Asthma is a heterogeneous inflammatory airways disorder where interleukin (IL)-1b is thought to be a key mediator, especially in the neutrophilic subtype of asthma. The generation of active IL-1b requires proteolytic cleavage typically mediated through the formation of a caspase-1-containing inflammasome. This study hypothesised that an IL-1b endotype associated with the nucleotide-binding domain, leucine-rich repeat-containing family protein (NLRP)3/apoptosis-associated speck-like protein containing a caspase-recruitment domain (ASC)/caspase-1 inflammasome is characteristic of patients with the neutrophilic subtype of asthma.Participants with asthma (n585) and healthy controls (n527) underwent clinical assessment, spirometry and sputum induction. Sputum was processed for differential cell count, gene expression and protein mediators. NLRP3 and caspase-1 expression was also determined by immunocytochemistry. Sputum macrophages were isolated (n58) and gene expression of NLRP3 and IL-1b determined.There was significantly elevated gene expression of NLRP3, caspase-1, caspase-4, caspase-5 and IL-1b in participants with neutrophilic asthma. Protein levels of IL-1b were significantly higher in those with neutrophilic asthma and correlated with sputum IL-8 levels. Sputum macrophages, as well as sputum neutrophils in neutrophilic asthma, expressed NLRP3 and caspase-1 protein.NLRP3 inflammasome is upregulated in neutrophilic asthma and may regulate the inflammation process observed in this asthma phenotype through production of IL-1b. @ERSpublications The NLRP3 inflammasome may be a key regulator of neutrophilic airway inflammation in asthma through production of IL-1b

Inflammatory phenotypes are recognised in stable adult asthma, but are less well established in childhood and acute asthma. Additionally, Chlamydophila pneumoniae infection as a cause of noneosinophilic asthma is controversial. This study examined the prevalence of inflammatory phenotypes and the presence of current C. pneumoniae infection in adults and children with stable and acute asthma.Adults with stable (n529) or acute (n522) asthma, healthy adults (n511), children with stable (n549) or acute (n528) asthma, and healthy children (n59) underwent clinical assessment and sputum induction. Sputum was assessed for inflammatory cells, and DNA was extracted from sputum cell suspensions and supernatants for C. pneumoniae detection using real-time PCR.The asthma phenotype was predominantly eosinophilic in children with acute asthma (50%) but neutrophilic in adults with acute asthma (82%). Paucigranulocytic asthma was the most common phenotype in both adults and children with stable asthma. C. pneumoniae was not detected in 99% of samples.The pattern of inflammatory phenotypes differs between adults and children, with eosinophilic inflammation being more prevalent in both acute and stable childhood asthma, and neutrophilic inflammation being the dominant pattern of acute asthma in adults. The aetiology of neutrophilic asthma is unknown and is not explained by the presence of current active C. pneumoniae infection.

In an Australian study population, exposure to maternal asthma during pregnancy is associated with differential methylation profiles of infants' peripheral blood DNA, which may act as risk factors for future asthma development.

Neutrophilic airway inflammation is associated with increased HAT and reduced HDAC activity in blood monocytes, demonstrating further systemic manifestations relating to the altered inflammatory gene transcription profile of neutrophilic asthma.

BackgroundRhinovirus (RV) is a major cause of chronic obstructive pulmonary disease (COPD) exacerbations, and primarily infects bronchial epithelial cells. Immune responses from BECs to RV infection are critical in limiting viral replication, and remain unclear in COPD. The objective of this study is to investigate innate immune responses to RV infection in COPD primary BECs (pBECs) in comparison to healthy controls.MethodsPrimary bronchial epithelial cells (pBECs) from subjects with COPD and healthy controls were infected with RV-1B. Cells and cell supernatant were collected and analysed using gene expression microarray, qPCR, ELISA, flow cytometry and titration assay for viral replication.ResultsCOPD pBECs responded to RV-1B infection with an increased expression of antiviral and pro-inflammatory genes compared to healthy pBECs, including cytokines, chemokines, RNA helicases, and interferons (IFNs). Similar levels of viral replication were observed in both disease groups; however COPD pBECs were highly susceptible to apoptosis. COPD pBECs differed at baseline in the expression of 9 genes, including calgranulins S100A8/A9, and 22 genes after RV-1B infection including the signalling proteins pellino-1 and interleukin-1 receptor associated kinase 2. In COPD, IFN-β/λ1 pre-treatment did not change MDA-5/RIG-I and IFN-β expression, but resulted in higher levels IFN-λ1, CXCL-10 and CCL-5. This led to reduced viral replication, but did not increase pro-inflammatory cytokines.ConclusionsCOPD pBECs elicit an exaggerated pro-inflammatory and antiviral response to RV-1B infection, without changing viral replication. IFN pre-treatment reduced viral replication. This study identified novel genes and pathways involved in potentiating the inflammatory response to RV in COPD.

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Background: Plasminogen activator inhibitor type-2 (PAI-2, SERPINB2) is an irreversible, specific inhibitor of the urokinase plasminogen activator (uPA). Since overexpression of uPA at the surface of cancer cells is linked to malignancy, targeting of uPA by exogenous recombinant PAI-2 has been proposed as the basis of potential cancer therapies. To this end, reproducible yields of high purity protein that maintains this targeting ability is required. Herein we validate the use in vitro of recombinant 6 × His-tagged-PAI-2 lacking the intrahelical loop between C and D alpha-helices (PAI-2 ΔCD-loop) for these purposes.

Background: Sleep apnoea is prevalent in dialysis patients. Previous studies identified excessive inflammation in patients with sleep apnoea. Online haemodiafiltration (OL-HDF) may reduce systematic inflammation through better clearance of middle molecules. We aimed to determine the feasibility of OL-HDF in sleep apnoea management. Methods: Eligible dialysis patients were screened for risk of sleep apnoea by nocturnal oximetry followed by a diagnostic sleep study to assess apnoea-hypopnea index (AHI). Patients with AHI ≥15/h were invited to a randomized crossover trial. The intervention was 2-month high-flux haemodialysis (HF-HD) followed by 2-month OL-HDF or vice versa with 1-month washout via HF-HD. Feasibility was assessed by patient recruitment and the primary outcome, severity of sleep apnoea (AHI). Secondary outcomes were pro-inflam-matory cytokines, patient-reported daytime sleepiness, quality of sleep and health-related quality of life. Results: Of 65 participants at risk of sleep apnoea, only 15 were consented and randomized (mean age 70 years, 80% male, mean AHI 42.2/h). AHI was not statistically different between OL-HDF versus HF-HD (55.6/h vs. 48.3/h, p = 0.134); however, when sleep apnoea was stratified into obstructive and central apnoea, patients had less obstructive episodes after treated by OL-HDF (23.2/h vs. 18.6/h, p = 0.178); a sensitivity analysis was performed excluding outliers, and the treatment effect for obstructive episodes was found to be statistically significant (11.1 vs. 18.2/h, p = 0.019). Pro-inflammatory biomarkers and patient-reported outcomes were similar between OL-HDF and HF-HD. Conclusion: Patient recruitment was a major challenge in this feasibility study. OL-HDF may reduce obstructive sleep apnoea; however, the result needs to be confirmed by larger studies.