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Background The histologic diagnosis of Pulmonary Langerhans cell histiocytosis (PLCH) is invasive and can cause complications. To confirm the diagnosis of PLCH, guidelines therefore recommend measuring CD1a-positive bronchoalveolar lavage fluid (BALF) cells despite its poor sensitivity and specificity. Thus, an improved diagnostic accuracy of BALF cell analysis would be desirable. Methods Using four-colour flow cytometry, plasmacytoid and myeloid dendritic cells (DCs) were analysed in BALF of 10 newly diagnosed, untreated, smoking patients with PLCH, and compared with BALF DCs from 40 asymptomatic smokers and 21 never-smokers. Results Compared with controls, myeloid DCs (median: 0.79% of BALF leukocytes) and their subpopulation of Langerhans cells (median: 0.44% of BALF leukocytes) were not increased in PLCH. Patients with PLCH displayed a normal expression of the maturity marker CD83 on BALF myeloid DCs. However, the expression of the co-signaling molecule CD80 on BALF myeloid DCs was significantly lower than in both control groups, with the lowest expression found in more severe disease (presence of cysts > 2 cm in diameter). Based on receiver operating characteristic (ROC) curve analysis, a cut-off of 53% CD80-positive BALF myeloid DCs was optimal for the diagnosis of PLCH, yielding a sensitivity of 0.90 and a specificity of 0.90. Conclusions BALF Langerhans cells are not increased in PLCH. However, PLCH is characterised by a low expression of CD80 on BALF myeloid DCs. Due to its considerably higher sensitivity and specificity, this marker appears to be more appropriate to diagnose PLCH than the currently recommended marker CD1a.

Here, we report that increasing treatment with inhaled corticosteroids (ICS) in patients with not well-controlled asthma from a medium to a high dose results in a profound reduction of blood eosinophils (median fall in blood eosinophil concentrations from 560 to 320 cells/µL). Therefore, ‘normal values’ of blood eosinophils in patients with asthma need to be considered in view of the individual ICS doses of the patients. In addition, increases in the dose of ICS may result in blood eosinophil concentrations which would formally preclude treatment with biologics targeting the interleukin-5 pathway.

Background: Beneficial effects of the anti-IgE antibody omalizumab in asthma are partly explained by a suppression of the expression of the high-affinity IgE receptor on plasmacytoid dendritic cells (DCs). However, the expression of this receptor on DCs in chronic obstructive pulmonary disease (COPD) is unknown. Methods: Using four-colour flow cytometry, high-affinity IgE receptor expression on myeloid DCs (mDCs) and plasmacytoid DCs (pDCs) in peripheral blood was analysed in 64 patients with COPD (median age: 65 years; median FEV 1 : 45.8 % predicted) and in control groups of 41 asymptomatic never-smokers, 21 asymptomatic current smokers and 20 patients with allergic asthma. Results: Asymptomatic current smokers displayed a significantly increased expression of the high-affinity IgE receptor on mDCs and pDCs, as compared with never-smokers. In patients with COPD, the expression of the high-affinity IgE receptor on pDCs, but not mDCs, increased with from spirometric GOLD stage II to IV, and correlated with lung function impairment. In patients with spirometric GOLD stages III and IV, the expression of the high-affinity IgE receptor on pDCs did not significantly differ from patients with allergic asthma. In all groups, there was a significant correlation between total IgE serum concentrations and the expression of the high-affinity IgE receptor on pDCs, suggesting that this correlation is a general feature in humans. Conclusion: The elevated expression of the high-affinity IgE receptor on plasmacytoid DCs in severe COPD is comparable with the expression in allergic asthma. Possible implications of this finding for therapies targeting IgE require further investigation.

Background The reduction of asthma exacerbations following omalizumab treatment has been related to the suppression of the high-affinity IgE receptor (FceRI) on plasmacytoid dendritic cells (DCs). However, the FceRI expression on DCs in chronic obstructive pulmonary disease (COPD) is unknown. Objective To compare FceRI expression on DCs in COPD with patients with allergic asthma and healthy controls, and to relate the findings to clinical parameters, blood eosinophil concentrations and serum immunoglobin E (IgE) concentrations. Methods Using four-colour flow cytometry, FceRI expression on blood myeloid DCs and plasmacytoid DCs was analysed in 64 patients with COPD, 20 patients with allergic asthma, 41 asymptomatic never-smokers and 21 asymptomatic current smokers. Results As compared with never-smokers, current smokers displayed an increased expression of the FceRI on myeloid and plasmacytoid DCs. In patients with COPD, the expression of the FceRI on plasmacytoid DCs, but not myeloid DCs, increased from spirometric GOLD stage 2 to GOLD stage 4, and was correlated with several lung function parameters. Patients with severe COPD and patients with allergic asthma displayed a similar FceRI overexpression on plasmacytoid DCs. In all groups, there was a positive correlation between total IgE serum concentrations and the FceRI expression on plasmacytoid DCs. Conclusions & Clinical Relevance Severe COPD and allergic asthma are characterised by a similar overexpression of the high-affinity IgE receptor on plasmacytoid DCs. In view of the effect of anti-IgE on exacerbations in asthma, trials investigating the effect of anti-IgE on exacerbations in severe COPD appear to be warranted. This article is protected by copyright. All rights reserved.

Background Dendritic cells (DCs) control immunity and play a role in the pathogenesis of chronic obstructive pulmonary disease (COPD). However, the expression of function-associated surface molecules on circulating DCs in COPD is unknown. Methods Four-colour flow cytometry was used to compare blood DC surface molecules of 54 patients with COPD (median age: 59 years; median FEV1: 38% predicted, median CAT score: 24) with two age-matched control groups with normal lung function: 21 current smokers and 21 never-smokers. Results Concentrations of plasmacytoid DCs (pDCs) and myeloid DCs (mDCs) and the mDC/pDC ratio did not differ between the groups. The increased expression of BDCA-1, BDCA-3, CD86 and CCR5 on mDCs in patients with COPD did not significantly differ from smokers with normal lung function. In contrast, COPD was specifically characterised by a decreased expression of the anti-inflammatory co-stimulatory molecule PD-L1 on pDCs and an increased expression of the pro-inflammatory co-stimulatory molecule OX40 ligand (OX40L) on mDCs. These changes were not confined to patients with elevated systemic inflammation markers (leukocytes, c-reactive protein, interleukin-6, fibrinogen). The ratio of OX40L to PD-L1 expression (OX40L/PD-L1 ratio), a quantitative measure of imbalanced DC co-stimulation, correlated with the severity of pulmonary emphysema in patients with COPD. Conclusion An imbalance of DC co-stimulation might contribute to the pathogenesis of COPD. Electronic supplementary material The online version of this article (doi:10.1186/s12931-015-0174-x) contains supplementary material, which is available to authorized users.

Anti-platelet treatment is a key therapeutic intervention in patients with cerebrovascular diseases. However, there is no information on its impact on the release of Brain-derived neurotrophic factor (BDNF), which is stored in large amounts in human platelets and essential for neuronal protection and repair. Here, we show that a single oral dose of clopidogrel, but not aspirin, significantly reduced the release of BDNF from platelets in healthy volunteers. These data point, for the first time, to possible differential effects of anti-platelet regimens on neuronal function in patients with cerebrovascular disorders.

Extracellular ATP promotes inflammation, but its role in chronic obstructive pulmonary disease (COPD) is unknown.To analyze the expression of ATP and its functional consequences in never-smokers, asymptomatic smokers, and patients with COPD.ATP was quantified in bronchoalveolar lavage fluid (BALF) of never-smokers, asymptomatic smokers, and patients with COPD of different severity. The expression of specific ATP (purinergic) receptors was measured in airway macrophages and blood neutrophils from control subjects and patients with COPD. The release of mediators by macrophages and neutrophils and neutrophil chemotaxis was assessed after ATP stimulation.Chronic smokers had elevated ATP concentrations in BALF compared with never-smokers. Acute smoke exposure led to a further increase in endobronchial ATP concentrations. Highest ATP concentrations in BALF were present in smokers and ex-smokers with COPD. In patients with COPD, BALF ATP concentrations correlated negatively with lung function and positively with BALF neutrophil counts. ATP induced a stronger chemotaxis and a stronger elastase release in blood neutrophils from patients with COPD, as compared with control subjects. In addition, airway macrophages from patients with COPD responded with an increased secretion of proinflammatory and tissue-degrading mediators after ATP stimulation. These findings were accompanied by an up-regulation of specific purinergic receptors in blood neutrophils and airway macrophages of patients with COPD.COPD is characterized by a strong and persistent up-regulation of extracellular ATP in the airways. Extracellular ATP appears to contribute to the pathogenesis of COPD by promoting inflammation and tissue degradation.

Airway dendritic cells (DCs) play a key role in smoke-related lung diseases; however, the acute effects of tobacco smoke on human airway DCs in vivo are unknown. A total of 16 smokers underwent bronchoalveolar lavage at two time-points: directly after a 4-h period of nonsmoking (no smoke exposure); and directly after a 4-h period during which eight cigarettes were smoked (acute smoke exposure). Using flow cytometry, myeloid DCs (mDCs) and plasmacytoid DCs (pDCs), as well as function-associated surface molecules on mDCs, were analysed in bronchoalveolar lavage fluid (BALF) and in blood. The numbers of macrophages, lymphocytes, neutrophils, eosinophils and pDCs were unchanged in BALF following acute smoke exposure, as compared to no smoke exposure. In contrast, there was a strong increase in mDC number in BALF and a concomitant decrease in mDC number in blood following acute smoke exposure. In addition, acute smoke exposure led to an increase in the expression of the surface molecules blood dendritic cell antigen 1 and 4 and a decrease in the expression of the lung homing receptor, CC chemokine receptor 5, on mDCs in BALF. Acute tobacco smoke inhalation results in an immediate and selective recruitment of mDCs into human airways, which might reflect the very early reaction of the adaptive immune system to smoke exposure.

A novel method of computer-assisted video image analysis (VIA) was used to determine the number of immunostained cells in tissue sections. This method permitted an accurate and objective quantification of cells of a particular phenotype. This enumeration was achieved by measuring the area stained by a test monoclonal antibody (such as the T cell marker, CD3) and comparing it with the area stained by a leukocyte common (LCA) monoclonal antibody (CD45). The proportion of T cells within the total leukocyte population in a particular tissue was then calculated. The differentiation of positive (stained) and negative (unstained) cells was uniformly maintained by setting the computer to detect a threshold for staining intensity. This enabled consistency to be maintained within a tissue section as well as between sections stained with the same antibody. In the present study, we determined the phenotype of leukocytes in colonic carcinomas by VIA and compared this with results obtained by normal visual analysis. The VIA method showed distinct advantages over normal visual analysis especially in sections which contained moderate numbers of stained cells.

Background Chronic Obstructive Pulmonary Disease (COPD) is characterised by complex inflammatory, neuronal and fibrotic changes. Brain-derived Neurotrophic Factor (BDNF) is a key regulator of neuronal plasticity, whereas Transforming Growth Factor-β1 (TGF-β1) plays a crucial role in tissue repair and emphysema pathogenesis. Both mediators are stored in platelets and released from platelets in inflammatory conditions and during serum preparation. In patients with asthma, it was previously shown that elevated serum BDNF concentrations correlate with disease severity, whereas TGF-β1 concentrations were normal. Methods In the present study, 63 patients with stable COPD (spirometric GOLD stages 2–4) and 17 age- and comorbidity-matched controls were studied. Lung function, smoking history, medication, platelet concentrations in peripheral blood and serum concentrations of BDNF, TGF-β1 and Serotonin (5-HT) were assessed in all participants. Results Serum levels of both BDNF and TGF-β1 (but not concentrations of platelets in peripheral blood) were significantly elevated in all stages of COPD as compared to controls. Highest BDNF concentrations were found in spirometric GOLD stage 3, whereas highest TGF-β1 serum levels were found in spirometric GOLD stage 4. There were specific, stage-dependent correlations of these mediators with lung function parameters of the patients. Conclusions Taken together, we show that, in contrast to asthma, COPD is characterised by elevated concentrations of both BDNF and TGF-β1 in serum. The stage-dependent association with lung function supports the hypothesis that these platelet mediators may play a role in the pathogenesis of COPD.

Background: Myeloid dendritic cells (DCs) are increased in the airway wall of patients with chronic obstructive pulmonary disease (COPD), and postulated to play a crucial role in COPD. However, DC phenotypes in COPD are poorly understood. Methods: Function-associated surface molecules on bronchoalveolar lavage fluid (BALF) DCs were analyzed using flow cytometry in current smokers with COPD, in former smokers with COPD and in never-smoking controls. Results: Myeloid DCs of current smokers with COPD displayed a significantly increased expression of receptors for antigen recognition such as BDCA-1 or Langerin, as compared with never-smoking controls. In contrast, former smokers with COPD displayed a significantly decreased expression of these receptors, as compared with neversmoking controls. A significantly reduced expression of the maturation marker CD83 on myeloid DCs was found in current smokers with COPD, but not in former smokers with COPD. The chemokine receptor CCR5 on myeloid DCs, which is also important for the uptake and procession of microbial antigens, was strongly reduced in all patients with COPD, independently of the smoking status. Conclusion: COPD is characterized by a strongly reduced CCR5 expression on myeloid DCs in the airway lumen, which might hamper DC interactions with microbial antigens. Further studies are needed to better understand the role of CCR5 in the pathophysiology and microbiology of COPD.