Microsporidiosis is a rapidly emerging protozoon infection that has been reported predominantly in severely immunosuppressed persons with acquired immunodeficiency syndrome (AIDS). Since the first case of human microsporidian infection was reported in 1956, over 400 cases have been documented. The initial description of microsporidian infection in AIDS patients occurred in 1985. Five genera have been identified as the agents of microsporidiosis in immunocompromised persons (Enterocytozoon, Encephalitozoon, Septata, Pleistophora and Nosema). Respiratory tract infection due to microsporidia is associated almost exclusively with disseminated disease produced by members of the genera Encephalitozoon and Septata. Metronidazole and albendazole were recently reported to be responsible for clinical improvement of patients. The authors reported a case of a woman with AIDS and respiratory symptoms related to two pulmonary pathogens: Mycobacterium tuberculosis and Encephalitozoon cuniculi, identified by polymerase chain reaction (PCR) using diagnostic primers targeting the small subunit ribosomal RNA.

Keywords: Microsporidiosis. Respiratory tract infection. Acquired immunodeficiency syndrome.

Behçet's disease is a systemic disease with clinical manifestations, whose underlying histopathologic lesion is a non-specific vasculitis. Pulmonary artery aneurysms and, more rarely, pleuropulmonary manifestations may be found. Some reports are available in the literature about the use of immunosuppressive agents in these conditions. The authors describe a case in whom clinical remission and radiologic resolution were observed after corticosteroid and cyclophophamide therapy.

Keywords: Behçet's disease. Pulmonary artery aneurysms.

Primary pulmonary hypertension (PPH) is a disease of rare, unclear etiology, leading to elevations in pulmonary artery pressure and pulmonary vascular resistance. The vascular lesions range from mild - consisting of neo-intimal proliferation - to severe - characterized by concentric intimal fibrosis, plexiform lesions, and necrotizing arteritis. There have been since 1987 reports describing the association between human immunodeficiency virus (HIV) and PPH, with as many as 60 patients in 1997. The role of HIV in the pathogenesis remains unclear. It is reported a case of a woman in whom this association was observed.

Keywords: Primary pulmonary hypertension. Human immunodeficiency virus.