Identification of cytoplasmic tubular structures in Pneumocystis carinii

Abstract

Pneumocystis carinii (PC) is an extracellular organism which frequently causes pneumonia in immunocompromised patients. In the United States more than 60% of patients with acquired immunodeficiency syndrome (AIDS) have at least one episode of PC pneumonia. The earliest published ultrastructural study of PC was undertaken by Dickmann et al. in 1954. A few articles which studied the ultrastructure of PC continued to appear in the German medical literature in the late 1950’s and early 1960’s. With the development of immunosuppressive chemotherapy for cancer patients and in later years the onslaught of the AIDS epidemic, the ultrastuctural literature concerned with PC has expanded. The internal morphology of PC has proved to be difficult to preserve and although extensively examined questions remain concerning the intracellular contents of PC. In this study we report the presence of cytoplasmic tubular structures (CTS) in PC. These structures have been identified in hepatocytes of Chimpanzees infected with non-A,non-B hepatitis and in the lymphocytes of humans with adult T-cell leukemia or AIDS.