No smoke without fire: the impact of cigarette smoking on the immune control of tuberculosis

DPF3 polymorphisms increased the risk of pulmonary tuberculosis in the Northwest Chinese Han population

PURPOSE

This study aimed to investigate the association between single nucleotide polymorphisms (SNPs) in DPF3 and susceptibility to pulmonary tuberculosis (PTB) in the Northwest Chinese Han population.

METHODS

Genotyping of four DPF3 SNPs (rs10140566, rs75575287, rs202075571, and rs61986330) was performed using Agena MassARRAY from 488 PTB patients and 488 healthy controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using logistic regression. Multifactor dimensionality reduction (MDR) analysis was employed to investigate the effect of SNP-SNP interactions on PTB risk. The GSE54992 dataset was analyzed using R software to ascertain DPF3 expression levels.

RESULTS

Overall analysis revealed that rs202075571 (allele: OR = 1.31, p = 0.015; CC vs. TT: OR = 1.97, p = 0.049; dominant: OR = 1.33, p = 0.032) and rs61986330 (allele: OR = 1.38, p = 0.010; CA vs. CC: OR = 1.35, p = 0.044; dominant: OR = 1.40, p = 0.019) were associated with an increased PTB risk. Stratified analysis showed that rs10140566 was a PTB risk factor in females, those aged ≤40 and non-smokers, and rs202075571 was associated with PTB risk in individuals aged >40 and smokers, and rs61986330 was associated with PTB risk in males, those aged >40 and smokers. The four SNPs model demonstrated significant predictive potential for PTB risk. Furthermore, DPF3 exhibited higher expression in PTB compared to healthy controls.

CONCLUSION

DPF3 polymorphisms (rs10140566, rs202075571, and rs61986330) are associated with an increased risk of PTB, providing valuable new insights into the mechanism of PTB.

Cigarette Smoking as a Risk Factor for Tuberculosis in Adults: Epidemiology and Aspects of Disease Pathogenesis

It has been noted by the World Health Organisation that cases of tuberculosis in 2022 globally numbered 10.6 million, resulting in 1.3 million deaths, such that TB is one of the infectious diseases causing the greatest morbidity and mortality worldwide. Since as early as 1918, there has been an ongoing debate as to the relationship between cigarette smoking and TB. However, numerous epidemiological studies, as well as meta-analyses, have indicated that both active and passive smoking are independent risk factors for TB infection, development of reactivation TB, progression of primary TB, increased severity of cavitary disease, and death from TB, among several other considerations. With this considerable body of evidence confirming the association between smoking and TB, it is not surprising that TB control programmes represent a key potential preventative intervention. In addition to coverage of the epidemiology of TB and its compelling causative link with smoking, the current review is also focused on evidence derived from clinical- and laboratory-based studies of disease pathogenesis, most prominently the protective anti-mycobacterial mechanisms of the alveolar macrophage, the primary intracellular refuge of M. tuberculosis. This section of the review is followed by an overview of the major strategies utilised by the pathogen to subvert these antimicrobial mechanisms in the airway, which are intensified by the suppressive effects of smoke inhalation on alveolar macrophage function. Finally, consideration is given to a somewhat under-explored, pro-infective activity of cigarette smoking, namely augmentation of antibiotic resistance due to direct effects of smoke per se on the pathogen. These include biofilm formation, induction of cellular efflux pumps, which eliminate both smoke-derived toxicants and antibiotics, as well as gene modifications that underpin antibiotic resistance.

Experiences with smoking habits and the need for cessation among habitual smokers in Japan: a qualitative study based on semi-structured interviews

BACKGROUND

Although more than half of the habitual smokers recognize that they want to quit smoking cigarettes, approximately half have failed to quit and experienced distress relapse; therefore, there is an urgent need to focus on these populations. When chronic behavior occurs, it is necessary to view the behavior in the context of the entire life of the person involved, considering the history of the person. In this study, we aimed to describe experiences with smoking from the onset to the present and the need for smoking cessation among habitual smokers in Japan and to explore efforts to address them.

METHODS

Semi-structured interviews that lasted for 55-90 min were conducted with the cooperation of 16 habitual smokers who smoked cigarettes daily. The content of the interviews included demographic characteristics, experiences with smoking from the onset to the present, whether they have attempted to quit and related experiences, and their thoughts on smoking. Interviews were transcribed verbatim and analyzed qualitatively. The Medical Research Ethics Review Committee of Jikei University approved this study (approval number: 33-384(11008)).

RESULTS

The participants were aged 26-59 years (mean ± SD: 40.8 ± 8.9 years) and included 10 men and 6 women. The participants started smoking between age 13 and 24 years. The highest number of cigarettes smoked in the participants' lives ranged from 10 to 80 daily, and 12 participants had attempted to quit smoking so far without success. Regarding experiences with smoking from the onset to the present, four themes of "expand one's world," "unconscious attachment," "attempts and failures," and "losing oneself" were extracted. Regarding the need for smoking cessation, four themes of "empowerment from experts," "peer interaction," "social commitment," and "recovery of confidence" were extracted.

CONCLUSION

To support smoking cessation from the perspective of habitual smokers, in addition to improvements through the existing approaches, it is important to recover their confidence using ongoing activities in peer groups according to the target background and support from experts incorporating visual assessments of lung function, along with multiple short-term goals. It is also necessary to raise awareness in communities through activities.

Long term management of people with post-tuberculosis lung disease

Post-tuberculosis lung disease (PTLD) is emerging as a significant area of global interest. As the number of patients surviving tuberculosis (TB) increases, the subsequent long-term repercussions have drawn increased attention due to their profound clinical and socioeconomic impacts. A primary obstacle to its comprehensive study has been its marked heterogeneity. The disease presents a spectrum of clinical manifestations which encompass tracheobronchial stenosis, bronchiectasis, granulomas with fibrosis, cavitation with associated aspergillosis, chronic pleural diseases, and small airway diseases-all persistent consequences of PTLD. The spectrum of symptoms a patient may experience varies based on the severity of the initial infection and the efficacy of the treatment received. As a result, the long-term management of PTLD necessitates a detailed and specific approach, addressing each manifestation individually-a tailored strategy. In the immediate aftermath (0-12 months after anti-TB chemotherapy), there should be an emphasis on monitoring for relapse, tracheobronchial stenosis, and smoking cessation. Subsequent management should focus on addressing hemoptysis, managing infection including aspergillosis, and TB-associated chronic obstructive pulmonary disease or restrictive lung function. There remains a vast expanse of knowledge to be discovered in PTLD. This review emphasizes the pressing need for comprehensive, consolidated guidelines for management of patients with PTLD.

Tobacco smoke exposure recruits inflammatory airspace monocytes that establish permissive lung niches for Mycobacterium tuberculosis

Tobacco smoking doubles the risk of active tuberculosis (TB) and accounts for up to 20% of all active TB cases globally. How smoking promotes lung microenvironments permissive to Mycobacterium tuberculosis (Mtb) growth remains incompletely understood. We investigated primary bronchoalveolar lavage cells from current and never smokers by performing single-cell RNA sequencing (scRNA-seq), flow cytometry, and functional assays. We observed the enrichment of immature inflammatory monocytes in the lungs of smokers compared with nonsmokers. These monocytes exhibited phenotypes consistent with recent recruitment from blood, ongoing differentiation, increased activation, and states similar to those with chronic obstructive pulmonary disease. Using integrative scRNA-seq and flow cytometry, we identified CD93 as a marker for a subset of these newly recruited smoking-associated lung monocytes and further provided evidence that the recruitment of monocytes into the lung was mediated by CCR2-binding chemokines, including CCL11. We also show that these cells exhibit elevated inflammatory responses upon exposure to Mtb and accelerated intracellular growth of Mtb compared with mature macrophages. This elevated Mtb growth could be inhibited by anti-inflammatory small molecules, providing a connection between smoking-induced pro-inflammatory states and permissiveness to Mtb growth. Our findings suggest a model in which smoking leads to the recruitment of immature inflammatory monocytes from the periphery to the lung, which results in the accumulation of these Mtb-permissive cells in the airway. This work defines how smoking may lead to increased susceptibility to Mtb and identifies host-directed therapies to reduce the burden of TB among those who smoke.

Post-tuberculosis lung disease and chronic obstructive pulmonary disease

ABSTRACT

The burden of chronic airway diseases, including chronic obstructive pulmonary disease (COPD), continues to increase, especially in low- and middle-income countries. Post-tuberculosis lung disease (PTLD) is characterized by chronic lung changes after the "cure" of pulmonary tuberculosis (TB), which may be associated with the pathogenesis of COPD. However, data on its prevalence, clinical manifestations, computed tomography features, patterns of lung function impairment, and influencing factors are limited. The pathogenic mechanisms underlying PTLD remain to be elucidated. This review summarizes the recent advances in PTLD and TB-associated COPD. Research is urgently needed both for the prevention and management of PTLD.

Modulation of pulmonary immune function by inhaled cannabis products and consequences for lung disease

The lungs, in addition to participating in gas exchange, represent the first line of defense against inhaled pathogens and respiratory toxicants. Cells lining the airways and alveoli include epithelial cells and alveolar macrophages, the latter being resident innate immune cells important in surfactant recycling, protection against bacterial invasion and modulation of lung immune homeostasis. Environmental exposure to toxicants found in cigarette smoke, air pollution and cannabis can alter the number and function of immune cells in the lungs. Cannabis (marijuana) is a plant-derived product that is typically inhaled in the form of smoke from a joint. However, alternative delivery methods such as vaping, which heats the plant without combustion, are becoming more common. Cannabis use has increased in recent years, coinciding with more countries legalizing cannabis for both recreational and medicinal purposes. Cannabis may have numerous health benefits owing to the presence of cannabinoids that dampen immune function and therefore tame inflammation that is associated with chronic diseases such as arthritis. The health effects that could come with cannabis use remain poorly understood, particularly inhaled cannabis products that may directly impact the pulmonary immune system. Herein, we first describe the bioactive phytochemicals present in cannabis, with an emphasis on cannabinoids and their ability to interact with the endocannabinoid system. We also review the current state-of-knowledge as to how inhaled cannabis/cannabinoids can shape immune response in the lungs and discuss the potential consequences of altered pulmonary immunity. Overall, more research is needed to understand how cannabis inhalation shapes the pulmonary immune response to balance physiological and beneficial responses with potential deleterious consequences on the lungs.

The association between diabetes status and latent-TB IGRA levels from a cross-sectional study in eastern China

Background

There is a debate regarding the sensitivity of the QuantiFERON-TB Gold In-Tube (QFT) among people with diabetes, and prior studies have shown heterogeneous results. We evaluated whether the QFT TB antigen was modified among persons with differing diabetes status and other related risk factors.

Methods

A cross-sectional study of 5,302 people was conducted to screen latent tuberculosis infection (LTBI) in eastern China. The QFT assay was performed as an indicator of LTBI. Fasting plasma glucose (FPG) was collected from each participant; the definition of diabetes followed the guidelines from the American Diabetes Association. Participants were classified into normoglycemia, prediabetes, undiagnosed diabetes, and previously diagnosed diabetes to evaluate the relationship between the QFT TB antigen and distinct diabetes status.

Results

TB antigen values from the QFT were statistically different among participants with differing diabetes status (P = 0.008). Persons with undiagnosed diabetes had a higher TB antigen value (0.96 ± 0.20) than persons with normoglycemia (0.50 ± 0.02, P < 0.05). However, the TB antigen values demonstrated no significant difference among the four different diabetic groups when stratified by the standard cutoff for the QFT (P = 0.492 for the positive group and P = 0.368 for the negative group). In a linear regression model, we found that FPG, age, and smoking were positively associated with the QFT TB antigen value (P = 0.017, P < 0.001, and P < 0.001).

Conclusions

Diabetes status had little influence on the level of QFT TB antigen response among IGRA-positive persons. However, FPG, old age, and smoking were important risk factors for increasing levels of QFT TB antigen.

Mycobacterium abscessus: It’s Complex

Mycobacterium abscessus (M. abscessus) is an opportunistic pathogen usually colonizing abnormal lung airways and is often seen in patients with cystic fibrosis. Currently, there is no vaccine available for M. abscessus in clinical development. The treatment of M. abscessus-related pulmonary diseases is peculiar due to intrinsic resistance to several commonly used antibiotics. The development of either prophylactic or therapeutic interventions for M. abscessus pulmonary infections is hindered by the absence of an adequate experimental animal model. In this review, we outline the critical elements related to M. abscessus virulence mechanisms, host–pathogen interactions, and treatment challenges associated with M. abscessus pulmonary infections. The challenges of effectively combating this pathogen include developing appropriate preclinical animal models of infection, developing proper diagnostics, and designing novel strategies for treating drug-resistant M. abscessus.