Abstract
Background and Rationale: IL-17A has been implicated in airway inflammation of severe asthma, but its role in SAFS and ABPA is uncertain.
Objectives: We investigated IL-17 in BAL and peripheral blood mononuclear cells (PBMCs) in asthmatic subjects with ABPA, SAFS, severe asthma, mild asthma compared to healthy subjects. We also investigated the relationship between IL-17A and asthma severity or blood neutrophils.
Methods: Airway lymphocytes and PBMCs were characterized by flow cytometry to determine the numbers of CD4+ Th17 cells: CD4 (APC-Cy7), IL-17A (PerCP-CY5.5). Asthma severity, blood neutrophils and lung function were evaluated.
Results: There were 59 patients analysed (ABPA=16, SAFS=16, severe asthma=10, mild asthma=6, NH=11), males 31 (52.5%), age 49 yrs (19-75), BMI (27.7, sd=5.5). Patients with severe asthma had significantly higher CD4+ IL-17 expressing cells in both BAL and PBMCs compared to non-severe groups (p=0.01, 0.001 respectively). There was no significant difference between ABPA and SAFS. The %CD4+ IL-17 expressing cells correlated positively with serum neutrophil counts in non-sensitised SA in both BAL and PBMCs (p=0.015 and 0.007 respectively), but not in other subject groups. BAL fungal culture positivity correlated positively with the number 1L-17A+cells (r=0.9, p=0.004) and the severity of asthma (r=1.89, p=0.012).
Conclusion: Our data suggests that both airway and PBMC IL-17 expressing caells are higher in severe asthma and correlates with FEV1,airway fungal burden and blood neutrophilia.
- Copyright ©ERS 2015