Contribution of dipeptidyl peptidase 10 to airway dysfunction in patients with NSAID-exacerbated respiratory disease

Update on Inflammatory Biomarkers for Defining Asthma Phenotype

Asthma is a chronic heterogeneous disease characterized by various symptoms and persistent airway inflammation, resulting in progressive lung function decline. Classifying asthma phenotypes/endotypes is crucial because the underlying mechanisms and long-term outcomes vary from patient to patient. Recent trials have identified several biomarkers for classifying asthma phenotypes/endotypes, and current treatments have been developed on the basis of these biomarkers. Conventional biomarkers, including immunoglobulin E, blood/sputum eosinophil counts, airway obstruction or reversibility, and fractional exhaled nitric oxide, are widely used to diagnose asthma. However, these markers have some limitations, necessitating the discovery of additional biomarkers. Therefore, this review summarizes recently suggested biomarkers for representing type 2-high (eosinophilic) vs. type 2-low (neutrophilic) asthma, non-steroidal anti-inflammatory drug-exacerbated respiratory disease, and severe asthma. Additionally, we discuss the potential benefits of these biomarkers in classifying specific phenotypes/endotypes and managing asthmatic patients.

Biomarkers of immediate drug hypersensitivity

Immediate drug hypersensitivity reactions (IDHRs) are a burden for patients and the health systems. This problem increases when taking into account that only a small proportion of patients initially labelled as allergic are finally confirmed after an allergological workup. The diverse nature of drugs involved will imply different interactions with the immunological system. Therefore, IDHRs can be produced by a wide array of mechanisms mediated by the drug interaction with specific antibodies or directly on effector target cells. These heterogeneous mechanisms imply an enhanced complexity for an accurate diagnosis and the identification of the phenotype and endotype at early stages of the reaction is of vital importance. Currently, several endophenotypic categories (type I IgE/non-IgE, cytokine release, Mast-related G-protein coupled receptor X2 (MRGPRX2) or Cyclooxygenase-1 (COX-1) inhibition and their associated biomarkers have been proposed. A precise knowledge of endotypes will permit to discriminate patients within the same phenotype, which is crucial in order to personalise diagnosis, future treatment and prevention to improve the patient's quality of life.

Diagnostic biomarkers for chronic rhinosinusitis in adult asthmatics in real-world practice

Background

Chronic rhinosinusitis (CRS) is a common comorbid condition of asthma that affects the long-term outcome of asthmatic patients. CRS is a heterogeneous disease requiring multiple biomarkers to explain its pathogenesis. This study aimed to develop potential biomarkers for predicting CRS in adult asthmatic patients in a real-world clinical setting.

Methods

This study enrolled 108 adult asthmatic patients who had maintained anti-asthmatic medications, including medium-to-high doses of inhaled corticosteroid plus long-acting β2-agonists, and compared clinical characteristics between patients with CRS (CRS group) and those without CRS (non-CRS group). CRS was diagnosed based on the results of paranasal sinus X-ray and/or osteomeatal-unit CT as well as clinical symptoms. Type-2 parameters, including blood eosinophil count, serum levels of periostin/dipeptidyl peptidase 10 (DPP10) and clinical parameters, such as FEV1% and fractional exhaled nitric oxide (FeNO), were analyzed. All biomarkers were evaluated by logistic regression and classification/regression tree (CRT) analyses.

Results

The CRS group had higher blood eosinophil counts/FeNO levels and prevalence of aspirin-exacerbated respiratory disease (AERD) than the non-CRS group (n = 57, 52.8% vs. n = 75, 47.2%; P < 0.05), but no differences in sex/smoking status or asthma control status were noted. The CRS group had higher serum periostin/DPP10 levels than the non-CRS group. Moreover, logistic regression demonstrated that serum periostin/DPP10 and the AERD phenotype were significant factors for predicting CRS in asthmatic patients (adjusted odds ratio, 2.14/1.94/12.39). A diagnostic algorithm and the optimal cutoff values determined by CRT analysis were able to predict CRS with 86.27% sensitivity (a 0.17 negative likelihood ratio).

Conclusion

Serum periostin, DPP10 and the phenotype of AERD are valuable biomarkers for predicting CRS in adult asthmatic patients in clinical practice.

Immunologic Basis of Type 2 Biologics for Severe Asthma

Asthma is a chronic airway inflammatory disease characterized by reversible airway obstruction and airway hyperreactivity to various environmental stimuli, leading to recurrent cough, dyspnea, and wheezing episodes. Regarding inflammatory mechanisms, type 2/eosinophilic inflammation along with activated mast cells is the major one; however, diverse mechanisms, including structural cells-derived and non-type 2/neutrophilic inflammations are involved, presenting heterogenous phenotypes. Although most asthmatic patients could be properly controlled by the guided treatment, patients with severe asthma (SA; classified as a treatment-refractory group) suffer from uncontrolled symptoms with frequent asthma exacerbations even on regular anti-inflammatory medications, raising needs for additional controllers, including biologics that target specific molecules found in asthmatic airway, and achieving the precision medicine for asthma. This review summarizes the immunologic basis of airway inflammatory mechanisms and current biologics for SA in order to address unmet needs for future targets.

Emerging Biomarkers Beyond Leukotrienes for the Management of Nonsteroidal Anti-inflammatory Drug (NSAID)-Exacerbated Respiratory Disease

Nonsteroidal anti-inflammatory drug (NSAID)-exacerbated respiratory disease (NERD) is a unique condition characterized by aspirin/NSAID hypersensitivity, adult-onset asthma, and/or chronic rhinosinusitis with nasal polyps. Arachidonic acid metabolism dysregulation and intense eosinophilic/type 2 inflammation are central mechanisms in NERD. Studies have been conducted on various biomarkers, and urinary leukotriene E4 is considered the most available biomarker of NERD. However, the pathophysiology of NERD is heterogeneous and complex. Epithelial cells and platelets can interact with immune cells in NERD, and novel biomarkers related to these interactions have recently been investigated. We summarize emerging novel biomarkers of NERD and discuss their roles in the management of NERD.