Systemic CD4+ and CD8+ T-cell cytokine profiles correlate with GOLD stage in stable COPD

Chronic obstructive pulmonary disease (COPD) is associated with pulmonary and systemic inflammation. Both CD4+ and CD8+ T-lymphocytes play a key role in COPD pathogenesis, but cytokine profiles in circulating T-lymphocytes have not been well characterised. Here we report the analysis of peripheral blood T-cells from 30 stable COPD patients and 10 healthy never-smokers for interferon (IFN)-γ, interleukin (IL)-4, tumour necrosis factor (TNF)-α and the T-helper 17 cytokines IL-17A, IL-17F and IL-22 by intracellular flow cytometry. We found significantly increased proportions of IFN-γ+ and TNF-α+ CD8+ T-cells in COPD patients, when compared with healthy controls. This was most evident in patients with less severe disease. In contrast, expression profiles in circulating CD4+ T-cells were similar in COPD patients and healthy controls for all cytokines tested, except for IL-17F. COPD patients with more severely reduced diffusing capacity had lower proportions of IL-17A+ CD4+ T-cells. Proportions of IL-22+ cells in the CD4+ memory T-cell population were significantly increased in active smokers, when compared with past smokers. Collectively, this comprehensive cytokine analysis of circulating T-cells in COPD patients revealed a correlation for CD8+ T-cells between Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage and IFN-γ or TNF-α expression, but not for CD4+ T-cells.     

Blunted gamma delta T-lymphocyte response in chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) is characterised by an excessive inflammatory response to inhaled particles, mostly tobacco smoking. Although inflammation is present in all smokers, only a percentage of them develop COPD. T-lymphocytes are important effector and regulatory cells that participate actively in the inflammatory response of COPD. They comprise the T-cell receptor (TCR)-alpha beta (CD4+ and CD8+) and TCR-gamma delta T-lymphocytes. The latter represent a small percentage of the total T-cell population, but play a key role in tissue repair and mucosal homeostasis. To investigate TCR-alpha beta (CD4+ and CD8+) and TCR-gamma delta T-lymphocytes in COPD, the present authors determined, by flow cytometry, the distribution of both subpopulations in peripheral blood and bronchoalveolar lavage (BAL) samples obtained from patients with COPD, smokers with normal lung function and never-smokers. The present study found that: 1) the distribution of CD4+ and CD8+ lymphocytes in blood and BAL was similar in all three groups; 2) compared with nonsmokers, gamma delta T-lymphocytes were significantly increased in smokers with preserved lung function; and 3) this response was blunted in patients with COPD. These results highlight a novel, potentially relevant, pathogenic mechanism in chronic obstructive pulmonary disease.     

The expression of lymphocyte surface antigens in bronchial biopsies, bronchoalveolar lavage cells and blood cells in healthy smoking and never-smoking men, 60 years old

In this study we investigated if smoking subjects with a normal or slightly decreased lung function differ in the lymphocyte pattern compared to never-smokers. In a group of 'healthy' smokers (n = 58) and never-smokers (n = 34) 60 years old, we investigated the lymphocyte pattern in both BAL (n = 30 and n = 18 respectively), bronchial epithelium and lamina propria (n = 14 and n = 10 respectively) and blood. We found that all subjects, despite smoking history, had a higher number of CD8+ cells per mm2 in the epithelium compared to the lamina propria in the bronchial biopsies. In smokers, these CD8+ cells were significantly negatively correlated to FEV1 (r = -0.56, P = 0.04). In smokers, the number of CD8+ lymphocytes was higher and the T cell activation markers (CD57+ and CD28+) were lower in BAL, than in never-smokers. This last finding was also seen in blood for CD3+ 57+. We conclude, that in 'healthy' smokers the lymphocyte patterns are different compared to never-smokers, to some extent in BAL. There is also a relation between lymphocytes in the bronchial mucosa and lung function. This has previously been shown in patients with chronic obstructive pulmonary disease (COPD) and chronic bronchitis but not in asymptomatic smokers.     

Modification of surface antigens in blood CD8+ T-lymphocytes in COPD: effects of smoking.

In contrast to the effects of cigarette smoke on T-lymphocyte subsets in the airways, it has not yet been determined whether smoking has immunomodulatory effects on surface antigens of peripheral blood T-lymphocytes and, if that is the case, whether these effects differ in smokers with and without chronic obstructive pulmonary disease (COPD). The present authors have, therefore, examined the expression of the surface activation marker CD28, the levels of cytotoxic effector lymphocytes (CD27-/CD45RA+) and the expression of the lung type (Tc)1-specific chemokine receptor CXCR(3)+ on peripheral blood CD8+ T-lymphocytes. The present authors have also studied the chemotactic activity of CD8+ T-lymphocytes on monocyte chemotactic protein (MCP)-1 and compared 13 nonsmoking controls, 12 smokers with COPD and 14 smokers without airflow limitation. There was a decrease in the total count of CD8+ T-cells and an increase in the CD4+/CD8+ ratio in smokers with COPD compared with smokers without COPD and controls. Expression of the Tc1-specific chemokine receptor CXCR(3)+ by CD8+ T-cells was increased in smokers with COPD compared with smokers without COPD and controls. The expression of activated and of cytotoxic effector CD8+ T-cells in smokers with and without COPD showed an increase compared with controls. CD8+ T-cells from smokers with and without COPD showed a decrease in chemotactic activity to MCP-1 compared with controls. In conclusion, chronic obstructive pulmonary disease may be a systemic immunomodulatory disease associated with the modification of surface antigens in blood CD8+ T-lymphocytes.     

Increased airway granzyme b and perforin in current and ex-smoking COPD subjects

Increased bronchial epithelial cell apoptosis and CD8+ T-cell numbers in the blood and airways have been reported in COPD. These cells can induce apoptosis via the granzyme-b/perforin-mediated pathway. We hypothesized that increased levels of granzyme-b/perforin would be detected in COPD, contributing to apoptosis and tissue damage. Intracellular granzyme-b/perforin were measured in blood-derived T-cells and natural killer (NK) cells from COPD subjects (30 current and 30 ex-smokers), 20 asymptomatic current-smokers and 30 never-smokers, and bronchoalveolar lavage (BAL)-derived T-cells from a cohort of these subjects using flow cytometry. Soluble granzyme-b was determined by ELISA. In blood, there was an increased percentage of T-cells expressing intracellular granzyme-b/perforin for both COPD groups but not asymptomatic smokers (versus never-smokers). Soluble granzyme-b was undetectable. In BAL, soluble granzyme-b levels and the percentage of T-cells expressing intracellular granzyme-b/perforin were increased in both COPD groups and asymptomatic smokers. There was a significant correlation between granzyme-b expression in BAL and apoptosis of bronchial epithelial cells. Most circulating NK cells expressed granzyme-b/perforin, with the median fluorescence intensity of staining increased in both COPD groups and asymptomatic smokers. Granzyme-mediated apoptosis may thus be one mechanism of lung injury in COPD. The changes that persist despite smoking cessation in COPD likely reflect pathophysiological changes in COPD as opposed to the effects of smoking per se.     

Peripheral blood lymphocyte subsets in patients with chronic hepatitis C – effects of interferon treatment

Abstract: Thirty-three patients with chronic hepatitis non-A, non-B/C were included in a randomized controlled study of recombinant alpha-2b interferon treatment 3 MU three times weekly for 36 weeks. In lysed whole blood, lymphocyte subpopulations were enumerated by flow cytometry detecting fluorescein or phycoerytrin conjugated monoclonal antibodies directed against seven different epitopes. Patients with chronic active hepatitis were significantly older than patients with chronic persistent hepatitis (p>0.05). Before treatment, the proportions of different subsets of lymphocytes were within the normal reference values and the CD4/CD8 ratio was also normal. No increased activation of T-cells was noticed. Patients over 50 years of age, however, had a significantly increased (p>0.01) proportion of HLA-DR + lymphocytes, mainly B-cells. Treatment decreased the absolute number of peripheral blood leukocytes and lymphocytes. There was also a significant decline in the proportion of CD8 + lymphocytes and NK-cells, and a significant increase in the proportion HLA-DR + cells and of the CD4/CD8 ratio. The increased proportion of HLA-DR + cells, however, did not reflect peripheral T-cell activation; instead, it was due to increasing B lymphocyte numbers.     

Increased proportion of Fas positive CD8+ cells in peripheral blood of patients with COPD

Chronic obstructive pulmonary disease (COPD) is characterised by chronic inflammation in pulmonary tissue and is also associated with systemic effects. The objective of this study was determination of lymphocyte subpopulation and the expression of Fas receptor on lymphocytes derived from peripheral blood of patients with stable COPD (n=18) and a control group: asymptomatic smokers (n=12) and non-smokers (n=12). Flow cytometry method with monoclonal antibodies was used for evaluation of lymphocyte subsets: CD4+ and CD8+ and the expression of Fas (CD95) on T lymphocytes. We found an elevated proportion of CD8+ cells in the blood of COPD patients. Proportion of Fas+ T lymphocytes was significantly higher in patients with COPD when compared with asymptomatic smokers and non-smokers (mean: 84.4% vs. 71.6% vs. 61.0% for Fas+/ CD4+ and 88.1% vs. 73.8% vs. 58.3% for Fas+/CD8+ lymphocytes). The proportion of Fas positive CD8+ cells significantly correlated with the degree of airway obstruction and hypoxemia. The significant correlations of Fas positive CD4+ and Fas positive CD8+ with smoking history expressed as pack years smoked were observed. Our observation of an elevated proportion of circulating lymphocytes bearing Fas receptor may play a role in induction of these cells' apoptosis and indicate the role of Fas/ FasL pathway in the changes in proportion of lymphocyte subpopulations in patients with COPD.     

Abnormal peripheral blood T-lymphocyte subsets in a subgroup of patients with COPD

BACKGROUND: Smoking may induce changes in T-lymphocyte subsets in peripheral blood. Abnormalities of T-lymphocyte subsets in peripheral blood and in BAL fluid, and increased CD8+ T lymphocytes in the airways have been reported in patients with COPD. These findings suggest that T-lymphocyte abnormalities might be involved in the pathogenesis of airflow limitation in people who smoke. DESIGN: Cross-sectional study. SETTING: Outpatient pulmonary department of a university hospital. METHODS: To investigate this hypothesis, peripheral blood T-lymphocyte subsets were measured by flow cytometry using specific monoclonal antibodies in 20 healthy nonsmokers, 20 healthy smokers, and 20 smokers with stable COPD. No significant differences in the peripheral blood T-lymphocyte subsets were observed among the three groups. Because a previous study showed peripheral blood T-lymphocyte abnormalities in the subgroup of nonsmoking patients with COPD, we wanted to investigate what factors determine the subgroup of COPD with abnormal T-lymphocyte subsets. We tried to measure the relationship between T-lymphocyte subsets and physiologic indexes of pulmonary function tests in patients with COPD. The proportion of CD8+ T lymphocytes significantly correlated with diffusing capacity of the lung for carbon monoxide (DLCO) and DLCO per unit of alveolar volume (DLCO/VA), and CD4+/CD8+ ratio correlated with DLCO/VA. Therefore, we attempted to classify the patients with COPD into two subgroups on the basis of DLCO/VA: 10 COPD patients with low DLCO/VA (< 80% predicted) and 10 patients with normal DLCO/VA (> or = 80% predicted). RESULTS: The normal DLCO/VA subgroup had a significantly higher proportion of CD8+ T lymphocytes and a lower CD4+/CD8+ ratio than the healthy smokers or the low DLCO/VA subgroup. Moreover, FEV1/FVC significantly correlated with the CD4+/CD8+ ratio only in the normal DLCO/VA subgroup. CONCLUSION: These findings suggest that T-lymphocyte abnormalities might be involved in the pathogenesis of airflow limitation in a subgroup of patients with COPD, presumably with small airways disease, but not in all cases of COPD.     

A comparison of the expression of lymphocyte activation markers in blood, bronchial biopsies and bronchoalveolar lavage: evidence for an enrichment of activated T lymphocytes in the bronchoalveolar space.

In this study healthy never-smoking subjects (n = 18) were recruited from a population study. Bronchoalveolar lavage (BAL), blood lymphocytes and bronchial biopsies, analysed both in the epithelium and lamina propria, were stained for T and B lymphocytes, natural killer (NK) cells and different subpopulations of T lymphocytes. In BAL, significantly higher proportions of T lymphocytes (CD3), T lymphocyte activation markers; HLA-DR, CD26+, CD49a+, CD54+ and CD69+, helper T (CD3+4+) and memory helper T lymphocytes (CD4+45RO+29+) and memory T lymphocytes (CD3+45RO+) were found, compared to blood. However, the proportion of IL-2 receptor-positive T lymphocytes (CD25+) was lower in BAL than in blood. A previously described higher ratio of CD3+4+/CD3+8+ in BAL than in blood (3.4 vs 1.7; P = 0.001) was confirmed. In bronchial biopsies, we found significantly higher numbers of CD8+ cell profiles per mm2 in the epithelial compared to the lamina propria compartment. We conclude that healthy never-smoking men have higher levels of activated memory T lymphocytes in BAL than in blood, and that the T-cell subpopulations differ in the epithelial compared to the lamina propria compartment in the bronchial mucosa and these compartments should be analysed separately. It is reasonable to think that there is a gradient from blood to the airway lumen where T cells are recruited from blood to take part in the defense towards damaging agents.     

Decreased maturation of T-cell populations in the healthy elderly: Influence of nutritional factors on the appearance of double negative CD4-, CD8-, CD2+ cells

Aging is characterized by decreased T-cell functions partly related to increase of T-cell immature subsets. In carefully selected populations we explored influences of decreased nutritional levels and/or diseases on the appearance of T-cell immaturity in elderly persons. Decrease of nutritional status is associated in healthy elderly fitting the "SENIEUR" protocol with decreased mature T-cells (CD3+), (CD8+) and increased immature double-negative T-cells (CD2+CD4-CD8-). Diseased undernourished patients express the same variations in T-cell subsets plus decreased CD4+ and increased double-positive T-cells (CD2+CD4+CD8+). This seems to indicate that aging-associated immature T-cells in peripheral blood are generated at two different, thymic and extra-thymic sites of maturation.     

Comparison of blood and synovial fluid lymphocyte subsets in rheumatoid arthritis and osteoarthritis

Summary Immunoregulatory T-cell deficiency is thought to underlie pathogenesis of rheumatoid arthritis (RA) as a systemic autoimmunopathy. The aim of this study was a simultaneous analysis of peripheral blood and synovial lymphocyte subsets (Ly-SS) of RA patients as compared to patients with locally active osteoarthritis (OA). Peripheral blood Ly-SS and paired synovial fluid Ly-SS from 87 RA patients were analysed by two dimensional flow cytometry (Simulset Becton Dickinson) as compared to 15 OA patients. The control group consisted of 32 healthy subjects. The peripheral blood analysis from RA and OA patients revealed a significant decrease of CD8+T-cells and increase of CD4+:CD8+ ratio when compared to the control group. The blood of RA patients showed a significant increase of HLA DR+ and IL 2R+T cells as compared to OA group. The synovial fluid from RA and OA patients showed a significant increase of CD3+, CD8+, HLA DR+ T-cells and decrease of CD4+:CD8+ ratio and CD19+ cells in comparison to the peripheral blood. This study shows, that the OA T-cell system seems not to be activated in peripheral blood in opposition to RA patients. Synovial fluid Ly-SS in OA, however, showed only quantitative but not qualitative differences. OA seems to be mainly a local inflammatory response depending on T-cells, when lymphocyte T activity in blood is diminished.     

Intraepithelial T-lymphocyte subsets in the airways of normal subjects and of patients with chronic bronchitis

Lymphocyte infiltration of central airway epithelium was evaluated in 13 normal nonsmoking subjects (Group 1), in 11 smokers without clinical signs of chronic bronchitis (Group 2), and in 34 patients who were smokers with chronic bronchitis and mild airflow limitation (Group 3). Bronchial samples were obtained through fiberoptic bronchoscopy. Murine monoclonal antibodies directed against cell-surface antigens and an immunoperoxidase technique were used on cryostat sections to label in situ the following lymphocyte populations: T-lymphocytes (CD3+), helper/inducer T-cells (CD4+), suppressor/cytotoxic T-cells (CD8+) and B-lymphocytes (leu 12+). Virtually no B-cells were found in central airway epithelium from subjects of any group. Conversely, consistent infiltration of epithelial layers with T-lymphocytes of both subsets was observed in all subjects, with a constant predominance of CD8+ over CD4+ cells. For any T-cell marker, differences between mean scores from Group 1 and Group 2 subjects were not statistically significant. On the other hand, mean lymphocyte numbers of both subsets were found increased in patients from Group 3 compared with subjects from the two other groups: statistically significant differences were observed for CD3+, CD4+, and CD8+ cells (p less than 0.001). Furthermore, lymphocyte scores at two different airway generation were compared in some patients from Groups 2 and 3, and a significant positive correlation was observed. These results suggest that T-lymphocyte infiltration of central airway epithelium (1) may be a naturally occurring phenomenon that is amplified in the airways of smokers with chronic bronchitis, and (2) may represent the counterpart to the intraepithelial population of the intestine.(ABSTRACT TRUNCATED AT 250 WORDS)     

Reduced bronchial CD4+ T-cell density in smokers with occupational asthma.

Cigarette smoking may alter bronchial inflammation in asthma. Multicolour immunohistofluorescent examination on bronchial cryosections was used to examine bronchial inflammatory cell infiltrate in patients with occupational asthma. Monoclonal antibodies to CD3, CD4, CD8, T-cell receptor-delta1, CD68 and human leukocyte antigen-DR were combined to identify T-cell subsets and macrophages in bronchial biopsies from 20 workers with occupational asthma (12 smokers and eight nonsmokers), 15 healthy workers (seven smokers and eight nonsmokers) and 10 nonsmoking, nonexposed controls. The increased subepithelial CD4+ T-cell density in nonsmoking asthmatics was not present in smoking asthmatics, who had the lowest CD4+ T-cell density of all groups. The decreased subepithelial CD4+ and CD8+ T-cell density correlated with a reduction in lung function, as measured by percentage predicted forced expiratory volume in one second, in smoking asthmatics only. Although smoking asthmatics had a significantly increased number of intraepithelial CD8+ T-cells and macrophages compared with nonsmoking asthmatics, the proportion of gammadelta-T-cells was significantly decreased in both asthmatic groups. Smoking asthmatics had a distinctly different distribution of T-cell subsets compared with nonsmoking asthmatics. The accumulation of subepithelial CD4+ T-cells, which was observed in nonsmoking asthmatics, appeared to be inhibited in smoking asthmatics, suggesting a smoking-induced bronchial immune modulation, at least in occupational asthma in the aluminium industry.     

T-cell activation by organic dust in vitro

Inhalation of swine dust causes intense airway inflammation with a multifold increase of inflammatory cells and lymphocyte activation as assessed by bronchoalveolar lavage. To further investigate the mechanism for lymphocyte activation the present in vitro study focuses on the lymphocyte response to swine dust in whole blood. Various concentrations of phytohaemagglutinin (PHA) (final concentrations: 3.16, 10.0, 3.16 and 100 microg ml(-1)) and swine dust (final concentrations: 10.0, 31.6, 100 and 316 microg ml(-1)) were added to heparinized whole blood from healthy donors. The blood samples were incubated in duplicate, using the homologous unstimulated blood as control, for 4, 24, 48 and 72 h in a water bath at 37 degrees C. The cells were stained with fluorochrome conjugated monoclonal antibodies. For analysis of T-cell activation CD3 was double-stained together with the activation markers CD69, CD25 and HLADR. Cell count percentages were analysed by flow cytometry. Soluble IL-2sRalpha in plasma was analysed using commercial sandwich ELISA technique. At baseline CD69, CD25 and HLA-DR were expressed in < 1%, approx 5% and < 1% of the T-cells respectively. We found a dose response relationship between swine dust exposure and the expression of all three T-cell activation markers which appeared at different time-points. Maximal expression of CD69 (8%, P<0.05) and CD25 (15%, P<0.001) was found after 24h of activation. HLA-DR was significantly expressed after 48h (8%) and maximally expressed after 72 h of activation (13%, P<0.05). The soluble IL-2sRalpha in plasma was maximally expressed after 24-48 h (1200 pg ml(1) and 1500 pg ml(-1), respectively. In conclusion, T-cells were activated by swine dust in vitro. Thus, our previous findings of T-cell activation following swine dust exposure, in vivo may be an effect of the dust either directly on T-cells or on other cells which in turn contribute to the T-cell activation.     

Elevated levels of activated CD4 T cells in common variable immunodeficiency: association with clinical findings

BackgroundCommon variable immunodeficiency (CVID) is a very heterogeneous syndrome defined by impaired immunoglobulin production. The primary defect remains unknown, but many reports describe peripheral blood T and B lymphocyte dysfunctions in a substantial proportion of CVID patients. Immunophenotypic alterations on memory B lymphocytes correlate with clinical findings. A B-cell-oriented classification principle of the patients has been proposed.Methods and resultsWe investigated the expression of activation surface molecules on CD4 and CD8 T-cells from 14 patients with CVID, 6 non-CVID hypogammaglobulinemic patients with recurrent infections, 47 asymptomatic HIV-positive patients without AIDS defining conditions and 23 healthy subjects. Lymphocyte subsets were analysed by three-colour flow cytometry. Monoclonal panel: CD38-FITC/HLADR-PE/CD4 or CD8-PerCP. In CVID patients serum levels of CD4 T-cells co-expressing the activation marker HLA-DR [CD4 + DR + (34 %), CD4 + CD38 + DR + (18 %)] were significantly elevated compared with controls. Significant increases in CD8 + DR + (54%), CD8 + CD38 + (43 %) and CD8 + CD38 + DR + (29 %) T-cells were observed in comparison with healthy controls. CVID patients with splenomegaly, lower pre-infusion IgG levels (< 600 mg/dl), autoimmune or lymphoproliferative conditions demonstrated even higher levels of CD4 + CD38 + DR + T cells (22, 22, 21 and 21 % respectively) compared with other CVID patients (13, 13, 15 and 15 % respectively).ConclusionThese findings indicate a state of ongoing T lymphocyte activation which is associated with clinical findings frequently observed in CVID.     

Accelerated immune senescence and HIV-1 infection

A recent consensus has emerged regarding the association between chronic immune activation and poor outcome in HIV-1 infection. However, its basis remains unclear. Accumulating evidence suggests that the cells of the immune system may have a limited replicative lifespan in vivo. In this context, persistent activation during chronic HIV infection may lead to an exhaustion of immune resources. This may occur at two levels: Clonal and Global. Some HIV-1-specific CD8+ T-cells start expressing the senescence marker CD57 soon after primary infection. Persistently activated HIV-1-specific T-cell clones may eventually reach stages of replicative senescence and disappear, resulting in the specific loss of CD8+ T-cell populations important to control viral replication. In addition, HIV-1 infected individuals are characterized by the accumulation of highly differentiated CD8+ and CD4+ T-cells overtime. Together with the decline of T-cell renewal capacities, this may reflect a general ageing of the lymphocyte population. Similar observations have been done in HIV non-infected elderly individuals, which suggests that premature immunosenescence occurs in HIV-1 infection, as a result of persistent immune activation.     

Increased Expression of Interleukin-18 and its Receptor in Peripheral Blood of Patients with Chronic Obstructive Pulmonary Disease

Abstract

Chronic obstructive pulmonary disease (COPD) is a complex systemic disorder characterized by both local pulmonary and systemic inflammation. Many studies suggested that activation of circulating inflammatory cells and increased circulating levels of inflammatory cytokines occur in COPD. Interleukin (IL)-18 is a unique proinflammatory cytokine that mediates its effects by binding to the IL-18 receptor (IL-18R). In the present study, the expression of IL-18 in serum and IL-18R on peripheral blood T lymphocytes was analyzed. Enzyme-linked immunosorbent assay (ELISA) was used to determine the serum levels of IL-18 and interferon (IFN)-©, and high sensitivity C-reactive protein (hsCRP) were measured by chemiluminiscent immunoassay. Expression of IL-18R was examined using a three-color flow cytometry method. In total, 120 subjects were recruited including 32 nonsmokers, 30 current smokers and 58 stable COPD patients. Serum levels of IL-18 and hsCRP were significantly higher in stable COPD patients than those in nonsmokers and current smokers. A significant negative correlation existed between pulmonary function and serum level of IL-18 rather than hsCRP in stable COPD patients. The proportions of IL-18R〈-expressing T lymphocytes and CD8⁺ T lymphocytes were significantly higher in stable COPD patients than in nonsmokers and current smokers. The current study extended prior analyses by examining IL-18R expression in peripheral blood. The results suggested that IL-18/IL-18R system was active in peripheral blood of COPD patients.     

Interplay between the Lung Microbiome,Pulmonary Immunity and Viral Reservoirs in People Living with HIV under Antiretroviral Therapy

Pulmonary dysbiosis may predispose people living with HIV (PLWH) to chronic lung disease. Herein, we assessed whether intrapulmonary HIV reservoir size and immune disruption are associated with reduced bacterial lung diversity in PLWH. Bacterial DNA was extracted and PCR-amplified from cell-free bronchoalveolar lavage (BAL) fluid from 28 PLWH and 9 HIV-negative controls. Amplicon sequence variant (ASV) relative abundances and taxonomic identities were analyzed using joint species distribution modeling. HIV-DNA was quantified from blood and pulmonary CD4+ T-cells using ultra-sensitive qPCR. Immunophenotyping of BAL T-cells was performed using flow cytometry. Lung microbiome diversity was lower in smokers than non-smokers and microbiome composition was more variable in PLWH than HIV-negative individuals. Frequencies of effector memory BAL CD4+ and CD8+ T-cells positively correlated with abundance of several bacterial families while frequencies of BAL activated CD4+ T-cells negatively correlated with abundance of most lung bacterial families. Higher HIV-DNA levels in blood, but not in BAL, as well as frequencies of senescent CD4+ T-cells were associated with reduced bacterial diversity. These findings suggest that HIV infection may weaken the relationship between the lung microbiome and smoking status. Viral reservoir and immune activation levels may impact the lung microbiome, predisposing PLWH to pulmonary comorbidities.