Anders Andersson

Systemic cytokine signaling via IL-17 in smokers with obstructive pulmonary disease: a link to bacterial colonization?

We examined whether systemic cytokine signaling via interleukin (IL)-17 and growth-related oncogene-α (GRO-α) is impaired in smokers with obstructive pulmonary disease including chronic bronchitis (OPD-CB). We also examined how this systemic cytokine signaling relates to bacterial colonization in the airways of the smokers with OPD-CB. Currently smoking OPD-CB patients (n=60, corresponding to Global initiative for chronic Obstructive Lung Disease [GOLD] stage I–IV) underwent recurrent blood and sputum sampling over 60 weeks, during stable conditions and at exacerbations. We characterized cytokine protein concentrations in blood and bacterial growth in sputum. Asymptomatic smokers (n=10) and never-smokers (n=10) were included as control groups. During stable clinical conditions, the protein concentrations of IL-17 and GRO-α were markedly lower among OPD-CB patients compared with never-smoker controls, whereas the asymptomatic smoker controls displayed intermediate concentrations. Notably, among OPD-CB patients, colonization by opportunistic pathogens was associated with markedly lower IL-17 and GRO-α, compared with colonization by common respiratory pathogens or oropharyngeal flora. During exacerbations in the OPD-CB patients, GRO-α and neutrophil concentrations were increased, whereas protein concentrations and messenger RNA for IL-17 were not detectable in a reproducible manner. In smokers with OPD-CB, systemic cytokine signaling via IL-17 and GRO-α is impaired and this alteration may be linked to colonization by opportunistic pathogens in the airways. Given the potential pathogenic and therapeutic implications, these findings deserve to be validated in new and larger patient cohorts.

systemic signs of neutrophil mobilization during clinically stable periods and during exacerbations in smokers with obstructive pulmonary disease

Background It is still unclear whether signs of neutrophil mobilization in the blood of patients with chronic obstructive pulmonary disease represent true systemic events and how these relate to bacterial colonization in the airways. In this study, we evaluated these issues during clinically stable periods and during exacerbations in smokers with obstructive pulmonary disease and chronic bronchitis (OPD-CB). Methods Over a period of 60 weeks for each subject, blood samples were repeatedly collected from 60 smokers with OPD-CB during clinically stable periods, as well as during and after exacerbations. Myeloperoxidase (MPO) and neutrophil elastase (NE) protein and mRNA, growth of bacteria in sputum, and clinical parameters were analyzed. Ten asymptomatic smokers and ten never-smokers were included as controls. Results We found that, during clinically stable periods, neutrophil and NE protein concentrations were increased in smokers with OPD-CB and in the asymptomatic smokers when compared with never-smokers. During exacerbations, neutrophil and MPO protein concentrations were further increased in smokers with OPD-CB, without a detectable increase in the corresponding mRNA during exacerbations. However, MPO and NE protein and mRNA displayed positive correlations. During exacerbations, only increased neutrophil concentrations were associated with growth of bacteria in sputum. Among patients with low transcutaneous oxygen saturation during exacerbations, PaO2 (partial oxygen pressure) correlated with concentrations of MPO and NE protein and neutrophils in a negative manner. Conclusion There are signs of systemic neutrophil mobilization during clinically stable periods and even more so during exacerbations in chronic obstructive pulmonary disease. In this condition, MPO and NE may share a cellular origin, but its location remains uncertain. Factors other than local bacteria, including hypoxemia, may be important for driving systemic signs of neutrophil mobilization.

Effects of tobacco smoke on IL-16 in CD8+ cells from human airways and blood: a key role for oxygen free radicals?

Chronic exposure to tobacco smoke leads to an increase in the frequency of infections and in the number of CD8(+) and CD4(+) cells as well as the CD4(+) chemoattractant cytokine IL-16 in the airways. Here, we investigated whether tobacco smoke depletes intracellular IL-16 protein and inhibits de novo production of IL-16 in CD8(+) cells from human airways and blood while increasing extracellular IL-16 and whether oxygen free radicals (OFR) are involved. Intracellular IL-16 protein in CD8(+) cells and mRNA in all cells was decreased in bronchoalveolar lavage (BAL) samples from chronic smokers. This was also the case in human blood CD8(+) cells exposed to water-soluble tobacco smoke components in vitro, in which oxidized proteins were markedly increased. Extracellular IL-16 protein was increased in cell-free BAL fluid from chronic smokers and in human blood CD8(+) cells exposed to water-soluble tobacco smoke components in vitro. This was not observed in occasional smokers after short-term exposure to tobacco smoke. A marker of activation (CD69) was slightly increased, whereas other markers of key cellular functions (membrane integrity, apoptosis, and proliferation) in human blood CD8(+) cells in vitro were negatively affected by water-soluble tobacco smoke components. An OFR scavenger prevented these effects, whereas a protein synthesis inhibitor, a β-adrenoceptor, a glucocorticoid receptor agonist, a phosphodiesterase, a calcineurin phosphatase, and a caspase-3 inhibitor did not. In conclusion, tobacco smoke depletes preformed intracellular IL-16 protein, inhibits its de novo synthesis, and distorts key cellular functions in human CD8(+) cells. OFR may play a key role in this context.

New evidence of increased risk of rhinitis in subjects with COPD: a longitudinal population study

Background The aim of this population-based study was to investigate the risk of developing noninfectious rhinitis (NIR) in subjects with chronic obstructive pulmonary disease (COPD). Materials and methods This is a longitudinal population-based study comprising 3,612 randomly selected subjects from Gothenburg, Sweden, aged 25–75 years. Lung function was measured at baseline with spirometry and the included subjects answered a questionnaire on respiratory symptoms. At follow-up, the subjects answered a questionnaire with a response rate of 87%. NIR was defined as symptoms of nasal obstruction, nasal secretion, and/or sneezing attacks without having a cold, during the last 5 years. COPD was defined as a spirometry ratio of forced expiratory volume in 1 second divided by forced vital capacity (FEV1/FVC) <0.7. Subjects who reported asthma and NIR at baseline were excluded from the study. The odds ratios for developing NIR (ie, new-onset NIR) in relation to age, gender, body mass index, COPD, smoking, and atopy were calculated. Results In subjects with COPD, the 5-year incidence of NIR was significantly increased (10.8% vs 7.4%, P=0.005) and was higher among subjects aged >40 years. Smoking, atopy, and occupational exposure to gas, fumes, or dust were also associated with new-onset NIR. COPD, smoking, and atopy remained individual risk factors for new-onset NIR in the logistic regression analysis. Conclusions This longitudinal population-based study of a large cohort showed that COPD is a risk factor for developing NIR. Smoking and atopy are also risk factors for NIR. The results indicate that there is a link present between upper and lower respiratory inflammation in NIR and COPD.

Interleukin-16-producing NK cells and T-cells in the blood of tobacco smokers with and without COPD

Background Long-term exposure to tobacco smoke causes local inflammation in the airways that involves not only innate immune cells, including NK cells, but also adaptive immune cells such as cytotoxic (CD8+) and helper (CD4+) T-cells. We have previously demonstrated that long-term tobacco smoking increases extracellular concentration of the CD4+-recruiting cytokine interleukin (IL)-16 locally in the airways. Here, we hypothesized that tobacco smoking alters IL-16 biology at the systemic level and that this effect involves oxygen free radicals (OFR). Methods We quantified extracellular IL-16 protein (ELISA) and intracellular IL-16 in NK cells, T-cells, B-cells, and monocytes (flow cytometry) in blood samples from long-term tobacco smokers with and without chronic obstructive pulmonary disease (COPD) and in never-smokers. NK cells from healthy blood donors were stimulated with water-soluble tobacco smoke components (cigarette smoke extract) with or without an OFR scavenger (glutathione) in vitro and followed by quantification of IL-16 protein. Results The extracellular concentrations of IL-16 protein in blood did not display any substantial differences between groups. Notably, intracellular IL-16 protein was detected in all types of blood leukocytes. All long-term smokers displayed a decrease in this IL-16 among NK cells, irrespective of COPD status. Further, both NK and CD4+ T-cell concentrations displayed a negative correlation with pack-years. Moreover, cigarette smoke extract caused release of IL-16 protein from NK cells in vitro, and this was not affected by glutathione, in contrast to the decrease in intracellular IL-16, which was prevented by this drug. Conclusion Long-term exposure to tobacco smoke does not markedly alter extracellular concentrations of IL-16 protein in blood. However, it does decrease the intracellular IL-16 concentrations in blood NK cells, the latter effect involving OFR. Thus, long-term tobacco smoking exerts an impact at the systemic level that involves NK cells; innate immune cells that are critical for host defense against viruses and tumors – conditions that are overrepresented among smokers.

Tobacco smoke causes release of IL-16 protein from NK cells in vitro

Background: The inflammatory process in chronic obstructive pulmonary disease (COPD) involves among other cells natural killer (NK) cells. Previous studies show that NK cells in smokers display a reduced cytotoxic capacity. Moreover, the cytokine interleukin (IL) -16 may modulate inflammatory responses both at extracellular and intracellular level. Extracellular IL-16 is a potent chemoattractant for CD4+ cells. These cells may be increased in the lower airways of tobacco smokers. In addition, intracellular IL-16 influences T cell cycle progression. Less is known of its role in NK cells but we have previously reported a reduced number of circulating IL-16+NK cells in smokers. Aims: To determine whether tobacco smoke is able to release IL-16 protein from NK cells in vitro. Methods: We isolated NK cells (CD3-CD16+CD56+) from buffy coat from clinically healthy blood donors using negative isolation by magnetic labeling. The isolated cells were cultured for 20 hours with or without cigarette smoke extract (CSE; concentration1:25). The concentration of extracellular IL-16 protein in conditioned medium was measured by ELISA. We also assessed the viability using exclusion of trypan blue after the culture. Results: The concentrations of IL-16 protein from CSE stimulated cells were 803 pg/ml (281-1100) compared with un-stimulated cells (vehicle) 40 pg/ml (8-87) [median (range)]. The viability was 97% (93-99) for CSE stimulated cells [median (range)] and 100% for vehicle. N=4. Conclusions: Tobacco smoke causes release of IL-16 protein from NK cells and we speculate that this effect leads to the decreased number of IL-16+NK cells observed in smokers, which may reflect an impaired ability to resist viruses and cancer tumors.