Retroviruses in Kaposi's sarcoma in acquired immune deficiency syndrome (AIDS).

The ultrastructure of Kaposi's sarcoma (KS) of the oral mucosa in patients with acquired immune deficiency syndrome (AIDS) was examined electron microscopically. The tumour consisted of pleomorphic vascular endothelial structures and spindle cell formations. The KS cells contained characteristically numerous multivesicular bodies, a large number of tubuloreticular structures and abundant Weibel-Palade bodies in their cytoplasm. Virus particles, 100-120 nm in diameter, were observed budding from the plasma membrane or as free particles already separated from the plasma membrane. Many mature virions manifested a dense cylindrical-shaped core. These virus particles and the human T-cell lymphotropic retroviruses subgroup HTLV-III are ultrastructurally identical. This report is based on recent immunological research.