Extrinsic allergic alveolitis from bird exposure. Studies on the immediate hypersensitivity reaction.

Six patients with extrinsic allergic alveolitis had weak immediate and strong late reactions of intracutaneous injection of bird serum. Biopsy of the late reaction revealed vasculitis and immunoglobulin and complement deposition in one. The antibody responsible for the immediate hypersensitivity could be transferred in serum. It was short lasting (4 hr) and resistant to heat and 2-mercaptoethanol. No evidence of an immediate reaction in the lungs could be detected following inhalation challenge as judged by examination of spirometry, flow volume loops and single breath nitrogen washout curves.