HIV-Mediated CD8 Encephalitis: Adding Fuel to the Immune-Dysregulation Fire
Clinicians describe a CNS inflammatory complication in HIV-infected patients on long-term antiretroviral therapy whose outcomes ranged from death to total recovery with adjunctive glucocorticoids.
HIV-mediated immune dysregulation frequently affects the central nervous system (CNS) and contributes to both HIV-associated neurocognitive disease and CNS immune reconstitution inflammatory syndrome (IRIS). Recently, a subacute encephalitis hallmarked by CD8 cells and not attributable to other infectious causes or IRIS has emerged. In a retrospective study, researchers explored the clinical and pathological features of this condition in 14 patients, of whom 2 were diagnosed with IRIS.
The patients' mean CD4 count during the 6 months before symptom onset was 369 cells/mm3. Among the patients for whom information was available, all but one (diagnosed with IRIS) had increasing plasma and detectable cerebrospinal fluid viral loads at the time of symptom onset. Six had minor upper respiratory tract infections preceding the encephalitis. Twelve were receiving antiretroviral therapy (mean duration, 4.2 years). Magnetic resonance imaging demonstrated abnormalities, mostly in the subcortical white matter, with areas of linear or punctate enhancement; cerebrospinal fluid analysis generally showed protein elevation and a CD8-predominant pleocytosis. Neuropathological tissue examination revealed weak expression of HIV proteins, presence of CD8 lymphocytes, and absence of multinucleated giant cells — features not seen in typical HIV encephalitis. All the patients received corticosteroids for a mean duration of 6 months, and all initially improved with treatment. Ultimately, five completely recovered, four survived but with cognitive impairment, and five died between 1 and 13 months after illness onset.
CITATION(S):
Lescure F-X et al. CD8 encephalitis in HIV-infected patients receiving cART: A treatable entity. Clin Inf Dis 2013 Apr 15; [e-pub ahead of print].
