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

Abstract

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.