Kaposi's sarcoma and HTLV-III infection. Virus-like particles in skin lesions: experimental observations

Skin biopsies from a subject affected by KS and AIDS were examined by means of EM. Samples were obtained both in correspondence of a typical nodule, and from an apparently normal area. The disease process had started at least 8 mo. before, and the patient showed a reduced number of OKT4 cells, with an inversion of the normal T4/T8 ratio. Besides that, high titre antibodies versus HTLV-III were present, whereas antibodies versus CMV and EBV were not demonstrable. Light and electron microscopy demonstrated the typical picture of KS, with marked proliferation of undifferentiated endothelial and spindle-like cells within a network of collagen fibers. Neoformed capillaries very rarely showed an organization comparable to small vessel of normal dermis. Retro-virus-like particles recalling the ones described in lymph-nodes of subjects affected by AIDS by Armstrong et al. (1984) were observed in the skin tissue obtained in correspondence of the Kaposi lesion; the same were either isolated or gathered in small groups within cytoplasmic vescicles. Similar particles were not evidenced in the tissue obtained from normal skin. The interpretation of morphological aspects requests of course a great caution. However the observation seems to be noteworthy, specially if one considers the demonstrated association between retro-virus of HTLV-III group and AIDS, and that its unusual frequency as well as the malignancy in an immunodepressed host are as yet poorly understood.