Multinucleated giant cells in AIDS encephalopathy: an immunohistochemical study.

We report the neuropathological findings of 5 post-mortem cases of AIDS. The most common causes of the death were multiple opportunistic infections associated with cutaneous and/or visceral Kaposi sarcoma in two cases. Cerebral edema, demyelination and spongiosis of the white matter were present but the most remarkable finding was the presence of multinucleated giant cell (MGC) within and nearby microglial nodules. On immunohistochemical investigation MGC and microglial cells exhibit positive stain only for RCA I and Ferritin, while immunohistochemical markers for astrocytes, neurons, macrophages, histiocytes, lymphocytes and endothelial cells were negative. No microrganism, nor viral inclusions were detected. These results support the hypothesis that MGC may be derived from microglial cells.