Impaired pulmonary function after treatment for tuberculosis: the end of the disease?

Effect of pulmonary rehabilitation in patients with post-tuberculosis sequelae with functional limitation

BACKGROUND

Pulmonary rehabilitation improves dyspnea, functional limitation and quality of life in patients with chronic respiratory disease especially Chronic obstructive pulmonary disease (COPD). Whether Pulmonary rehabilitation (PR) will have similar effect in patients with post-tuberculosis sequelae or not and whether the two morphological variants will respond similarly or not was the purpose of our study.

METHODS

Adult patients fulfilling the inclusion criteria of a diagnosis of post-tuberculosis sequelae with functional limitation (modified medical research council [mMRC] grade 1 or more) were recruited over a period of two years. A baseline health assessment in the different domains of health was done at the beginning and repeated just after the completion of the rehabilitation program at 6 weeks.

RESULTS

26 patients completed the PR protocol of our study. Dyspnea improved from an mMRC grade of 1.5 to 0.7 post-PR (p < 0.001). 6MWD increased by 34 meters from a baseline value of 408.6 meters to 442.7 meters post-PR. (p-value 0.3) St. George's Respiratory Questionnaire (SGRQ) symptom score decreased by 13 points, SGRQ activity score decreased by 18 points, SGRQ impact score decreased by 18 and SGRQ total score decreased by 17 points with p-values of 0.037, 0.002, 0.004 and 0.002 for SGRQ symptom score, SGRQ activity score, SGRQ impact score, SGRQ total score respectively. Depression Anxiety Stress Scale (DASS) Stress score decreased by 6.7, DASS Anxiety score decreased by 6.6, and DASS Depression score decreased by 5.5 points. Intergroup comparison revealed both bronchiectasis predominant group and fibrosis predominant group responded similarly to PR.

CONCLUSION

PR improved parameters assessing dyspnea, quality of life and mental health indices significantly. Improvement in functional capacity was not statically significant. Both the morphological variants responded similarly to the PR.

Inhibition of host PARP1 contributes to the anti-inflammatory and antitubercular activity of pyrazinamide

The antibiotic pyrazinamide (PZA) is a cornerstone of tuberculosis (TB) therapy that shortens treatment durations by several months despite being only weakly bactericidal. Intriguingly, PZA is also an anti-inflammatory molecule shown to specifically reduce inflammatory cytokine signaling and lesion activity in TB patients. However, the target and clinical importance of PZA's host-directed activity during TB therapy remain unclear. Here, we identify the host enzyme Poly(ADP-ribose) Polymerase 1 (PARP1), a pro-inflammatory master regulator strongly activated in TB, as a functionally relevant host target of PZA. We show that PZA inhibits PARP1 enzymatic activity in macrophages and in mice where it reverses TB-induced PARP1 activity in lungs to uninfected levels. Utilizing a PZA-resistant mutant, we demonstrate that PZA's immune-modulatory effects are PARP1-dependent but independent of its bactericidal activity. Importantly, PZA's bactericidal efficacy is impaired in PARP1-deficient mice, suggesting that immune modulation may be an integral component of PZA's antitubercular activity. In addition, adjunctive PARP1 inhibition dramatically reduces inflammation and lesion size in mice and may be a means to reduce lung damage and shorten TB treatment duration. Together, these findings provide insight into PZA's mechanism of action and the therapeutic potential of PARP1 inhibition in the treatment of TB.

Post-tuberculosis lung impairment: systematic review and meta-analysis of spirometry data from 14 621 people

BACKGROUND

A substantial proportion of tuberculosis patients remain with pulmonary symptoms and reduced physical capacity despite successful treatment. We performed a systematic review to analyse the burden of post-tuberculosis lung impairment measured by lung function testing.

METHODS

We searched the PubMed database for articles published between database inception and November 2020 and performed meta-analyses to estimate the prevalence, type and severity of lung impairment among drug-susceptible and multidrug-resistant tuberculosis survivors. Methodological quality of included studies was assessed using the Newcastle-Ottawa scale.

RESULTS

54 articles were included in this review. For subjects with former drug-susceptible tuberculosis, the combined estimated mean was 76.6% (95% CI 71.6-81.6) of predicted for forced expiratory volume in 1 s (FEV1) and 81.8% (95% CI 77.4-86.2) for forced vital capacity (FVC). In former patients with multidrug-resistant tuberculosis, it was 65.9% (95% CI 57.1-74.7) for FEV1 and 76.0% (95% CI 66.3-85.8) for FVC, respectively. The analysis of impairment types in former patients with drug-susceptible and multidrug-resistant tuberculosis showed that 22.0% versus 19.0% had obstructive, 23.0% versus 22.0% restrictive and 15.0% versus 43.0% had mixed impairment type, respectively. In the majority of studies, at least 10-15% of tuberculosis survivors had severe lung impairment.

CONCLUSIONS

This systematic review showed long-term abnormal spirometry results in a significant proportion of tuberculosis survivors.

Mechanisms of lung damage in tuberculosis: implications for chronic obstructive pulmonary disease

Pulmonary tuberculosis is increasingly recognized as a risk factor for COPD. Severe lung function impairment has been reported in post-TB patients. Despite increasing evidence to support the association between TB and COPD, only a few studies describe the immunological basis of COPD among TB patients following successful treatment completion. In this review, we draw on well-elaborated Mycobacterium tuberculosis-induced immune mechanisms in the lungs to highlight shared mechanisms for COPD pathogenesis in the setting of tuberculosis disease. We further examine how such mechanisms could be exploited to guide COPD therapeutics.

Residual respiratory disability after successful treatment of pulmonary tuberculosis: a systematic review and meta-analysis

Background

Pulmonary tuberculosis (PTB) can result in long-term health consequences, even after successful treatment. We conducted a systematic review and meta-analysis to estimate the occurrence of respiratory impairment, other disability states, and respiratory complications following successful PTB treatment.

Methods

We identified studies from January 1, 1960, to December 6, 2022, describing populations of all ages that successfully completed treatment for active PTB and had been assessed for at least one of the following outcomes: occurrence of respiratory impairment, other disability states, or respiratory complications following PTB treatment. Studies were excluded if they reported on participants with self-reported TB, extra-pulmonary TB, inactive TB, latent TB, or if participants had been selected on the basis of having more advanced disease. Study characteristics and outcome-related data were abstracted. Meta-analysis was performed using a random effects model. We adapted the Newcastle Ottawa Scale to evaluate the methodological quality of the included studies. Heterogeneity was assessed using the I² statistic and prediction intervals. Publication bias was assessed using Doi plots and LFK indices. This study is registered with PROSPERO (CRD42021276327).

Findings

61 studies with 41,014 participants with PTB were included. In 42 studies reporting post-treatment lung function measurements, 59.1% (I² = 98.3%) of participants with PTB had abnormal spirometry compared to 5.4% (I² = 97.4%) of controls. Specifically, 17.8% (I² = 96.6%) had obstruction, 21.3% (I² = 95.4%) restriction, and 12.7% (I² = 93.2%) a mixed pattern. Among 13 studies with 3179 participants with PTB, 72.6% (I² = 92.8%) of participants with PTB had a Medical Research Council dyspnoea score of 1-2 and 24.7% (I² = 92.2%) a score of 3-5. Mean 6-min walk distance in 13 studies was 440.5 m (I² = 99.0%) in all participants (78.9% predicted, I² = 98.9%) and 403.0 m (I² = 95.1%) among MDR-TB participants in 3 studies (70.5% predicted, I² = 97.6%). Four studies reported data on incidence of lung cancer, with an incidence rate ratio of 4.0 (95% CI 2.1-7.6) and incidence rate difference of 2.7 per 1000 person-years (95% CI 1.2-4.2) when compared to controls. Quality assessment indicated overall low-quality evidence in this field, heterogeneity was high for pooled estimates of nearly all outcomes of interest, and publication bias was considered likely for almost all outcomes.

Interpretation

The occurrence of post-PTB respiratory impairment, other disability states, and respiratory complications is high, adding to the potential benefits of disease prevention, and highlighting the need for optimised management after successful treatment.

Funding

Canadian Institutes of Health Research Foundation Grant.

A ready-to-use dry powder formulation based on protamine nanocarriers for pulmonary drug delivery

The use of oral antibiotic therapy for the treatment of respiratory diseases such as tuberculosis has promoted the appearance of side effects as well as resistance to these treatments. The low solubility, high metabolism, and degradation of drugs such as rifabutin, have led to the use of combined and prolonged therapies, which difficult patient compliance. In this work, we develop inhalable formulations from biomaterials such as protamine to improve the therapeutic effect. Rifabutin-loaded protamine nanocapsules (NCs) were prepared by solvent displacement method and were physico-chemically characterized and evaluated for their dissolution, permeability, stability, cytotoxicity, hemocompatibility, internalization, and aerodynamic characteristics after a spray-drying procedure. Protamine NCs presented a size of around 200 nm, positive surface charge, and drug association up to 54%. They were stable as suspension under storage, as well as in biological media and as a dry powder after lyophilization in the presence of mannitol. Nanocapsules showed a good safety profile and cellular uptake with no tolerogenic effect on macrophages and showed good compatibility with red blood cells. Moreover, the aerodynamic evaluation showed a fine particle fraction deposition up to 30% and a mass median aerodynamic diameter of about 5 µm, suitable for the pulmonary delivery of therapeutics.

Airflow obstruction and small airway dysfunction following pulmonary tuberculosis: a cross-sectional survey

OBJECTIVES

Pulmonary function impairment and chronic respiratory symptoms after tuberculosis are relatively common in low-income and middle-income countries. We aimed to estimate the impact of post-tuberculosis (post-TB) on pulmonary function.

METHODS

This large cross-sectional, population-based study included subjects aged 15 years or older with technically acceptable postbronchodilator spirometry measurements. Post-TB was diagnosed on the basis of radiological evidence and/or medical history. Airflow obstruction was defined as a postbronchodilator forced expiratory volume in 1 s/forced vital capacity ratio below the lower limit of normal of Global Lung Function Initiative (GLI) lung function equations. Small airway dysfunction was diagnosed if at least two of the following indicators were less than 65% of predicted: maximal mid-expiratory flow, forced expiratory flow (FEF) 50% or FEF 75%.

RESULTS

In this population sample (N=8680, mean age: 40.1 years), 610 (7.0% (95% CI 6.5 to 7.6) participants were post-TB. Post-TB subjects had more frequent respiratory symptoms (46.8% vs 28.3%). Among post-TB subjects, 130 (21.3% (95% CI 18.1 to 24.8)) had airflow obstruction; OR of airflow obstruction was significantly associated with post-TB after adjustment for other confounding factors (OR 1.31, 95% CI 1.05 to 1.62). Post-TB was also associated with small airway dysfunction (OR 1.28, 95% CI1.07 to 1.53), which was present in 297 (48.9% (95% CI 33.9 to 53.0)) post-TB subjects.

CONCLUSIONS

Our findings support existing knowledge that post-TB is positively associated with pulmonary function impairment and make for frequent respiratory symptoms. Post-TB should be considered as a potentially important cause of airflow obstruction and respiratory symptoms in patients originating from countries with a high burden of tuberculosis.

Molecular mechanisms of inflammation in the pathogenesis of respiratory disorders in patients with pulmonary tuberculosis

Aim. To assess external respiration (ER) and its relationship with the activity of enzymes involved in purine metabolism in patients with acute and chronic forms of pulmonary tuberculosis (TB).

Materials and methods. In patients with acute and chronic TB, we assessed the activity of adenosine deaminase (ADA)-1, 2 in the blood serum (eADA), mononuclear cells, and neutrophils, the concentration of ecto-5’-nucleotidase (eNT5E) in the blood serum, the level of CD26 (dipeptidyl peptidase-4, DPPIV) in the blood serum and mononuclear cells, production of reactive oxygen intermediates (ROI) and reactive nitrogen intermediates (RNI) in mononuclear cells and neutrophils, as well as parameters of ER.

Results. Patients with TB were found to have an increase in the concentration of eNT5E and eADA-2 activity in the blood serum, stimulated production of ROI in neutrophils, a decrease in the concentration of DPPIV (CD26) in mononuclear cells, and a fall in the production of RNI in mononuclear cells and neutrophils. In patients with chronic TB, a decrease in the activity of ADA-1 in mononuclear cells and a fall in the concentration of DPPIV (CD26) in the blood serum were noted. In patients with acute TB, a decrease in the activity of eADA-1 in the blood serum and ADA-1 in neutrophils, reduced production of ROI in mononuclear cells, and an increase in spontaneous production of ROI in neutrophils were revealed. Correlations were found between the parameters of ER and the concentration of eNT5E in the blood serum, spontaneous production of ROI in mononuclear cells and production of RNI in neutrophils in chronic TB, as well as between eADA-2 in the blood serum, ADA-1 in neutrophils, DPPIV (CD26) activity in mononuclear cells, and ROI and RNI production in mononuclear cells and neutrophils.

Conclusion. The data obtained make it possible to associate regulation of external respiration with parameters of purine metabolism, in particular with the concentration and activity of enzymes responsible for generation and metabolism of adenosine, that determine its level outside cells and inside mononuclear cells and neutrophils, with expression of cofactor molecules, as well as with the duration of activation of cells in innate immunity, neutrophils, and monocytes/ macrophages, determined largely by the potential of adenosine regulation.

Tuberculosis Treatment Response Monitoring by the Phenotypic Characterization of MTB-Specific CD4+ T-Cells in Relation to HIV Infection Status

HIV infection causes systemic immune activation, impacts TB disease progression and hence may influence the diagnostic usability of Mycobacterium tuberculosis-specific T cell profiling. We investigated changes of activation and maturation markers on MTB-specific CD4+ T-cells after anti-tuberculosis treatment initiation in relation to HIV status and the severity of lung impairment. Thawed peripheral blood mononuclear cells from TB patients with (n = 27) and without HIV (n = 17) were analyzed using an intracellular IFN-γ assay and flow cytometry 2 and 6 months post-TB treatment initiation. H37Rv antigen was superior to the profile MTB-specific CD4+ T-cells phenotype when compared to PPD and ESAT6/CFP10. Regardless of HIV status and the severity of lung impairment, activation markers (CD38, HLA-DR and Ki67) on MTB-specific CD4+ T-cells declined after TB treatment initiation (p < 0.01), but the expression of the maturation marker CD27 did not change over the course of TB treatment. The MTB-specific T cell phenotype before, during and after treatment completion was similar between people living with and without HIV, as well as between subjects with severe and mild lung impairment. These data suggest that the assessment of activation and maturation markers on MTB-specific CD4+ T-cells can be useful for TB treatment monitoring, regardless of HIV status and the severity of lung disease.

Neutrophils Contribute to Severity of Tuberculosis Pathology and Recovery From Lung Damage Pre- and Posttreatment

BACKGROUND

Despite microbiological cure, about 50% of tuberculosis (TB) patients have poor lung recovery. Neutrophils are associated with lung pathology; however, CD16/CD62L-defined subsets have not been studied in TB. Using flow cytometry, we monitored frequencies, phenotype, and function of neutrophils following stimulation with Mycobacterium tuberculosis (Mtb) whole cell lysate (WCL) and ESAT-6/CFP-10 fusion protein (EC) in relation to lung pathology.

METHODS

Fresh blood from 42 adult, human immunodeficiency virus (HIV)-negative TB patients were analyzed pre- and post-therapy, with disease severity determined using chest radiography and bacterial load. Flow cytometry was used to monitor frequencies, phenotype, and function (generation of reactive oxygen species [ROS], together with CD11b, tumor necrosis factor, and interleukin 10 [IL-10] expression) of neutrophils following 2-hour stimulation with Mtb-specific antigens.

RESULTS

Total neutrophils decreased by post-treatment compared to baseline (P = .0059); however, CD16brCD62Lbr (segmented) neutrophils increased (P = .0031) and CD16dimCD62Lbr (banded) neutrophils decreased (P = .038). Banded neutrophils were lower in patients with severe lung damage at baseline (P = .035). Following WCL stimulation, ROS from segmented neutrophils was higher in patients with low Mtb loads even after adjusting for sex (P = .038), whereas IL-10-expressing CD16dimCD62Llo cells were higher in patients with mild damage (P = .0397) at baseline.

CONCLUSIONS

High ROS generation, low levels of banded neutrophils, and high levels of IL-10-expressing CD16dimCD62Llo neutrophils are associated with reduced lung pathology at diagnosis. Hence, neutrophils are potential early indicators of TB severity and promising targets for TB host-directed therapy.

Lung health after tuberculosis: clinical and functional assessment in post-pulmonary tuberculosis Egyptian patients

Background

Some of the pulmonary tuberculous patients who completed their medication course experience lung function impairment which may influence their quality of life. However, the pattern and nature of post-tuberculosis lung impairment are still not identified. Thus, the aim of this study was to determine the type and degree of lung physiology changes in previously treated tuberculous patients which latter may affect their quality of life, thus helping clinicians for early diagnosis of lung impairment, especially in tuberculous endemic areas.

Results

Adults (≥18 years) who were treated from first attack pulmonary tuberculosis were included in the study. Demographic data, respiratory symptoms, smoking history, comorbidities, Medical Research Council dyspnea score (MRC), spirometry, chest radiography, and oxygen saturation were collected. One hundred ninety-seven participants were finally included in the study. The mean age was 49.50±13.26 years with males representing 75.6% of total patients. MRC dyspnea scale grading showed that about 13.2% and 5.1% of patients suffer from dyspnea grade II and grade III, respectively. Main respiratory symptoms were cough in 38.1%, sputum production in 24.9%, and hemoptysis in 6.6% cases. Normal spirometry was documented in 53.3%, obstructive pattern in 31.98%, and mixed pattern in 7.11%, whereas 7.61% cases had a restrictive pattern. According to ATS staging of obstructive pattern, 27 patients (42.8%) had mild obstruction, 22 (34.9%) patients had moderate obstruction, 13 (20.6%) patients had moderate to severe obstruction, and one patient (1.6%) had severe obstruction.

Conclusions

Impairment of respiratory function after tuberculosis is one of the causes of chronic lung disease that is underestimated, especially in endemic countries. This impairment in function occurs early in the course of the diseases and even without symptoms, affecting the quality of life. Thus, clinicians should encourage patients for an earlier visit to a respiratory clinic for follow-up and further management if needed. Guidelines for the management of cured tuberculous patients are urgently needed.

Trial registration

ClinicalTrials.gov, NCT05097638. Registered on October 28, 2021—retrospectively registered

Mycobacterium tuberculosis and Pulmonary Rehabilitation: From Novel Pharmacotherapeutic Approaches to Management of Post-Tuberculosis Sequelae

Tuberculosis (TB) is still a worldwide public health burden, as more than 1.3 million deaths are expected to be reported in 2021. Even though almost 20 million patients have completed specific anti-TB treatment and survived in 2020, little information is known regarding their pulmonary sequelae, quality of life, and their need to follow rehabilitation services as researchers shifted towards proper diagnosis and treatment rather than analyzing post-disease development. Understanding the underlying immunologic and pathogenic mechanisms during mycobacterial infection, which have been incompletely elucidated until now, and the development of novel anti-TB agents could lead to the proper application of rehabilitation care, as TB sequelae result from interaction between the host and Mycobacterium tuberculosis. This review addresses the importance of host immune responses in TB and novel potential anti-TB drugs’ mechanisms, as well as the assessment of risk factors for post-TB disease and usefulness of guidance and optimization of pulmonary rehabilitation. The use of rehabilitation programs for patients who successfully completed anti-tuberculotic treatment represents a potent multifaceted measure in preventing the increase of mortality rates, as researchers conclude that a patient with a TB diagnosis, even when properly completing pharmacotherapy, is threatened by a potential life loss of 4 years, in comparison to healthy individuals. Dissemination of pulmonary rehabilitation services and constant actualization of protocols could strengthen management of post-TB disease among under-resourced individuals.

Structural and functional pulmonary impairment in treated cases of pulmonary tuberculosis: a cross-sectional study

Background

Pulmonary impairment after tuberculosis treatment is seen in 40%-75% of patients despite bacteriological cure. Study aimed to find prevalence of structural and functional pulmonary impairment in a group of previously fit serving soldiers at the end of supervised institutional treatment for pulmonary tuberculosis.

Methods

Descriptive cross-sectional study was conducted in a tertiary care center on 375 newly diagnosed patients of pulmonary tuberculosis completed treatment. They underwent spirometry and chest X ray (CXR) at end of treatment. Their lung function was classified as normal or abnormal (obstructive, restrictive, or mixed pattern). Chest radiographs were reported as normal/abnormal. Logistic regression models were used to explore the factors associated with abnormal lung function.

Results

Functional impairment was present in 145/375 (38.7%). 115/375 (30.66%) had restrictive, 24/375 (6.4%) had mixed, and 6/375 (1.6%) had obstructive pattern on spirometry, respectively. Out of the 115 patients having restrictive pattern, 103 (89.56%) had mild restriction, 11(9.56%) had moderate restriction, and 1 (0.86%) had severe restriction. Structural impairment on CXR was present in 309/375 (82.4%) of patients. Significant factors associated with pulmonary impairment in our study were time to diagnosis (>1 month) adj odds ratio (OR) = 1.71, 95% confidence interval (CI) 1.07-2.74, sputum conversion of >2 months, Adj OR 2.52, 95% CI 1.25-5.07, and sputum/culture positivity Adj OR 1.57, 95% CI 1.02-2.42. CXR abnormality was significantly associated with sputum and/culture positivity Adj OR 4.54, 95% CI 2.28-9.03.

Conclusion

Despite successful treatment, pulmonary impairment was present in 38.7% of patients, and structural changes evident on CXR was present in 82.4% of patients.

"This is not my body": Therapeutic experiences and post-treatment health of people with rifampicin-resistant tuberculosis

Background

There are few data on the on post-treatment experiences of people who have been successfully treated for rifampicin-resistant (RR-)TB.

Objective

To describe the experiences and impact of RR-TB disease and therapy on post-treatment life of individuals who were successfully treated.

Methods

In this qualitative study in-depth interviews were conducted among a purposively selected sample from a population of individuals who were successfully treated for RR-TB between January 2008 and December 2018. Interview transcripts and notes were analysed using a thematic network analysis which included grounded theory and a framework for understanding pathophysiological mechanisms for post-TB morbidity and mortality. The analysis was iterative and the coding system developed focused on disease, treatment and post-treatment experiences of individuals. This paper follows the COREQ guidelines.

Results

For all 12 participants interviewed, the development of RR-TB disease, its diagnosis and the subsequent treatment were a major disruption to their lives as well as a transformative experience. On diagnosis of RR-TB disease, participants entered a liminal period in which their lives were marked with uncertainty and dominated by physical and mental suffering. Irrespective of how long ago they had completed their treatment, they all remembered with clarity the signs and symptoms of the disease and the arduous treatment journey. Post-treatment participants reported physical, social, psychological and economic changes as consequences of their RR-TB disease and treatment. Many participants reported a diminished ability to perform physical activities and, once discharged from the RR-TB hospital, inadequate physical rehabilitation. For some, these physical limitations impacted on their social life, and ultimately on their psychological health as well as on their ability to earn money and support their families.

Conclusion

The experiences and impact of RR-TB disease and therapy on post-treatment life of individuals successfully treated, highlights gaps in the current health care system that need to be addressed to improve the life of individuals post-treatment. A more holistic and long-term view of post-TB health, including the provision of comprehensive medical and social services for post-treatment care of physical ailments, social re-integration and the mitigation of the perceived fear and risk of getting TB again could be a central part of person-centred TB care.

Pulmonary functional assessment: longitudinal study after treatment of pulmonary tuberculosis

Even when treated adequately, pulmonary tuberculosis can lead to pulmonary sequelae. Patients treated for PTB between 2012 and 2016 answered a standardized questionnaire and underwent chest radiography and spirometry, measurement of absolute pulmonary volume, Diffusing Capacity for Carbon Monoxide (DLCO) and the 6-min walk test (6MWT) on two occasions: within the first year after the end of treatment (follow-up 1), and one and two years after follow-up 1 (follow-up 2). A total of 55 patients they underwent spirometry, 23 (41.82%) had obstructive ventilatory disorder (OVD) and eight (14.5%) had moderate OVD. In total, 29 patients underwent pulmonary function tests (PFTs) and 24 patients underwent the 6MWT on two occasions. The functional changes after PTB treatment appear not to have varied between one and two years of follow-up. There was a correlation between low FEV1 and low DLCO (p<0.001); low DLCO and low 6MWT (p<0.001) and radiographic abnormalities and low FEV1 (p=0.033). The most frequently observed change in spirometry was found in patients with OVD.

Host-Directed Therapies: Modulating Inflammation to Treat Tuberculosis

Following infection with Mycobacterium tuberculosis, the causative agent of tuberculosis (TB), most human hosts are able to contain the infection and avoid progression to active TB disease through expression of a balanced, homeostatic immune response. Proinflammatory mechanisms aiming to kill, slow and sequester the pathogen are key to a successful host response. However, an excessive or inappropriate pro-inflammatory response may lead to granuloma enlargement and tissue damage, which may prolong the TB treatment duration and permanently diminish the lung function of TB survivors. The host also expresses certain anti-inflammatory mediators which may play either beneficial or detrimental roles depending on the timing of their deployment. The balance between the timing and expression levels of pro- and anti-inflammatory responses plays an important role in the fate of infection. Interestingly, M. tuberculosis appears to manipulate both sides of the human immune response to remodel the host environment for its own benefit. Consequently, therapies which modulate either end of this spectrum of immune responses at the appropriate time may have the potential to improve the treatment of TB or to reduce the formation of permanent lung damage after microbiological cure. Here, we highlight host-directed TB therapies targeting pro- or anti-inflammatory processes that have been evaluated in pre-clinical models. The repurposing of already available drugs known to modulate these responses may improve the future of TB therapy.

Neutrophils in Tuberculosis-Associated Inflammation and Lung Pathology

Protective immunity to Mycobacterium tuberculosis (Mtb)—the causative agent of tuberculosis (TB)—is not fully understood but involves immune responses within the pulmonary airways which can lead to exacerbated inflammation and immune pathology. In humans, this inflammation results in lung damage; the extent of which depends on specific host pro-inflammatory processes. Neutrophils, though increasingly linked to the development of inflammatory disorders, have been less well studied in relation to TB-induced lung pathology. Neutrophils mode of action and their specialized functions can be directly linked to TB-specific lung tissue damage observed on patient chest X-rays at diagnosis and contribute to long-term pulmonary sequelae. This review discusses aspects of neutrophil activity associated with active TB, including the resulting inflammation and pulmonary impairment. It highlights the significance of neutrophil function on TB disease outcome and underlines the necessity of monitoring neutrophil function for better assessment of the immune response and severity of lung pathology associated with TB. Finally, we propose that some MMPs, ROS, MPO, S100A8/A9 and Glutathione are neutrophil-related inflammatory mediators with promising potential as targets for developing host-directed therapies for TB.

Spirometry results after treatment for pulmonary tuberculosis: comparison between patients with and without previous lung disease: a multicenter study

OBJECTIVE

To compare patients with and without previous lung disease, in terms of the spirometry results after they had been treated for pulmonary tuberculosis (PTB) and cured, as well as to analyze risk factors related to functional severity.

METHODS

This was a cross-sectional, multicenter study conducted at four referral centers in Brazil. Patients were divided into two groups: those with a history of lung disease or smoking (LDS+ group); and those with no such history (LDS- group). Patients underwent spirometry (at least six months after being cured). Sociodemographic and clinical data were collected.

RESULTS

A total of 378 patients were included: 174 (46.1%) in the LDS+ group and 204 (53.9%) in the LDS- group. In the sample as a whole, 238 patients (62.7%) had spirometric changes. In the LDS+ group, there was a predominance of obstructive lung disease (in 33.3%), whereas restrictive lung disease predominated in the LDS- group (in 24.7%). Radiological changes were less common in the LDS- group than in the LDS+ group (p < 0.01), as were functional changes (p < 0.05). However, of the 140 (79.1%) LDS- group patients with a normal or minimally altered chest X-ray, 76 (54%) had functional changes (p < 0.01). The risk factors associated with functional severity in the LDS- group were degree of dyspnea (p = 0.03) and moderate or severe radiological changes (p = 0.01).

CONCLUSIONS

Impaired pulmonary function is common after treatment for PTB, regardless of the history of lung disease or smoking. Spirometry should be suggested for patients who develop moderate/severe dyspnea or relevant radiological changes after treatment for PTB.

Post-tuberculosis health-related quality of life, lung function and exercise capacity in a cured pulmonary tuberculosis population in the Breede Valley District, South Africa

BACKGROUND

Pulmonary tuberculosis (PTB) remains a major concern worldwide. Albeit curable, PTB continues to negatively affect patients' health-related quality of life (HRQoL) and functioning even after cure.

OBJECTIVES

To describe the demographics, respiratory symptoms, pulmonary airflow patterns, HRQoL and exercise capacity of cured PTB patients, in the Breede Valley district of South Africa.

METHODS

A cross-sectional study conducted at five primary health care facilities included adult patients diagnosed with PTB, who had completed anti-tuberculosis treatment. Post-treatment bronchodilator lung function, HRQoL and 6-min walk distance (6MWD) were measured.

RESULTS

Three hundred and twenty-four patients were screened. Specific challenges resulted in 45 patients being included (male n = 25 [56%]; mean population age 39.9 [± 10.2]). HRQoL was assessed using the short-form 12v2, part of the burden of lung disease core questionnaire. In general, self-reported physical scores (physical health component summary score = 45) were higher than mental scores (mental health component summary score = 39). The mean 6MWD was 294.5 m (± 122.7) m (range 110 m - 600 m), which is well below normal reference values. Forty-eight percent (48%) of the sample presented with abnormal lung function, including obstructive (n = 9; 21%), restrictive (n = 11; 25%) and mixed (n = 1; 2%).

CONCLUSIONS

This pilot study suggests that most cured PTB patients have decreased HRQoL, exercise capacity and abnormal lung function. This study is the first to describe the combination of these three outcomes in a South African population.

CLINICAL IMPLICATIONS

Clinicians must recognise that holistic management of PTB patients is required after cure.