Deterioration of the Immune Response Induced by Sulfamethoxazole-trimethoprim in a Rheumatoid Arthritis Patient with Pneumocystis jirovecii Pneumonia

Abstract

A 73-year-old woman with rheumatoid arthritis treated with methotrexate and prednisolone was admitted with dyspnea and ground-glass opacity on chest CT. We diagnosed her with Pneumocystis jirovecii pneumonia (PCP) based on a positive PCR analysis of Pneumocystis jirovecii and the presence of cysts in bronchoalveolar lavage fluid. The PaO₂ was 74.7 Torr on room air, and treatment with sulfamethoxazole-trimethoprim only was initiated. The hypoxemia and ground-glass opacity increased on hospital day 3, and the administration of adjunctive steroid therapy resulted in an improvement in the patient's condition. Although patients with PCP with HIV infection and hypoxemia are often treated with adjunctive steroid therapy to prevent adverse immune reactions, the efficacy of additive steroid administration in case of non-HIV PCP has not been established.