[A case of AIDS with Pneumocystis jirovecii pneumonia which required differentiation from ANCA-related lung disease].

A 41-year-old man with fever, diarrhea and skin rash received a diagnosis of drug-induced lupus. He was given corticosteroids for 3 months and was subsequently admitted to a local hospital due to dyspnea. Pneumonia was then diagnosed and he was given a new quinolone antibacterial agent. Despite this treatment, his symptoms and signs gradually worsened and he was referred to our hospital. High resolution CT (HRCT) of the chest showed diffuse ground-glass opacities, reticular shadows, parenchymal abnormalities, traction bronchiectasis, a subpleural curvilinear shadow and septal lines. Serological examinations were positive for anti-myeloperoxidase antineutrophil cytoplasmic antibodies (MPO-ANCA) and subsequent HRCT findings were consistent with ANCA-related lung disease. However, the patient had complications such as previous syphilis infection, oral candidiasis, herpes zoster, hepatitis B virus and cytomegalovirus infection. Additionally, his serum was positive for HIV antibody and HIV-1 RNA, and therefore we diagnosed AIDS. His bronchoalveolar lavage fluid revealed Pneumocystis jirovecii. It is known that HIV infection is associated with many types of autoantibodies including MPO-ANCA. Therefore, in HIV/AIDS patients with interstitial lung diseases, it is important to differentiate opportunistic Pneumocystis pneumonia infection from collagen vascular disease-associated interstitial lung diseases.