Increased serum antibody responses to Aspergillus fumigatus and house dust mite antigens in dogs with idiopathic eosinophilic bronchopneumopathy.

BACKGROUND

Eosinophilic bronchopneumopathy (EBP) in dogs is an idiopathic disease presumably caused by hypersensitivity to causative allergens that remain unidentified. In humans, allergic bronchopulmonary aspergillosis (ABPA) is a hypersensitivity to Aspergillus fumigatus in uncontrolled asthma in patients.

HYPOTHESIS/

OBJECTIVES

Investigate potential implications of A fumigatus and other ubiquitous antigens (house dust mites, HDMs) in dogs with EBP compared to healthy dogs and dogs with chronic bronchitis (CB).

ANIMALS: Paired serum and bronchoalveolar lavage fluid (BALF) from dogs with EBP or CB and healthy dogs.

METHODS

Case-control observational study. Quantitative PCR (qPCR) for A fumigatus was performed on BALF and A fumigatus-specific antibodies were investigated using a validated ELISA on serum and BALF. An ELISA also was performed for HDM-specific antibodies.

RESULTS

Aspergillus fumigatus qPCR was weakly positive in BALF in 2 of 23 EBP dogs and negative in all other dogs. Concentrations of A fumigatus-specific immunoglobulin E (IgE) in serum and BALF were very low and did not differ between groups. Concentrations of A fumigatus-specific serum immunoglobulin G (IgG) were higher in EBP dogs than in CB dogs and healthy dogs (P = .01) but concentrations in BALF were not different. Concentrations of HDM-specific IgG were higher in both serum and BALF in EBP dogs compared with CB dogs (P = .01).

CONCLUSIONS AND CLINICAL

IMPORTANCE

Higher concentrations of serum IgG for A fumigatus and HDM observed in EBP dogs might suggest an IgG-dependent disease. Based on our results, EBP is not mediated by A fumigatus-specific IgE.