Hypersensitivity pneumonitis (HP) can be caused by drugs administered via routes other than the airway. We report a case of HP causedby intravesical bacille Calmette-Guérin (BCG) administered for the treatment of bladder cancer. We attempt to identify the causative agents of HP.
A 60-year-old, nonsmoking homemaker was referred to our hospital with nonresolving pneumonia. The patient had dyspnea, cough, and fever that started after 3 weekly cycles of intravesical BCG. High-resolution computed tomography of the chest revealed multiple
tiny nodules and ground-glass opacities on both lung fi elds. Pulmonary function tests revealed a restrictive ventilatory defect with decreased diffusion capacity. Histopathology of the transbronchial lung biopsy specimens showed immature noncaseating granulomata. Immunoblotting analysis of serum and BCG demonstrated more than 10 immunoglobulin G fractions binding to BCG. This case illustrates that HP can be caused by intravesical instillation of BCG.

Key words: Alveolitis. Extrinsic allergic. BCG vaccine.