Department of Medicine and Physiology, Copperbelt University, M.C. Sata School of Medicine, ZambiaFulltext PDF
Abstract Asthma is a heterogeneous chronic airway disease with several distinct phenotypes characterized by different immunopathological pathways, clinical presentation, physiology, co-morbidities, biomarker of allergic inflammation, and response to treatment. Asthma can be categorized into four inflammatory phenotypes using quantitative induced sputum cytometry. The four phenotypes of asthma include eosinophilic asthma, neutrophilic asthma, paucigranulocytic asthma, and mixed cellularity asthma. Paucigranulocytic Asthma (PGA) is the most common asthma phenotype in adults, and children with stable asthma. It is characterized by less severe refractory asthma compared with eosinophilic and neutrophilic asthma, and significantly better lung function than the other asthma phenotypes. Patients with PGA have lower levels of biomarkers of eosinophilic inflammation, such as fractional exhaled nitric oxide, and serum periostin; and neutrophilic inflammatory responses, including lower serum levels of neutrophil elastase, metalloproteinase-9, and interleukin-8. Additionally, PGA patients have poor response to corticosteroids, and anti-interleukin monoclonal antibodies. The pathophysiology of the paucigranulocytic phenotype involves uncoupling of Airway Hyper Responsiveness (AHR) from inflammation, and is characterized by excessive Airway Smooth Muscle (ASM) hyperplasia and hypertrophy, leading to persistent airflow obstruction. PGA patients require exploration of alternative therapeutic options targeting ASM hypertrophy, and AHR, such as long-acting muscarinic antagonists, phosphodiesterase 4 inhibitors, stem cell factor (protein kinase, c-kit) receptor inhibitors, and bronchial thermoplasty.
Keywords: Paucigranulocytic asthma; Airway smooth muscle; Monoclonal antibodies; Phosphodiesterase 4 inhibitors; Bronchial thermoplasty
Syabbalo N. Clinical Features and Management of Paucigranulocytic Asthma. Ann Clin Med Res. 2020; 1(3): 1011..