Rôle de l’immunité dans le développement de la leucoencéphalopathie multifocale progressive

Progressive multifocal leukoencephalopathy: what's new?

Progressive multifocal leukoencephalopathy (PML), a severe demyelinating disease that is caused by human JC polyomavirus, was first described as a complication of immune suppression 50 years ago and emerged as a major complication of HIV infection in the 1980s. The prognosis has remained dismal since then, with discouraging results from clinical trials of various therapeutic approaches, including immunomodulation and/or inhibition of viral replication. PML is caused by reactivation of latent JC virus, and serotonergic 5-HT(2a) receptors have been identified as being critical for viral infection of glial cells. In recent years, immunosuppressive therapeutic antibodies have been associated with an increased incidence rate of PML. Here, the authors review findings on the pathogenesis of PML and the encouraging case reports of novel treatments.

Molecular regulation of JC virus tropism: insights into potential therapeutic targets for progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is a growing concern for patients undergoing immune modulatory therapies for treatment of autoimmune diseases such as multiple sclerosis. Currently, there are no drugs approved for the treatment of PML that have been demonstrated in the patient to effectively and reproducibly alter the course of disease progression. The human polyoma virus JC is the causative agent of PML. JC virus (JCV) dissemination is tightly controlled by regulation of viral gene expression from the promoter by cellular transcription factors expressed in cells permissive for infection. JCV infection likely occurs during childhood, and latent virus containing PML-associated promoter sequences is maintained in lymphoid cells within the bone marrow. Because development of PML is tightly linked to suppression and or modulation of the immune system as in development of hematological malignancies, AIDS, and monoclonal antibody treatments, further scrutiny of the course of JCV infection in immune cells will be essential to our understanding of development of PML and identification of new therapeutic targets.

Progressive multifocal leukoencephalopathy: report of three cases in HIV-negative hematological patients and review of literature

Progressive multifocal leukoencephalopathy (PML) is a central nervous system (CNS) disease usually observed in immunodeficient patients, especially human immunodeficiency virus (HIV)-positive, caused by John Cunningham virus. This infectious complication has been described in many HIV-negative hematological patients, especially affected by lymphoproliferative diseases. PML has been observed after both chemotherapy and bone marrow transplantation and, recently, in association with rituximab. Diagnosis can be complicated, and often a CNS biopsy is required. Current treatment approaches are not effective in both HIV-positive and HIV-negative patients, and the outcome remain very poor in the majority of cases, even after combination therapies. We report three cases of PML in hematological patients, treated respectively with conventional chemotherapy and autologous and haploidentical transplantation, and review the literature on PML. All of them received rituximab, which has recently been in the focus of a Food and Drug Administration warning.