Leucoencefalopatía multifocal progresiva en un paciente con leucemia linfática crónica tratado con fludarabina

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.

Changes in the natural history of progressive multifocal leukoencephalopathy in HIV-negative lymphoproliferative disorders: impact of novel therapies

The aims of this study were to evaluate the clinical characteristics of HIV-negative patients affected by lymphoproliferative disorders (LPD) who developed progressive multifocal leukoencephalopathy (PML), to delineate the risk factors, and to analyze whether the new antineoplastic therapies are changing the natural history of this infectious disease. We retrospectively analyzed 46 cases with confirmed LPD-associated PML published from 1958 to 2004. Patients were stratified according to two different time periods: group A included patients diagnosed before 1989, and group B included patients diagnosed since 1990, after introduction of purine analogues. Group A patients (n = 22) had received alkylating agents and/or radiotherapy, and the majority (63.6%) had advanced Hodgkin disease. At univariate analysis, uncontrolled Hodgkin disease was the only risk factor for PML. In group B patients (n = 24), the most frequent treatments received were purine analogues (58.3%) and high-dose therapy with hematopoietic stem cell transplantation (33.3%; HDT/HSCT). B-cell chronic lymphocytic leukemia (45.8%) and aggressive non-Hodgkin lymphoma (24.9%) were the most frequent underlying LPDs. Patients treated with purine analogues were more likely to have active LPD, lower CD4 cell counts, and to be older and male than were HSCT recipients. The median interval from purine analogues or HDT/HSCT to PML was 11 months. In HDT/HSCT recipients, this interval was delayed for 10 months when peri-transplantation rituximab was used. Univariate analysis identified age >55 years, male sex, and CD4 cell counts <or=0.2 x 10(9)/L as risk factors for PML in patients treated with purine analogues. Mortality rates were 95.4% (group A patients), 90% (purine analogues), and 62.5% (HDT/HSCT recipients). At univariate analysis, the only factor that significantly correlated with recovery from infection was female sex. Our findings indicate (1) the possible reduction in reported cases associated with Hodgkin disease and the increasing number of published cases associated with the new antineoplastic therapies (purine analogues and HDT/HSCT); (2) among patients treated with purine analogues, PML is more common in male patients with CD4 cell counts <or=0.2 x 10(9)/L; (3) the use of rituximab after HDT/HSCT seems to delay the onset of PML; and (4) the prognosis is slightly better in transplant recipients.

Progressive multifocal leukoencephalopathy in chronic lymphocytic leukemia after treatment with fludarabine

A 65-year-old man with chronic lymphocytic leukemia (CLL) diagnosed 11 years ago and treated with standard dose of fludarabine developed a rapidly fatal progressive neurological syndrome. Differential diagnoses included brain infiltration by CLL as opposed to progressive multifocal leukoencephalopathy (PML). A magnetic resonance imaging (MRI) scan showed a hyperintense T2-weighted signal in the left frontal region. Cerebro-spinal fluid polymerase chain reaction (PCR) was positive for virus JC (JCV). These findings were compatible with the diagnosis of PML. Fludarabine has been used to treat acute leukemias, CLL and follicular lymphomas. Its toxicity includes myelosuppression, immunosuppression and sporadic life-threatening neurotoxicity, although standard doses of it are considered safe. Late-onset fatal cerebral dysfunction caused by JCV after standard-dose fludarabine has been described previously. The widespread and increasing use of fludarabine makes it interesting to define the potential of standard doses of fludarabine for causing severe neurological side-effects such as PML.