[A case of bucillamine-induced pneumonitis]

A 65-year-old woman with rheumatoid arthritis was treated with gold (gold sodium thiomalate), bucillamine, and other drugs. Gold was discontinued because of rash. Consequently she presented with high fever and alopecia, and was admitted with dyspnea. Chest X-ray showed diffuse bilateral reticulolinear infiltrates. The percentage of lymphocytes was increased and OKT4/8 ratio was decreased to 0.22 in bronchoalveolar lavage fluid (BALF). In lung tissue specimens obtained by TBLB, alveolitis with Masson's bodies was seen on light microscopy, and electron micrography showed interstitial edema with desquamated macrophages in the alveolar space and lipid-laden pericytes, secondary to extensive destruction of the alveolar-capillary barrier. After discontinuation of drugs, her symptoms and infiltrates on the chest X-ray resolved. Furthermore, the results of drug lymphocyte stimulation test (DLST) were positive for both drugs. We diagnosed this case as bucillamine-induced pneumonitis, since the symptoms developed after the administration of bucillamine; however, an interaction between bucillamine and gold may have contributed to the occurrence.