Impact of HIV infection and smoking on lung immunity and related disorders

Abstract

HIV-infected persons not only have higher rates of smoking than the general population, but are also unusually vulnerable to the associated adverse health effects, both infective and noninfective in origin. Indeed, in the setting of well-organised care and availability of highly active antiretroviral therapy, HIV-infected smokers lose more life-years to smoking than to HIV infection per se, presenting a major challenge to healthcare providers. Not surprisingly, the respiratory system is particularly susceptible to the damaging interactive chronic inflammatory and immunosuppressive effects of HIV and smoking, intensifying the risk of the development of opportunistic infections, as well as lung cancer and obstructive lung disorders. The impact of smoking on the immunopathogenesis and frequencies of these respiratory conditions in the setting of HIV infection, as well as on the efficacy of antiretroviral therapy, represent the primary focus of this review. @ERSpublications Smoking exacerbates the immunosuppressive/pro-inflammatory effects of HIV, increasing the risk of pulmonary disease

The Differential Impact of Emphysema on Respiratory Symptoms and 6-Minute Walk Distance in HIV Infection

“…8-12 They demonstrate that symptoms and functional limitation may be more prevalent in those HIV+ patients with emphysema, even in those with less severe emphysema and without airflow obstruction, who may not come to clinical attention if evaluation for pulmonary disease stops after obtaining normal spirometry. Based on our analyses the effect of emphysema on outcomes in HIV+ patients may not be entirely reflected in pulmonary function measures that are often used to diagnose and assess the severity of COPD clinically.…”

“…1-3 This has been accompanied by an epidemiologic transition in pulmonary disease, characterized by fewer infectious complications but an increasing burden of chronic disease including chronic obstructive pulmonary disease (COPD). 4-7 A high prevalence of tobacco use – between 40-70% 8-10 – is a major factor accounting for the increase in COPD in this group.…”

New therapies for the prevention and treatment of exacerbations of bronchiectasis

“…Less frequent causes such as allergic bronchopulmonary aspergillosis, connective tissue disease, non-tuberculous mycobacterial disease and immunodeficiency must be identified and treated as they usually require a specific treatment not described below. (20)(21)(22)(23) Once the initial identification and treatment of underlying causes has been performed, the disease still presents individual "phenotypes". (24) Exacerbations of bronchiectasis typically presenting with a combination of increasing cough, sputum production, increasing sputum purulence, malaise, fever or worsening breathlessness.…”

The respiratory microbiome of HIV-infected individuals

“…HIV preferentially infects CD4 T cells, but due to the high frequency of HIV-specific CD4 T cells and robust alveolar Th17 responses in the lung mucosa, HIV-mediated CD4 T cell depletion is initially delayed [27]. Cytopathic effects of HIV infection eventually cause CD4 T cell depletion, which drives infiltration of interferon-gamma (IFN-γ)-producing CD8 T cells into the alveolar space resulting in lymphocytic alveolitis [28].…”

“…Additionally, HIV infection impairs B cell and antibody function which also mediate poor pathogen control [28]. Cross-talk with the gut mucosa and further exposure to microbial products activates plasmacytoid dendritic cells in the lung which produce IFN-α and indolamine 2, 3-dioxygenase (IDO), and thereby promote further T cell apoptosis, T reg recruitment and perpetuate the cycle of chronic immune activation [27, 31]. These conditions may contribute to alterations in lung microbial composition.…”