Recent developments in the use of monoclonal antibodies targeting the type 2 cytokines for severe asthma treatment.

Severe or refractory asthma is seen in approximately 5% of asthmatic subjects who have unsatisfactory symptom control despite adherence to high-dose inhaled glucocorticoid therapies resulting in significant morbidity, reduced quality of life with attendant implications for healthcare costs. Marked heterogeneity in symptoms and at the molecular phenotypic level are hallmarks of asthma resulting in the requirement of specifically targeted treatments to block the key pathways of the disease. Monoclonal antibody (mAb)-based biologics targeted at inhibition of the type 2 cytokines IL-4, IL-5 and IL-13 have become established as effective treatments for severe asthma, with significant clinical benefit seen in carefully selected patient populations that take asthma phenotypes and endotypes into account. The further development of reproducible and straightforward discriminatory biomarkers may aid identification of those patients most likely to benefit from treatment with these interventions.

Molecular Biology of Eosinophils: Introduction.

The eosinophil is an enigmatic cell with a continuing ability to fascinate. A considerable history of research endeavor on eosinophil biology stretches from the present time back to the nineteenth century. Perhaps one of the most fascinating aspects of the eosinophil is how accumulating knowledge has changed the perception of its function from passive bystander, modulator of inflammation, to potent effector cell loaded with histotoxic substances through to more recent recognition that it can act as both a positive and negative regulator of complex events in both innate and adaptive immunity. This book consists of chapters written by experts in the field of eosinophil biology that provide comprehensive clearly written protocols for techniques designed to underpin research into the function of the eosinophil in health and disease.

Anti-IL-5 monoclonal antibodies for the treatment of asthma: an update.

INTRODUCTION: Asthma exhibits marked heterogeneity in symptoms with severe or refractory asthma representing a clear area of unmet medical need. These patients require more specifically targeted treatments with monoclonal antibody-based biologics targeted at inhibition of the type 2 cytokines IL-4, IL-5 and IL-13 having considerable potential as effective treatments for severe asthma. For the most part, anti-cytokine-based biologic therapies are more likely to give significant clinical benefit in carefully selected patient populations that take asthma phenotypes and endotypes into account. AREAS COVERED: This review is based on recent English-language original articles in Pub Med or MedLine that reported significant clinical findings on the current status, therapeutic potential and safety of the anti-IL-5 biologics mepolizumab, reslizumab and benralizumab in the treatment of severe refractory asthma. EXPERT OPINION: Anti-IL-5 treatment appears effective in patients with eosinophilic asthma through exacerbation prevention with accumulating evidence of glucocorticoid-sparing effects with an acceptable safety profile for these biologics.

Recent developments in the use of biologics targeting IL-5, IL-4, or IL-13 in severe refractory asthma.

INTRODUCTION: Severe or refractory asthma is seen in approximately 5% of asthmatic subjects who have unsatisfactory symptom control despite adherence to high-dose inhaled glucocorticoid therapies resulting in significant morbidity, reduced quality of life and health-care cost implications. Asthma exhibits marked heterogeneity both clinically and at the molecular phenotypic level requiring specifically targeted treatments to block the key pathways of the disease. Monoclonal antibody-based biologics targeted at inhibition of the type 2 cytokines IL-4, IL-5, and IL-13 have considerable potential as effective treatments for severe asthma. Areas covered: This review is based on recent English-language original articles in PubMed or Medline that reported significant clinical findings on the current status, therapeutic potential, and safety of biologics targeted at IL-4, IL-5, and IL-13 in the treatment of asthma together with the potential utility of simple reproducible non-invasive biomarkers to guide the effective use of biologic-based therapy that do not require direct sampling of the airways Expert commentary: The further development of reproducible and straightforward discriminatory non-invasive biomarkers may aid identification of those patients most likely to benefit from treatment with these interventions.

Reslizumab in the treatment of severe eosinophilic asthma: an update.

A marked heterogeneity is exhibited by asthma both clinically and at the molecular level with different phenotypes driven by diverse mechanistic pathways that require specifically targeted treatments. Biologics aimed at IL-4/13, IL-5 or IgE are proven or potentially effective treatments for patients with difficult to treat eosinophilic asthma. Importantly, it is now widely accepted that biologic-based therapies give significant clinical improvements in those patient populations where asthma phenotypes are taken into account. Such asthma phenotypes have been identified by reproducible and straightforward discriminatory biomarkers. This short review discusses recent studies of the effectiveness of the anti-IL-5 reslizumab in relation to the use of simple reproducible biomarkers in eosinophilic asthma.

Pro-inflammatory mediator responses from neonatal airway epithelial cells and early childhood wheeze.

BACKGROUND: Airway epithelial cell (AEC) function differs between children with and without asthma. Here, we associated neonatal AEC function with asthma symptoms at 4 years of age. METHODS: Nasal AEC were collected from neonates within 48 h of birth. Cells were cultured and stimulated with tumor necrosis factor alpha/interleukin-1 beta (TNFα/IL-1ß), lipopolysaccharide (LPS), or house dust mite (HDM). Absolute concentrations of pro-inflammatory mediators in the culture supernatant were quantified and expressed as median [interquartile range] in pg/mg protein. A parent-completed respiratory questionnaire was returned when the child was 4 years old. RESULTS: AEC were successfully cultured in 139 neonates, of whom 120 were contacted at 4 years and 91 (76%) questionnaires were returned. Sixteen children had wheezed ever and 11 had recent wheeze. At birth, when compared to those with no recent wheeze, supernatants from cultured neonatal AEC from the children with recent wheeze had reduced median IL-8 (CXCL8) release after treatment with culture medium alone (P = 0.049), with TNFα/IL-1ß (P < 0.001) and LPS (P = 0.004). Additionally, and when compared to those with no recent wheeze, 4 year olds with recent wheeze had reduced neonatal AEC release of IL-6 (P = 0.013), GMCSF (P = 0.012), and ICAM-1 (P = 0.017) after treatment with TNFα/IL-1ß and reduced release of ICAM-1 (P = 0.038) and RANTES (P = 0.042) after treatment with HDM. CONCLUSIONS: Abnormalities in AEC function are present at birth before the onset of childhood wheeze. The relationship between reduced AEC function at birth and wheeze at 4 years was not exclusive, suggesting that post-natal factors are required for the AEC abnormality to translate into symptoms.

Biologics for asthma and allergy.

PURPOSE OF REVIEW: The development of monoclonal antibody-based biologics targeted at inhibition of the Th2 cytokines interleukin-4, interleukin-5 and interleukin-13 represent potentially effective treatments for asthma and allergic diseases. This short review is based on English-language original articles in PubMed or MedLine that reported significant clinical findings on the evidence demonstrating the effectiveness or otherwise of the targeting of interleukin-4, interleukin-5 or interleukin-13 in asthma or allergic disease. RECENT FINDINGS: Asthma exhibits marked heterogeneity both clinically and at the molecular phenotypic level requiring specifically targeted treatments to block the key pathways of the disease. It is becoming apparent that significant clinical effects with anticytokine-based biologic therapies are more likely in carefully selected patient populations that take asthma phenotypes into account. Biologics aimed at interleukin-4/13, interleukin-5 or immunoglobulin E are potentially effective treatments for patients with difficult to treat allergic disease. The development of reproducible and straightforward discriminatory biomarkers may aid identification of those patients most likely to benefit from treatment with these expensive interventions. SUMMARY: Overall these biologics-based therapies are effective treatments for difficult to treat asthma and allergic disease with a safety profile comparable with placebo in the majority of published studies.

Biologics targeting IL-5, IL-4 or IL-13 for the treatment of asthma - an update.

INTRODUCTION: The development of monoclonal antibody-based biologics targeted at inhibition of the Th2 cytokines IL-4, IL-5 and IL-13 represent potentially effective treatments for patients with the glucocorticoid refractory eosinophilic asthma phenotype. Areas covered: Asthma exhibits marked heterogeneity both clinically and at the molecular phenotypic level, requiring specifically targeted treatments to block the key pathways of the disease. It is becoming apparent that significant clinical effects with anti-cytokine-based biologic therapies are more likely in carefully selected patient populations that take asthma phenotypes into account. The development of reproducible and straightforward discriminatory biomarkers may aid identification of those patients most likely to benefit from treatment with these expensive interventions. This narrative review is based on English-language original articles in PubMed or Med-Line that reported significant clinical findings published in the last two years on the evidence demonstrating the effectiveness or otherwise of the targeting of IL-4, IL-5, or IL-13 in carefully selected patients with severe refractory asthma. Expert commentary: The use of a baseline peripheral blood eosinophilia as a simple reproducible biomarker to identify patients with particular sub-phenotypes of asthma to guide the effective use of biologic therapy represents a significant step forward.

Effective antigen presentation to helper T cells by human eosinophils.

Although eosinophils are inflammatory cells, there is increasing attention on their immunomodulatory roles. For example, murine eosinophils can present antigen to CD4+ T helper (Th) cells, but it remains unclear whether human eosinophils also have this ability. This study determined whether human eosinophils present a range of antigens, including allergens, to activate Th cells, and characterized their expression of MHC class II and co-stimulatory molecules required for effective presentation. Human peripheral blood eosinophils purified from non-allergic donors were pulsed with the antigens house dust mite extract (HDM), Timothy Grass extract (TG) or Mycobacterium tuberculosis purified protein derivative (PPD), before co-culture with autologous CD4+ Th cells. Proliferative and cytokine responses were measured, with eosinophil expression of HLA-DR/DP/DQ and the co-stimulatory molecules CD40, CD80 and CD86 determined by flow cytometry. Eosinophils pulsed with HDM, TG or PPD drove Th cell proliferation, with the response strength dependent on antigen concentration. The cytokine responses varied with donor and antigen, and were not biased towards any particular Th subset, often including combinations of pro- and anti-inflammatory cytokines. Eosinophils up-regulated surface expression of HLA-DR/DP/DQ, CD80, CD86 and CD40 in culture, increases that were sustained over 5 days when incubated with antigens, including HDM, or the major allergens it contains, Der p I or Der p II. Human eosinophils can, therefore, act as effective antigen-presenting cells to stimulate varied Th cell responses against a panel of antigens including HDM, TG or PPD, an ability that may help to determine the development of allergic disease.

Mepolizumab-based therapy in asthma: an update.

PURPOSE OF REVIEW: There is considerable evidence that implicates eosinophils as important effector cells in the inflammation characteristic of eosinophilic asthma. IL-5 is central to eosinophil maturation and release from the bone marrow, their subsequent accumulation, activation and persistence in the tissues. IL-5 therefore represents an attractive target to prevent or blunt eosinophil-mediated inflammation resulting in the development of humanized anti-IL-5 monoclonal antibody such as mepolizumab. This review is an update of the evidence demonstrating the effectiveness of mepolizumab treatment of patients with asthma. RECENT FINDINGS: Although early clinical trials with mepolizumab in patients with asthma gave disappointing clinical outcomes, it is becoming apparent that significant clinical effects with this biologic are more likely in carefully selected patient populations that take the eosinophilic asthma phenotype into account. A number of recent studies have reported significant effects by mepolizumab on reductions in exacerbations together with a significant glucocorticoid-sparing effect. SUMMARY: Mepolizumab is a potentially important and well tolerated therapy in carefully selected populations of patients with asthma.

Anti-IL-4/-13 based therapy in asthma.

It is recognised that airway inflammation is key to asthma pathogenesis. Biopharmaceutical approaches have identified new therapies that target key cells and mediators that drive the inflammatory responses in the asthmatic lung. Such an approach resulted in the development of biologics targeted at inhibition of IL-4, IL-5 and IL-13. However, early clinical trials with these biologics in patients with asthma were for the most part disappointing even though they were highly effective in animal models of asthma. It is becoming apparent that significant clinical effects with anti-cytokine-based biologic therapies are more likely in carefully selected patient populations that take asthma phenotypes into account. The development of discriminatory biomarkers and genetic profiling may aid identification of such patients with asthma. This review is an update of the evidence demonstrating the effectiveness or otherwise of the targeting of the TH2 cytokines IL-4 and IL-13 with biologics in patients with asthma.

Airway epithelial cytokine responses in childhood wheeze are independent of atopic status.

BACKGROUND: Airway epithelial cells (AEC) are key contributors to immune function in the lungs but little is known about their role and function in children. OBJECTIVES: Having previously established that nasal AEC mediator release correlates with that of bronchial AEC, we assessed AEC responses in children with and without a history of wheeze. METHODS: Nasal AEC cultures were established from children (0.6-14.9 years) undergoing elective surgical procedures under general anaesthetic categorised as atopic asthmatic (n = 12), virus-induced wheeze (n = 8) or children without wheeze (n = 32). Mediator release by AEC monolayers at passage 2 was determined by cytometric bead array assay or ELISA. RESULTS: Unstimulated AEC from children with a history of wheeze produced significantly less IL-8, IL-6, MCP-1 and G-CSF than AEC from healthy controls. There were no group differences in AEC release of VEGF, RANTES, MMP-9 or TIMP-1. After stimulation with the pro-inflammatory cytokines IL-1ß and TNFα, AEC from children with current wheeze produced significantly less IL-8, IL-6 and MCP-1 than children without wheeze. Release of G-CSF, VEGF, MMP-9 and TIMP-1 did not differ between the wheeze and control group. There were no differences in mediator release between subjects with atopic asthma and those with virus-induced wheeze or between atopic and non-atopic controls. On multivariate analysis, wheeze was the only significant predictor of AEC mediator release. CONCLUSION & CLINICAL RELEVANCE: Intrinsic differences in AEC from children with a history of wheeze may reflect a defect in cytokine production in vivo or an altered state of differentiation in vitro, independent of atopic status.

Eosinophil overview: structure, biological properties, and key functions.

The eosinophil is an enigmatic cell with a continuing ability to fascinate. A considerable history of research endeavor on eosinophil biology stretches from the present time back to the nineteenth century. Perhaps one of the most fascinating aspects of the eosinophil is how accumulating knowledge has changed the perception of its function from passive bystander, modulator of inflammation, to potent effector cell loaded with histotoxic substances through to more recent recognition that it can act as both a positive and negative regulator of complex events in both innate and adaptive immunity. This book consists of 26 chapters written by experts in the field of eosinophil biology that provide comprehensive and clearly written protocols for techniques designed to underpin research into the function of the eosinophil in health and disease.

An update on biologic-based therapy in asthma.

Although it is recognized that airway inflammation is key to asthma pathogenesis, the marked heterogeneity in its clinical course and variations in response to treatment make it a challenging condition for the development of novel and effective biologic-based therapies. Biopharmaceutical approaches have identified new therapies that target key cells and mediators that drive inflammatory responses in the asthmatic lung. Such an approach resulted in the development of biologics targeted at inhibiting IL-4, IL-5 and IL-13. With the notable exception of the anti-IgE monoclonal antibody omalizumab, early clinical trials with cytokine-targeted biologics in patients with asthma were, for the most part, disappointing, despite being highly effective in animal models of asthma. It is becoming apparent that significant clinical effects with anticytokine-based therapies are more likely in carefully selected patient populations that take asthma phenotypes into account. The development of discriminatory biomarkers and genetic profiling may aid identification of such patients with asthma. This review summarizes recent evidence demonstrating the effectiveness or otherwise of monoclonal antibody-based therapies in patients with asthma.

Culture of airway epithelial cells from neonates sampled within 48-hours of birth.

INTRODUCTION: Little is known about how neonatal airway epithelial cell phenotype impacts on respiratory disease in later life. This study aimed to establish a methodology to culture and characterise neonatal nasal epithelial cells sampled from healthy, non-sedated infants within 48 hours of delivery. METHODS: Nasal epithelial cells were sampled by brushing both nostrils with an interdental brush, grown to confluence and sub-cultured. Cultured cells were characterised morphologically by light and electron microscopy and by immunocytochemistry. As an exemplar pro-inflammatory chemokine, IL-8 concentrations were measured in supernatants from unstimulated monolayers and after exposure to IL-1ß/TNF-α or house dust mite extract. RESULTS: Primary cultures were successfully established in 135 (91%) of 149 neonatal samples seeded, with 79% (n  =  117) successfully cultured to passage 3. The epithelial lineage of the cells was confirmed by morphological analysis and immunostaining. Constitutive IL-8 secretion was observed and was upregulated by IL-1ß/TNF-α or house dust mite extract in a dose dependent manner. CONCLUSION: We describe a safe, minimally invasive method of culturing nasal epithelial cells from neonates suitable for functional cell analysis offering an opportunity to study "naïve" cells that may prove useful in elucidating the role of the epithelium in the early origins of asthma and/or allergic rhinitis.

Therapeutic potential of targeting interleukin 5 in asthma.

It is recognised that airway inflammation is key to asthma pathogenesis. Biopharmaceutical approaches have identified new therapies that target key cells and mediators that drive the inflammatory responses in the asthmatic lung. Such an approach resulted in the development of biologics targeted at inhibition of interleukin (IL)-4, IL-5 and IL-13. However, early clinical trials with these biologics in patients with asthma were, for the most part, disappointing even though they were highly effective in animal models of asthma. It is becoming apparent that significant clinical effects with anti-cytokine-based therapies are more likely in carefully selected patient populations that take asthma phenotypes into account. The development of discriminatory biomarkers and genetic profiling may aid identification of such patients with asthma. This review summarises the current evidence, demonstrating the effectiveness or otherwise of the targeting of IL-5 in patients with asthma.

Profile of reslizumab in eosinophilic disease and its potential in the treatment of poorly controlled eosinophilic asthma.

Eosinophils are important proinflammatory cells that make a major contribution to the inflammation seen in allergic diseases including asthma. Interleukin-5 is central to eosinophil maturation, release from the bone marrow, and subsequent accumulation, activation, and persistence in the tissues. Reslizumab (Cinquil™) is a humanized monoclonal antibody with potent interleukin-5 neutralizing effects, which represents a potential treatment for poorly controlled eosinophilic asthma. This review will consider the current status of the clinical development of reslizumab for asthma and in other inflammatory diseases with a marked eosinophilic component.

Eosinophil apoptosis and clearance in asthma.

Asthma is an increasingly common respiratory condition characterized by reversible airway obstruction, bronchial hyper-responsiveness and airway inflammation with a clear unmet need for more effective therapy. Eosinophilic asthma is a phenotype of the condition that features increased blood or sputum eosinophils whose numbers correlate with disease severity. Several lines of evidence are now emerging, which implicate increased persistence of eosinophils in the lungs of patients with asthma as a consequence of inhibition of and defects in the apoptotic process, together with impaired apoptotic cell removal mechanisms. This article will update our knowledge of the mechanisms controlling eosinophil apoptosis and clearance, together with evidence implicating defects in apoptosis and pro-inflammatory cell removal in asthma. Recent developments in novel therapies for asthma that target eosinophil apoptotic and/or clearance pathways will also be discussed.