ABSTRACT
It remains a mystery why HIV-associated end-organ pathologies persist in the era of combined antiretroviral therapy (ART). One possible mechanism is the continued production of HIV-encoded proteins in latently HIV-infected T cells and macrophages. The proapoptotic protein HIV-Nef persists in the blood of ART-treated patients within extracellular vesicles (EVs) and peripheral blood mononuclear cells. Here we demonstrate that HIV-Nef is present in cells and EVs isolated from BAL of patients on ART. We hypothesize that HIV-Nef persistence in the lung induces endothelial apoptosis leading to endothelial dysfunction and further pulmonary vascular pathologies. The presence of HIV-Nef in patients with HIV correlates with the surface expression of the proapoptotic endothelial-monocyte-activating polypeptide II (EMAPII), which was implicated in progression of pulmonary emphysema via mechanisms involving endothelial cell death. HIV-Nef protein induces EMAPII surface expression in human embryonic kidney 293T cells, T cells, and human and mouse lung endothelial cells. HIV-Nef packages itself into EVs and increases the amount of EVs secreted from Nef-expressing T cells and Nef-transfected human embryonic kidney 293T cells. EVs from BAL of HIV+ patients and Nef-transfected cells induce apoptosis in lung microvascular endothelial cells by upregulating EMAPII surface expression in a PAK2-dependent fashion. Transgenic expression of HIV-Nef in vascular endothelial-cadherin+ endothelial cells leads to lung rarefaction, characterized by reduced alveoli and overall increase in lung inspiratory capacity. These changes occur concomitantly with lung endothelial cell apoptosis. Together, these data suggest that HIV-Nef induces endothelial cell apoptosis via an EMAPII-dependent mechanism that is sufficient to cause pulmonary vascular pathologies even in the absence of inflammation.
Subject(s)
Cell Death/physiology , Endothelial Cells/virology , HIV Infections/virology , nef Gene Products, Human Immunodeficiency Virus/metabolism , Animals , Apoptosis/physiology , Cell Line , Cell Line, Tumor , Cells, Cultured , Cytokines/metabolism , Endothelial Cells/metabolism , Endothelium/metabolism , Endothelium/virology , HEK293 Cells , HIV Infections/metabolism , Humans , Jurkat Cells , Leukocytes, Mononuclear/metabolism , Leukocytes, Mononuclear/virology , Lung/metabolism , Lung/virology , Macrophages/metabolism , Macrophages/virology , Mice , Neoplasm Proteins/metabolism , Pulmonary Emphysema/metabolism , Pulmonary Emphysema/virology , RNA-Binding Proteins/metabolism , T-Lymphocytes/metabolism , T-Lymphocytes/virologyABSTRACT
BACKGROUND: The increase in the use of monoclonal antibodies (mAB) as a targeted therapy for a variety of diseases has been accompanied by an increase in reports of interstitial lung abnormalities in treated patients. OBJECTIVE: Bronchoalveolar lavage (BAL) is routinely performed in these patients to rule out infection, so we sought to determine the BAL cellular pattern in individuals with mAB-induced lung disease (mAB-ILD). METHODS: We utilized a case-control study design. Among patients treated with mAB, cases were defined as those with otherwise-unexplained interstitial lung abnormalities, which resolved after cessation of treatment, while controls were defined as those with interstitial abnormalities clearly explained by other etiologies. RESULTS: From 2000 to 2012, we identified 9 cases and 7 controls. The mean age of the cases was 62.6 ± 26 years and 6 were female. The most common radiographic finding was diffuse ground-glass opacities. The most common BAL cellular pattern was mixed inflammation with moderate lymphocytic and mild neutrophilic alveolitis. The cases had a higher mean lymphocyte count than the controls (40.1 ± 32.6 vs. 13.1 ± 25.5, p = 0.008). The rest of the BAL cellular analyses were similar between the 2 groups. The median CD4:CD8 ratio in 7 patients with >15% lymphocytes was 0.9 (0.6-3). There was no significant difference in the CD4:CD8 ratio between the 2 groups. CONCLUSIONS: Mixed inflammation with moderate lymphocytic and mild neutrophilic alveolitis is the most common BAL cellular pattern in patients with mAB-ILD. Such findings may be useful for the early identification of mAB-ILD.
Subject(s)
Antibodies, Monoclonal/adverse effects , Bronchoalveolar Lavage Fluid/cytology , Lung Diseases, Interstitial/immunology , Lymphocytes/cytology , Neutrophils/cytology , Adult , Aged , Bronchoalveolar Lavage Fluid/immunology , CD4-CD8 Ratio , Case-Control Studies , Female , Humans , Lung Diseases, Interstitial/chemically induced , Lymphocyte Count , Lymphocytes/immunology , Male , Middle Aged , Neutrophils/immunology , Retrospective StudiesABSTRACT
BACKGROUND: Human immunodeficiency virus (HIV) is readily detectable in the lungs of infected subjects and leads to an accumulation of CD8(+) lymphocytes in the alveolar space. Although highly active antiretroviral therapy (HAART) is effective in reducing viremia, less is known about its effect on tissue compartments. The AIDS Clinical Trials Group Protocol 723 Team evaluated the effect of HAART on lung viral load and cellular constituents. METHODS: Bronchoalveolar lavage (BAL) fluid and blood were collected before initiation of HAART and again at 4 and 24 weeks after initiation of therapy. The BAL cell differential was determined, lymphocyte phenotyping was performed, and acellular BAL fluid, plasma HIV RNA load, and BAL cell and peripheral blood mononuclear cell HIV RNA and DNA loads were measured. RESULTS: HAART induced a rapid decrease in HIV that was detectable in acellular BAL fluid and a slower decrease in the HIV RNA and DNA loads in BAL cells. HAART was associated with a significant decrease in the absolute number and percentage of CD8(+) alveolar lymphocytes. There was a significant correlation between residual BAL cell DNA at 24 weeks and the absolute number of CD4(+) lymphocytes in the alveolar space. CONCLUSION: HAART is associated with a significant decrease in the pulmonary HIV burden and a return of alveolar cellular constituents to normal.
