Clinical, functional and inflammatory characteristics in patients with paucigranulocytic asthma

Abstract

Introduction: According to induced sputum cell count,4 different asthma phenotypes have been recognised(eosinophilic, neutrophilic,mixedand paucigranulocytic). Aim: To detect the differences in functional and inflammatory characteristics of asthmatic patients according to the phenotype. Methods: 240(169 female)optimally treated asthmatic patients underwent pulmonary function tests, sputum induction and measurement of FeNO. The levels ofIL-8,IL-13, and ECP were measured in sputum supernatant. Patients treatment, asthma control [using the Asthma Control Test, (ACT)] and the presence of Severe Refractory Asthma(SRA) (according to the ATS workshop consensus) were also recorded. Results: Although ACT did not differ between the groups(p=0.288)patients with paucigranulocytic asthma had better lung function (i.e FEV1%74.2±19.8 vs 69.7±18.2 vs72.2±20.2 vs 81.9±20.4 for eosinophilic, mixed, neutrophilic and paucigranulocytic asthma respectively, p=0.009).SRA occurred more frequently in the eosinophilic and mixed phenotype (41.6% and 43.7% respectively) and less frequently in the neutrophilic and paucigranulocytic phenotype (25% and 21.7% respectively) (p=0.01).As expected,FeNO and ECP were higher in eosinophilic and mixed asthma while IL-8 was increased in patients with neutrophilic and mixed asthma (p Conclusion: According to our results,paucigranulocyticasthma is characterised bylower levels of inflammatory cells and inflammatory biomarkers,better pulmonary function and lower frequency of SRA which might reflect a better response to therapy in these patients.