Neuropathology of acquired immune deficiency syndrome (AIDS) in 53 autopsy cases with particular emphasis on microglial nodules and multinucleated giant cells.

Brains from 53 autopsied acquired immune deficiency syndrome (AIDS) cases were examined with special attention to microglial nodules and multinucleated giant cells, which are two histological features of AIDS encephalopathy. Twenty-four (45%) of the 53 brains had microglial nodules in varying frequency. Four of these had microglial nodules alone and the rest had other pathological changes, such as opportunistic infections, CNS lymphomas, cerebrovascular lesions, and multinucleated giant cells. Eleven (46%) of the 24 brains with microglial nodules were accompanied by cytomegalovirus infection in the brain (one case) or body (five cases), or both (five cases). However, the remaining 54% of the brains had no morphological evidence of cytomegalovirus infection either in the brain or body. Five brains had multinucleated giant cells and microglial nodules. Two of these brains had numerous multinucleated giant cells, especially in the cerebral white matter, where, in one case, a spectrum of forms included mononuclear macrophages, intermediate forms of binuclear and trinuclear cells, and multinucleated giant cells. Images suggesting cell fusion were also observed. Electron microscopic examination of this area revealed many viral particles (80-130 nm in diameter) with rod-like cores, reminiscent of HTLV-III, in the cytoplasm of one cell.