The role of oral methotrexate as a steroid sparing agent in refractory eosinophilic asthma.

The use of oral methotrexate for refractory eosinophilic asthma in a tertiary asthma referral centre, Glenfield Hospital, Leicester, was evaluated between January 2006 and December 2014. The patients ( n = 61) were carefully phenotyped at baseline with markers of airway inflammation. In addition, a structured oral methotrexate proforma was utilized to evaluate response to therapy and adverse events. Oral steroid withdrawal was attempted 3 months after commencing treatment. Several outcomes were evaluated at 12 months, including both efficacy and adverse effects; 15% ( n = 9/61) responded by achieving a decrease in daily oral corticosteroid dose (mean 8.43 (±8.76) mg), although we were unable to identify factors that predicted a treatment response. There were no other significant changes in any other clinical outcome measures. There was a high rate of adverse events (19/61 (31%)), primarily gastrointestinal/hepatitis. Our findings support the use of biological agents in preference to using oral methotrexate as a steroid sparing agent at the first instance. In the event of failure of these agents, oral methotrexate remains a therapeutic option, which can be considered in highly specialist severe asthma centres.

The current and future role of biomarkers in type 2 cytokine-mediated asthma management.

Assessment and management of asthma is complicated by the heterogeneous pathophysiological mechanisms that underlie its clinical presentation, which are not necessarily reflected in standardized management paradigms and which necessitate an individualized approach to treatment. This is particularly important with the emerging availability of a variety of targeted forms of therapy that may only be appropriate for use in particular patient subgroups. The identification of biomarkers can potentially aid diagnosis and inform prognosis, help guide treatment decisions and allow clinicians to predict and monitor response to treatment. Biomarkers for asthma have been identified from a variety of sources, including airway, exhaled breath and blood. Biomarkers from exhaled breath include fractional exhaled nitric oxide, measurement of which can help identify patients most likely to benefit from inhaled corticosteroids and targeted anti-immunoglobulin E therapy. Biomarkers measured in blood are relatively non-invasive and technically more straightforward than those measured from exhaled breath or directly from the airway. The most well established of these are the blood eosinophil count and serum periostin, both of which have demonstrated utility in identifying patients most likely to benefit from targeted anti-interleukin and anti-immunoglobulin E therapies, and in monitoring subsequent treatment response. For example, serum periostin appears to be a biomarker for responsiveness to inhaled corticosteroid therapy and may help identify patients as suitable candidates for anti-IL-13 treatment. The use of biomarkers can therefore potentially help avoid unnecessary morbidity from high-dose corticosteroid therapy and allow the most appropriate and cost-effective use of targeted therapies. Ongoing clinical trials are helping to further elucidate the role of established biomarkers in routine clinical practice, and a range of other circulating novel potential biomarkers are currently being investigated in the research setting.

Diagnosing eosinophilic asthma using a multivariate prediction model based on blood granulocyte responsiveness.

BACKGROUND: The identification of inflammatory asthma phenotypes, using sputum analysis, has proven its value in diagnosis and disease monitoring. However due to technical limitations of sputum analysis, there is a strong need for fast and noninvasive diagnostics. This study included the activation state of eosinophils and neutrophils in peripheral blood to phenotype and monitor asthma. OBJECTIVES: To (i) construct a multivariable model using the activation state of blood granulocytes, (ii) compare its diagnostic value with sputum eosinophilia as gold standard and (iii) validate the model in an independent patient cohort. METHODS: Clinical parameters, activation of blood granulocytes and sputum characteristics were assessed in 115 adult patients with asthma (training cohort/Utrecht) and 34 patients (validation cohort/Oxford). RESULTS: The combination of blood eosinophil count, fractional exhaled nitric oxide, Asthma Control Questionnaire, medication use, nasal polyposis, aspirin sensitivity and neutrophil/eosinophil responsiveness upon stimulation with formyl-methionyl-leucyl phenylalanine was found to identify sputum eosinophilia with 90.5% sensitivity and 91.5% specificity in the training cohort and with 77% sensitivity and 71% specificity in the validation cohort (relatively high percentage on oral corticosteroids [OCS]). CONCLUSIONS: The proposed prediction model identifies eosinophilic asthma without the need for sputum induction. The model forms a noninvasive and externally validated test to assess eosinophilic asthma in patients not on OCS.

What goes up must come down: biomarkers and novel biologicals in severe asthma.

Asthma is a heterogeneous airway disease characterized by typical symptoms in combination with variable airway obstruction. Most patients with asthma have well controlled symptoms and a low risk of asthma attacks with inhaled corticosteroid (ICS) treatment. However, a clinically important subgroup (~ 10%) remains symptomatic and/or at risk of asthma attacks despite maximum inhaled therapy. Patients with severe asthma are responsible for a significant proportion of healthcare costs attributable to asthma and have a large unmet need for better treatments. An important advance in recent years has been the recognition that severe asthma is heterogeneous with respect to clinical problems and the pattern of lower airway inflammation. Identification of eosinophilic inflammation in the airways has become an important priority as novel biologicals that target Th2 cytokines, such as anti-IL5, anti-IL-13 and combined anti-IL-4/13 are showing considerable promise as treatments for this subgroup. It has also become clear that anti-IgE (Omalizumab), the first monoclonal antibody registered for treatment of severe asthma, is only active in patients with active eosinophilic airway inflammation. The future will be identification of potentially responsive patients on the basis of raised biomarkers and, as suggested by the title of this review, targeted treatment with specific cytokine blockade that has a direct effect on the biomarkers. In this review, we outline an approach to the clinical assessment of patients potentially suitable for biological treatment and describe in detail the likely clinical impact of established and new biological treatments.

Blood eosinophils as a marker of likely corticosteroid response in children with preschool wheeze: time for an eosinophil guided clinical trial?

Childhood wheezing is common particularly in children under the age of 6 years and in this age group is generally referred to as preschool wheezing. Particular diagnostic and treatment uncertainties exist in these young children due to the difficulty in obtaining objective evidence of reversible airways narrowing and inflammation. A diagnosis of asthma depends on the presence of relevant clinical signs and symptoms and the demonstration of reversible airways narrowing on lung function testing, which is difficult to perform in young children. Few treatments are available and inhaled corticosteroids are the recommended preventer treatment in most international asthma guidelines. There is, however, considerable controversy about its effectiveness in children with preschool wheeze and a corticosteroid responder phenotype has not been established. These diagnostic and treatment uncertainties in conjunction with the knowledge of corticosteroid side effects, in particular the reduction of growth velocity, have resulted in a variable approach to inhaled corticosteroid prescribing by medical practitioners and a reluctance in carers to regularly administer the treatment. Identifying children who are likely responders to corticosteroid therapy would be a major benefit in the management of this condition. Eosinophils have emerged as a promising biomarker of corticosteroid responsive airways disease, and evaluation of this biomarker in sputum has successfully been employed to direct management in adults with asthma. Obtaining sputum from young children is time consuming and difficult, and it is hard to justify more invasive procedures such as a bronchoscopy in young children routinely. Recently, in children, interest has shifted to assessing the value of less invasive biomarkers of likely corticosteroid response and the biomarker 'blood eosinophils' has emerged as an attractive candidate. The aim of this review was to summarize the evidence for blood eosinophils as a predictive biomarker for corticosteroid responsive disease with a particular focus on the difficult area of preschool wheeze.

The Asthma Control Questionnaire as a clinical trial endpoint: past experience and recommendations for future use.

The goal of asthma treatment is to control the disease according to guidelines issued by bodies such as the Global Initiative for Asthma. Effective control is dependent upon evaluation of symptoms, initiation of appropriate treatment and minimization of the progressive adverse effects of the disease and its therapies. Although individual outcome measures have been shown to correlate with asthma control, composite endpoints are preferred to enable more accurate and robust monitoring of the health of the individual patient. A number of validated instruments are utilized to capture these component endpoints; however, there is no consensus on the optimal instrument for use in clinical trials. The Asthma Control Questionnaire (ACQ) has been shown to be a valid, reliable instrument that allows accurate and reproducible assessment of asthma control that compares favourably with other commonly used instruments. This analysis provides a summary of the use of ACQ in phase II, III and IV asthma trials. Comparisons between the ACQ and other instruments are also presented. Our analysis suggests that the ACQ is a valid and robust measure for use as a primary or secondary endpoint in future clinical trials.

Phenotyping airways disease: an A to E approach.

The airway diseases asthma and chronic obstructive pulmonary disease (COPD) are heterogeneous conditions with overlapping pathophysiological and clinical features. It has previously been proposed that this heterogeneity may be characterized in terms of five relatively independent domains labelled from A to E, namely airway hyperresponsiveness (AHR), bronchitis, cough reflex hypersensitivity, damage to the airways and surrounding lung parenchyma, and extrapulmonary factors. Airway hyperresponsiveness occurs in both asthma and COPD, accounting for variable day to day symptoms, although the mechanisms most likely differ between the two conditions. Bronchitis, or airway inflammation, may be predominantly eosinophilic or neutrophilic, with different treatments required for each. Cough reflex hypersensitivity is thought to underlie the chronic dry cough out of proportion to other symptoms that can occur in association with airways disease. Structural changes associated with airway disease (damage) include bronchial wall thickening, airway smooth muscle hypertrophy, bronchiectasis and emphysema. Finally, a variety of extrapulmonary factors may impact upon airway disease, including rhinosinusitis, gastroesophageal reflux disease, obesity and dysfunctional breathing. This article discusses the A to E concept in detail and describes how this framework may be used to assess and treat patients with airway diseases in the clinic.

Isolation of filamentous fungi from sputum in asthma is associated with reduced post-bronchodilator FEV1.

BACKGROUND: Fungal sensitization is common in severe asthma, but the clinical relevance of this and the relationship with airway colonization by fungi remain unclear. The range of fungi that may colonize the airways in asthma is unknown. OBJECTIVE: To provide a comprehensive analysis on the range of filamentous fungi isolated in sputum from people with asthma and report the relationship with their clinico-immunological features of their disease. METHODS: We recruited 126 subjects with a diagnosis of asthma, 94% with moderate-severe disease, and 18 healthy volunteers. At a single stable visit, subjects underwent spirometry; sputum fungal culture and a sputum cell differential count; skin prick testing to both common aeroallergens and an extended fungal panel; specific IgE to Aspergillus fumigatus. Fungi were identified by morphology and species identity was confirmed by sequencing. Four patients had allergic bronchopulmonary aspergillosis. RESULTS: Forty-eight percent of asthma subjects were IgE-sensitized to one fungal allergen and 22% to ≥ 2. Twenty-seven different taxa of filamentous fungi were isolated from 54% of their sputa, more than one species being detected in 17%. This compared with 3 (17%) healthy controls culturing any fungus (P < 0.01). Aspergillus species were most frequently cultured in isolation followed by Penicillium species. Post-bronchodilator FEV (1) (% predicted) in the subjects with asthma was 71(± 25) in those with a positive fungal culture vs. 83 (± 25) in those culture-negative, (P < 0.01). CONCLUSION AND CLINICAL RELEVANCE: Numerous thermotolerant fungi other than A. fumigatus can be cultured from sputum of people with moderate-to-severe asthma; a positive culture is associated with an impaired post-bronchodilator FEV (1) , which might be partly responsible for the development of fixed airflow obstruction in asthma. Sensitization to these fungi is also common.

CRTH2 expression on T cells in asthma.

Mast cell-derived prostaglandin D2 (PGD2) is the major prostanoid found within the airway of asthmatics immediately following allergen challenge. PGD2 has been shown to have chemokinetic effects on eosinophils and T helper type 2 (Th2) cells in vitro. This occurs through the interaction of PGD2 with the G-protein-coupled chemokine receptor homologous molecule expressed on Th2 lymphocytes (CRTH2). The expression of CRTH2 has been shown to be highly selective for Th2 cells. Using flow cytometry we have studied the expression of CRTH2 on T cells in blood and bronchoalveolar lavage fluid in asthmatics and normal subjects. CRTH2 expression was confined to a small percentage of blood T cells in asthmatics (1.8%+/-0.2) and normal (1.6%+/-0.2) subjects. CRTH2 was enriched significantly on interleukin (IL)-4+/IL-13+ T cells compared to interferon (IFN)-gamma+ T cells (P<0.001). There was a small population of CRTH2+ T cells in the bronchoalveolar lavage (BAL) of asthmatics (2.3%+/-0.6) and normal subjects (0.3%+/-0.1), and there was a significant difference between the two groups (P<0.05). There were similar amounts of PGD2 in the BAL of asthma and normal subjects. Within paired blood-BAL samples from the same subject there was no increase in CRTH2+ T cells in the BAL compared to blood in asthmatics. Enrichment of CRTH2 on IL-4+ and IL-13+ T cells compared to IFN-gamma+ T cells was also seen in BAL from asthmatics (P<0.001). CRTH2 is expressed preferentially by IL-4+/IL-13+ T cells compared to IFN-gamma+ T cells. However, given their small numbers they are unlikely to have a significant involvement in the pathogenesis of asthma. CRTH2 antagonism may not diminish T cell accumulation in the asthmatic lung.

The A to E of airway disease.

The terms asthma and chronic obstructive pulmonary disease have evolved from their original very specific physiology-based definition to describe additional disease entities such as symptoms, airway inflammation and airway structure. We argue that as a result there is widespread confusion about what the terms mean. This has become a significant hurdle to optimal disease management and drug development. We propose that these disease labels should be replaced with a new alphabetical assessment tool for characterizing airway disease, which provides a checklist of five relatively independent factors potentially responsible for morbidity in patients with airway disease: Airway hyperresponsiveness, Bronchitis, Cough reflex hypersensitivity, Damage to the airway and surrounding lung and Extrapulmonary factors. We speculate that the use of this system to characterize airway disease will improve outcomes by promoting better targeting of new and existing treatments.

Expression of CCR8 is increased in asthma.

BACKGROUND: Chemokines and their receptors could play key roles in the recruitment of T cells to the asthmatic lung. CCR8 is preferentially expressed on T-helper type 2 cells, and is thought to play a role in the pathogenesis of human asthma. OBJECTIVE: Determine the expression of CCR8 on T cells in blood, bronchoalveolar lavage (BAL) and bronchial mucosa from asthmatics and normal subjects. METHODS: CCR8 expression in blood and BAL from asthma and normal subjects was studied using flow cytometry. CCR8 expression on IFN-gamma+ and IL-4+/IL-13+ blood and BAL T cells was studied following stimulation with Phorbol-Myristate-Acetate and Calcium Ionophore. Paraffin-embedded bronchial biopsies were used to study CCR8 in bronchial epithelium. RESULTS: The percentage of CD3+ cells expressing CCR8 in the blood was higher in asthmatics (4.7+/-0.4%) compared with normal subjects (3.0+/-0.4%; P<0.01). There was an approximately sixfold enrichment of CCR8 on IL-4+/IL-13+ cells compared with IFN-gamma+ T cells (P<0.001) in both asthmatic and normal subjects in both blood and BAL. Significantly more BAL T cells expressed CCR8 in asthmatic (8.6+/-0.8%) compared with normal subjects (3.9+/-0.7%) (P<0.01). In paired blood-BAL samples from asthmatics, significantly more CCR8+CD3+ T cells were present in BAL (9.0+/-0.9%) than in blood (5.6+/-0.9%; P<0.05). There were more CCR8-positive cells in bronchial biopsies from asthmatic (93+/-11 cells/mm2) compared with normal subjects (30+/-16 cells/mm2) (P<0.05). The ligand CCL1 was increased in the BAL of asthmatics compared with normal subjects (35+/-6 vs. 12.9+/-7 pg/mL; P<0.05). CONCLUSION: There may be a role for CCR8 in the recruitment of T cells to the lung in asthmatics.

Sputum IL-5 concentration is associated with a sputum eosinophilia and attenuated by corticosteroid therapy in COPD.

BACKGROUND: Airway inflammation in chronic obstructive pulmonary disease (COPD) is predominately neutrophilic, but some subjects demonstrate eosinophilic airway inflammation. Whether these inflammatory phenotypes have differential cytokine and chemokine expression is unknown. OBJECTIVES: To assess the sputum concentrations of cytokines and chemokines and their response to oral corticosteroid therapy in COPD subjects with or without a sputum eosinophilia. METHODS: Cytokine and chemokine concentrations were measured using the meso-scale device platform. To assess validity, recovery of exogenous spikes was examined. The concentrations of the validated mediators were measured in COPD sputum from subjects with or without a sputum eosinophilia. In a subgroup with a sputum eosinophilia, the response to oral prednisolone 10 mg for 1 month was examined. RESULTS: The recovery in sputum of exogenous spiked mediators was >80% in 11/26 cytokines and chemokines. In supernatants from eosinophilic (n = 39) versus non-eosinophilic (n = 59) sputa, the geometric mean (95% CI) concentration was increased for IL-5 [9.0 (4.5-18) pg/ml vs. 3.6 (2.7-6.3) pg/ml, p = 0.03]. IL-5 alone was correlated with sputum eosinophil counts (r = 0.33, p = 0.001), and was attenuated following treatment with prednisolone [n = 9; mean difference 2.3 pg/ml (0.2-4.3), p = 0.032]. CONCLUSION: We have validated the use of the meso-scale device platform for cytokine and chemokine measurements in the sputum supernatants in COPD. Sputum IL-5 was associated with a sputum eosinophilia and was attenuated following oral corticosteroid therapy. Whether this cytokine is important in the pathogenesis of COPD in a subgroup of patients warrants further investigation.

The acute wheezy adult with airways disease in the emergency department: a retrospective case-note review of exacerbations of COPD.

Introduction: There has been an increase in interest in the peripheral blood eosinophil count as a biomarker in COPD. Few studies have examined the eosinophil count in patients attending the emergency department (ED) with acute exacerbations of COPD (AECOPD). We investigated the relationship between the blood eosinophil and other variables collected routinely at ED presentation and outcomes. Methods: Retrospective case note review of patients attending the ED with an AECOPD over 18 months. Demographic, clinical and pharmacological data were analyzed at the time of presentation, and clinical outcomes relating to hospital admission, length of hospital stay and mortality were investigated. Results: There were 743 AECOPD index events in 537 patients. Over half (57%) of all attendees were admitted to hospital. They were older, reported an increased number of exacerbations and higher levels of total leukocytes and neutrophils. Length of stay was shorter in patients with a blood eosinophil count ≥2% compared to <2% (median (IQR) 3 days (1-7) vs 4 days (2-8) respectively, p<0.05). Length of stay correlated with peripheral blood neutrophils (r=0.12, p=0.021), peripheral blood absolute and relative eosinophils (r=-0.12, p=0.024 and r=-0.11, p=0.035, respectively) and CRP (r=0.16, p=0.027). Non-eosinophilic AECOPD were associated with an increased risk of mortality during an exacerbation (χ2 5.9, OR 3.08, 95% CI 1.19-7.96, p=0.015). Conclusion: In exacerbations of COPD presenting to ED, a higher blood eosinophil count is associated with a shorter length of stay and reduced mortality.

The Leicester Cough Monitor: preliminary validation of an automated cough detection system in chronic cough.

Chronic cough is a common condition that presents to both primary and secondary care. Assessment and management are hampered by the absence of well-validated outcome measures. The present study comprises the validation of the Leicester Cough Monitor (LCM), an automated sound-based ambulatory cough monitor. Cough frequency was measured with the LCM and compared with coughs and other sounds counted manually over 2 h of a 6-h recording by two observers in nine patients with chronic cough in order to determine the sensitivity and specificity of the LCM. Automated cough frequency was also compared with manual counts from one observer in 15 patients with chronic cough and eight healthy subjects. All subjects underwent 6-h recordings. A subgroup consisting of six control and five patients with stable chronic cough underwent repeat automated measurements > or = 3 months apart. A further 50 patients with chronic cough underwent 24-h automated cough monitoring. The LCM had a sensitivity and specificity of 91 and 99%, respectively, for detecting cough and a false-positive rate of 2.5 events x h(-1). Mean+/-SEM automated cough counts x patient x h(-1) was 48+/-9 in patients with chronic cough and 2+/-1 in the control group (mean difference 46 counts x patient x h(-1); 95% confidence interval (CI) 20-71). The automated cough counts were repeatable (intra-subject SD 11.4 coughs x patient x h(-1); intra-class correlation coefficient 0.9). The cough frequency in patients undergoing 24-h automated monitoring was 19 coughs x patient x h(-1); daytime (08:00-22:00 h) cough frequency was significantly greater than overnight cough frequency (25 versus 10 coughs x patient x h(-1); mean difference 15 coughs x patient x h(-1), 95% CI 8-22). The Leicester Cough Monitor is a valid and reliable tool that can be used to assess 24-h cough frequency in patients with cough. It should be a useful tool to assess patients with cough in clinical trials and longitudinal studies.

A new perspective on concepts of asthma severity and control.

Concepts of asthma severity and control are important in the evaluation of patients and their response to treatment but the terminology is not standardised and the terms are often used interchangeably. This review, arising from the work of an American Thoracic Society/European Respiratory Society Task Force, identifies the need for separate concepts of control and severity, describes their evolution in asthma guidelines and provides a framework for understanding the relationship between current concepts of asthma phenotype, severity and control. "Asthma control" refers to the extent to which the manifestations of asthma have been reduced or removed by treatment. Its assessment should incorporate the dual components of current clinical control (e.g. symptoms, reliever use and lung function) and future risk (e.g. exacerbations and lung function decline). The most clinically useful concept of asthma severity is based on the intensity of treatment required to achieve good asthma control, i.e. severity is assessed during treatment. Severe asthma is defined as the requirement for (not necessarily just prescription or use of) high-intensity treatment. Asthma severity may be influenced by the underlying disease activity and by the patient's phenotype, both of which may be further described using pathological and physiological markers. These markers can also act as surrogate measures for future risk.

Induced sputum and bronchial mucosal expression of interleukin-13 is not increased in chronic obstructive pulmonary disease.

BACKGROUND: The Th2 cytokine interleukin-13 (IL-13) has been implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD). We sought to examine IL-13 expression in COPD subjects in induced sputum and bronchus specimens. We hypothesized that inflammatory cells expressing IL-13 localize to the airway smooth muscle bundle and bronchial glands. METHODS: Interleukin-13 was measured in sputum samples from subjects with COPD (n = 34) across a range of severity (Global initiative for chronic Obstructive Lung Disease 2-4) and controls (n = 14) using ELISA. IL-13+ cells and inflammatory cells were enumerated within surgically resected proximal airway using immunohistochemical techniques from subjects with COPD (n = 10), smoking (n = 10) and nonsmoking controls (n = 8). RESULTS: Sputum IL-13 was measurable in only 6/34 subjects with COPD and was not found in the smoking or nonsmoking control subjects. In subjects with COPD and controls there was a paucity of IL-13+ cells. The distribution of inflammatory cells within different airway compartments was similar in COPD and controls except for an increase in CD3(+) lymphocytes within bronchial glands in COPD (P = 0.04). CONCLUSIONS: Our findings do not support a role for IL-13 in COPD. However, the tissue localization of inflammatory cells to airway compartments, particularly the increase of T cells in glands in COPD may be important in disease.

Prevalence of inflammatory bowel disease in patients with airways disease.

BACKGROUND: Case reports and case series have suggested an association between inflammatory bowel disease (IBD) and airways disease, but there are no data demonstrating a higher prevalence of IBD among patients with airways disease. Furthermore, no consistent radiological, pulmonary or pathological abnormalities have been demonstrated in patients with both conditions. AIMS: To determine the prevalence of IBD among patients with airways disease and to evaluate clinical and pathophysiological features. METHODS: A retrospective analysis of outpatients with airways disease over a 10-year period. RESULTS: IBD was four times more prevalent among patients with airways disease compared with published local IBD prevalence [Odds Ratio 4.26, 95% CI 1.48, 11.71, p=0.006; Crohn's disease OR 5.96, 95% CI 1.94, 18.31, p=0.002 and ulcerative colitis OR 4.21, 95% CI 1.71, 10.41, p=0.001]. IBD was more frequent in all types of airways disease except asthma; the association was particularly strong for conditions associated with productive cough. All except 1 patient had established IBD before the onset of respiratory symptoms. There were no obvious radiological differences between ulcerative colitis and Crohn's disease cases. There was a trend for a higher lymphocyte count (despite a tendency to lower blood lymphocyte count) but lower sputum neutrophil count in patients with Crohn's disease compared with ulcerative colitis. There were no significant differences in physiological measurements of pulmonary function between the two types of IBD. CONCLUSION: Our findings support an association between airways disease and inflammatory bowel disease, particularly non-asthmatic airways disease with productive cough.

Biomarkers in the assessment and management of airways diseases.

A plethora of biomarkers are becoming available in the field of respiratory medicine, but their application in clinical practice has been limited. This is changing. There is increasing scope for biomarkers to be used to define pathological as well as treatment responder phenotypes in asthma and chronic obstructive pulmonary disease. In some situations, conventional diagnostic labelling is being superseded by this approach and clinical outcomes are improved. Biomarkers are potentially very important in the development and assessment of new therapeutic agents, particularly for the treatment of severe asthma. They also have a potential role in monitoring disease activity and predicting future clinical outcomes for asthma and chronic obstructive pulmonary disease. Current evidence in relation to these issues is explored in this review.