative for Mycobacterium bovis antigens, using flow cytometry and hematological analysis. The evaluation of the T cell subpopulations revealed a decrease in CD8(+) T cells of the seropositive and seronegative animals compared with the control animals (p=0.0001). Moreover, the seropositive group exhibited a lower percentage of CD8(+) T cells than the seronegative group. The percentage of B cells was significantly increased in the seropositive group compared with the seronegative group and the control group (p=0.0009). No difference was observed in the percentage of WC1(+) γδ and CD4(+) T cells among the groups. Furthermore, following 24h of peripheral blood culture with bovine purified protein derivative (PPD), both apparently infected groups showed an increase in the levels of cellular activation compared with the control group (p<0.0001). The seropositive group displayed a higher level of cellular activation than the seronegative group. In both apparently infected groups, the hematological analysis showed an increase in total leukocyte (p=0.0012), lymphocyte (p=0.0057), monocyte (p=0.0010) and neutrophil (p=0.0320) counts in comparison with the healthy animals. Our results demonstrated differences in immune peripheral blood cells of tuberculin reactor cattle that are seropositive or seronegative for M. bovis antigens, probably due to different stages of bTB among the groups. The percentages of CD8(+) T cells, B cells and the T cell activation levels may represent biomarkers for the progression of the disease. However, general characteristics shared by both apparently infected groups as lymphocytosis and monocytosis may also be indicative of the disease. Further experiments are required to understand the variations between cellular and humoral immunities throughout the course of bTB infection. A detailed knowledge of the peripheral blood cells involved in all stages of the bTB immune response of naturally infected cattle is essential for the optimal exploitation of diagnosis and vaccination models.

Significance of the frequency of CD4+CD25+CD127- T-cells in patients with pulmonary tuberculosis and diabetes mellitus

BACKGROUND AND OBJECTIVE

Pulmonary tuberculosis and diabetes mellitus (DM) are closely associated. The objective of this study was to determine whether the expression of CD4+CD25+CD127- T-cells (regulatory T-cells (Treg)) is associated with diabetic pulmonary tuberculosis.

METHODS

Flow cytometry was used to determine the frequencies of CD4+CD25+ and CD4+CD25+CD127- T-cells in peripheral blood, bronchoalveolar lavage fluid (BALF) and pleural effusions from 120 patients (30 with pulmonary tuberculosis and DM (TBDM), 30 with pulmonary tuberculosis without DM (TB), 30 with tuberculous pleurisy without DM (TBP) and 30 healthy volunteers). The concentrations of interferon (IFN)-γ and interleukin (IL)-10 in BALF and pleural effusions were determined by enzyme-linked immunosorbent assay.

RESULTS

Treg frequencies in peripheral blood were significantly higher in patients with TBDM, TB and TBP than in the control group, with the frequency in TBDM being the highest (P < 0.01 for all). In TBP patients, Treg frequencies were significantly lower in pleural effusions than in peripheral blood. In TB patients, Treg frequencies in BALF and peripheral blood were not significantly different. However, in TBDM patients, Treg frequencies were significantly higher in BALF than in peripheral blood. IL-10 expression was significantly higher, and IFN-γ expression was significantly lower in BALF of TBDM patients compared with BALF and pleural effusions of TB patients.

CONCLUSIONS

In patients with pulmonary tuberculosis and DM, the imbalance between Treg and effector T-cells at pathological sites may be associated with weakened immunity and clinical manifestations of TB.

Pneumonitis induced by rifampicin: a case report and literature review

An 84-year-old woman being treated for miliary tuberculosis (TB) with rifampicin (RFP), isoniazid (INH), ethambutol (EB) and corticosteroids suffered from a persistent fever for five months. While tapering the dose of prednisolone, chest computed tomography (CT) revealed diffuse ground glass opacities (GGO) and bronchoalveolar lavage fluid (BALF) showed an increase in lymphocytes. After the anti-TB drugs were discontinued and the dose of the corticosteroids was increased, the CT findings and fever improved considerably. However, readministration of RFP provoked an inflammatory reaction, leading to a diagnosis of RFP-induced pneumonitis. This condition is very rare. This is the first report of RFP-induced pneumonitis occurring during adjunct steroid therapy.

Immune responses in the lungs of patients with tuberculous pleural effusion without pulmonary tuberculosis

Background

Tuberculous pleural effusion (TPE) is one of the most common forms of extrapulmonary tuberculosis. Because most studies of TPE focused on the pleural space, little information regarding lung parenchyma is available. We therefore aimed to investigate immune responses in the lung parenchyma of TPE patients without pulmonary tuberculosis.

Methods

Patients with any evidence of pulmonary tuberculosis, either from radiologic or bacteriologic evaluation, were excluded. Bronchoalveolar lavage fluid (BALF) was collected from 10 newly diagnosed, untreated, HIV-negative TPE patients and 10 healthy controls. We analyzed T-lymphocyte subpopulations and measured 10 cytokines in BALF. Cytokine levels in BALF were standardised using urea.

Results

The concentrations of interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), vascular endothelial growth factor (VEGF), and the CD4+/CD8+ ratio of T-lymphocytes were significantly higher in TPE patients without pulmonary tuberculosis than in the controls. Of the cytokines measured in BALF, VEGF showed the highest concentration. No difference was observed in T-helper type 2 cytokines between the 2 groups.

Conclusion

There were significant immune responses and increases in IFN-γ, TNF-α, and VEGF in the lung parenchyma of TPE patients without pulmonary tuberculosis. This result suggests that TPE may induce a significant immune response in lung parenchyma.

Immunodiagnosis of tuberculosis: a dynamic view of biomarker discovery

Infection with Mycobacterium tuberculosis causes a variety of clinical conditions ranging from life-long asymptomatic infection to overt disease with increasingly severe tissue damage and a heavy bacillary burden. Immune biomarkers should follow the evolution of infection and disease because the host immune response is at the core of protection against disease and tissue damage in M. tuberculosis infection. Moreover, levels of immune markers are often affected by the antigen load. We review how the clinical spectrum of M. tuberculosis infection correlates with the evolution of granulomatous lesions and how granuloma structural changes are reflected in the peripheral circulation. We also discuss how antigen-specific, peripheral immune responses change during infection and how these changes are associated with the physiology of the tubercle bacillus. We propose that a dynamic approach to immune biomarker research should overcome the challenges of identifying those asymptomatic and symptomatic stages of infection that require antituberculosis treatment. Implementation of such a view requires longitudinal studies and a systems immunology approach leading to multianalyte assays.

Significant increase in natural-killer T cells in patients with tuberculosis complicated by type 2 diabetes mellitus

This study examined the frequency of Vα24(+)/Vβ11(+) natural-killer T (NKT) cells from peripheral blood and bronchoalveolar lavage fluid in pulmonary tuberculosis (TB) patients with or without diabetes mellitus (DM). The clinical grade of TB was significantly higher among diabetic patients. NKT cells from both peripheral blood and bronchoalveolar lavage were significantly increased in diabetic TB patients compared with non-diabetic TB patients. This may be due to the generally higher bacillary burden in diabetic TB patients. NKT cells from peripheral blood mononuclear cells in TB patients with or without DM were significantly increased, compared with levels in non-TB diabetic patients and healthy controls. The measurement of NKT cells from peripheral blood has the potential to be a reliable, non-invasive, practical diagnostic marker for active TB.

Decreased expression of T-cell costimulatory molecule CD28 on CD4 and CD8 T cells of mexican patients with pulmonary tuberculosis

Patients with tuberculosis frequently develop anergy, a state of T-cell hyporesponsiveness in which defective T-cell costimulation could be a factor. To know if the expression of T-cell costimulatory molecules was altered in tuberculosis, we analyzed the peripheral blood T-cell phenotype of 23 Mexican patients with pulmonary tuberculosis. There was severe CD4 (P < .001) and CD8 (P < .01) lymphopenia and upregulation of costimulatory molecule CD30 on CD4 and CD8 T cells (P < .05); this increase was higher in relapsing tuberculosis. The main finding was severe downregulation of the major costimulatory molecule CD28 on both CD8 and CD4 T cells (P < .001). Depletion of the CD4/CD28 subset, a hitherto undescribed finding, is relevant because CD4 T cells constitute the main arm of the cell-mediated antimycobacterial immune response.

Pulmonary disorders, including vocal cord dysfunction

The lung is a very complex immunologic organ and responds in a variety of ways to inhaled antigens, organic or inorganic materials, infectious or saprophytic agents, fumes, and irritants. There might be airways obstruction, restriction, neither, or both accompanied by inflammatory destruction of the pulmonary interstitium, alveoli, or bronchioles. This review focuses on diseases organized by their predominant immunologic responses, either innate or acquired. Pulmonary innate immune conditions include transfusion-related acute lung injury, World Trade Center cough, and acute respiratory distress syndrome. Adaptive immunity responses involve the systemic and mucosal immune systems, activated lymphocytes, cytokines, and antibodies that produce CD4(+) T(H)1 phenotypes, such as for tuberculosis or acute forms of hypersensitivity pneumonitis, and CD4(+) T(H)2 phenotypes, such as for asthma, Churg-Strauss syndrome, and allergic bronchopulmonary aspergillosis.

Can immune parameters be used as predictors to distinguish between pulmonary multidrug-resistant and drug-sensitive tuberculosis?

INTRODUCTION

Despite the development and wide implementation of Directly Observed Therapy Strategies (DOTS), multidrug-resistant tuberculosis (MDR-TB) remains a serious global health threat. In this study, the role of host immune response in patients with MDR-TB is investigated and compared with that of patients with smear-positive drug-sensitive tuberculosis (SP-TB).

MATERIAL AND METHODS

27 patients with SP-TB, 20 patients with MDR-TB, and 20 healthy controls were included in the study. Immune parameters were determined by flow cytometry using monoclonal antibodies in order to compare the percentage values of these markers in the two study groups and the control group.

RESULTS

The levels of lymphocyte subgroups in the gate of CD45(+)/CD14(-) lymphocyte: CD45(+), CD3(+), CD4(+), NK, CD3/HLA-DR, CD 95(+) cells were significantly lower; by contrast CD23(+), CD25(+), CD19(+), CD4(+)/CD8(+), HLA-DR cells were found to be lower, but not significantly so in patients with MDR-TB, compared to levels in patients in the SP-TB and control groups. Besides these findings, the levels of NKT cells and (γ)δ TCR(+) cells were significantly higher in the MDR-TB than in the healthy control and SP-TB group.

CONCLUSIONS

The lower levels of CD3/ HLA-DR, CD4 (+), Fas (+), and NK, and the higher level of NKT together with (γ)δ T cells in patients with MDR-TB compared to those in SP-TB may indicate a profound immune suppression in MDR-TB patients and thereby may denote an accumulation in the bacterial load. Our findings may shed light on the pathogenesis and prognosis of MDR tuberculosis, and may point towards the use of flow cytometry findings as an aid to early diagnosis in MDR-TB patients.

Toll-like receptor 2 gene polymorphisms, pulmonary tuberculosis, and natural killer cell counts

Background

To investigate whether the toll-like receptor 2 polymorphisms could influence susceptibility to pulmonary TB, its phenotypes, and blood lymphocyte subsets.

Methods

A total of 368 subjects, including 184 patients with pulmonary TB and 184 healthy controls, were examined for TLR2 polymorphisms over locus -100 (microsatellite guanine-thymine repeats), -16934 (T>A), -15607 (A>G), -196 to -174 (insertion>deletion), and 1350 (T>C). Eighty-six TB patients were examined to determine the peripheral blood lymphocyte subpopulations.

Results

We newly identified an association between the haplotype [A-G-(insertion)-T] and susceptibility to pulmonary TB (p = 0.006, false discovery rate q = 0.072). TB patients with systemic symptoms had a lower -196 to -174 deletion/deletion genotype frequency than those without systemic symptoms (5.7% vs. 17.7%; p = 0.01). TB patients with the deletion/deletion genotype had higher blood NK cell counts than those carrying the insertion allele (526 vs. 243.5 cells/μl, p = 0.009). TB patients with pleuritis had a higher 1350 CC genotype frequency than those without pleuritis (12.5% vs. 2.1%; p = 0.004). TB patients with the 1350 CC genotype had higher blood NK cell counts than those carrying the T allele (641 vs. 250 cells/μl, p = 0.004). TB patients carrying homozygous short alleles for GT repeats had higher blood NK cell counts than those carrying one or no short allele (641 vs. 250 cells/μl, p = 0.004).

Conclusions

TLR2 genetic polymorphisms influence susceptibility to pulmonary TB. TLR2 variants play a role in the development of TB phenotypes, probably by controlling the expansion of NK cells.

Changes in lymphocyte subsets in the peripheral blood of patients with active pulmonary tuberculosis

The aim of this study was to determine the percentage of lymphocyte subsets in peripheral blood in patients with active tuberculosis. A total of 21 patients with active tuberculosis and 15 healthy volunteers were included in the study. T-lymphocyte subsets, B-lymphocytes (CD19(+) cells), natural killer (NK) cells and cells positive for costimulatory molecules CD28 and CD152 were evaluated using flow cytometry. Patients with tuberculosis had a significantly decreased percentage of CD3(+) and CD3(+)CD4(+) cells, and a significantly decreased ratio of CD3(+)CD4(+) to CD3(+)CD8(+) cells compared with healthy controls. In contrast, the percentage of B-cells (CD19(+) cells), CD3(+)CD8(+) cells, CD28(+) cells, CD152(+) cells, and subpopulations of CD4(+)CD152(+), CD8(+)CD152(+) and CD8(+)CD28(+) T-cells were all significantly increased compared with healthy controls. There were no statistically significant differences in the percentages of NK cells or CD4(+)CD28(+) cells between patients and controls. These results indicate that patients with active tuberculosis have altered lymphocyte homeostasis.

Different inflammatory mechanisms in lungs of severe and mild asthma: crosstalk of NF-kappa-B, TGFbeta1, Bax, Bcl-2, IL-4 and IgE

OBJECTIVE

To examine differences in the apoptotic, inflammatory, allergic and immunological features in the lungs of adults with asthma.

MATERIAL AND METHODS

Thirty-six patients with mild asthma (MA), 16 with severe asthma (SA) and 20 healthy volunteers (HVs) were enrolled. Bronchoalveolar lavage fluid (BALF) was processed into cell-free fluid for enzyme-linked immunosorbent assay detecting soluble TGFbeta1, IL-4 and IgE and BALF lymphocytes for immunocytochemical staining of cellular Bax, Bcl-2 and nuclear factor-Kappa-B (NFkappaB).

RESULTS

Cellular NFkappaB expression was higher in SA than in MA and HVs, while extracellular TGFbeta1 was high in both the SA and MA groups but low in the HVs. Bcl-2/Bax ratio was higher in SA than in MA and in MA than in HV groups and correlated significantly with NFkappaB level. Interestingly, the levels of IgE and, to a lesser extent, IL-4 were higher in MA than in SA and both were much higher than in HVs, and were inversely correlated with NFkappaB level in the SA group and with TGFbeta1 level in the MA group.

CONCLUSIONS

NFkappaB has a central role in the perpetuation of persistent inflammation in SA and might induce apoptosis via Bcl-2. The SA group appears not associated much with allergen-based IgE and IL-4 reactions as efficiently as in MA. This was supported by the lower levels of IgE and IL-4 in SA compared to MA. TGFbeta1 appears to be associated with asthma pathogenesis, especially allergen-based MA.

Paradoxical worsening of tuberculosis in a heart?lung transplant recipient

We report on a heart-lung transplant recipient who presented with pulmonary tuberculosis (TB) 2.5 months after transplantation and then developed a paradoxical reaction after 4 months of adequate anti-TB treatment. She eventually recovered with anti-TB and high-dose steroid treatments.

METHODS

Using sequential bronchoalveolar lavages, we assessed the inflammatory response in the lung and investigated the alveolar immune response against a Mycobacterium tuberculosis antigen.

RESULTS

The paradoxical reaction was characterized by a massive infiltration of the alveolar space by M. tuberculosis antigen-specific CD4(+) T cells and by the presence of a CD4(-)CD8(-) T lymphocyte subpopulation bearing phenotypic markers (CD16(+)/56(+)) classically associated with NK cells.

CONCLUSION

This case report illustrates that even solid organ transplant recipients receiving intense triple-drug immune suppression may be able to develop a paradoxical reaction during TB treatment. Transplant physicians should be aware of this phenomenon in order to differentiate it from treatment failure.

Differences in reactivation of tuberculosis induced from anti-TNF treatments are based on bioavailability in granulomatous tissue

The immune response to Mycobacterium tuberculosis (Mtb) infection is complex. Experimental evidence has revealed that tumor necrosis factor (TNF) plays a major role in host defense against Mtb in both active and latent phases of infection. TNF-neutralizing drugs used to treat inflammatory disorders have been reported to increase the risk of tuberculosis (TB), in accordance with animal studies. The present study takes a computational approach toward characterizing the role of TNF in protection against the tubercle bacillus in both active and latent infection. We extend our previous mathematical models to investigate the roles and production of soluble (sTNF) and transmembrane TNF (tmTNF). We analyze effects of anti-TNF therapy in virtual clinical trials (VCTs) by simulating two of the most commonly used therapies, anti-TNF antibody and TNF receptor fusion, predicting mechanisms that explain observed differences in TB reactivation rates. The major findings from this study are that bioavailability of TNF following anti-TNF therapy is the primary factor for causing reactivation of latent infection and that sTNF--even at very low levels--is essential for control of infection. Using a mathematical model, it is possible to distinguish mechanisms of action of the anti-TNF treatments and gain insights into the role of TNF in TB control and pathology. Our study suggests that a TNF-modulating agent could be developed that could balance the requirement for reduction of inflammation with the necessity to maintain resistance to infection and microbial diseases. Alternatively, the dose and timing of anti-TNF therapy could be modified. Anti-TNF therapy will likely lead to numerous incidents of primary TB if used in areas where exposure is likely.

Peripheral blood mononuclear cells immunophenotyping in pulmonary tuberculosis patients before and after treatment

Tuberculosis (TB) is a lung disease caused by Mycobacterium tuberculosis. The interaction between the bacillus and the host may lead to a protective cellular immune response. In the present study, we propose the "in vitro" evaluation of this cellular immune response in patients with tuberculosis before and after chemotherapic treatment. Eleven patients with TB and 9 asymptomatic subjects with tuberculin skin test negative (TST-) (purified protein derivative (PPD) <or=10 mm) were evaluated. The peripheral lymphocytes of the subjects were analyzed utilizing the following surface markers: CD3(+), CD4(+), CD8(+), CD19(+), CD25(+), CD56(+), CD14(+), CD16(+) and HLA-DR(+). At the end of the treatment, symptomatic patients presented a significant predominance (P <0.05) of CD4(+) lymphocytes, a significant decrease (P <0.05) in activated CD8(+) T cells and a significant increase (P <0.05) in the marker CD19(+). A predominance of mature NK cells and a significant decrease (P <0.05) in NKT cells were observed. Also observed was a trend toward decrease in immunoregulatory T cells and a predominance of pro-inflammatory macrophages. TST- subjects presented a predominance of CD4(+) over CD8(+) and predominance of CD19(+) and of mature NK cells in comparison to the group of patients, both before and after treatment. Thus, several cell types, such as CD4(+) and CD8(+) T cells, NK cells and their subpopulations, NKT cells and pro-inflammatory macrophages could act in a synergic way to control the growth and multiplication of M. tuberculosis.

Contribution of CD8+T Cells to Control ofMycobacterium tuberculosisInfection

Tuberculosis is the number one cause of death due to infectious disease in the world today. Understanding the dynamics of the immune response is crucial to elaborating differences between individuals who contain infection vs those who suffer active disease. Key cells in an adaptive immune response to intracellular pathogens include CD8(+) T cells. Once stimulated, these cells provide a number of different effector functions, each aimed at clearing or containing the pathogen. To explore the role of CD8(+) T cells in an integrative way, we synthesize both published and unpublished data to build and test a mathematical model of the immune response to Mycobacterium tuberculosis in the lung. The model is then used to perform a series of simulations mimicking experimental situations. Selective deletion of CD8(+) T cell subsets suggests a differential contribution for CD8(+) T cell effectors that are cytotoxic as compared with those that produce IFN-gamma. We also determined the minimum levels of effector memory cells of each T cell subset (CD4(+) and CD8(+)) in providing effective protection following vaccination.

Dynamics of cytokine generation in patients with active pulmonary tuberculosis

PURPOSE OF REVIEW

Cytokines have been implicated in the protective immunity, pathophysiology and development of tuberculosis. Most people who become infected with Mycobacterium tuberculosis mount an effective protective immune response, but 5-10% develop disease. Active pulmonary tuberculosis can be considered to reflect an ineffective immune response against mycobacterial infection. A better understanding of how cytokine production contributes to immunity and pathology would aid the development of new vaccines and therapeutic strategies.

RECENT FINDINGS

At the time of diagnosis, production of M. tuberculosis or mycobacterial antigen-induced interferon-gamma by peripheral blood mononuclear cells from tuberculosis patients is usually depressed, compared with that of healthy control subjects, whereas cytokine production at the site of disease is elevated. In most patients, depressed interferon-gamma production by peripheral blood mononuclear cells seems to be a transient response because it is significantly increased in most active tuberculosis patients during and following successful antituberculous therapy. However, some patients remain anergic in vivo and in vitro after chemotherapy, and the underlying biochemical mechanisms for T cell anergy in modulating protection or pathology in tuberculosis needs further clarification. Among the cytokines contributing to protective immunity, interleukins 12 and 18, and tumour necrosis factor-alpha are important, the basis of recent studies with tuberculosis patients.

SUMMARY

A more complete understanding of cytokine dynamics in individual cells in active pulmonary tuberculosis patients will provide further knowledge about immunopathogenesis and protective immunity in human tuberculosis. This should ultimately enhance development of preventive and therapeutic strategies against this enormously successful intracellular pathogen.