Background and objective The aim of this study is to compare the inflammatory profile before and after specific inhalation challenge (SIC) in induced sputum from patients with hypersensitivity pneumonitis (HP) and to investigate whether different causal antigens define the resulting profile. Methods A prospective study was conducted in 27 patients with HP: 15 patients due to exposure to birds (BHP) and 12 due to exposure to fungi (FHP), confirmed by SIC. Induced sputum was obtained before and/or 24-h after SIC. Cell types were determined by differential cell count using optical microscopy. Interferon-γ, interleukin (IL)-12p70, IL-2, IL-10, IL-8, IL-6, IL-4, IL-5, IL-1β, tumour necrosis factor (TNF)-α and TNF-β levels were measured in the supernatants. Results Following SIC, higher sputum neutrophilia levels (P-=-0.048) and an increase in IL-8 levels (P-=-0.017) were found in patients with FHP than in those with BHP. FHP patients also showed increased IL-1β, IL12-p70 and IL5 levels (P-=-0.011, P-=-0.036 and P-=-0.018, respectively) after SIC. In BHP, a trend towards increases in sputum eosinophils and TH2 cytokines (IL4, IL5) was seen following SIC (P-=-0.059, P-=-0.068 and P-=-0.075 respectively). Conclusions This study shows that bronchial inflammation is present in patients with HP evidenced by increases in sputum neutrophils and eosinophils following exposure to the offending antigen during SIC. Induced sputum analysis is of established value in the diagnosis and management of asthma and chronic obstructive pulmonary disease; its usefulness in interstitial lung diseases is less clear. This study shows that bronchial inflammation is present in patients with hypersensitivity pneumonitis following exposure to the offending antigen. © 2014 Asian Pacific Society of Respirology.
- induced sputum