Brain CD8+ and cytotoxic T lymphocytes are associated with, and may be specific for, human immunodeficiency virus type 1 encephalitis in patients with acquired immunodeficiency syndrome

Abstract

CD8+ T cells infiltrate brains with human immunodeficiency virus type-1 (HIV-1) encephalitis (HIVE) and related animal models; their perineuronal localization suggests cytotoxic T cell (CTL)-mediated neuronal killing. Because CTLs have not been identified in acquired immunodeficiency syndrome (AIDS) brains, the authors identified their cytotoxic granules in autopsy AIDS brains with HIVE and without HIVE (HIVnE) plus controls (7 to 13 cases/group) and determined gene expression profiles of CTL-associated genes in a separate series of cases. CD3+ and CD8+ T cells were significantly increased (P < .01) in perivascular spaces and inflammatory nodules in HIVE but were rare or absent in brain parenchyma in HIVnE and control brains. Eight HIVE brains contained granzyme B+ T cells and five contained perforin+ T cells. Their T-cell origin was confirmed by colocalization of CD8 and granzyme B in the same cell and the absence of CD56+ natural killer cells. The CTLs directly contacted with neurons, as the authors showed previously for CD3+ and CD8+ T cells. CTLs were rare or absent in HIV nonencephalitis (HIVnE) and controls. Granzyme B and H precursor gene expression was up-regulated and interleukin (IL)-12A precursor, a maturation factor for natural killer cells and CTLs, was down-regulated in HIVE versus HIVnE brain. This study demonstrates, for the first time, CTLs in HIVE and shows that parenchymal T cells and CTLs are sensitive biomarkers for HIVE. Consequently, CD8+ T cells and CTLs could mediate brain injury in HIVE and may represent an important biomarker for productive brain infection by HIV-1.

Copolymer-1 Induces Adaptive Immune Anti-inflammatory Glial and Neuroprotective Responses in a Murine Model of HIV-1 Encephalitis

“…CTLs directly contact with neurons. These are rare or absent in patients who died of HIV disease, but had no evidence of encephalitis, (63). CTL could affect brain injury in HIVE, and as such, could be a biomarker for productive HIV-1 infection in brain in disease.…”

Cholesterol-Depleting Statin Drugs Protect Postmitotically Differentiated Human Neurons against Ethanol- and Human Immunodeficiency Virus Type 1-Induced Oxidative Stress In Vitro

“…Studies have demonstrated that although the major reservoirs for productive infection within the CNS of HIV-1-infected individuals are microglia and monocytes/macrophages, infection of other CNSbased cell types, such as microvascular endothelial cells and neurons, also appears to occur (44,57,92). The role of lymphocytes in AIDS dementia has also been described previously (59,67,68). Of note, viral replication in cerebrospinal fluid is considered to be a marker for the severity of AIDS-related neurodegeneration (16,20).…”

“…The role of lymphocytes in AIDS dementia has also been described previously (59,67,68). Of note, viral replication in cerebrospinal fluid is considered to be a marker for the severity of AIDS-related neurodegeneration (16,20).…”

Neurologic Complications of HIV-1 Infection and Its Treatment in the Era of Antiretroviral Therapy

“…CD8+ T cells have been found immediately adjacent to neurons in HIV encephalitis, implicating cytotoxic T cells in neuronal toxicity. 75 Alternatively, an HIV-infected patient with encephalitis after ART has been described with a fulminant focal area…”