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Objectives : The majority of HIV-1-infected individuals manifest a plethora of central nervous system (CNS) diseases unrelated to opportunistic infections, including AIDS dementia complex, encephalitis, and various other disorders of the CNS. The present study sought to evaluate the cellular reservoirs and expression patterns of HIV-1 in brain tissue to gain further understanding of HIV-1 neuropathogenesis. Design : CNS tissue, obtained post-mortem from 22 patients with AIDS and four HIV-i -seronegative controls, was analyzed. Methods : CNS samples were evaluated using a combination of in situ DNA polymerase chain reaction (PCR), reverse transcriptase (RT)-initiated in situ PCR, and immunohistochemistry. By utilizing this triple-staining methodology, HIV-1 proviral DNA and HIV-1-specific mRNA can be identified at the single cell level. Results : HIV-1 was detected in all 22 AIDS brain specimens and in none of the four brains from HIV-1-seronegative individuals. The most commonly infected cells in AIDS brains were microglia cells and macrophages, but variable levels of HIV-1 infection were demonstrated in many of the major histological cell types within the CNS, including neurons, microvascular endothelial cells (MVEC) and astrocytes. The presence of HIV-1-infected cells was not uniform with infected cells unevenly distributed throughout the brain parenchyma. The degree of HIV-1 mRNA expression varied from 39-65% of the cells in the CNS harboring HIV-1 provirus. Choroid plexus and MVEC exhibited relatively high levels of productive infection. Conclusions : These findings demonstrate that several cell types in the CNS, in addition to microglia or macrophages, may become infected with HIV-1 in vivo with variable levels of HIV-1 mRNA expression. The diverse cellular reservoirs for HIV-1 in the CNS may be critically linked to the molecular mechanisms involved in HIV-1 neuropathogenesis. In addition, in vivo infection of MVEC, and possibly cells in the choroid plexus, may directly contribute to penetration of the blood-brain barrier by HIV-1.

Spinal dural arteriovenous fistulas (SDAVFs) are the most common type of spinal vascular malformation. The arteriovenous shunts, located entirely outside the spinal cord, cause a clinical picture of chronic progressive myelopathy believed to arise from the effects of increased venous pressure and impaired venous drainage on the spinal cord. Despite their well-described clinical and angiographic features, no reports have documented the spinal cord pathology in a case of angiographically or pathologically proven SDAVF. We report such a patient in whom a spinal cord biopsy supported increased venous pressure as a mechanism of neurologic dysfunction.

Mycobacterium haemophilum is a nontuberculous mycobacterium that primarily manifests as cutaneous ulcerations in immunocompromised adults and cervical lymphadenitis in immunocompetent children.1 We present a case of M haemophilum infection of the optic chiasm, tract, and hypothalamus in a patient with AIDS. Acknowledgment: The authors thank Dr. Marshall Glesby, who cared for the patient.

I read with interest the article by Gilden et al.,1 but found myself questioning the reported findings and conclusions. The immunohistochemistry describing the presence of varicella-zoster virus (VZV) protein in the majority of temporal artery biopsies of patients with giant cell arteritis (GCA) is intriguing. However, the findings of VZV antigen staining in the vessel wall, mostly in smooth muscle cells, was not addressed by the authors in other arteries or in other smooth muscle cells. In my experience, the VZV antibodies bind nonspecifically to smooth muscle and skeletal muscle cells, and therefore can be detected in similar frequencies in GCA cases, non-GCA temporal arteries, any other arteries, or even in endometrial leiomyoma. The detection of this staining pattern, similar to the one described,1 is seen without surrounding inflammatory response, supporting …

Creutzfeldt-Jakob disease (CJD) is a rare and invariably fatal neurologic disorder caused by an abnormal prion protein. Perceptual disturbances, including visual and auditory agnosias, have been reported in the course of CJD but are not typically the initial complaint. We report a case of hyperacusis as the initial presentation of sporadic CJD.

Reply from the Authors: We thank Drs. Nacimiento and Thron for their letter regarding the role of myelography in the diagnosis of spinal dural arteriovenous fistula (SDAVF). They correctly indicate that a positive myelogram is a very sensitive test for SDAVF and emphasize the limited specificity …