Serological investigations in 15 cases of bird fanciers disease.

Serological studies in 15 patients with bird fanciers disease are reported. Quantitative analysis of serum proteins showed elevation of IgG in almost every case. High IgE was observed in three patients with isolated asthmatic reactions. In four patients alpha1-antitrypsin was transiently diminished. Two of these had heterozygous deficiency of this protein (genotype MS and MZ). Precipitins against avian sera and avian droppings were found in all patients, but also in some exposed and nonexposed controls. Cross-reactions to avian antigens from different species were observed quite regularly in patients but not in controls. One case is presented suggesting that these cross-reactions may be of clinical importance. Precipitins against other inhaled antigens such as Aspergillus fumigatus, cereals or Micropolyspora faeni were observed significantly more frequently in patients than in controls. These precipitins showed no cross-reactions with those against avian antigens.