In situ evidence of JC virus control by CD8+ T cells in PML-IRIS during HIV infection

Neurology. 2013 Sep 10;81(11):964-70. doi: 10.1212/WNL.0b013e3182a43e6d. Epub 2013 Aug 9.


Objective: To determine the pathophysiologic features of progressive multifocal leukoencephalopathy (PML) associated with immune reconstitution inflammatory syndrome (PML-IRIS) in HIV-infected patients.

Methods: In a cross-sectional study, we retrospectively analyzed 11 HIV-infected patients with a firm diagnosis of PML-IRIS. Brain biopsies were collected from 5 patients and their histopathologic features were compared to those of 4 HIV-infected patients with classic PML.

Results: PML-IRIS developed soon after initiation of antiretroviral therapy in late-presenting HIV-infected patients. The lesions from the 5 biopsied PML-IRIS patients were characterized by a reduction in the density of JC virus (JCV)-infected cells when compared to the 4 patients with PML (11.1 ± 3.2/mm² vs 51.2 ± 4.3/mm², p = 0.01). Comparing the 5 patients with PML-IRIS vs the 4 patients with PML, this correlated with an increased accumulation of CD8+ T cells (818.2 ± 192.8/mm² vs 52.5 ± 10.6/mm², p = 0.01), CD20+ B cells (33.4 ± 13.5/mm² vs 0.5 ± 0.5/mm², p = 0.01), and CD138+ plasma cells (177 ± 84.1/mm² vs 0.25 ± 0.25/mm², p = 0.01), while the number of CD68+ macrophages/microglia did not differ. The ratio between CD8+ T cells and JCV-infected cells was 70 times higher in the 5 patients with PML-IRIS. These findings indicate a clear relationship between an enhanced recruitment of CD8+ T cells and the associated control of the JCV infection.

Conclusions: Our data provide in situ evidence that PML-IRIS brain lesions are enriched in cytotoxic CD8+ T cells that engage JCV-infected oligodendrocytes. This leads to a better control of JCV dissemination, but at the cost of oligodendrocyte cell death and demyelination.

MeSH terms

  • Adult
  • CD8-Positive T-Lymphocytes / pathology*
  • CD8-Positive T-Lymphocytes / virology*
  • Cross-Sectional Studies
  • Female
  • Granzymes / metabolism
  • HIV Infections / complications*
  • Humans
  • Immune Reconstitution Inflammatory Syndrome / etiology*
  • Immune Reconstitution Inflammatory Syndrome / pathology*
  • JC Virus / metabolism*
  • Leukoencephalopathy, Progressive Multifocal / etiology*
  • Leukoencephalopathy, Progressive Multifocal / pathology*
  • Male
  • Middle Aged
  • Retrospective Studies
  • Simian virus 40 / metabolism


  • Granzymes