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.

Delivery outcomes associated with maternal congenital heart disease, 2000-2018

PURPOSE

To characterize temporal trends and outcomes of delivery hospitalization with maternal congenital heart disease (CHD).

MATERIALS AND METHODS

For this repeated cross-sectional analysis, deliveries to women aged 15-54 years with maternal CHD were identified in the 2000-2018 National Inpatient Sample. Temporal trends in maternal CHD were analyzed using joinpoint regression to estimate the average annual percentage change (AAPC) with 95% CIs. The relationship between maternal CHD and several adverse maternal outcomes was analyzed with log-linear regression models. Risk for adverse outcomes in the setting of maternal CHD was further characterized based on additional diagnoses of cardiac comorbidity including congestive heart failure, arrhythmia, valvular disease, pulmonary disorders, and history of thromboembolism.

RESULTS

Of 73,109,790 delivery hospitalizations, 51,841 had a diagnosis of maternal CHD (7.1 per 10,000). Maternal CHD rose from 4.2 to 10.9 per 10,000 deliveries (AAPC 4.8%, 95% CI 4.2%, 5.4%). Maternal CHD deliveries with a cardiac comorbidity diagnosis also increased from 0.6 to 2.6 per 10,000 from 2000 to 2018 (AAPC 8.4%, 95% CI 6.3%, 10.6%). Maternal CHD was associated with severe maternal morbidity (adjusted risk ratios [aRR] 4.97, 95% CI 4.75, 5.20), cardiac severe maternal morbidity (aRR 7.65, 95% CI 7.14, 8.19), placental abruption (aRR 1.30, 95% 1.21, 1.38), preterm delivery (aRR 1.47, 95% CI 1.43, 1.51), and transfusion (aRR 2.28, 95% CI 2.14, 2.42). Risk for severe morbidity (AAPC 4.7%, 95% CI 2.5%, 6.9%) and cardiac severe morbidity (AAPC 4.7%, 95% CI 2.5%, 6.9%) increased significantly among women with maternal CHD over the study period. The presence of cardiac comorbidity diagnoses was associated with further increased risk.

CONCLUSION

Maternal CHD is becoming more common among US deliveries. Among deliveries with maternal CHD, risk for severe morbidity is increasing. These findings support that an increasing burden of risk from maternal CHD in the obstetric population.

Trends in and outcomes associated with obstructive sleep apnea during deliveries in the United States, 2000-2019

BACKGROUND

Population-level data on obstructive sleep apnea among pregnant women in the United States and associated risk for adverse outcomes during delivery may be of clinical importance and public health significance.

OBJECTIVE

This study aimed to assess trends in and outcomes associated with obstructive sleep apnea during delivery hospitalizations.

STUDY DESIGN

This repeated cross-sectional study analyzed delivery hospitalizations using the National Inpatient Sample. Temporal trends in obstructive sleep apnea were analyzed using joinpoint regression to estimate the average annual percentage change with 95% confidence intervals. Survey-adjusted logistic regression models were fit to assess the association between obstructive sleep apnea and mechanical ventilation or tracheostomy, acute respiratory distress syndrome, hypertensive disorders of pregnancy, peripartum hysterectomy, pulmonary edema/heart failure, stillbirth, and preterm birth.

RESULTS

From 2000 to 2019, an estimated 76,753,013 delivery hospitalizations were identified, of which 54,238 (0.07%) had a diagnosis of obstructive sleep apnea. During the study period, the presence of obstructive sleep apnea during delivery hospitalizations increased from 0.4 to 20.5 cases per 10,000 delivery hospitalizations (average annual percentage change, 20.6%; 95% confidence interval, 19.1-22.2). Clinical factors associated with obstructive sleep apnea included obesity (4.3% of women without and 57.7% with obstructive sleep apnea), asthma (3.2% of women without and 25.3% with obstructive sleep apnea), chronic hypertension (2.0% of women without and 24.5% with obstructive sleep apnea), and pregestational diabetes mellitus (0.9% of women without and 10.9% with obstructive sleep apnea). In adjusted analyses accounting for obesity, other clinical factors, demographics, and hospital characteristics, obstructive sleep apnea was associated with increased odds of mechanical ventilation or tracheostomy (adjusted odds ratio, 21.9; 95% confidence interval, 18.0-26.7), acute respiratory distress syndrome (adjusted odds ratio, 5.9; 95% confidence interval, 5.4-6.5), hypertensive disorders of pregnancy (adjusted odds ratio, 1.6; 95% confidence interval, 1.6-1.7), stillbirth (adjusted odds ratio, 1.2; 95% confidence interval, 1.0-1.4), pulmonary edema/heart failure (adjusted odds ratio, 3.7; 95% confidence interval, 2.9-4.7), peripartum hysterectomy (adjusted odds ratio, 1.66; 95% confidence interval, 1.23-2.23), and preterm birth (adjusted odds ratio, 1.2; 95% confidence interval, 1.1-1.2).

CONCLUSION

Obstructive sleep apnea diagnoses are increasingly common in the obstetrical population and are associated with a range of adverse obstetrical outcomes during delivery hospitalizations.

Smoking and HIV-1 Infection Promote Retention of CD8+ T Cells in the Airway Mucosa

Smoking and HIV-1 infection are risk factors for COPD, which is among the most common comorbid conditions in people living with HIV-1. HIV-1 infection leads to persistent expansion of CD8+ T cells, and CD8+ T cell-mediated inflammation has been implicated in COPD pathogenesis. In this study, we investigated the effects of HIV-1 infection and smoking on T cell dynamics in patients at risk of COPD. Bronchoalveolar lavage (BAL), endobronchial brushings and blood from HIV-1 infected and uninfected non-smokers and smokers were analyzed by flow cytometry, and lungs were imaged by computed tomography. Chemokines were measured in BAL fluid, and CD8+ T cell chemotaxis in the presence of cigarette smoke extract was assessed in vitro. HIV-1 infection increased CD8+ T cells in the BAL, but this increase was abrogated by smoking. Smokers had reduced BAL levels of the T cell-recruiting chemokines CXCL10 and CCL5, and cigarette smoke extract inhibited CXCL10 and CCL5 production by macrophages and CD8+ T cell transmigration in vitro. In contrast to the BAL, CD8+ T cells in endobronchial brushings were increased in HIV-1 infected smokers, driven by an accumulation of effector memory T cells in the airway mucosa and an increase in tissue resident memory T cells. Mucosal CD8+ T cell numbers inversely correlated with lung aeration, suggesting an association with inflammation and remodeling. HIV-1 infection and smoking lead to retention of CD8+ T cells within the airway mucosa.

T cell-tropic HIV efficiently infects alveolar macrophages through contact with infected CD4+ T cells

Alveolar macrophages (AMs) are critical for defense against airborne pathogens and AM dysfunction is thought to contribute to the increased burden of pulmonary infections observed in individuals living with HIV-1 (HIV). While HIV nucleic acids have been detected in AMs early in infection, circulating HIV during acute and chronic infection is usually CCR5 T cell-tropic (T-tropic) and enters macrophages inefficiently in vitro. The mechanism by which T-tropic viruses infect AMs remains unknown. We collected AMs by bronchoscopy performed in HIV-infected, antiretroviral therapy (ART)-naive and uninfected subjects. We found that viral constructs made with primary HIV envelope sequences isolated from both AMs and plasma were T-tropic and inefficiently infected macrophages. However, these isolates productively infected macrophages when co-cultured with HIV-infected CD4+ T cells. In addition, we provide evidence that T-tropic HIV is transmitted from infected CD4+ T cells to the AM cytosol. We conclude that AM-derived HIV isolates are T-tropic and can enter macrophages through contact with an infected CD4+ T cell, which results in productive infection of AMs. CD4+ T cell-dependent entry of HIV into AMs helps explain the presence of HIV in AMs despite inefficient cell-free infection, and may contribute to AM dysfunction in people living with HIV.

HIV-1 and SIV Infection Are Associated with Early Loss of Lung Interstitial CD4+ T Cells and Dissemination of Pulmonary Tuberculosis

Lung interstitial CD4+ T cells are critical for protection against pulmonary infections, but the fate of this population during HIV-1 infection is not well described. We studied CD4+ T cells in the setting of HIV-1 infection in human lung tissue, humanized mice, and a Mycobacterium tuberculosis (Mtb)/simian immunodeficiency virus (SIV) nonhuman primate co-infection model. Infection with a CCR5-tropic strain of HIV-1 or SIV results in severe and rapid loss of lung interstitial CD4+ T cells but not blood or lung alveolar CD4+ T cells. This is accompanied by high HIV-1 production in these cells in vitro and in vivo. Importantly, during early SIV infection, loss of lung interstitial CD4+ T cells is associated with increased dissemination of pulmonary Mtb infection. We show that lung interstitial CD4+ T cells serve as an efficient target for HIV-1 and SIV infection that leads to their early depletion and an increased risk of disseminated tuberculosis.

Corleis et al. show that lung parenchymal CD4+ T cells are permissive to HIV-1-dependent cell death. CD4+ T cell loss is highly significant in the interstitium but not the alveolar space, and loss of interstitial CD4+ T cells is associated with extrapulmonary dissemination of M. tuberculosis.