BackgroundThe electronic nose (e-nose) detects volatile organic compounds (VOCs) in exhaled air. We hypothesized that the exhaled VOCs print is different in stable vs. exacerbated patients with chronic obstructive pulmonary disease (COPD), particularly if the latter is associated with airway bacterial infection, and that the e-nose can distinguish them.MethodsSmell-prints of the bacteria most commonly involved in exacerbations of COPD (ECOPD) were identified in vitro. Subsequently, we tested our hypothesis in 93 patients with ECOPD, 19 of them with pneumonia, 50 with stable COPD and 30 healthy controls in a cross-sectional case-controlled study. Secondly, ECOPD patients were re-studied after 2 months if clinically stable. Exhaled air was collected within a Tedlar bag and processed by a Cynarose 320 e-nose. Breath-prints were analyzed by Linear Discriminant Analysis (LDA) with “One Out” technique and Sensor logic Relations (SLR). Sputum samples were collected for culture.ResultsECOPD with evidence of infection were significantly distinguishable from non-infected ECOPD (p = 0.018), with better accuracy when ECOPD was associated to pneumonia. The same patients with ECOPD were significantly distinguishable from stable COPD during follow-up (p = 0.018), unless the patient was colonized. Additionally, breath-prints from COPD patients were significantly distinguished from healthy controls. Various bacteria species were identified in culture but the e-nose was unable to identify accurately the bacteria smell-print in infected patients.ConclusionE-nose can identify ECOPD, especially if associated with airway bacterial infection or pneumonia.

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VO is not the unique parameter to consider when CPET is performed to evaluate the postoperative risk of lung cancer surgery in COPD patients. The signs of ventilatory inefficiency such as VE/VCO slope predict complications better than VO does.

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BackgroundChronic obstructive pulmonary disease (COPD) is an inflammatory disorder partially resistant to glucocorticoids. A reduced histone deacetylase (HDAC) activity has been proposed to explain this resistance. Haemophilus influenzae frequently colonizes the airways of COPD patients, where it enhances inflammation. The effects of Haemophilus influenzae on HDAC activity have not been investigated before.MethodsThe effects of the presence or absence of Haemophilus influenzae ex-vivo and in vitro were studied. To this end, we determined: (1) cytokine release in alveolar macrophages (AM) from 7 patients with COPD, 5 healthy smokers, 6 healthy non-smokers and (2) HDAC activity, nuclear factor kappa B (NF-κB) activation in a macrophage-like cell line (PMA-transformed U937 cells) co-cultured with epithelial cells. Experiments were repeated with dexamethasone (1 μM) and/or the HDAC enhancer theophylline (10 μM).ResultsHaemophilus influenzae induced a steroid-resistant inflammatory response in AM from COPD and controls and decreased HDAC activity, activated NF-κB and induced the secretion of several cytokines (IL-6, IL-8, IL-1β, IL-10 and TNF-α) (p < 0.001 for all comparisons) in the macrophage-like cell line. Dexamethasone reduced NF-κB activation but it did not modify HDAC activity. The addition of theophylline to dexamethasone increased HDAC activity and suppressed cytokine release completely, without modifying NF-κB activation.ConclusionsThese results indicate that Haemophilus influenzae reduces HDAC activity and induces a NF-κB mediated inflammatory response that is only partially suppressed by glucocorticoids irrespective of having COPD. Yet, the latter can be fully restored by targeting HDAC activity.Electronic supplementary materialThe online version of this article (doi:10.1186/s12890-015-0155-3) contains supplementary material, which is available to authorized users.

Background: Probe-based confocal laser endomicroscopy (pCLE) is a novel technique that provides in vivo microscopic imaging of the distal lung. We hypothesized that the intra-alveolar exudates characterizing Pneumocystis jirovecii pneumonia (PJP) can be identified by pCLE in vivo and help in its diagnosis. Objectives: We aimed toassess the usefulness of pCLE for the in vivo diagnosis of PJP. Methods: Thirty-two human immunodeficiency virus (HIV)-positive patients with new pulmonary infiltrates and fever were studied using pCLE. Real-time alveolar images were recorded during the bronchoscopy for off-line analysis by two independent observers. Bronchoalveolar lavage samples were also obtained and processed for microbiology and cytological evaluation, including Grocott stain for P. jirovecii. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of pCLE for the diagnosis of PJP in these patients were calculated. Results: Fourteen patients (44%) were confirmed to have PJP by cultures/staining. pCLE was well tolerated in all patients. It identified intra-alveolar exudates in 13 of them (41%), where 11 of them (85%) had positive Grocott stain for P. jirovecci, with 93% concordance between observers. Sensitivity, specificity, PPV and NPV of pCLE for the diagnosis of PJP were 79, 89, 85 and 84%, respectively. In smokers, these figures improved to be 92, 88, 85 and 94%. Conclusions: pCLE is a quick and safe procedure for on-site diagnosis of PJP in HIV+ patients with excellent specificity and sensitivity mainly in smokers.

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