COPD is characterized by increased detection of Haemophilus influenzae, Streptococcus pneumoniae and a deficiency of Bacillus species.

BACKGROUND AND OBJECTIVE: Chronic obstructive pulmonary disease (COPD) is characterized by progressive airflow limitation and inflammation. Airway bacterial colonization is increased in COPD; however, the role of potentially pathogenic and non-pathogenic bacteria in the pathogenesis of disease is unclear. This study characterized the presence of bacteria in a well-characterized cohort of adults with COPD and healthy controls. METHODS: Adults with COPD (n = 70) and healthy controls (n = 51) underwent clinical assessment and sputum induction. Sputum was dispersed, and total and differential cell counts were performed. Bacteria were cultured, identified and enumerated. Supernatants were assessed for neutrophil elastase (NE) and IL-1ß. Common respiratory pathogens were also determined using real-time PCR. RESULTS: Participants with COPD had a typical neutrophilic inflammatory profile. The total load of bacteria was increased in COPD and was associated with poorer respiratory health status, as measured by the St George's Respiratory Questionnaire (Spearman's r = 0.336, P = 0.013). Significantly lower levels of culturable Bacillus species were identified compared with healthy controls. PCR analyses revealed increased rates of detection of potentially pathogenic bacteria with Haemophilus influenzae detection associated with higher sputum levels of NE and IL-1ß, while Streptococcus pneumoniae was more common in male ex-smokers with emphysema and a deficit in diffusion capacity. CONCLUSION: Non-pathogenic and pathogenic bacteria were altered in the sputum of patients with COPD. These observations highlight the potential to identify treatment and management strategies that both target specific bacterial pathogens and restore the microbial balance, which may lead to reductions in inflammation and subsequent improvements in lung health.

Novel immune genes associated with excessive inflammatory and antiviral responses to rhinovirus in COPD.

BACKGROUND: Rhinovirus (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. METHODS: Primary 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. RESULTS: COPD 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-ß/λ1 pre-treatment did not change MDA-5/RIG-I and IFN-ß 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. CONCLUSIONS: COPD 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.

Viral and bacterial infection in acute asthma and chronic obstructive pulmonary disease increases the risk of readmission.

BACKGROUND AND OBJECTIVE: Infection is as an important trigger for acute asthma and chronic obstructive pulmonary disease (COPD). The aim of this article was to determine the prevalence and impact of virus and bacterial infections in acute asthma and COPD. METHODS: Subjects were recruited, within 24 h of hospital admission for acute exacerbations of asthma and COPD. Nose/throat swabs and sputum samples were collected and examined by multiplex polymerase chain reaction for respiratory viruses and cultured for bacteria. The primary outcomes were length of stay (LOS) and readmission to hospital within 60 days. RESULTS: A total of 199 subjects were recruited (96 had asthma and 103 COPD) for 235 events (36 re-presented). A virus was detected in 79 subjects (40%), bacteria in 41 (21%), and of these, 18 had both. Rhinovirus A was the most frequently isolated virus. A multivariate analysis was performed to control for confounders. It found that detection of a virus, a virus and bacteria, forced expiratory volume in 1 s (FEV(1)) and a diagnosis of COPD were all independent predictors of prolonged LOS, while risk of readmission within 60 days was increased with virus infection alone, virus and bacterial infection, lower FEV(1) and current smoking. CONCLUSIONS: Virus infection, especially in the presence of chronic bacterial infection, is an important determinant of more severe acute exacerbations in both asthma and COPD, and patients with co-infections are more likely to be readmitted to hospital following their exacerbation.

The E3 ubiquitin ligase midline 1 promotes allergen and rhinovirus-induced asthma by inhibiting protein phosphatase 2A activity.

Allergic airway inflammation is associated with activation of innate immune pathways by allergens. Acute exacerbations of asthma are commonly associated with rhinovirus infection. Here we show that, after exposure to house dust mite (HDM) or rhinovirus infection, the E3 ubiquitin ligase midline 1 (MID1) is upregulated in mouse bronchial epithelium. HDM regulates MID1 expression in a Toll-like receptor 4 (TLR4)- and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-dependent manner. MID1 decreases protein phosphatase 2A (PP2A) activity through association with its catalytic subunit PP2Ac. siRNA-mediated knockdown of MID1 or pharmacological activation of PP2A using a nonphosphorylatable FTY720 analog in mice exposed to HDM reduces airway hyperreactivity and inflammation, including the expression of interleukin-25 (IL-25), IL-33 and CCL20, IL-5 and IL-13 release, nuclear factor (NF)κB activity, p38 mitogen-activated protein kinase (MAPK) phosphorylation, accumulation of eosinophils, T lymphocytes and myeloid dendritic cells, and the number of mucus-producing cells. MID1 inhibition also limited rhinovirus-induced exacerbation of allergic airway disease. We found that MID1 was upregulated in primary human bronchial epithelial cells upon HDM or rhinovirus exposure, and this correlated with TRAIL and CCL20 expression. Together, these findings identify a key role of MID1 in allergic airway inflammation and links innate immune pathway activation to the development and exacerbation of asthma.