House dust protein level of pigeon drooping and feather in environmental bird exposure-related hypersensitivity pneumonitis "A pilot study".

Abstract

Background: Bird fancier's disease is a type of HP occurring due to exposure to bird's antigen. The diagnosis is quite difficult as it requires the identification of an inciting agent with findings of HRCT and lung biopsy. The exposure is usually done by history with antigen-specific IgG and/or specific inhalational challenge testing. The study aimed to investigate the role of pigeon allergens in house dust in bird exposure-related HP patients.

Methods: This was a descriptive, mixed-method observational study. We retrospectively screened all the files of HP patients for exposure history and pigeon-specific IgG of one-year duration. Finally, Finally house dust from 18 cases with HP was collected for analysis of concentration of pigeon droppings and feather proteins.

Results: The mean age was 47.8 ± 11.5 years with 78% being female. The median duration of symptoms was 1.75 years with a median exposure history to pigeons of 7 years. The level of specific IgG was raised in 11 (60%) patients with a mean level of 50.6 ± 39.5. The concentration of pigeon-drooping protein was present in all the dust samples with a mean of 17.6 ± 5.6 μg/mg. The highest concentration was 27 μg/mg and the lowest of 9 μg/mg. The concentration of pigeon father protein was present in nearly 50% of the dust sample with a mean of 5.6 ± 6.7 μg/mg and the highest concentration was 15.8 μg/mg.

Conclusion: The confirmation history of exposure in bird exposure-related HP is difficult because bird antigen exposure can be presents anywhere. The house dust bird protein concentration measurement is a simple, non-invasive, adjunct test for confirmation of bird exposure.