Bird Keeper's lung without bird keepinge

The identification of disease inducing allergens in hypersensitivity pneumonitis can be very problematic, and only by a thorough analysis of anamnestic data the source of allergen can be identified. We report a case of a 32-year-old female diagnosed with hypersensitivity pneumonitis caused by the inhalation of budgerigar antigen in her home. She had been living there for two years and had never been a bird keeper at all. The former proprietor of the house was a budgerigar keeper for years. When we detected precipitating antibodies against different antigens including pigeon and budgerigar antigens as well as hay and Aureobasidium pullulans, the source of antigen exposition was not definitely clear. In the serum of our patient we found precipitating antibodies against protein structures extracted from dust samples from the patient's home, which were not detected in the serum of her husband. Using Western blots of budgerigar serum and of the dust sample from the patient's home we could demonstrate an IgG reactive banding pattern in our patient's serum. The banding pattern against budgerigar serum correlated very closely to that of a control patient, who was a budgerigar keeper with hypersensitivity pneumonitis. The patient's husband reacted neither against budgerigar serum nor against the dust sample, while he and his wife showed double banding at about 9 kDA, when their serum was exposed to dust from a home free of bird keeping. These results point to the fact, that the house dust sample of our patient contained budgerigar antigen, leading to an indirect antigen expositon causing hypersensitivity alveolitis. However, the positive reaction of the patient serum against the protein extract from the dust sample of her home needs further confirmation by inhibition experiments using budgerigar antigen. - Our patient received a prolonged treatment with corticosteroids, and after about one year the vital capacity of the lungs, which was reduced by 50% at the beginning of the treatment, returned to normal. The patient is still living in her home. Although she has been off medication for one year, lung function has not deteriorated. This fact points to a reduction of the amount of antigen in the patient's home.