Analysis of Patients with Asthma and Mixed Granulocytic Inflammatory Pattern in Sputum

Background: Patients with asthma usually present airway inflammation classified as eosinophilic, neutrophilic, mixed granulocytic, and paucigranulocytic pattern according to sputum inflammatory cells. Objective: The aim of the study was to analyze clinical and biological characteristics of patients with asthma and mixed granulocytic pattern in comparison with the other groups. Methods: Induced sputum was used to assess airway inflammation; lung function was evaluated as well as blood leukocytes and disease control. History of comorbidities was collected. Results: We retrospectively analyzed 231 subjects with asthma; patients with mixed granulocytic pattern were more frequently male compared with paucigranulocytic subjects, older than eosinophilic and paucigranulocytic patients with increased number and vitality of sputum cells compared to eosinophilic and paucigranulocytic patients and higher cumulative illness rating score, related to increased age. Smoking history, age of disease onset, and ICS treatment were not associated with higher mixed granulocytic pattern occurrence. Subjects with neutrophilic inflammation (mixed granulocytic and neutrophilic patterns considered altogether) were more frequently obese. In subjects under 67 years of age (median of the enrolled subjects), arterial hypertension was the only comorbidity more frequent in mixed granulocytic than in the other groups. 137/231 subjects were re-valuated during follow-up. Lung function of patients with mixed granulocytic, neutrophilic, and paucigranulocytic patterns improved less than that of eosinophilic patients. Conclusion: Aging and presence of comorbidities, in particular obesity and hypertension, are characteristics of patients with asthma and mixed granulocytic pattern. They could respond less well to treatment than eosinophilic patients.