Arjun Ravi

Increased levels of soluble interleukin-6 receptor and CCL3 in COPD sputum.

BackgroundCOPD patients have increased numbers of macrophages and neutrophils in the lungs. Interleukin-6 (IL-6) trans-signaling via its soluble receptor sIL-6R, governs the influx of innate immune cells to inflammatory foci through regulation of the chemokine CCL3. We hypothesized that there would be enhanced levels of IL-6, sIL-6R and CCL3 in COPD sputum.Methods59 COPD patients, 15 HNS and 15 S underwent sputum induction and processing with phosphate buffered saline to obtain supernatants for IL-6, sIL-6R and CCL3 analysis. Cytoslides were produced for differential cell counting and immunocytochemistry (COPD; n = 3) to determine cell type surface expression of the CCL3 receptors CCR5 and CCR1.ResultsCOPD patients expressed higher levels (p < 0.05) of sIL-6R and CCL3 compared to controls (sIL-6R medians pg/ml: COPD 166.4 vs S 101.1 vs HNS 96.4; CCL3 medians pg/ml: COPD 117.9 vs S 0 vs HNS 2.7). COPD sIL-6R levels were significantly correlated with sputum neutrophil (r = 0.5, p < 0.0001) and macrophage (r = 0.3, p = 0.01) counts. Immunocytochemical analysis revealed that CCR5 and CCR1 were exclusively expressed on airway macrophages.ConclusionEnhanced airway generation of sIL-6R may promote IL-6 trans-signaling in COPD. Associated upregulation of CCL3 may facilitate the recruitment of macrophages into the airways by ligation of CCR1 and CCR5.

Clinical characteristics of eosinophilic COPD versus COPD patients with a history of asthma

Eosinophilic COPD appears to be a distinct patient subgroup with an increased corticosteroid response. Eosinophilic COPD has been labelled as part of the asthma COPD overlap syndrome (ACOS). We compared the clinical characteristics of eosinophilic COPD patients (without any clinical history of asthma) and COPD patients with a childhood history of asthma. COPD patients with asthma were characterised by more allergies and more exacerbations, but less eosinophilic inflammation. While terms such as “ACOS” are used to “lump” patients together, we report distinct differences between eosinophilic COPD and COPD patients with asthma, and propose that these groups should be split rather than lumped.

CRTH2 antagonists in asthma: current perspectives

Chemoattractant receptor-homologous molecule expressed on TH2 cells (CRTH2) binds to prostaglandin D2. CRTH2 is expressed on various cell types including eosinophils, mast cells, and basophils. CRTH2 and prostaglandin D2 are involved in allergic inflammation and eosinophil activation. Orally administered CRTH2 antagonists are in clinical development for the treatment of asthma. The biology and clinical trial data indicate that CRTH2 antagonists should be targeted toward eosinophilic asthma. This article reviews the clinical evidence for CRTH2 involvement in asthma pathophysiology and clinical trials of CRTH2 antagonists in asthma. CRTH2 antagonists could provide a practical alternative to biological treatments for patients with severe asthma. Future perspectives for this class of drug are considered, including the selection of the subgroup of patients most likely to show a meaningful treatment response.

Characterisation of lung macrophage subpopulations in COPD patients and controls

Lung macrophage subpopulations have been identified based on size. We investigated characteristics of small and large macrophages in the alveolar spaces and lung interstitium of COPD patients and controls. Alveolar and interstitial cells were isolated from lung resection tissue from 88 patients. Macrophage subpopulation cell-surface expression of immunological markers and phagocytic ability were assessed by flow cytometry. Inflammatory related gene expression was measured. Alveolar and interstitial macrophages had subpopulations of small and large macrophages based on size and granularity. Alveolar macrophages had similar numbers of small and large cells; interstitial macrophages were mainly small. Small macrophages expressed significantly higher cell surface HLA-DR, CD14, CD38 and CD36 and lower CD206 compared to large macrophages. Large alveolar macrophages showed lower marker expression in COPD current compared to ex-smokers. Small interstitial macrophages had the highest pro-inflammatory gene expression levels, while large alveolar macrophages had the lowest. Small alveolar macrophages had the highest phagocytic ability. Small alveolar macrophage CD206 expression was lower in COPD patients compared to smokers. COPD lung macrophages include distinct subpopulations; Small interstitial and small alveolar macrophages with more pro-inflammatory and phagocytic function respectively, and large alveolar macrophages with low pro-inflammatory and phagocytic ability.

The pharmacokinetics, pharmacodynamics and tolerability of PUR0200, a novel tiotropium formulation, in chronic obstructive pulmonary disease

PUR0200 is a tiotropium bromide formulation engineered with the iSPERSE dry powder delivery technology. PUR0200 is being developed as a bioequivalent alternative to tiotropium bromide, delivered using Spiriva® HandiHaler® (HH). We investigated the bronchodilator effects, pharmacokinetics and safety of PUR0200 in patients with chronic obstructive pulmonary disease (COPD).

P105 Identification of ‘large’ alveolar macrophages and pulmonary intra-vascular macrophages in COPD patients

Background A population of small macrophages with increased pro-inflammatory activity has been reported in COPD sputum. We have investigated macrophage size in the alveoli of COPD patients using immunofluorescence for the markers CX3CR1 and CD68. Methods Formalin fixed paraffin embedded tissue blocks were obtained from an area of the lung as far distal to the tumour as possible from COPD patients, smokers (S) and healthy non-smokers (HNS) undergoing lung resection for lung carcinoma. Sections were labelled with an anti-CX3CR1 antibody and detected using an Alexafluor conjugated secondary antibody. Immunohistochemical detection of CD68 (enzymatic non-biotin amplification technique) confirmed the macrophage phenotype of CX3CR1+ cells. Results All CX3CR1+ cells expressed CD68. The diameters of COPD macrophages were greater than controls (Table 1). Intravascular CX3CR1+CD68+ macrophages were observed in COPD and S (Table 1).Abstract P105 Table 1 COPD (n = 9) S (n = 9) HNS (n = 6) 25th percentile (μm) 11.6 10.3 10 Median ( μm) 13.9 12.2* 12.1* 75th percentile ( μm) 16.5 14.4 13.9 Vessels with intra-vascular macrophages (%) 15.6 22.2 0 The Kruskal-Wallis test with application of Dunn’s post-test was used to determine the statistical significance of differences observed in the alveolar macrophage diameter between the three groups. *p < 0.0001 against COPD. Conclusion Increased macrophage size in COPD may be linked to altered function. Pulmonary intravascular macrophages have been observed in other mammalian species and may promote pulmonary inflammation through direct release of cytokines into the pulmonary circulation.