Mucus plugs in the airways of asthmatic subjects and smoking status.

BACKGROUND: Mucus plugs have been described in the airways of asthmatic subjects, particularly those with associated with type 2 inflammation and sputum eosinophilia. In the current study we addressed the question of whether smoking, neutrophilic inflammation and airway dimensions affected the prevalence of mucus plugs. METHODS: In a cohort of moderate to severe asthmatics (n = 50), including a group of ex-smokers and current smokers, the prevalence of mucus plugs was quantified using a semi-quantitative score based on thoracic computerized tomography. The relationships between mucus score, sputum inflammatory profile and airway architecture were tested according to patient's smoking status. RESULTS: Among the asthmatics (37% former or active smokers), 74% had at least one mucus plug. The median score was 3 and was unrelated to smoking status. A significant but weak correlation was found between mucus score, FEV1 and FEV1/FVC. Mucus score was significantly correlated with sputum eosinophils. Among former and active smokers, mucus score was correlated with sputum neutrophils. Mucus score was positively associated with FeNO in non-smoking subjects. The lumen dimensions of the main and lobar bronchi were significantly inversely correlated with mucus score. CONCLUSION: Airway mucus plugs could define an asthma phenotype with altered airway architecture and can occur in asthmatic subjects with either neutrophilic or eosinophilic sputum according to their smoking status.

HIV Infection and Persistence in Pulmonary Mucosal Double Negative T Cells In Vivo.

The lungs are relatively unexplored anatomical human immunodeficiency virus (HIV) reservoirs in the antiretroviral therapy (ART) era. Double negative (DN) T cells are a subset of T cells that lack expression of CD4 and CD8 (CD4- CD8-) and may have both regulatory and effector functions during HIV infection. Notably, circulating DN T cells were previously described as cellular HIV reservoirs. Here, we undertook a thorough analysis of pulmonary versus blood DN T cells of people living with HIV (PLWH) under ART. Bronchoalveolar lavage (BAL) fluid and matched peripheral blood were collected from 35 PLWH on ART and 16 uninfected volunteers without respiratory symptoms. Both PLWH and HIV-negative (HIV-) adults displayed higher frequencies of DN T cells in BAL versus blood, and these cells mostly exhibited an effector memory phenotype. In PLWH, pulmonary mucosal DN T cells expressed higher levels of HLA-DR and several cellular markers associated with HIV persistence (CCR6, CXCR3, and PD-1) than blood. We also observed that DN T cells were less senescent (CD28- CD57+) and expressed less immunosuppressive ectonucleotidase (CD73/CD39), granzyme B, and perforin in the BAL fluid than in the blood of PLWH. Importantly, fluorescence-activated cell sorter (FACS)-sorted DN T cells from the BAL fluid of PLWH under suppressive ART harbored HIV DNA. Using the humanized bone marrow-liver-thymus (hu-BLT) mouse model of HIV infection, we observed higher infection frequencies of lung DN T cells than those of the blood and spleen in both early and late HIV infection. Overall, our findings show that HIV is seeded in pulmonary mucosal DN T cells early following infection and persists in these potential cellular HIV reservoirs even during long-term ART.IMPORTANCE Reservoirs of HIV during ART are the primary reasons why HIV/AIDS remains an incurable disease. Indeed, HIV remains latent and unreachable by antiretrovirals in cellular and anatomical sanctuaries, preventing its eradication. The lungs have received very little attention compared to other anatomical reservoirs despite being immunological effector sites exhibiting characteristics ideal for HIV persistence. Furthermore, PLWH suffer from a high burden of pulmonary non-opportunistic infections, suggesting impaired pulmonary immunity despite ART. Meanwhile, various immune cell populations have been proposed to be cellular reservoirs in blood, including CD4- CD8- DN T cells, a subset that may originate from CD4 downregulation by HIV proteins. The present study aims to describe DN T cells in human and humanized mice lungs in relation to intrapulmonary HIV burden. The characterization of DN T cells as cellular HIV reservoirs and the lungs as an anatomical HIV reservoir will contribute to the development of targeted HIV eradication strategies.

Toll-Like Receptor 7/8 Ligand, S28463, Suppresses Ascaris suum-induced Allergic Asthma in Nonhuman Primates.

S28463 (S28), a ligand for Toll-like receptor 7/8, has been shown to have antiinflammatory properties in rodent models of allergic asthma. The principle goal of this study was to assess whether these antiinflammatory effects can also be observed in a nonhuman primate (NHP) model of allergic asthma. NHPs were sensitized then challenged with natural allergen, Ascaris suum extract. The animals were treated with S28 orally before each allergen challenge. The protective effect of S28 in NHPs was assessed by measuring various asthma-related phenotypes. We also characterized the metabolomic and proteomic signatures of the lung environment and plasma to identify markers associated with the disease and treatment. Our data demonstrate that clinically relevant parameters, such as wheal and flare response, blood IgE levels, recruitment of white blood cells to the bronchoalveolar space, and lung responsiveness, are decreased in the S28-treated allergic NHPs compared with nontreated allergic NHPs. Furthermore, we also identified markers that can distinguish allergic from nonallergic or allergic and drug-treated NHPs, such as metabolites, phosphocreatine and glutathione, in the plasma and BAL fluid, respectively; and inflammatory cytokines, IL-5 and IL-13, in the bronchoalveolar lavage fluid. Our preclinical study demonstrates that S28 has potential as a treatment for allergic asthma in primate species closely related to humans. Combined with our previous findings, we demonstrate that S28 is effective in different models of asthma and in different species, and has the antiinflammatory properties clinically relevant for the treatment of allergic asthma.

Effects of benralizumab on airway eosinophils in asthmatic patients with sputum eosinophilia.

BACKGROUND: Many asthmatic patients exhibit sputum eosinophilia associated with exacerbations. Benralizumab targets eosinophils by binding IL-5 receptor α, inducing apoptosis through antibody-dependent cell-mediated cytotoxicity. OBJECTIVES: We sought to evaluate the safety of benralizumab in adults with eosinophilic asthma and its effects on eosinophil counts in airway mucosal/submucosal biopsy specimens, sputum, bone marrow, and peripheral blood. METHODS: In this multicenter, double-blind, placebo-controlled phase I study, 13 subjects were randomized to single-dose intravenous placebo or 1 mg/kg benralizumab (day 0; cohort 1), and 14 subjects were randomized to 3 monthly subcutaneous doses of placebo or 100 or 200 mg of benralizumab (days 0, 28, and 56; cohort 2). Cohorts 1 and 2 were consecutive. RESULTS: The incidence of adverse events was similar between groups. No serious adverse events related to benralizumab occurred. In cohort 1 intravenous benralizumab produced a median decrease from baseline of 61.9% in airway mucosal eosinophil counts (day 28; placebo: +19.6%; P = .28), as well as an 18.7% decrease (day 21) in sputum and a 100% decrease (day 28) in blood counts. Eosinophils were not detectable in bone marrow of benralizumab-treated subjects (day 28, n = 4). In cohort 2 subcutaneous benralizumab demonstrated a combined (100 + 200 mg) median reduction of 95.8% in airway eosinophil counts (day 84; placebo, 46.7%; P = .06), as well as an 89.9% decrease (day 28) in sputum and a 100% decrease (day 84) in blood counts. CONCLUSION: Single-dose intravenous and multiple-dose subcutaneous benralizumab reduced eosinophil counts in airway mucosa/submucosa and sputum and suppressed eosinophil counts in bone marrow and peripheral blood. The safety profile supports further development. Additional studies are needed to assess the clinical benefit in asthmatic patients.

IL-17 promotes p38 MAPK-dependent endothelial activation enhancing neutrophil recruitment to sites of inflammation.

Neutrophilic inflammation plays an important role in lung tissue destruction occurring in many chronic pulmonary diseases. Neutrophils can be recruited to sites of inflammation via the action of the cytokine IL-17. In this study, we report that IL-17RA and IL-17RC mRNA expression is significantly increased in asthmatic bronchoscopic biopsies and that these receptors are not only expressed on epithelial and inflammatory cells but also on endothelial cells. IL-17 potently stimulates lung microvascular endothelial cells to produce chemoattractants (CXCL8 and derivatives of the 5-lipoxygenase pathway) that selectively drive neutrophil but not lymphocyte chemotaxis. Moreover, IL-17 promotes endothelial activation by inducing the expression of endothelial adhesion markers (E-selectin, VCAM-1, and ICAM-1) in a p38 MAPK-dependent manner. This increased expression of adhesion molecules stimulates the trans-endothelial migration of neutrophils, as well as the transmigration of HT-29 colon carcinoma cells, suggesting a further role in promoting lung metastasis. Finally, IL-17 increased neutrophil adhesion to the endothelium in vivo as determined by intravital microscopy of mice cremaster muscle. Overall, our results demonstrate that IL-17 is a potent activator of the endothelium in vivo leading to neutrophil infiltration. Therefore, preventing neutrophil recruitment by blocking the action of IL-17 on endothelial cells may prove to be highly beneficial in diseases in which neutrophilic inflammation plays a key role.

Interplay between the Lung Microbiome, Pulmonary Immunity and Viral Reservoirs in People Living with HIV under Antiretroviral Therapy.

Pulmonary dysbiosis may predispose people living with HIV (PLWH) to chronic lung disease. Herein, we assessed whether intrapulmonary HIV reservoir size and immune disruption are associated with reduced bacterial lung diversity in PLWH. Bacterial DNA was extracted and PCR-amplified from cell-free bronchoalveolar lavage (BAL) fluid from 28 PLWH and 9 HIV-negative controls. Amplicon sequence variant (ASV) relative abundances and taxonomic identities were analyzed using joint species distribution modeling. HIV-DNA was quantified from blood and pulmonary CD4+ T-cells using ultra-sensitive qPCR. Immunophenotyping of BAL T-cells was performed using flow cytometry. Lung microbiome diversity was lower in smokers than non-smokers and microbiome composition was more variable in PLWH than HIV-negative individuals. Frequencies of effector memory BAL CD4+ and CD8+ T-cells positively correlated with abundance of several bacterial families while frequencies of BAL activated CD4+ T-cells negatively correlated with abundance of most lung bacterial families. Higher HIV-DNA levels in blood, but not in BAL, as well as frequencies of senescent CD4+ T-cells were associated with reduced bacterial diversity. These findings suggest that HIV infection may weaken the relationship between the lung microbiome and smoking status. Viral reservoir and immune activation levels may impact the lung microbiome, predisposing PLWH to pulmonary comorbidities.

Steroid-insensitive ERK1/2 activity drives CXCL8 synthesis and neutrophilia by airway smooth muscle.

Severe or refractory asthma affects 5 to 15% of all patients with asthma, but is responsible for more than half of the health burden associated with the disease. Severe asthma is characterized by a dramatic increase in smooth muscle and airway inflammation. Although glucocorticoids are the mainstay of treatment in asthma, they are unable to fully control the disease in individuals with severe asthma. We found that airway smooth muscle cells (ASMCs) from individuals with severe asthma showed elevated activities of the ERK1/ERK2 and p38 MAPK pathways despite treatment with oral and inhaled glucocorticoids, which increased the expression of DUSP1, a phosphatase shown to limit p38 MAPK activity. In ex vivo ASMCs, TNF-α but not IL-17A induced expression of the neutrophil chemoattractant CXCL8. Moreover, TNF-α led to up-regulation of the ERK1/ERK2 and p38 MAPKs pathways, with only the latter being sensitive to pretreatment with the glucocorticoid dexamethasone. In contrast to epithelial and endothelial cells, TNF-α-stimulated CXCL8 synthesis was dependent on ERK1/ERK2 but not on p38 MAPK. Moreover, suppressing ERK1/ERK2 activation prevented neutrophil recruitment by ASMCs, whereas suppressing p38 MAPK activity had no impact. Taken together, these results highlight the ERK1/ERK2 MAPK cascade as a novel and attractive target in severe asthma because the activation of this pathway is insensitive to the action of glucocorticoids and is involved in neutrophil recruitment, contributing the to inflammation seen in the disease.

Increased expression of IL-33 in severe asthma: evidence of expression by airway smooth muscle cells.

IL-33, a new member of the IL-1 cytokine family, promotes Th2 inflammation, but evidence on the implications of this cytokine in asthma is lacking. IL-33 would be mainly expressed by structural cells, but whether proinflammatory cytokines modulate its expression in airway smooth muscle cells (ASMC) is unknown. Endobronchial biopsies were obtained from adults with mild (n = 8), moderate (n = 8), severe (n = 9), asthma and from control subjects (n = 5). Immunocytochemistry, laser-capture microdissection, reverse transcriptase, and real-time quantitative PCR were used for determining IL-33 expression in the lung tissues. ASMC isolated from resected lung specimens were cultured with proinflammatory cytokines and with dexamethasone. IL-33 expression by ASMC was determined by PCR, ELISA, and Western blotting. Higher levels of IL-33 transcripts are detected in biopsies from asthmatic compared with control subjects, and especially in subjects with severe asthma. ASMC show IL-33 expression at both protein and mRNA levels. IL-33 and TNF-alpha transcript levels correlate in the lung tissues, and TNF-alpha up-regulates IL-33 expression by cultured ASMC in a time- and dose-dependent manner. IFN-gamma also increases IL-33 expression and shows synergistic effect with TNF-alpha. Dexamethasone fails to abolish TNF-alpha-induced IL-33 up-regulation. IL-33 expression increases in bronchial biopsies from subjects with asthma compared with controls, as well as subjects with asthma severity. ASMC are a source of the IL-33 cytokine. Our data propose IL-33 as a novel inflammatory marker of severe and refractory asthma.

T Cells localize with proliferating smooth muscle alpha-actin+ cell compartments in asthma.

RATIONALE: Airway remodeling in asthma comprises increased airway smooth muscle (ASM), an alteration linked to airway hyperresponsiveness and disease severity. Experimental studies showed that T cells adhere to ASM through vascular cell adhesion molecule-1 (VCAM-1) and drive ASM growth through direct contact between the T cells and smooth muscle alpha-actin (alpha-SMA)(+) cells. OBJECTIVES: To support the hypothesis of a T-cell/alpha-SMA(+) cell contact mechanism of ASM remodeling in asthma, using bronchial biopsies. METHODS: We performed quantitative morphology on T cells, proliferating cell nuclear antigen (PCNA), alpha-SMA, and VCAM-1 on biopsies from subjects with moderate and severe asthma and healthy control subjects. MEASUREMENTS AND MAIN RESULTS: We demonstrate ASM cell proliferation and infiltration by T cells in proportion to severity in the subjects with asthma. T cells localized with alpha-SMA(+)PCNA(+) cells, suggesting direct intercellular contact and a relationship with alpha-SMA(+) cell proliferation. Furthermore, the subjects with asthma developed a proliferating compartment of subepithelial alpha-SMA(+), nonorganized airway contractile elements (NOACE), suggesting a phenotype gradient from undifferentiated cells to smooth muscle-like cells. T-cell juxtaposition events were also observed in this compartment and correlated to its mass. The subjects with asthma showed VCAM-1 expression in postcapillary venules and clusters of VCAM-1 immunoreactivity in ASM and NOACE, consistent with a role of VCAM-1 in T-cell/alpha-SMA(+) cell interaction. CONCLUSIONS: T cells may induce alpha-SMA(+) cell proliferation through direct intercellular contact. NOACE may in part contribute to ASM growth through differentiation and translocation of alpha-SMA(+) cells. The findings support the role of the T cell in ASM remodeling in asthma.

Cost-Effectiveness of Once-Daily, Single-Inhaler Indacaterol Acetate/ Glycopyrronium Bromide/ Mometasone Furoate in Patients with Uncontrolled Moderate-to-Severe Asthma in Canada.

PURPOSE: We evaluated the cost-effectiveness of high-dose indacaterol acetate (IND)/glycopyrronium bromide (GLY)/mometasone furoate (MF) (150/50/160 µg, once daily) compared with high-dose salmeterol/fluticasone (SAL/FLU; 50/500 µg, twice daily)+tiotropium (TIO; 5 µg, once daily) (SAL/FLU+TIO) and with high-dose SAL/FLU (50/500 µg, twice daily) for the treatment of inadequately controlled moderate-to-severe asthma. PATIENTS AND METHODS: A Markov model estimated the incremental cost-effectiveness ratio of treatment with high-dose IND/GLY/MF compared with SAL/FLU+TIO and high-dose IND/GLY/MF compared with SAL/FLU. The model included three health states (day-to-day symptoms without exacerbations, day-to-day symptoms with exacerbations, and death) with a 4-week cycle length. A lifetime time horizon was used. Exacerbation rates and utility values were derived from ARGON and IRIDIUM clinical trials. Canadian dollars (CAD$, 2020) were applied. RESULTS: IND/GLY/MF was the less costly and more effective treatment strategy compared with SAL/FLU+TIO and SAL/FLU in the base-case analyses. IND/GLY/MF had lower costs (CAD $33,501 versus CAD $50,907) and higher quality-adjusted life-years (QALYs) (18.37 versus 18.06 QALYs) compared with SAL/FLU+TIO. Compared with SAL/FLU, IND/GLY/MF had lower costs (CAD $33,408 versus CAD $36,577) and higher QALYs (19.33 versus 19.04 QALYs). IND/GLY/MF was the most cost-effective option in all scenarios tested. CONCLUSION: IND/GLY/MF was cost-effective at a willingness-to-pay threshold of CAD $50,000/QALY in patients with uncontrolled, moderate-to-severe asthma versus SAL/FLU+TIO and SAL/FLU in the base case and all scenarios tested.

Alveolar macrophages from persons living with HIV show impaired epigenetic response to Mycobacterium tuberculosis.

Persons living with HIV (PLWH) are at increased risk of tuberculosis (TB). HIV-associated TB is often the result of recent infection with Mycobacterium tuberculosis (M. tuberculosis) followed by rapid progression to disease. Alveolar macrophages (AMs) are the first cells of the innate immune system that engage M. tuberculosis, but how HIV and antiretroviral therapy (ART) affect the anti-mycobacterial response of AMs is not known. To investigate the impact of HIV and ART on the transcriptomic and epigenetic response of AMs to M. tuberculosis, we obtained AMs by bronchoalveolar lavage from 20 PLWH receiving ART, 16 control subjects who were HIV-free (HC), and 14 subjects who received ART as preexposure prophylaxis (PrEP) to prevent HIV infection. Following in vitro challenge with M. tuberculosis, AMs from each group displayed overlapping but distinct profiles of significantly up- and downregulated genes in response to M. tuberculosis. Comparatively, AMs isolated from both PLWH and PrEP subjects presented a substantially weaker transcriptional response. In addition, AMs from HC subjects challenged with M. tuberculosis responded with pronounced chromatin accessibility changes while AMs obtained from PLWH and PrEP subjects displayed no significant changes in their chromatin state. Collectively, these results revealed a stronger adverse effect of ART than HIV on the epigenetic landscape and transcriptional responsiveness of AMs.

Processing of Bronchoalveolar Lavage Fluid and Matched Blood for Alveolar Macrophage and CD4+ T-cell Immunophenotyping and HIV Reservoir Assessment.

Bronchoscopy is a medical procedure whereby normal saline is injected into the lungs via a bronchoscope and then suction is applied, removing bronchoalveolar lavage (BAL) fluid. The BAL fluid is rich in cells and can thus provide a 'snapshot' of the pulmonary immune milieu. CD4 T cells are the best characterized HIV reservoirs, while there is strong evidence to suggest that tissue macrophages, including alveolar macrophages (AMs), also serve as viral reservoirs. However, much is still unknown about the role of AMs in the context of HIV reservoir establishment and maintenance. Therefore, developing a protocol for processing BAL fluid to obtain cells that may be used in virological and immunological assays to characterize and evaluate the cell populations and subsets within the lung is relevant for understanding the role of the lungs as HIV reservoirs. Herein, we describe such a protocol, employing standard techniques such as simple centrifugation and flow cytometry. The CD4 T cells and AMs may then be used for subsequent applications, including immunophenotyping and HIV DNA and RNA quantification.

Quality of bronchial biopsies for morphology study and cell sampling: a comparison of asthmatic and healthy subjects.

BACKGROUND: Bronchial biopsies are widely used for histopathological, primary cell culture and genetic studies, but very few reports have evaluated their quality. OBJECTIVES AND METHODS: The present project evaluated the quality (using a scoring system) and the general morphology of a pool of six bronchial biopsy specimens taken from three different sampling sites (the lobar, segmental and subsegmental carinae) in 27 subjects (13 asthmatic subjects and 14 healthy controls). The present study also assessed quantitative measurements of structural changes related to asthma. RESULTS: In total, 94.4% of the biopsy attempts had enough tissue to be processed. From these, 61.7% were scored with a good to excellent quality, while 76.5% presented smooth muscle bundles and 40.5% had an intact epithelium wall. The data also confirmed the structural changes observed in asthma, such as increased apparent thickening of the basement membrane, reduced amounts of smooth muscle for healthy controls and decreased percentage of intact epithelium for asthmatic subjects. CONCLUSION: A pool of six bronchial biopsy specimens can provide tissue of excellent quality in both asthmatic and healthy subjects and, consequently, a valuable sample for morphological analysis of mucosal structures.

HIV persistence in mucosal CD4+ T cells within the lungs of adults receiving long-term suppressive antiretroviral therapy.

BACKGROUND: The lungs were historically identified as one of the major anatomic sites for HIV replication in the pre-antiretroviral therapy (ART) era. However, their contribution to HIV persistence in individuals under suppressive ART remains understudied. DESIGN: We assessed HIV persistence and comprehensively characterized pulmonary mucosal CD4 T cells in HIV-infected (HIV) individuals receiving long-term suppressive ART versus uninfected participants. METHODS: Bronchoalveolar lavage (BAL), bronchial biopsies, and matched peripheral blood were obtained from n = 24 HIV-infected adults receiving long-term suppressive ART (median: 9 years) and n = 8 healthy volunteers without respiratory symptoms. HIV-DNA and cell-associated HIV-RNA were quantified by ultra-sensitive PCR, and lung mucosal CD4 T-cell subsets were characterized by multiparameter flow cytometry. RESULTS: The levels of HIV-DNA were 13-fold higher in total BAL cells compared to blood. Importantly, FACS-sorted CD4 T cells from BAL contained greater levels of HIV-DNA compared to peripheral CD4 T cells. BAL CD4 T cells in HIV individuals were characterized mostly by an effector memory phenotype, whereas naive and terminally differentiated cells were underrepresented compared to blood. Furthermore, BAL CD4 T cells expressed higher levels of immune activation (HLA-DR/CD38) and senescence (CD57) markers. Importantly, BAL was enriched in T-cell subsets proposed to be preferential cellular HIV reservoirs, including memory CD4CCR6, Th1Th17 (CD4CCR6CCR4CXCR3), CD4CCR6CXCR3CCR4, and CD4CD32a T cells. CONCLUSION: The pulmonary mucosa represents an important immunological effector site highly enriched in activated and preferential CD4 T-cell subsets for HIV persistence during long-term ART in individuals without respiratory symptoms. Our findings raise new challenges for the design of novel HIV eradication strategies in mucosal tissues.

It's better to be lucky successful management of an acute endobronchial tumour embolism in the ICU: a case report and review of the literature.

Endobronchial tumour embolism is a rare cause of acute central airway obstruction. It is primarily reported during pneumonectomy, and the outcome is frequently fatal. Successful management requires the urgent removal of tumour with rigid or flexible bronchoscopy. We present the case of a 62-year-old woman with poorly differentiated non-small cell lung cancer (NSCLC), referred to our institution for Nd:YAG laser photoresection of endobronchial tumour completely obstructing the right mainstem bronchus (RMSB). Soon after admission, our patient developed critical hypoxemia, rapidly followed by cardiac arrest. Bronchoscopy was urgently performed and revealed a necrotic tumour occluding the left mainstem bronchus (LMSB), with some residual tumour and clot at the RMSB. The tumour acutely obstructing the LMSB was successfully extracted using a foreign body retrieval basket and large flexible biopsy forceps via a large (therapeutic) flexible bronchoscope. Ventilation immediately improved, with the return of a pulse, and the patient was successfully extubated the next day. Pathology of the tumour embolism revealed NSCLC with necrosis and an adherent clot. Here, we review 16 published reports of endobronchial tumour embolism in relation to our case.

Asthma biomarkers in the age of biologics.

The heterogeneous nature of asthma has been understood for decades, but the precise categorization of asthma has taken on new clinical importance in the era of specific biologic therapy. The simple categories of allergic and non-allergic asthma have given way to more precise phenotypes that hint at underlying biologic mechanisms of variable airflow limitation and airways inflammation. Understanding these mechanisms is of particular importance for the approximately 10% of patients with severe asthma. Biomarkers that aid in phenotyping allow physicians to "personalize" treatment with targeted biologic agents. Unfortunately, testing for these biomarkers is not routine in patients whose asthma is refractory to standard therapy. Scientific advances in the recognition of sensitive and specific biomarkers are steadily outpacing the clinical availability of reliable and non-invasive assessment methods designed for the prompt and specific diagnosis, classification, treatment, and monitoring of severe asthma patients. This article provides a practical overview of current biomarkers and testing methods for prompt, effective management of patients with severe asthma that is refractory to standard therapy.

Effects of hydrofluoroalkane and dry powder-formulated corticosteroids on sputum inflammatory markers in asthmatic patients.

BACKGROUND: Inhaled corticosteroids are powerful drugs that can suppress airway inflammation in asthmatic patients. Deposition of most of the inhaled corticosteroid occurs mainly in the central airways. However, a new hydrofluoroalkane formulation of beclomethasone dipropionate (HFA-BDP) is preferentially deposited in the distal airways. Inflammatory characteristics of induced sputum have been shown to differ in samples collected early after sputum induction compared with later. OBJECTIVE: To compare the effects of HFA-BDP and budesonide in a dry powder inhaler (DPI-BUD) on inflammatory cells and inflammatory cytokine expression in early and late induced sputa compared with placebo. METHODS: Seventeen patients with mild, intermittent bronchial asthma were randomly assigned to two treatment groups: eight patients received HFA-BDP and nine patients received DPI-BUD. Each patient was treated with one of the active treatments and placebo (for four weeks), with a two-week washout interval in between. Inflammatory cells and expression of interleukin (IL)-4 and IL-5 were measured in early and late induced sputa before and after active treatment, as well as before and after placebo treatment using immunocytochemistry and in situ hybridization. RESULTS: Compared with placebo, eosinophils were significantly reduced in both early and late induced sputa after HFA-BDP treatment (P<0.05), whereas DPI-BUD had a significant effect only on early induced sputum. Both HFA-BDP and DPI-BUD decreased IL-4 expression in early and late induced sputa, but the effect was more prominent with HFA-BDP. IL-5 expression was reduced in both early and late induced sputa after HFA-BDP treatment. DPI-BUD significantly decreased IL-5 expression in early but not in late induced sputum. The number of lymphocytes was not altered by either treatment. CONCLUSIONS: HFA-BDP reduced eosinophilic inflammation and T helper 2-type cytokine expression in both early and late induced sputa, whereas the effect of DPI-BUD on inflammation was predominantly demonstrated in early induced sputum.