AIDS RESEARCH AND HUMAN RETROVIRUSES Volume 3, Number 4, 1987 Mary Ann Liebert, Inc., Publishers Human Immunodeficiency Virus (HIV) Infection in Brains with AIDS-Related Leukoencephalopathy STEVEN W. ROSTAD,1 S. MARK SUMÍ,1 CHENG-MEI SHAW,1 KRISTIN OLSON,2 and JAMES K. McDOUGALL2 'Laboratory ofNeuropathology, Department of Pathology, University of Washington, Seattle, WA 2Laboratory of Tumor Biology, Fred Hutchinson Cancer Research Center, Seattle, WA ABSTRACT In addition to central nervous system (CNS) opportunistic infections and neoplasms, patients with acquired immunodeficiency syndrome (AIDS) develop unexplained dementia and encephalopathy and degeneration of the white matter. We studied autopsied brains from 20 adult patients who expired from AIDS to determine the relationship of human immunodeficiency virus (HIV) infection to white matter lesions and to clinical findings. In four patients with dementia/encephalopathy and abnormalities of the white matter, there was evi- dence of HIV infection as shown by in situ hybridization. In contrast, the remaining 16 patients who had no evidence of white matter degeneration revealed no hybridization to the HIV probe. The cells infected with HIV included endo- thelial cells, perivascular macrophages/monocytes, and multinucleated giant cells and were found in or adjacent to white matter degeneration. These results demonstrate a correlation between HIV-infected cells and AIDS leuko- encephalopathy and provide further evidence for HIV-related dementia/encepha- lopathy. INTRODUCTION Well-recognized neurologic complications of AIDS include opportunistic infections, neoplasms, and dementia/encephalopathy (see Ref. 1 for review). The pathologic basis of AIDS dementia/encephalopathy appears to be heterogene- ous. However, a common denominator appears to be various alterations of the white matter (2-5). Reported white matter lesions which are associated with dementia include vacuolar degeneration, and "subacute encephalitis" with rare- faction of the white matter and foamy perivascular macrophages and multinucle- ated giant cells (2-6). Although these lesions have been variously ascribed to infection by oppor- tunistic agents or by human immunodeficiency virus (HIV), the etiology of these white matter lesions still remains to be elucidated (2-6). Four out of the 20 363