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RationaleBronchopulmonary Dysplasia (BPD) in preterm born infants is a risk factor for chronic airway obstruction in adulthood. Cytotoxic T-cells are implicated in chronic obstructive pulmonary disease (COPD), but their involvement in BPD is not known.ObjectivesTo characterise the distribution of airway T-cell subsets in adults with a history of BPD.MethodsYoung adults with former BPD (n=22; median age 19.6 years), age-matched adults born preterm (n=22), patients with allergic asthma born at term (n=22), and healthy control subjects born at term (n=24) underwent bronchoalveolar lavage (BAL). T-cell subsets in BAL were analysed using flow cytometry.ResultsThe total number of cells and the differential cell counts in BAL were similar among the study groups. The percentage of CD3+CD8+T-cells was higher (p=0.005) and the proportion of CD3+CD4+T-cells was reduced (p=0.01) in the BPD group, resulting in a lower CD4/CD8 ratio (p=0.007) compared to the healthy controls (median 2.2 versus 5.3). In BPD and preterm born study subjects, both CD3+CD4+T cells (rs=0.38, p=0.03) and CD4/CD8 ratio (rs=0.44, p=0.01) correlated positively with FEV1. Further, CD3+CD8+T-cells were negatively correlated with both FEV1 and FEV1/FVC (rs=−0.44, p=0.09 and rs=−0.41, p=0.01, respectively).ConclusionsYoung adults with former BPD have a T-cell subset pattern in the airways resembling features of COPD. Our findings are compatible with the hypothesis that CD3+CD8+T-cells are involved in mechanisms behind chronic airway obstruction in these patients.

There is incomplete mechanistic understanding of the mobilization of neutrophils in the systemic and local compartment in smokers with chronic obstructive pulmonary disease (COPD). In this pilot study, we characterized how the adhesion molecules CD11b and CD62L, surface markers indicative of priming, are altered as neutrophils extravasate, and whether surface density of CD11b and CD62L differs between long-term tobacco smokers (LTS) with and without COPD compared with healthy never-smokers (HNS). Unstimulated blood neutrophils from LTS with (<i>n</i> = 5) and without (<i>n</i> = 9) COPD displayed lower surface density of CD62L compared with HNS (<i>n</i> = 8). In addition, surface density of CD11b was higher in bronchoalveolar lavage (BAL) neutrophils from LTS without COPD compared with those with COPD and HNS. Moreover, in BAL neutrophils from all study groups, CD62L was lower compared with matched blood neutrophils. In addition, BAL neutrophils responded with a further decrease in CD62L to ex vivo TNF stimulation. Thus, neutrophils in the airway lumen display a higher state of priming than systemic neutrophils and bear the potential to be further primed by local cytokines even with no smoking or the presence of COPD, findings that may represent a universal host defense mechanism against local bacteria. Moreover, systemic neutrophils are primed in LTS regardless of COPD. Further studies in larger materials are warranted to determine whether the priming of neutrophils is protective against COPD or merely preceding it.

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Background  The main long-term complication after lung transplantation is bronchiolitis obliterans syndrome (BOS), a deadly condition in which neutrophils may play a critical pathophysiological role. Recent studies show that the cytokine interleukin IL-26 can facilitate neutrophil recruitment in response to pro-inflammatory stimuli in the airways. In this pilot study, we characterized the local involvement of IL-26 during BOS and acute rejection (AR) in human patients. Method  From a biobank containing bronchoalveolar lavage (BAL) samples from 148 lung transplant recipients (LTR), clinically-matched patient pairs were identified to minimize the influence of clinical confounders. We identified ten pairs (BOS/non-BOS) with BAL samples harvested on three occasions for our longitudinal investigation and 12 pairs of patients with and without AR. The pairs were matched for age, gender, preoperative diagnosis, type of and time after surgery. Extracellular IL-26 protein was quantified in cell-free BAL samples using an enzyme-linked immunosorbent assay. Intracellular IL-26 protein in BAL cells was determined using immunocytochemistry (ICC) and flow cytometry. Results  The median extracellular concentration of IL-26 protein was markedly increased in BAL samples from patients with BOS (p < 0.0001) but not in samples from patients with AR. Intracellular IL-26 protein was confirmed in alveolar macrophages and lymphocytes (through ICC and flow cytometry) among BAL cells obtained from BOS patients. Conclusions  Local IL-26 seems to be involved in BOS but not AR, and macrophages as well as lymphocytes constitute cellular sources in this clinical setting. The enhancement of extracellular IL-26 protein in LTRs with BOS warrants further investigation of its potential as a target for diagnosing, monitoring, and treating BOS.

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Purpose Type 2 diabetes mellitus (T2DM) and metabolic syndrome (MetS) are common comorbidities in chronic obstructive pulmonary disease (COPD), but the underlying pathogenic mechanisms are poorly understood. Given that these morbidities all display increased neutrophil mobilization, the current study aimed to address whether glucose homeostasis relates to signs of neutrophil mobilization in COPD. Methods The study population included healthy non-smokers (HNS) and long-term smokers without (LTS) and with COPD (LTS+COPD). No subject had T2DM or MetS. Serum cotinine was quantified to evaluate current smoking. Capillary blood glucose was measured after overnight fasting and during an oral glucose tolerance test (OGTT). Neutrophils were quantified in blood and bronchoalveolar lavage samples (BAL). The neutrophil-related cytokines IL-36α, -β and -γ were quantified (ELISA) along with IL-6, IL-8, INF-γ and CXCL10 (U-Plex ® ) in plasma and cell-free BAL fluid (BALF). In addition, we quantified neutrophil elastase (ELISA) and net proteinase activity (substrate assay) in BALF. Results The LTS+COPD group had lower fasting glucose, greater change in glucose during OGTT and higher neutrophil concentrations in BAL and blood compared with HNS. Fasting glucose correlated in a positive manner with blood neutrophil concentration, forced expiratory volume in 1 second/forced vital capacity ratio (FEV 1 /FVC) and FEV 1 (% of predicted) in LTS+COPD. In this group, the concentration of IL-36α in BALF correlated in a negative manner with fasting glucose, blood neutrophil concentration and FEV 1 , while the CXCL10 concentration in BALF correlated in a negative manner with glucose at the end of OGTT (120 min). We observed no corresponding correlations for neutrophil elastase, net proteinase or gelatinase activity. Conclusion In smokers with COPD, altered glucose homeostasis is associated with local and systemic signs of increased neutrophil mobilization, but not with local proteinases. This suggests that other specific aspects of neutrophil mobilization constitute pathogenic factors that affect glucose homeostasis in COPD.