Central nervous system immune reconstitution disease in acquired immunodeficiency syndrome patients receiving highly active antiretroviral treatment

Highly active antiretroviral therapy (HAART)-induced immune restoration has been very beneficial for acquired immunodeficiency syndrome (AIDS) patients. In rare instances, HAART may induce a paradoxical clinical deterioration due to an immune reconstitution inflammatory syndrome (IRIS). This syndrome has been described with a wide variety of systemic infections and, in the central nervous system, with Cryptococcus neoformans infection, cytomegalovirus retinitis, and progressive multifocal leukoencephalopathy (PML). The authors have examined brain tissue in eight cases of IRIS: two autopsy cases and three biopsy cases of HIV encephalitis with IRIS and one autopsy case and two biopsy cases of PML with IRIS. All the patients presented with clinical deterioration following initiation of HAART and imaging showed contrast enhancement of the lesions. The symptoms regressed in four patients whereas the other four patients died. Neuropathological examination revealed severe inflammatory and demyelinating lesions with marked intraparenchymal and perivascular infiltration by macrophages and T lymphocytes. In some cases abundant viral proliferation was identified by immunocytochemistry or in situ hybridization, but in others the infectious agent could only be detected using PCR. T lymphocytes were predominantly CD8(+). In those cases with the more favorable course, inflammation was less severe with marked macrophage activation and a number of CD4(+) lymphocytes; in contrast, in the lethal cases inflammation was severe and mostly composed of CD8(+) cytotoxic lymphocytes. We conclude that HAART-induced paradoxical aggravation of HIV encephalitis or AIDS-related PML due to IRIS is reversible in most cases but may be lethal in others. In fatal cases, fulminant viral infection and/or acute perivenous leukoencephalitis may result from a dysregulation of the CD8(+)/CD4(+) T-cell balance.     

Pathology for severe inflammatory PML with PD1/PD-L1 expression of favorable prognosis: What's a prognostic factor for PML-IRIS?

A 72-year-old woman with dermatomyositis (DM) developed neurological manifestation, and magnetic resonance imaging (MRI) revealed multiple T2/fluid-attenuated inversion recovery (FLAIR)-hyperintense lesions predominantly in the deep white matter of the cerebral hemisphere. Punctate or linear contrast enhancement was observed surrounding the T1-hypointense area. Multiple T2/FLAIR-hyperintense lesions were aligned along with the corona radiata. Malignant lymphoma was first suspected, and a brain biopsy was performed. Pathological investigation suggested the provisional diagnosis of “suspicious of malignant lymphoma.” Owing to emergent clinical conditions, high-dose methotrexate (MTX) therapy was conducted, and then T2/FLAIR-hyperintense lesions were dramatically reduced. However, the diagnosis of malignant lymphoma was concerning since multiplex PCR demonstrated clonal restriction of the Ig H gene for B cells and TCR beta genes for T cells. Histopathology revealed the infiltration of both CD4⁺ and CD8⁺ T cells, and the CD4⁺/CD8⁺ ratio was 4.0. Moreover, prominent plasma cells were observed, in addition to CD20⁺ B cells. Atypical cells with enlarged nuclei were present, and they were not hematopoietic but found as glial cells. JC virus (JCV) infection was verified with both immunohistochemistry and in situ hybridization; the final diagnosis was progressive multifocal leukoencephalopathy (PML). The patient was treated with mefloquine and discharged. This case is informative in understanding the host anti-viral response. Variable inflammatory cells were observed, including CD4⁺ and CD8⁺ T cells, plasma cells, and a small amount of perivascular CD20⁺ B cells. PD-1 and PD-L1 expression was observed in lymphoid cells and macrophages, respectively. PML with inflammatory reactions was thought fatal, and autopsy cases of PML with immune reconstitution inflammatory syndrome (IRIS) demonstrated excessive infiltration of only CD8⁺ T cells. However, this case revealed infiltration of variable inflammatory cells, and a favorable prognosis would be expected under PD-1/PD-L1 immune-checkpoint regulation.     

Case of highly active anti-retroviral therapy-induced immune reconstitution inflammatory syndrome in AIDS-related progressive multifocal leukoencephalopathy]

A 44-year-old man presented with difficulties in gripping a ball with the left hand upon playing tennis. He developed muscle weakness involving the left limbs, as well as memory decline, with subsequent gradual worsening of such symptoms. Cranial MRI showed multiple high intensity lesions in the white matter on T2-weighted imaging and FLAIR imaging. Serologic testing was positive for HIV infection and laboratory studies revealed a CD4+T cell count of 103 cells/microl and a plasma HIV-1 RNA load of 240,000 copies/ml. Accordingly, the diagnosis of AIDS was made. Although the initial result of DNA amplification by PCR for detection of the JC virus with CSF was negative, PML was suspected because of the presence of multifocal white matter lesions. Four weeks after the commencement of highly active anti-retroviral therapy (HAART), the HIV-1 RNA load was decreased from 680,000 to 480 copies/ml, although the CD4+T cell count was unchanged. JC virus DNA became positive at the second examination. Five weeks after the commencement of HAART, general fever, disturbance of consciousness, and brain edema suddenly developed, and the patient died within two days. Histological examination of the autopsied brain revealed demyelination and reactive gliosis within the white matter and JC virus antigen was detected in oligodendrocytes, consistent with a diagnosis of PML. The most striking feature was an intense perivascular infiltration by CD8+T cells with proteinaceous fluid exudation, suggesting an occurrence of HAART-induced immune reconstitution inflammatory syndrome. Immune reconstitution inflammatory syndrome should be considered as a fatal complication of HAART in patients with AIDS-related PML.     

Progressive multifocal leukoencephalopathy in an HIV patient receiving successful long-term HAART

Progressive multifocal leukoencephalopathy (PML) has been traditionally associated to severe immunosuppression and described mainly in highly active antiretroviral therapy (HAART)-naïve patients with a low lymphocyte CD4+ count. In the last years, some cases of PML have been described in HIV patients with a higher CD4+ count shortly after initiation of HAART and in association with the immune reconstitution inflammatory syndrome (IRIS). We report on a rare case of PML, not IRIS associated, that occurred in a HIV-positive patient with a lymphocyte CD4+ count greater than 700/µl and with an undetectable HIV viral load resulting from a long-term HAART. We describe the pathological and the ultrastructural features of the brain lesion. This case confirms that a severe immunosuppression or an IRIS is not required for the development of PML in HIV positives. The diagnosis of PML should always be considered in patients with consistent neurological symptoms, even with a high lymphocyte CD4+ level and a full viral suppression resulting from a long-term HAART.     

Inflammatory reaction in progressive multifocal leukoencephalopathy: Harmful or beneficial?

Progressive multifocal leukoencephalopathy (PML) occurs in patients with profound immunosuppression. Although lesions are usually devoid of lymphoplasmocytic infiltrates, inflammatory forms of PML have been described, in both human immunodeficiency virus (HIV)-seropositive (HIV+) and-seronegative (HIV?) patients. In addition, PML has been shown to develop in HIV+ patients shortly after introduction of highly active antiretroviral therapy (HAART), despite a recovery of the immune system. Therefore, one could postulate that PML might arise in the context of an immune reconstitution syndrome. To examine the clinical and neuroradiological characteristics of inflammatory forms of PML, the authors performed a retrospective analysis of the patients seen at their institution since 1996 as well as a review of the literature. Of 39 HIV+ and HIV?PML patients, 5 (13%) presented with an inflammatory form of this disease. Two HIV+ patients developed PML soon after the onset of HAART, concomitant to immune recovery, as demonstrated by a decrease of HIV viral load (VL) and an increase of CD4+ T-cell count. Three patients (2 HIV+ and 1 HIV?) had signs of inflammation in the central nervous system (CNS) characterized by contrast-enhancing lesions on neuroimaging studies, and/or inflammatory infiltrates on brain biopsy. The presence of JC virus-specific cytotoxic T lymphocytes was demonstrated in 4/4 patients tested and the outcome was favorable in 3 of them. In agreement with previously published case reports, the data indicate that inflammatory reactions in PML are not infrequent, and that they are generally associated with a favorable prognosis. Therefore clinicians should not disregard the diagnosis of PML in presence of contrast-enhancing brain lesions, and should use caution before treating these immunosuppressed individuals with steroids.     

Inflammatory progressive multifocal leukoencephalopathy in human immunodeficiency virus-negative patients

OBJECTIVE: Inflammatory progressive multifocal leukoencephalopathy (iPML) with enhancing magnetic resonance imaging (MRI) lesions and leukocyte infiltration occurs in human immunodeficiency virus (HIV)-infected individuals after highly active antiretroviral therapy (HAART) treatment. MRI diagnostic criteria for PML suggest that iPML does not occur in HIV-negative individuals. METHODS: We studied pathologically proved PML (12 by biopsy, 9 with MRI, 32 at autopsy). RESULTS: HIV-negative (2/5) and -positive (2/4) PML patients had enhancing MRI lesions, correlated with CD3(+) lymphocyte infiltration. Inflammatory infiltrates occurred in the majority of HIV-negative (7/8) and HIV-positive/HAART (17/20) cases (p > 0.2), but in only 2 of 16 HIV-positive/non-HAART cases (p < 0.001). INTERPRETATION: iPML showed radiographic and pathological similarity in HIV-positive/HAART and HIV-negative patients. HIV-negative iPML necessitates further consideration of MRI criteria for PML.     

Progressive multifocal leukoencephalopathy in idiopathic CD4+ lymphocytopenia: A case report and review of literature

Progressive multifocal leukoencephalopathy (PML) is a rare demyelinating disease due to a lytic infection of oligodendrocytes caused by polyoma virus (JC virus) infection. PML usually occurs in a setting of severe immunosuppression and is most commonly associated with human immunodeficiency virus (HIV) infection. Idiopathic CD4⁺ lymphocytopenia is a very rare cause of PML and only a few cases have been reported in the literature. We present a case of a 45‐year‐old man who presented with behavioral alteration followed by progressive weakness of right side of the body. Contrast‐enhanced magnetic resonance imaging of the brain revealed confluent irregular areas of T2‐weighted/fluid‐attenuated inversion recovery hyperintensities in left frontoparietal and right temporoparietal regions. His hematological work up showed a decreased absolute CD4⁺ count of 217 per microliter, but was negative for HIV serology. Keeping a differential diagnoses of central nervous system lymphoma, brain biopsy was performed. Histopathology revealed demyelination with presence of intranuclear inclusions in the oligodendrocytes, which were positive for SV40 immunostain. Adjacent areas showed reactive gliosis with hypertrophic astrocytes, hence a diagnosis of PML was made. The patient died due to aspiration pneumonia. PML can occur very rarely in association with idiopathic CD4⁺ lymphocytopenia in the absence of other immunosuppressive illnesses. This report highlights the importance of high index of clinical suspicion and need for a careful histological examination for diagnosis of PML to facilitate adequate patient management.     

Progressive multifocal leukoencephalopathy: a review of the neuroimaging features and differential diagnosis

Progressive multifocal leukoencephalopathy (PML) is an uncommon and often fatal demyelinating disease of human central nervous system, which is caused by reactivation of the polyomavirus JC (JCV). PML generally occurs in patients with profound immunosuppression such as AIDS patients. Recently, a number of PML cases have been associated with administration of natalizumab for treatment of multiple sclerosis (MS) patients. Diagnosis and management of PML became a major concern after its occurrence in multiple sclerosis patients treated with natalizumab. Diagnosis of PML usually rests on neuroimaging in the appropriate clinical context and is further confirmed by cerebrospinal fluid polymerase chain reaction (PCR) for JCV DNA. Treatment with antiretroviral therapies in HIV-seropositive patients or discontinuing natalizumab in MS patients with PML may lead to the development of immune reconstitution inflammatory syndrome (IRIS) which presents with deterioration of the previous symptoms and may lead to death. In patients under treatment with monoclonal antibodies in routine practice, or new ones in ongoing clinical trials, differentiating PML from new MS lesions on brain MRI is critical for both the neurologists and neuroradiologists. In this review, we discuss the clinical features, neuroimaging manifestations of PML, IRIS and neuroimaging clues to differentiate new MS lesions from PML. In addition, various neuroimaging features of PML on the non-conventional MR techniques such as diffusion-weighted imaging (DWI), diffusion tensor imaging (DTI), and MR spectroscopy (MRS) are discussed.     

Pathology of immune reconstitution inflammatory syndrome in multiple sclerosis with natalizumab-associated progressive multifocal leukoencephalopathy

Natalizumab is an approved medication for highly active multiple sclerosis (MS). Progressive multifocal leukoencephalopathy (PML) may occur as a severe side effect of this drug. Here, we describe pathological and radiological characteristics of immune reconstitution inflammatory syndrome (IRIS), which occurs in natalizumab-associated PML after the cessation of therapy, and we differentiate it from ongoing PML. Brain biopsy tissue and MRI scans from five MS patients with natalizumab-associated PML were analyzed and their histology compared with non-MS PML. Histology showed an extensive CD8-dominated T cell infiltrate and numerous macrophages within lesions, and in nondemyelinated white and grey matter, in four out of five cases. Few or no virally infected cells were found. This was indicative of IRIS as known from HIV patients with PML. Outstandingly high numbers of plasma cells were present as compared to non-MS PML and typical MS lesions. MRI was compatible with IRIS, revealing enlarging lesions with a band-like or speckled contrast enhancement either at the lesion edge or within lesions. Only the fifth patient showed typical PML pathology, with low inflammation and high numbers of virally infected cells. This patient showed a similar interval between drug withdrawal and biopsy (3.5 months) to the rest of the cohort (range 2.5-4 months). MRI could not differentiate between PML-associated IRIS and ongoing PML. We describe in detail the histopathology of IRIS in natalizumab-associated PML. PML-IRIS, ongoing PML infection, and MS exacerbation may be impossible to discern clinically alone. MRI may provide some clues for distinguishing different pathologies that can be differentiated histologically. In our individual cases, biopsy helped to clarify diagnoses in natalizumab-associated PML.     

Macrophage chemoattractant protein-1 levels in cerebrospinal fluid correlate with containment of JC virus and prognosis of acquired immunodeficiency syndrome-associated progressive multifocal leukoencephalopathy

In the highly active antiretroviral therapy (HAART) era, the role of the inflammatory response in acquired immunodeficiency syndrome (AIDS)-related progressive multifocal leukoencephalopathy (PML) remains controversial. In this study, JC virus DNA load and levels of cytokines were determined in cerebrospinal fluid (CSF) from 32 human immunodeficiency virus (HIV)-1-infected patients with confirmed PML who underwent HAART; cytokines were also measured in 12 HIV-positive controls. Predictors of survival were analyzed by Cox's models. Macrophage chemoattractant protein (MCP)-1 levels were significantly higher in PML patients than in controls (mean +/- SD, 2.45 +/- 0.64 versus 1.32 +/- 0.64 log(10) pg/ml, P<.0001). In PML patients, the higher concentration of MCP-1 correlated with lower JC viral load (r=-.405, P=.036). Higher concentrations of MCP-1 in CSF were associated with longer survival on HAART after adjusting for CD4 counts (for each log(10) pg/ml higher, hazard ratio for death 0.28, 95% confidence interval 0.08--1.00). Predictors of shorter survival were lower baseline CD4 counts, higher JCV DNA concentrations, lower Karnofsky, and no prior HAART exposure. These results showed that higher CSF levels of MCP-1, an inflammatory cytokine, were correlated with better prognosis in HAART-treated patients with PML.     

Inflammatory reaction in progressive multifocal leukoencephalopathy: harmful or beneficial?

Progressive multifocal leukoencephalopathy (PML) occurs in patients with profound immunosuppression. Although lesions are usually devoid of lymphoplasmocytic infiltrates, inflammatory forms of PML have been described, in both human immunodeficiency virus (HIV)-seropositive (HIV+) and -seronegative (HIV-) patients. In addition, PML has been shown to develop in HIV+ patients shortly after introduction of highly active antiretroviral therapy (HAART), despite a recovery of the immune system. Therefore, one could postulate that PML might arise in the context of an immune reconstitution syndrome. To examine the clinical and neuroradiological characteristics of inflammatory forms of PML, the authors performed a retrospective analysis of the patients seen at their institution since 1996 as well as a review of the literature. Of 39 HIV+ and HIV- PML patients, 5 (13%) presented with an inflammatory form of this disease. Two HIV+ patients developed PML soon after the onset of HAART, concomitant to immune recovery, as demonstrated by a decrease of HIV viral load (VL) and an increase of CD4+ T-cell count. Three patients (2 HIV+ and 1 HIV-) had signs of inflammation in the central nervous system (CNS) characterized by contrast-enhancing lesions on neuroimaging studies, and/or inflammatory infiltrates on brain biopsy. The presence of JC virus-specific cytotoxic T lymphocytes was demonstrated in 4/4 patients tested and the outcome was favorable in 3 of them. In agreement with previously published case reports, the data indicate that inflammatory reactions in PML are not infrequent, and that they are generally associated with a favorable prognosis. Therefore clinicians should not disregard the diagnosis of PML in presence of contrast-enhancing brain lesions, and should use caution before treating these immunosuppressed individuals with steroids.     

Human herpesvirus 6-meningoencephalitis in an HIV patient with progressive multifocal leukoencephalopathy

Human herpesvirus 6 (HHV6) has been reported as a rare cause of meningoencephalitis and leukoencephalitis. We present an HIV-infected patient with lesions of progressive multifocal leukoencephalopathy (PML), but also meningoencephalitis apparently due to HHV6. Immunohistochemistry for HHV6 antigens and in situ polymerase chain reaction for HHV6 genome showed many positive lymphocytes and microglia in the meningeal and cortical lesions. More importantly, dead and dying neurons were conspicuous; some were undergoing neuronophagia and some displayed evidence of HHV6 infection. A pathogenic role for this almost universal, and usually commensal, virus in inflammatory brain lesions and PML is briefly discussed.     

Central nervous system opportunistic infections in developed countries in the highly active antiretroviral therapy era

A marked decrease in incidence has been observed for most central nervous system (CNS) opportunistic infections (OIs) after the use of highly active antiretroviral therapy (HAART) in developed countries. However, the spectrum of these OIs in acquired immunodeficiency syndrome (AIDS) patients has remained almost unchanged. CNS toxoplasmosis, cryptococcosis, tuberculosis, and progressive multifocal leukoencephalopathy (PML) remain the most frequent ones. Primary CNS lymphoma should be included in the differential diagnosis of all cases with focal lesions. Final diagnosis is currently made by combining neuroimaging techniques (single-photon emission computed tomography [SPECT], positron emission tomography [PET], magnetic resonance imaging [MRI] and/or computed tomography [CT] scan) and molecular studies of cerebrospinal fluid (CSF) and therapeutical response. Stereotactic biopsy should only be performed in the case of atypical lesions or nonresponse to recommended treatments. After treatment of the acute phase, lifelong maintenance therapy is necessary to prevent OI recurrences. Once HAART is initiated, some patients can develop a clinical worsening of some CNS OIs with or without atypical neuroimaging manifestations. This paradoxical worsening is known as the immune reconstitution inflammatory syndrome (IRIS) and it results from reconstitution of the immune system's ability to recognize pathogens/antigens in patients with prior OIs and low CD4+ T-cell counts. In this context, IRIS can be seen in patients with CNS cryptococcosis, tuberculosis, or PML. On the other hand, HAART-induced immune reconstitution can improve the prognosis of some untreatable diseases such as PML, and can allow maintenance therapy of some CNS OI to be safely discontinued in patients with high and sustained CD4+ T-cell response.     

Progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is a disease of the central nervous system (CNS) with destructive infection of oligodendrocytes by JC virus. PML belongs to the opportunistic infections. It is observed in patients with HIV infection, lymphoid malignancies, after organ- and stem cell transplantations and more recently in the context of modern immune-therapies with monoclonal antibodies (mAb) like natalizumab, rituximab, infliximab and efalizumab. The natural course of PML is fatal within months. More recently, the Immune Reconstitution Inflammatory Syndrome (IRIS) has been observed in patients with HIV infection treated with combination antiretroviral therapy (cART) as well as patients in whom the PML-inducing immune therapy has been terminated. In PML-IRIS the immune system contributes to the elimination of JC virus from the CNS and if PML-IRIS emerges, PML can be survived but can lead as well to catastrophic outcomes with brain herniation and death. Therefore the management of IRIS requires special knowledge in JC virus biology and patient care. JC virus infection is possibly involved in a variety of additional neurological conditions and cancer. Much will be learned within the next years that could change our view on the understanding of JC virus and human disease.     

Acquired immunodeficiency syndrome-associated progressive multifocal leukoencephalopathy treated with highly active anti-retroviral therapy]

We reported a patient with acquired immunodeficiency syndrome (AIDS)-associated progressive multifocal leukoencephalopathy (AIDS-PML), whose condition improved after highly active anti-retroviral therapy (HAART). A 70-year-old man was admitted to our hospital because of worsening left hemiplegia and disturbance of consciousness. During the past 30 years, he frequently traveled to the United States and southeast Asia. On neurological examination, he was somnolent and left hemiplegia with severe rigospasticity was present. The deep tendon reflexes showed hyper-reflexes with extensor plantar responses. Laboratory studies showed pancytopenia and positive HIV-1 antibodies. The CD4 cell count was 38/mm3 and his HIV viral RNA load in the blood was 9,500 copies/ml. T2-weighted magnetic resonance imaging (MRI) of the brain revealed asymmetrical high intensity white matter lesions in the right fronto-parietal, and left frontal regions and in the cerebellar hemisphere. The cerebrospinal fluid (CSF) protein elevated to 91 mg/dl with a normal cell count. The diagnosis of PML was confirmed by the detection of JC virus DNA in the CSF using a nested polymerase chain reaction assay. Three weeks after starting HAART with zidovudine, lamivudine, and indinavir, he was able to respond to simple commands. Two months later, the HIV viral RNA load decreased to less than 400 copies/mm3, and no JC virus DNA was detected in the CSF, with an increase of the CD4 cell count to 285/mm3 in the blood. A follow-up MRI of the brain showed a reduction in the cerebellar and cerebral white matter lesions. The recovering immune function by decreasing of the HIV load after HAART might suppress JC virus replication. It was suggested that HAART would become a beneficial treatment for patients with AIDS-PML.     

Characterization of lymphocytic infiltrates in progressive multifocal leukoencephalopathy: Co-localization of CD8+ T cells with JCV-infected glial cells

We characterized inflammatory infiltrates in archival brain biopsy and autopsy samples from 26 HIV(+) and 20 HIV(-) patients with progressive multifocal leukoencephalopathy (PML). The predominant inflammatory cells were CD8(+) T lymphocytes. We defined CD8(+) T cell distribution with regard to JCV-infected glial cells, PML lesions and the extent of demyelination. In most samples from either HIV(+) and HIV(-) patients, we found positive correlations between the parenchymal CD8(+) T cells and JCV-infected glial cells and conversely, negative correlations between the perivascular CD8(+) T cells and JCV-infected glial cells in the surrounding brain. Most of these correlations remained significant after accounting for the degree of demyelination and location of the cells relative to lesions. Moreover, high numbers of CD8(+) T cells were found within and at the border of active PML lesions. These results suggest that CD8(+) T cells are primarily associated with JCV-infected glial cells in most PML cases and that an active ongoing recruitment of CD8(+) T cells and possibly viral antigen-specific retention could occur. These observations are discussed in the context of the recent evidence of PML in multiple sclerosis and Crohn's patients treated with natalizumab, underscoring the role of CD8(+) T lymphocytes in continued immunosurveillance of the CNS.     

Failure of mefloquine therapy in progressive multifocal leukoencephalopathy: Report of two Japanese patients without human immunodeficiency virus infection

Although progressive multifocal leukoencephalopathy (PML) cases showing responses to mefloquine therapy have been reported, the efficacy of mefloquine for PML remains unclear. We report on the failure of mefloquine therapy in two Japanese patients with PML unrelated to human immunodeficiency virus. One of the patients was a 47-year-old male who had been treated with chemotherapy for Waldenström macroglobulinemia, and the other was an 81-year-old male with idiopathic CD4⁺ lymphocytopenia. Diagnosis of PML was established based on MRI findings and increased JC virus DNA in the cerebrospinal fluid in both patients. Mefloquine was initiated about 5 months and 2 months after the onset of PML, respectively. During mefloquine therapy, clinical and radiological progression was observed, and JC virus DNA in the cerebrospinal fluid was increased in both patients. Both patients died about 4 months and 2 months after initiation of mefloquine, respectively. Further studies are necessary to clarify the differences between mefloquine responders and non-responders in PML.     

Potent anti-retroviral therapy with or without cidofovir for AIDS-associated progressive multifocal leukoencephalopathy: extended follow-up of an observational study

To analyze the clinical efficacy of cidofovir combined with highly active anti-retroviral therapy (HAART) in AIDS-related progressive multifocal leukoencepalopathy (PML), a multicenter observational study was performed. Consecutive HIV-positive patients with histologically or virologically proven PML and at least 4 weeks of treatment after diagnosis were examined: 27 patients were treated with HAART, whereas 16 patients were treated with HAART plus cidofovir 5 mg/kg intravenously per week for the first 2 weeks and every other week thereafter. JC virus DNA was quantified in cerebrospinal fluid (CSF) by PCR. Baseline virologic, immunologic, and clinical characteristics as well as HIV RNA and CD4 responses to HAART were homogeneous between the groups. The median follow-up was 132 weeks. In one case (6%), cidofovir was permanently discontinued because of severe proteinuria. One-year cumulative probability of survival was 0.61 with cidofovir and 0.29 without (log rank test P = 0.02). After adjusting for baseline CD4 counts, JC viral load in CSF, Karnofsky, and use of HAART prior to the onset of PML, the use of cidofovir was independently associated with a reduced risk of death (hazard ratio, 0.21, 95% confidence interval, 0.07-0.65; P = 0.005). A randomized study will definitively establish whether cidofovir confers significant advantage over HAART alone in AIDS-related PML.     

Progressive multifocal leukoencephalopathy

Before the AIDS epidemic, progressive multifocal leukoencephalopathy (PML) was a rare disorder occurring most often in association with leukemia and lymphoma. Current estimates indicate that PML ultimately develops in up to 5% of all patients with AIDS. This demyelinating disease results from infection with JC virus, a papova virus, that most of the world's population is exposed to prior to adulthood. Although PML commonly occurs in the setting of advanced immunosuppression, it may be observed in patients with CD4 lymphocyte counts in excess of 200 cells/mm3. Focal neurological symptoms and signs coupled with hyperintense signals abnormalities of the white matter on T2-weighted cranial magnetic resonance imaging are highly suggestive of the disease. In this setting, a positive CSF polymerase chain reaction for JCV DNA has been felt to be sufficiently diagnostic to eliminate the need for brain biopsy. Survival of AIDS-associated PML is poor with median survivals averaging just 6 months. However, as many as 10% of AIDS patients with PML will have prolonged (>12 months) survival and partial recovery. Highly active antiretroviral therapy (HAART) has been demonstrated to have a salutary effect on survival.     

Progressive multifocal leukoencephalopathy showing extensive spinal cord involvement in a patient with lymphocytopenia

A 64‐year‐old Japanese man who was diagnosed as having cerebral infarcts at an early clinical stage was found to have progressive multifocal leukoencephalopathy (PML). A decrease of leukocytes and lymphocytes had been detected in the previous year. During a total clinical course of 11 months, he showed marked depletion of lymphocytes ranging from 264/µL to 459/µL. Autopsy disclosed no underlying diseases such as malignancies or tuberculosis. Extensive PML lesions were seen in the cerebral white matter. Small perivascular cuffs comprising many CD8+ T lymphocytes and a few CD4+ T cells were scattered in the PML lesions. CD20+ B cells were rarely evident. The subsets of the infiltrating lymphocytes differed from those of primary or spontaneous PML. Similar extensive PML lesions were observed not only in the cerebellum and brainstem but also in the spinal cord. All 26 segments of the spinal cord, especially the cervical, lumbar and sacral cord, showed extensive lesions involving the lateral and anterior columns. To our knowledge, only three cases of PML with such extensive spinal cord lesions have been reported previously. These three cases, and the present one, may represent a group of PML that shows extensive lesions in the spinal cord as well as the cerebrum, cerebellum and brainstem. The underlying disease in the present case was unclear. Because lymphocytopenia is not observed in primary or spontaneous PML, and the immunohistochemical findings of the infiltrating lymphocytes in the present case are different from primary or spontaneous PML, the decrease in his total blood lymphocytes may have played a significant role in his immunosuppressed condition as the underlying disease.