Immune Reconstitution Inflammatory Syndrome Associated with Pneumocystis jirovecii Pneumonia and Cytomegalovirus Colitis in a Patient with Rheumatoid Arthritis

A 68-year-old woman presenting with rheumatoid arthritis was admitted due to pancytopenia caused by methotrexate. Pneumocystis jirovecii pneumonia was diagnosed based on the abnormal shadows observed on chest computed tomography, the presence of serum β-D-glucan, and positive P. jirovecii-DNA results in a sputum analysis. Subsequently, after treatment with leucovorin and trimethoprim-sulfamethoxazole, lung consolidation was found to be aggravated, along with a rapidly increasing leukocyte count. In addition, cytomegalovirus colitis was diagnosed. Both conditions were associated with immune reconstitution inflammatory syndrome caused by recovery from leukopenia. The patient was successfully treated with intravenous methylprednisolone pulse therapy and ganciclovir.