Highly active antiretroviral therapy and progressive multifocal leukoencephalopathy: effects on cerebrospinal fluid markers of JC virus replication and immune response

Biomarkers for progressive multifocal leukoencephalopathy: emerging data for use of JC virus DNA copy number in clinical trials

Progressive multifocal leukoencephalopathy is a rare but devastating demyelinating disease caused by the JC virus (JCV), for which no therapeutics are approved. To make progress towards addressing this unmet medical need, innovations in clinical trial design are needed. Quantitative JCV DNA in CSF has the potential to serve as a valuable biomarker of progressive multifocal leukoencephalopathy disease and treatment response in clinical trials to expedite therapeutic development, as do neuroimaging and other fluid biomarkers such as neurofilament light chain. Specifically, JCV DNA in CSF could be used in clinical trials as an entry criterion, stratification factor, or predictor of clinical outcomes. Insights from the investigation of candidate biomarkers for progressive multifocal leukoencephalopathy might inform approaches to biomarker development for other rare diseases.

Progressive Multifocal Leukoencephalopathy Treated by Immune Checkpoint Inhibitors

OBJECTIVE

Our aim was to assess the real-world effectiveness of immune checkpoint inhibitors for treatment of patients with progressive multifocal leukoencephalopathy (PML).

METHODS

We conducted a multicenter survey compiling retrospective data from 79 PML patients, including 38 published cases and 41 unpublished cases, who received immune checkpoint inhibitors as add-on to standard of care. One-year follow-up data were analyzed to determine clinical outcomes and safety profile. Logistic regression was used to identify variables associated with 1-year survival.

RESULTS

Predisposing conditions included hematological malignancy (n = 38, 48.1%), primary immunodeficiency (n = 14, 17.7%), human immunodeficiency virus/acquired immunodeficiency syndrome (n = 12, 15.2%), inflammatory disease (n = 8, 10.1%), neoplasm (n = 5, 6.3%), and transplantation (n = 2, 2.5%). Pembrolizumab was most commonly used (n = 53, 67.1%). One-year survival was 51.9% (41/79). PML-immune reconstitution inflammatory syndrome (IRIS) was reported in 15 of 79 patients (19%). Pretreatment expression of programmed cell death-1 on circulating T cells did not differ between survivors and nonsurvivors. Development of contrast enhancement on follow-up magnetic resonance imaging at least once during follow-up (OR = 3.16, 95% confidence interval = 1.20-8.72, p = 0.02) was associated with 1-year survival. Cerebrospinal fluid JC polyomavirus DNA load decreased significantly by 1-month follow-up in survivors compared to nonsurvivors (p < 0.0001). Thirty-two adverse events occurred among 24 of 79 patients (30.4%), and led to treatment discontinuation in 7 of 24 patients (29.1%).

INTERPRETATION

In this noncontrolled retrospective study of patients with PML who were treated with immune checkpoint inhibitors, mortality remains high. Development of inflammatory features or overt PML-IRIS was commonly observed. This study highlights that use of immune checkpoint inhibitors should be strictly personalized toward characteristics of the individual PML patient. ANN NEUROL 2023;93:257-270.

MRI Shrimp Sign in Cerebellar Progressive Multifocal Leukoencephalopathy: Description and Validation of a Novel Observation

BACKGROUND AND PURPOSE

There are no validated imaging criteria for the diagnosis of progressive multifocal leukoencephalopathy in the cerebellum. Here we introduce the MR imaging shrimp sign, a cerebellar white matter lesion identifiable in patients with cerebellar progressive multifocal leukoencephalopathy, and we evaluate its sensitivity and specificity.

MATERIALS AND METHODS

We first identified patients with progressive multifocal leukoencephalopathy seen at Massachusetts General Hospital between 1998 and 2019 whose radiology reports included the term "cerebellum." Drawing on a priori knowledge, 2 investigators developed preliminary diagnostic criteria for the shrimp sign. These criteria were revised and validated in 2 successive stages by 4 additional blinded investigators. After defining the MR imaging shrimp sign, we assessed its sensitivity, specificity, positive predictive value, and negative predictive value.

RESULTS

We identified 20 patients with cerebellar progressive multifocal leukoencephalopathy: 16 with definite progressive multifocal leukoencephalopathy (mean, 46.4 [SD, 9.2] years of age; 5 women), and 4 with possible progressive multifocal leukoencephalopathy (mean, 45.8 [SD, 8.5] years of age; 1 woman). We studied 40 disease controls (mean, 43.6 [SD, 21.0] years of age; 16 women) with conditions known to affect the cerebellar white matter. We defined the MR imaging shrimp sign as a T2- and FLAIR-hyperintense, T1-hypointense, discrete cerebellar white matter lesion abutting-but-sparing the dentate nucleus. MR imaging shrimp sign sensitivity was 0.85; specificity, 1; positive predictive value, 1; and negative predictive value, 0.93. The shrimp sign was also seen in fragile X-associated tremor ataxia syndrome, but radiographic and clinical features distinguished it from progressive multifocal leukoencephalopathy.

CONCLUSIONS

In the right clinical context, the MR imaging shrimp sign has excellent sensitivity and specificity for cerebellar progressive multifocal leukoencephalopathy, providing a new radiologic marker of the disease.

Dual engineered gold nanoparticle based synergistic prophylaxis delivery system for HIV/AIDS

HIV is a pandemic and continuously raises problem across the world. This disease puts an immense pressure on treatment modalities. There are only few clinically accepted drugs available for the treatment and few molecules under clinical development. Although, the antiretroviral drugs give reliable and positive response on control of virus replication but during the long treatment, it has been affirmed that there are number of side effects. With recent advancements in biotechnology, nanomaterials such as gold and silver etc. are proving to be a game changer in targeted drug delivery treatment. As gold nanoparticles (AuNPs) are biocompatible natural excipients, a lot of scientists are very eager to investigate more about the immune effects of AuNPs to create a safe and cost effective treatment that could potentially help in the reduction of numerous toxic effects present in the existing treatments of various critical diseases like cancer and HIV etc. In this context, the present hypothesis recommends the use of combination drug delivery strategy based on gold nanoparticles that could pave the way to overcome adverse results of existing delivery techniques of antiretroviral drugs to treat HIV. This review also highlights the fact that a proper development of this gold nanoparticle combination antiretroviral drug delivery approach will not only help to suppress the virus multiplication but also target the viral entry area by attaching with gp120 (glycoprotein 120), and inhibit the binding with CD4 (Cluster of differentiation 4) T cells.

Remission of progressive multifocal leukoencephalopathy in HIV- positive patient after multidisciplinary rehabilitation: a case report

Introduction: One of the most common neurologic disease in Acquired Immunodeficiency Syndrome (AIDS) caused by Human Immunodeficiency Virus (HIV) is represented by progressive multifocal leukoencephalopathy (PML), being caused by John Cunningham (JC) polyoma virus. Case presentation: We report a case of a 27 years old women, HIV-positive since childhood, under specific antiretroviral therapy with good adherence to it in that period but starting with adolescence adherence to highly active antiretroviral therapy (HAART) decreased. In this context her HIV viral load increased to a 690.000 copies/ml, and CD4 collapsed at 57 cells/mmc. She presented in our clinic with ataxic left hemiparesis, truncal ataxia and left hemi-hypoesthesia. Cerebrospinal fluid (CSF) showed a slightly pleocytosis and polymerase chain reaction performed from CSF diagnosed John Cunningham (JC) virus. Once diagnosis established, we reinitiated HAART, but some neurologic disorders persisted like difficulty of the left upper member, having the modified Rankin scale (mRS) of 5. The patient started a multidisciplinary rehabilitation (MDR) treatment, specifically adapted. It consisted of 4 sessions of neuromotor treatments, 20 sessions of massages, and 12 sessions of occupational therapy. According to MDR, the patient improved the ataxic walking, without support, presenting an improvement mRS of 3. Conclusions: AIDS patients with PML could require a prolonged MDR treatment for neurological disorders and rehabilitation treatment promptly should be applied when such diagnosis is suspected. Key words: progressive multifocal leukoencephalopathy, human immunodeficiency virus, neurological disorder, multidisciplinary rehabilitation,

Role of nanotechnology in HIV/AIDS vaccine development

HIV/AIDS is one of the worst crises affecting global health and influencing economic development and social stability. Preventing and treating HIV infection is a crucial task. However, there is still no effective HIV vaccine for clinical application. Nanotechnology has the potential to solve the problems associated with traditional HIV vaccines. At present, various nano-architectures and nanomaterials can function as potential HIV vaccine carriers or adjuvants, including inorganic nanomaterials, liposomes, micelles and polymer nanomaterials. In this review, we summarize the current progress in the use of nanotechnology for the development of an HIV/AIDS vaccine and discuss its potential to greatly improve the solubility, permeability, stability and pharmacokinetics of HIV vaccines. Although nanotechnology holds great promise for applications in HIV/AIDS vaccines, there are still many inadequacies that result in a variety of risks and challenges. The potential hazards to the human body and environment associated with some nano-carriers, and their underlying mechanisms require in-depth study. Non-toxic or low-toxic nanomaterials with adjuvant activity have been identified. However, studying the confluence of factors that affect the adjuvant activity of nanomaterials may be more important for the optimization of the dosage and immunization strategy and investigations into the exact mechanism of action. Moreover, there are no uniform standards for investigations of nanomaterials as potential vaccine adjuvants. These limitations make it harder to analyze and deduce rules from the existing data. Developing vaccine nano-carriers or adjuvants with high benefit-cost ratios is important to ensure their broad usage. Despite some shortcomings, nanomaterials have great potential and application prospects in the fields of AIDS treatment and prevention.

Progressive multifocal leukoencephalopathy and immune reconstitution inflammatory syndrome (IRIS)

Progressive multifocal leukoencephalopathy is a viral encephalitis induced by the John Cunningham (JC) virus, an ubiquitous neurotropic papovavirus of the genus polyomavirus that in healthy people in latency resides in kidney and bone marrow cells. Activation and entry into the CNS were first seen in patients with malignancies of the hematopoietic system and an impaired immune system. During the 1980 and the 1990s with the appearance of human immunodeficiency virus infection in humans, PML was found to be the most important opportunistic infection of the central nervous system. As a result of highly efficient immunosuppressive and immunomodulatory treatments, in recent years, the number of PML cases again increased. PML is prevented by an intact cellular immune response and accordingly immune reconstitution can terminate established disease in the CNS. However, forced immune reconstitution can lead to massive destruction of virus-infected cells. This may result in clinical exacerbation associated with high morbidity and mortality and referred to as PML with immune reconstitution inflammatory syndrome (PML-IRIS). In the present review, we discuss virological properties and routes of infection in the CNS, but mostly focus on the pathology of PML and PML-IRIS and on the role of the immune system in these disorders. We show that PML and PML-IRIS result from predominant JC virus infection of oligodendrocytes and, to a lesser extent, of infected neurons. Inflammation in these encephalitides seems to be driven by a dominant cytotoxic T cell response which is massively exaggerated during IRIS.

Cerebrospinal fluid JC virus antibody index for diagnosis of natalizumab-associated progressive multifocal leukoencephalopathy

OBJECTIVE

Progressive multifocal leukoencephalopathy (PML), caused by JC virus (JCV), can occur in patients receiving natalizumab for multiple sclerosis (MS). JCV detection by quantitative polymerase chain reaction (qPCR) in cerebrospinal fluid (CSF), or brain biopsy, is required for probable or definite diagnosis of PML. However, in some patients only low levels of JCV DNA (<100 copies/ml) are present in CSF, making the diagnosis challenging. Our objective was to assess the complementary value of a CSF JCV antibody index (AIJCV ) in the diagnosis of natalizumab-associated PML.

METHODS

AIJCV was assessed in 37 cases of natalizumab-associated PML and 89 MS-patients treated with natalizumab without PML. Sera and CSF were tested in a capture enzyme-linked immunosorbent assay, using JCV-VP1 fused to glutathione S-transferase as antigen. Albumin levels and total immunoglobulin G concentration were determined by immunonephelometry, and the AIJCV was calculated as published.

RESULTS

Twenty-six of 37 (70%) patients with natalizumab-associated PML exhibited an AIJCV > 1.5, whereas this was seen in none of the controls (p < 0.0001). At time of the first positive qPCR for JCV DNA, 11 of 20 (55%) patients with natalizumab-associated PML had an AIJCV > 1.5. JCV DNA levels of <100 copies/ml were seen in 14 (70%) of these 20 patients, of whom 8 (57%) demonstrated an AIJCV > 1.5.

INTERPRETATION

Determination of the AIJCV could be an added tool in the diagnostic workup for PML and should be included in the case definition of natalizumab-associated PML.

Continued declining incidence and improved survival of progressive multifocal leukoencephalopathy in HIV/AIDS patients in the current era

To evaluate the situation and perspectives of progressive multifocal leukoencephalopathy (PML) in human immunodeficiency virus (HIV)-infected patients, we investigated changes in the incidence, causes, and long-term outcome of this disease in 72 acquired immunodeficiency syndrome (AIDS) patients who were diagnosed with PML from 1996 to 2011. Patients were classified according to the date of diagnosis in the first (1996-2000, n = 35), second (2001-2006, n = 26), and recent or third highly active antiretroviral therapy (HAART) period (2007-2011, n = 11). Overall, the incidence of PML decreased from 14.8 cases/1,000 patients/year in 1996 to 2.6 in 2005 and 0.8 in 2011, and nearly two-thirds of recent cases (64 %) were observed in HIV patients not attending clinical visits. The baseline median CD4+ count was higher in recently PML-diagnosed patients (77 vs. 86 vs. 101 cells/mm(3); p < 0.01), and this fact was associated with a cerebrospinal fluid (CSF) inflammatory profile (from 11 to 31 to 55 %, p = 0.007) and with a significantly longer survival (attributable death, 54 vs. 35 vs. 36 %, respectively, p < 0.01). Thus, the overall 1-year and 3-year survival rates were 55 and 50 %, respectively, increasing to 79 % at 1 year for patients with CD4+ count above 100 cells/mm(3) at diagnosis. In a Cox regression analysis, an older age (hazard ratio, HR 0.76), a baseline CD4+ count above 100 cells/mm(3) (HR 0.33), and a CSF inflammatory profile (HR 0.12) were significantly associated with a longer survival. The clinical presentation and outcome of PML in AIDS patients continue to change dramatically. Now, a declining incidence and long-term survival is observed.

JC virus detection and JC virus-specific immunity in natalizumab-treated multiple sclerosis patients

Background

The use of natalizumab in multiple sclerosis (MS) may favour JC virus reactivation; this phenomenon is usually asymptomatic but can, albeit rarely, evolve into frank progressive multifocal leucoencephalopathy (PML).

Methods

JCV-specific CD8+ T lymphocytes were evaluated by flow cytometry over a 24-month period in 24 natalizumab-treated MS patients in whom JCV DNA was or was not detected in blood using quantitative real-time polymerase chain reaction; all these cases were asymptomatic.

Results

Perforin- and grazymes-containing VP-1-specific CD8+ T lymphocytes were reduced whereas CD107a-expressing cells were increased in JCV positive patients, suggesting an active degranulation of these cells; naïve CD8+ T lymphocytes were also decreased whereas memory cells were increased in patients in whom JCV reactivation was observed.

Conclusion

The presence of a CD8+ T lymphocyte-mediated effector immune response offers a greater insight into reactivation of JCV and its clinical sequelae, and may help the monitoring of patients on natalizumab therapy.

JC virus load in cerebrospinal fluid and transcriptional control region rearrangements may predict the clinical course of progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is a severe disease of the central nervous system (CNS), caused by infection with the Polyomavirus JC virus (JCV). Because there are no known treatments or prognostic factors, we performed a long-term study focusing mainly on cerebrospinal fluid (CSF) samples from PML patients to describe the virological features akin to the different forms of the disease. Twenty-eight PML patients were enrolled: 10 HIV-1+ patients with classical PML (CPML), 9 HIV-1+ patients with slowly progressing or stable neurological symptoms (benign PML), 3 HIV-1+ asymptomatic patients, and 6 HIV-1-negative patients. CSF, urine, and blood samples were collected at the enrollment (baseline) and every 6 months afterwards when possible. The JCV DNA and HIV-1 RNA loads were determined, and the JCV strains were characterized. At baseline, the mean CSF JCV load was log 6.0 ± 1.2 copies/ml for CPML patients, log 4.0 ± 1.0 copies/ml for benign PML patients, log 4.2 ± 0.5 copies/ml for asymptomatic PML patients, and log 5.8 ± 1.3 copies/ml for HIV-1-negative PML patients (CPML vs. benign: P < 0.01; CPML vs. asymptomatic: P < 0.05; HIV-1 negative vs. benign: P < 0.01). Organization of the JCV transcriptional control region (TCR) showed unusual archetype structures in two long-term survival patients; the NF1 sequence was found most commonly, whereas the Sp1 binding site was the most common for both CPML patients and HIV-1 negative patients. Our results suggest that the JCV load in the CSF and the organization of the TCR should be considered as indicators of PML clinical outcome.

Molecular biology, epidemiology, and pathogenesis of progressive multifocal leukoencephalopathy, the JC virus-induced demyelinating disease of the human brain

Progressive multifocal leukoencephalopathy (PML) is a debilitating and frequently fatal central nervous system (CNS) demyelinating disease caused by JC virus (JCV), for which there is currently no effective treatment. Lytic infection of oligodendrocytes in the brain leads to their eventual destruction and progressive demyelination, resulting in multiple foci of lesions in the white matter of the brain. Before the mid-1980s, PML was a relatively rare disease, reported to occur primarily in those with underlying neoplastic conditions affecting immune function and, more rarely, in allograft recipients receiving immunosuppressive drugs. However, with the onset of the AIDS pandemic, the incidence of PML has increased dramatically. Approximately 3 to 5% of HIV-infected individuals will develop PML, which is classified as an AIDS-defining illness. In addition, the recent advent of humanized monoclonal antibody therapy for the treatment of autoimmune inflammatory diseases such as multiple sclerosis (MS) and Crohn's disease has also led to an increased risk of PML as a side effect of immunotherapy. Thus, the study of JCV and the elucidation of the underlying causes of PML are important and active areas of research that may lead to new insights into immune function and host antiviral defense, as well as to potential new therapies.

Suppressive effect of PARP-1 inhibitor on JC virus replication in vitro

The incidence of progressive multifocal leukoencephalopathy (PML) has increased due to the AIDS pandemic, hematological malignancies, and immunosuppressive therapies. Recently, the number of cases of monoclonal antibody-associated PML has increased in patients treated with immunomodulatory drugs such as natalizumab. However, no common consensus regarding PML therapy has been reached in clinical studies. In order to examine the suppression of JC virus (JCV) replication by 3-aminobenzamide (3-AB), a representative PARP-1 inhibitor, a DNA replication assay was carried out using the neuroblastoma cell line IMR-32 and IMR-adapted JCV. The suppression of JCV propagation by 3-AB was also examined using JCI cells, which are a carrier culture producing continuously high JCV titers. The results indicated that PARP-1 inhibitors, such as 3-aminobenzamide (3-AB), suppress JCV replication and propagation significantly in vitro, as judged by DNA replication assay, hemagglutination, and real-time PCR analysis. It has been also shown that 3-AB reduced PARP-1 activity in IMR-32 cells. According to the results of the MTT assay, the enzyme activity of 3-AB-treated cells was slightly lower than that of DMSO-treated cells. However, the significant suppression of JCV propagation is not related to the slight decrease in cell growth. To our knowledge, this is the first report that PARP-1 inhibitor suppresses the replication of JCV significantly in neuroblastoma cell lines via the reduction of PARP-1 activity. Thus, PARP-1 inhibitors also may be a novel therapeutic drug for PML.

Management and outcome of CSF-JC virus PCR-negative PML in a natalizumab-treated patient with MS

OBJECTIVE

To describe the diagnosis and management of a 49-year-old woman with multiple sclerosis (MS) developing a progressive hemiparesis and expanding MRI lesion suspicious of progressive multifocal leukoencephalopathy (PML) 19 months after starting natalizumab.

RESULTS

Polyomavirus JC (JCV)-specific qPCR in CSF was repeatedly negative, but JCV-specific antibodies indicated intrathecal production. Brain biopsy tissue taken 17 weeks after natalizumab discontinuation and plasmapheresis was positive for JCV DNA with characteristic rearrangements of the noncoding control region, but histology and immunohistochemistry were not informative except for pathologic features compatible with immune reconstitution inflammatory syndrome. A total of 22 months later, the clinical status had returned close to baseline level paralleled by marked improvement of neuroradiologic abnormalities.

CONCLUSIONS

This case illustrates diagnostic challenges in the context of incomplete suppression of immune surveillance and the potential of recovery of PML associated with efficient immune function restitution.

Rituximab-associated progressive multifocal leukoencephalopathy in rheumatoid arthritis

OBJECTIVE

To describe the development of progressive multifocal leukoencephalopathy (PML) in patients with rheumatoid arthritis (RA) treated with rituximab.

DESIGN

Case study.

SETTING

Clinical care for patients with rheumatologic diseases. Most were referred to academic centers for care after diagnosis (Washington University, St Louis, Missouri; Karolinska Insitute, Stockholm, Sweden; and Royal Melbourne Hospital, Melbourne, Australia) while one was cared for in a neurology practice in Dallas, Texas, with consultation by an academic neurovirologist from the University of Colorado in Denver.

PATIENTS

Four patients developing PML in the setting of rituximab therapy for RA.

INTERVENTION

Rituximab therapy.

MAIN OUTCOME MEASURES

Clinical and pathological observations.

RESULTS

Four patients from an estimated population of 129 000 exposed to rituximab therapy for RA are reported in whom PML developed after administration of this drug. All were women older than 50 years, commonly with Sjögren syndrome and a history of treatment for joint disease ranging from 3 to 14 years. One case had no prior biologic and minimal immunosuppressive therapy. Progressive multifocal leukoencephalopathy presented as a progressive neurological disorder, with diagnosis confirmed by detection of JC virus DNA in the cerebrospinal fluid or brain biopsy specimen. Two patients died in less than 1 year from PML diagnosis, while 2 remain alive after treatment withdrawal. Magnetic resonance scans and tissue evaluation confirmed the frequent development of inflammatory PML during the course of the disease.

CONCLUSION

These cases suggest an increased risk, about 1 case per 25 000 individuals, of PML in patients with RA being treated with rituximab. Inflammatory PML may occur in this setting even while CD20 counts remain low.

Progressive multifocal leucoencephalopathy after autologous bone marrow transplantation: a treatment option

A patient with multiple myeloma was treated with high-dose chemotherapy followed by two autologous bone marrow transplantations (ABMTs). Nine months after the second ABMT the patient complained of severe left hemiparesis, paraesthesias, left homonymous visual field defects and gait ataxia. She was diagnosed with progressive multifocal leucoencephalopathy (PML) confirmed by detection of JC virus (JCV) DNA and prescribed cidofovir every other week and mirtazapine daily. Her symptoms and signs remained stable and after 6 months the JCV DNA was undetectable in the cerebrospinal fluid. Repeated MRI scans demonstrated the stabilisation of demyelinating lesion volume; after more than 2 years of follow-up the patient's neurological examination does not show significant variations. Combination of cidofovir and mirtazapine may be helpful in the treatment of PML in HIV-negative patients.

JC virus infection of the brain

Since its initial description, there have been significant changes in the epidemiology, pathogenesis, and clinical and imaging manifestations of JCV infection of brain. The most common clinical manifestation is PML. Other recently described CNS manifestations are JCE, JCVGCN, and JCM. Although AIDS is the most common predisposing factor for JCV reactivation, there is increasing incidence of brain manifestations of JCV reactivation in non-HIV settings, including different rheumatologic, hematologic, and oncologic conditions; monoclonal antibody therapy; transplant recipients; primary immunodeficiency syndromes; and even in patients without any recognizable immune deficiency. IRIS may develop secondary to restoration of immunity in HIV-positive patients with PML receiving antiretroviral therapy. This is of profound clinical significance and needs to be diagnosed promptly. Imaging plays a crucial role in the diagnosis of the disease, monitoring of treatment response, identifying disease progression, and predicting prognosis. In this article, current understanding of the epidemiology, pathogenesis, clinical presentations, and all aspects of imaging of JCV infection of the brain have been comprehensively reviewed.

Progressive multifocal leukoencephalopathy and promyelocytic leukemia nuclear bodies: a review of clinical, neuropathological, and virological aspects of JC virus-induced demyelinating disease

Progressive multifocal leukoencephalopathy is a fatal viral-induced demyelinating disease that was once rare but has become more prevalent today. Over the past decades, much has been learned about the disease from molecular study of the etiological agent of the disease, JC virus. Recently, promyelocytic leukemia nuclear bodies (PML-NBs), punctuate structures for important nuclear functions in eukaryotic cells, were identified as an intranuclear target of JC virus infection. Neuropathologically, JC virus-infected glial cells display diffuse amphophilic viral inclusions by hematoxylin–eosin staining (full inclusions), a diagnostic hallmark of this disease. Recent results using immunohistochemistry, however, revealed the presence of punctate viral inclusions preferentially located along the inner nuclear periphery (dot-shaped inclusions). Dot-shaped inclusions reflect the accumulation of viral progeny at PML-NBs, which may be disrupted after viral replication. Structural changes to PML-NBs have been reported for a variety of human diseases, including cancers and neurodegenerative disorders. Thus, PML-NBs may provide clues to the further pathogenesis of JC virus-induced demyelinating disease. Here, we review what we have learned since the disease entity establishment, including a look at recent progress in understanding the relationship between JC virus, etiology and PML-NBs.

Rearranged JC virus noncoding control regions found in progressive multifocal leukoencephalopathy patient samples increase virus early gene expression and replication rate

Polyomavirus JC (JCV) infects ∼ 60% of the general population, followed by asymptomatic urinary shedding in ∼ 20%. In patients with pronounced immunodeficiency, including HIV/AIDS, JCV can cause progressive multifocal leukoencephalopathy (PML), a devastating brain disease of high mortality. While JCV in the urine of healthy people has a linear noncoding control region called the archetype NCCR (at-NCCR), JCV in brain and cerebrospinal fluid (CSF) of PML patients bear rearranged NCCRs (rr-NCCRs). Although JCV NCCR rearrangements are deemed pathognomonic for PML, their role as a viral determinant is unclear. We sequenced JCV NCCRs found in CSF of eight HIV/AIDS patients newly diagnosed with PML and analyzed their effect on early and late gene expression using a bidirectional reporter vector recapitulating the circular polyomavirus early and late gene organization. The rr-NCCR sequences were highly diverse, but all increased viral early reporter gene expression in progenitor-derived astrocytes, glia-derived cells, and human kidney compared to the expression levels with the at-NCCR. The expression of simian virus 40 (SV40) large T antigen or HIV Tat expression in trans was associated with a strong increase of at-NCCR-controlled early gene expression, while rr-NCCRs were less responsive. The insertion of rr-NCCRs into the JCV genome backbone revealed higher viral replication rates for rr-NCCR compared to those of the at-NCCR JCV in human progenitor-derived astrocytes or glia cells, which was abrogated in SV40 large T-expressing COS-7 cells. We conclude that naturally occurring JCV rr-NCCR variants from PML patients confer increased early gene expression and higher replication rates compared to those of at-NCCR JCV and thereby increase cytopathology.

Update on immune reconstitution inflammatory syndrome: progress and unanswered questions

The immune reconstitution inflammatory syndrome (IRIS) is characterized by clinical deterioration occurring after the initiation of effective antiretroviral therapy (ART) and results from a disordered and exuberant immune response. The syndrome may present as paradoxical IRIS or unmasking IRIS, depending on whether an opportunistic infection was recognized and treated before ART initiation. Numerous descriptions of IRIS caused by many pathogens were published in the years after the introduction of effective ART. In recent years, with enhanced rollout of ART in resource-limited settings, attention has again focused on IRIS because of the enormous burden of opportunistic infections. This review highlights recent findings elucidating risk factors for and the pathogenesis and treatment of IRIS.

Progressive multifocal leukoencephalopathy and other disorders caused by JC virus: clinical features and pathogenesis

Progressive multifocal leukoencephalopathy (PML) is a rare but often fatal brain disease caused by reactivation of the polyomavirus JC. Knowledge of the characteristics of PML has substantially expanded since the introduction of combination antiretroviral therapy during the HIV epidemic and the development of immune reconstitution inflammatory syndrome (IRIS) in patients with PML. Recently, the monoclonal antibodies natalizumab, efalizumab, and rituximab--used for the treatment of multiple sclerosis, psoriasis, haematological malignancies, Crohn's disease, and rheumatic diseases--have been associated with PML. Additionally, the JC virus can also lead to novel neurological disorders such as JC virus granule cell neuronopathy and JC virus encephalopathy, and might also cause meningitis. The increasingly diverse populations at risk and the recent discovery of the presence of the JC virus in the grey matter invite us to reappraise the pathogenesis of this virus in the CNS.

[Demyelinating disorders]

Leukoencephalopathies in adults are frequent and exhibit highly variable aetiology, including multiple acquired causes such as inflammatory, vascular or toxic diseases and neoplasias. In contrast leukodystrophies are genetically determined, chronic progressive myelin disorders with a variable pathogenetic background and a great diversity of clinical and paraclinical findings. Some diseases, namely those with an additional inborn error of metabolism, are treatable. Genetic counselling appears to be of major importance for patients and their families. In the light of numerous acquired adulthood leukoencephalopathies a clear delineation of late-onset genetic leukodystrophies is necessary. Clinical symptoms and MRI patterns of some of the major leukodystrophies are reported, including possibilities of biochemical and genetic testing.

Neurologic presentations of AIDS

The human immunodeficiency virus (HIV), the cause of AIDS, has infected an estimated 33 million individuals worldwide. HIV is associated with immunodeficiency, neoplasia, and neurologic disease. The continuing evolution of the HIV epidemic has spurred an intense interest in a hitherto neglected area of medicine, neuroinfectious diseases and their consequences. This work has broad applications for the study of central nervous system (CNS) tumors, dementias, neuropathies, and CNS disease in other immunosuppressed individuals. HIV is neuroinvasive (can enter the CNS), neurotrophic (can live in neural tissues), and neurovirulent (causes disease of the nervous system). This article reviews the HIV-associated neurologic syndromes, which can be classified as primary HIV neurologic disease (in which HIV is both necessary and sufficient to cause the illness), secondary or opportunistic neurologic disease (in which HIV interacts with other pathogens, resulting in opportunistic infections and tumors), and treatment-related neurologic disease (such as immune reconstitution inflammatory syndrome).

Clinical vigilance for progressive multifocal leukoencephalopathy in the context of natalizumab use

Natalizumab therapy for patients with multiple sclerosis (MS) has been associated with both improved clinical outcomes and an increased incidence of progressive multifocal leukoencephalopathy (PML). We provide details of the etiology and recent history of PML as associated with immunosuppressive disease states, including MS. Furthermore, it offers clinical guidance on differentiating PML from a MS relapse and a review of the current treatment options for patients suspected of having developed the complication.

Progressive multifocal leukoencephalopathy in HIV-1 infection

Progressive multifocal leukoencephalopathy is caused by the JC polyomavirus (JCV) and is one of the most feared complications of HIV-1 infection. Unlike other opportunistic infections, this disease can present when CD4 counts are higher than those associated with AIDS and when patients are receiving combined antiretroviral therapy, either shortly after starting or, more rarely, during long term successful treatment. Clinical suspicion of the disease is typically when MRI shows focal neurological deficits and associated demyelinating lesions; however, the identification of JCV in cerebrospinal fluid or brain tissue is needed for a definitive diagnosis. Although no specific treatment exists, the reversal of immunosuppression by combined antiretroviral therapy leads to clinical and MRI stabilisation in 50-60% of patients with the disease, and JCV clearance from cerebrospinal fluid. A substantial proportion of patients treated with combined antiretroviral therapy develop inflammatory lesions, which can be associated with either a favourable outcome or clinical worsening. The reasons for variability in the natural history of progressive multifocal leukoencephalopathy and treatment responses are largely undefined, and more specific and rational approaches to management are needed.

Inhibitory effect of serotonin antagonists on JC virus propagation in a carrier culture of human neuroblastoma cells

Human polyomavirus, JCV, causes fatal demyelinating disease, progressive multifocal leukoencephalopathy (PML). It has been shown that 5HT(2A)R acts as a cellular receptor for JCV on human glial cells. In the current study, we examined the inhibitory effects of 5HT(2A)R antagonists, ketanserin and ritanserin, both on JCV infection and on propagation by using human neuroblastoma cells IMR-32 and JCI, which continuously produce JCV. Transcriptional analysis revealed that 5HT(2A)R was constitutively expressed in JCI cells. Treatments with 5HT(2A)R antagonists led to a significant reduction in the titers of progeny viruses and the population of infected JCI cells. In addition, the amount of JCV genomic DNA was decreased in JCI cells in the presence of 5HT(2A)R antagonists. These results indicate that 5HT(2A)R antagonists have an inhibitory effect on JCV infection and reproduction, and JCI cells are applicable to an experimental model for pharmacological evaluation of antiviral agents against JCV.

Treatment options for AIDS patients with progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is a demyelinating viral disease produced by the John Cunningham (JC) virus, which is ubiquitously distributed. Up to 80% of adults seroconvert to JC virus. Classically, PML is a life-threatening AIDS-defining disease of the CNS, usually occurring in severely immunocompromised individuals. Until now, and despite several therapeutic attempts, there is no specific treatment for PML. Soon after the widespread use of combination antiretroviral therapy (CART), several studies showed prolonged survival for patients with AIDS-associated PML who were treated with CART. The outcome of PML in patients receiving CART is unpredictable at disease onset. Prognostic markers are needed. The JC virus DNA detection in cerebrospinal fluid by nucleic acid amplification techniques and the CD4+ cell count are the most promising parameters. Higher levels of CD4+ cell counts were independently associated with an improved survival in different clinical observations. A summary of the main current knowledge about AIDS-related PML is presented. The most effective strategy is to optimize CART to completely suppress HIV-1 viral load and allow the best CD4+ T-cell immune recovery. Nowadays, AIDS-related PML is no longer an ultimately fatal disease. A substantial number of HIV-1-infected patients with this condition can improve with CART.

Remission of progressive multifocal leukoencephalopathy and primary central nervous system lymphoma in an HIV-infected patient

The coexistence of progressive multifocal leukoencephalopathy (PML) and primary central nervous system lymphoma (PCNSL) is a rare event, usually associated with a fatal outcome. We report the case of a human immunodeficiency virus (HIV)-infected individual presenting with both PML and PCNSL who made a remarkable recovery after highly active anti retroviral therapy (HAART) and radiation therapy, and discuss diagnostic and therapeutic aspects of both conditions.

Visual loss secondary to acquired immunodeficiency virus–related progressive multifocal leukoencephalopathy demonstrating clinical improvement with highly active antiretroviral therapy

BACKGROUND

Progressive multifocal leukoencephalopathy (PML) is a demyelinating brain disease caused by the JC papovavirus. This disease afflicts the immunocompromised, particularly those infected with the human immunodeficiency virus (HIV). PML progresses rapidly, causing a variety of visual and neurologic complications.

CASE REPORT

A 49-year-old HIV-positive man presented with reduced vision, a bilateral left hemianopsia, left-sided motor dysfunction, and mild dementia. Confirmation of the presence of the JC virus in the cerebrospinal fluid and characteristic computed tomography and magnetic resonance imaging changes led to the diagnosis of PML. No treatment was initiated other than continuation of highly active antiretroviral therapy (HAART). The patient was re-examined 8 months later and found to have significant resolution of his visual and neurological symptoms.

CONCLUSION

PML often results in devastating and deadly neurologic deterioration in HIV-positive patients. Although treatment options are limited, HAART can lead to clinical improvement of symptoms and prolong survival time.

Management of infections by the human polyomavirus JC: past, present and future

Progressive multifocal leukoencephalopathy is a fatal demyelinating disease caused by infection of oligodendrocytes by the human polyomavirus known as JC virus. Over the past 10 years, the disease has been documented almost exclusively in AIDS patients, who constitute a rapidly growing population of immunosuppressed individuals. More recently, progressive multifocal leukoencephalopathy has also been described in patients undergoing solid organ or cell transplant, as a result of immunosuppressive therapy to avoid graft rejection. Although there are several reports of successful treatment of progressive multifocal leukoencephalopathy, large-scale prospective trials have been few, and with mixed results. As more is discovered about the biology of JC virus infection and advances are made in targeted parenchymal delivery of therapeutic agents, there is hope for the development of an effective therapy for progressive multifocal leukoencephalopathy.

Central nervous system infections - a potential complication of systemic immunotherapy

PURPOSE OF REVIEW

Multiple sclerosis is a chronic inflammatory disease of the central nervous system, characterized by demyelination and axonal damage. With the emergence of more efficient immune therapies, severe sometimes even fatal central nervous system infections were observed. This review will address the role of the systemic immune system in central nervous system immune surveillance and discuss implications for the development of novel immunotherapies in multiple sclerosis.

RECENT FINDINGS

In the last decade, a number of immunosuppressive and immunomodulatory agents have been approved for the treatment of multiple sclerosis, based on the results of double-blind placebo-controlled randomized clinical trials. A better understanding of the pathogenesis of the disease has prompted exploration of the therapeutic utility of new drugs that more potently disrupt the pathophysiological cascade of events that culminates in central nervous system tissue damage. One potential side-effect of these newer therapies is their interference with the control of central nervous system infections by the immune system.

SUMMARY

Any increase in potency of multiple sclerosis therapies could well interfere with protective immunosurveillance of the central nervous system. One possible outcome is an increased incidence of opportunistic infections. A heightened vigilance for central nervous system infections in the setting of immunosuppression is necessary to prevent serious side-effects in the future.

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

INTRODUCTION

Progressive multifocal leukoencephalopathy (PML) caused by JC virus (JCV) mostly occurs in different conditions of impaired cellular immunity like acquired immunodeficiency syndrome (AIDS) and rarely when humoral immunity is involved. PML remains unusual although there is a high prevalence of JCV among the population and immunosuppression is not rare because of chemotherapies.

METHODS

We present two groups of patients: first, we studied reports of three patients suffering from lymphoma type B who developed a PML, proved by cerebral biopsy. The second group included six HIV-infected patients who developed a PML. No biopsy was made but MRI and the physical examination suggested strong arguments for the diagnosis.

RESULTS

In the first group, PML was furthered by humoral immunosuppression (rate of immunoglobulin G under 4 g/l). Average survival was five months. In the second group, HIV-infected patients had a survival range from 2 to 58 months after the first PML symptoms and one of them is still alive.

CONCLUSION

Humoral immunosuppression in lymphoma can contribute to the development of PML. PML prognosis is often severe but prolonged survivals were described. So it is necessary to restore a sufficient immunity level. But immunity failure may be insufficient to lead to PML. In the case of lymphomas, the role of malignant lymphocytes in multiplication and mutation of JCV might be an interesting pathophysiological hypothesis.

Prognostic significance of JC virus DNA levels in cerebrospinal fluid of patients with HIV-associated progressive multifocal leukoencephalopathy

BACKGROUND

Progressive multifocal leukoencephalopathy (PML) remains a frequent and life-threatening complication of human immunodeficiency virus (HIV) infection in the era of highly active antiretroviral therapy (HAART). Although one-half of patients with this disease will survive, the outcome is unpredictable at diagnosis, and prognostic markers are needed.

METHODS

JC virus (JCV) DNA levels were measured in cerebrospinal fluid (CSF) samples obtained from 61 HIV-infected patients with PML, including 38 patients who were treated with HAART and 23 patients who did not receive HAART, with use of real-time polymerase chain reaction. The diagnostic reliability of the assay was evaluated by comparing CSF findings with histopathological findings in patients with PML or other HIV-related diseases of the central nervous system. The prognostic value was assessed by comparing JCV DNA levels with survival and other patient variables.

RESULTS

The assay had a diagnostic sensitivity of 76% and specificity of 100%. In the first CSF sample obtained after onset of PML symptoms, JCV DNA values ranged from undetectable to 7.71 log copies/mL (median, 3.64 log copies/mL). JCV DNA levels >3.64 log copies/mL correlated significantly with shorter survival and lower CD4+ cell counts in patients not receiving HAART. However, neither relationship was found in patients who were treated with HAART. The analysis of sequential CSF samples obtained from 24 patients demonstrated a marked decrease in JCV DNA levels over time in HAART-treated patients showing PML stabilization, but not in untreated or HAART-treated patients with progressively fatal disease.

CONCLUSIONS

Measurement of JCV DNA levels in CSF samples may be a useful virological marker for management of PML in patients receiving HAART.

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.

Evolution of purely infratentorial PML under HAART--negative outcome under rapid immune reconstitution

Progressive multifocal leukoencephalopathy (PML) caused by the polyomavirus JC is a well-recognised complication of AIDS. Purely infratentorial manifestations are rare. Introduction of highly active antiretroviral therapy (HAART) has been associated with a reduction in morbidity and an improvement in overall survival among HIV-infected individuals. Recently, several reports have described adverse events in patients with PML who begin HAART and show evidence for immune reconstitution. We describe the clinical course of two patients with PML with purely infratentorial manifestation, whose clinical course deteriorated despite the successful introduction of HAART. Possible underlying immunological mechanisms are discussed.

Illness of immune reconstitution: Recognition and management

Some individuals who initiate highly active antiretroviral therapy (HAART) develop new or worsening opportunistic infections or malignancies despite improvements in surrogate markers of HIV-1 infection. These events of paradoxical clinical worsening, also known as immune reconstitution syndromes (IRS), are increased in individuals with prior opportunistic infections or low CD4+ T-cell nadirs. They are thought to result from reconstitution of the immune system's ability to recognize pathogens or tumor antigens that were previously present, but clinically asymptomatic. There is no consensus regarding the diagnostic criteria or pathogenesis of IRS. Knowledge of their presentation and treatment is largely based on case reports. With the introduction of HAART into resource-limited settings, it is likely that significantly more and distinct forms of IRS will be observed. Prospective studies of the incidence and treatment of IRS in multiple settings are critical to better understand their pathogenesis and optimal management.

[Progressive multifocal leukoencephalopathy confirmed by PCR for JC virus in cerebrospinal fluid: case report]

A case of progressive multifocal leukoencephalopathy (PML) is presented, with literature review. PML diagnosis and its differential diagnosis are presented, with emphasis on neuroradiology, cerebrospinal fluid analysis and polymerase chain reaction studies. The prognosis of PML is usually poor, with a median survival of 1-6 months. There is yet no proven effective treatment for this condition; HAART has become the standard of care for these patients.

Inhibition of virus production in JC virus-infected cells by postinfection RNA interference

RNA interference has been applied for the prevention of virus infections in mammalian cells but has not succeeded in eliminating infections from already infected cells. We now show that the transfection of JC virus-infected SVG-A human glial cells with small interfering RNAs that target late viral proteins, including agnoprotein and VP1, results in a marked inhibition both of viral protein expression and of virus production. RNA interference directed against JC virus genes may thus provide a basis for the development of new strategies to control infections with this polyomavirus.

Progressive multifocal leukoencephalopathy after initiation of highly active antiretroviral therapy in a child with advanced human immunodeficiency virus infection: a case of immune reconstitution inflammatory syndrome

Five weeks after commencing highly active antiretroviral therapy, a 12-year-old boy with advanced human immunodeficiency virus infection presented with acute cerebellar dysfunction and hemiparesis. Progressive multifocal leukoencephalopathy was diagnosed by cerebrospinal fluid polymerase chain reaction for JC virus and magnetic resonance imaging of the brain. Rapid and sustained improvement followed a prolonged course of glucocorticosteroid therapy while continuing antiretrovirals.

Analysis of JC virus genotype distribution and transcriptional control region rearrangements in human immunodeficiency virus-positive progressive multifocal leukoencephalopathy patients with and without highly active antiretroviral treatment

After the introduction of highly active antiretroviral therapy (HAART), the incidence of many acquired immunodeficiency syndrome (AIDS)-related opportunistic infections, but not of progressive multifocal leukoencephalopathy (PML), has been dramatically decreased. However, it has been shown that about 50% of the HAART-treated PML patients had a significantly prolonged (>6 months) survival time, in comparison to the short (<6 months) survival time of the classical form of PML. In order to verify if a particular genotype or genomic rearrangements of JC virus (JCV) could affect the clinical course of PML, the authors performed nucleotide sequencing of 25 virion protein (VP1) and 18 transcriptional control region (TCR) DNA amplified in the cerebrospinal fluid (CSF) of HAART-untreated PML patients, of 17 HAART-treated PML patients, and in the urine of 23 healthy individuals. In nontreated PML patients, 52% and 44% of amplified JCV were respectively type 1 and type 2, whereas in HAART-treated PML patients, 59% of the amplified JCV were type 1, 23% type 2, and 18% type 4, without differences between long and short survivors. In both groups, the amplified TCR had unique and extensive rearrangements, whereas archetype TCR without rearrangements was detected in all the healthy subjects and in the CSF of two long-survivor PML patients. The data obtained indicate that the introduction of HAART has induced changes in JCV genotype distribution and probably reduced the rate of rearrangements of TCR region among PML patients.

The evolving face of human immunodeficiency virus-related progressive multifocal leukoencephalopathy: defining a consensus terminology

There is a need for consistent definition of human immunodeficiency virus (HIV)-associated cases of progressive multifocal leukoencephalopathy (PML), especially following the profound disease changes that have resulted from the use of highly active antiretroviral therapy (HAART). According to the criteria used for diagnosis, PML cases should be either referred to as "histology-confirmed," with evidence of JC virus (JCV) infection in brain, "laboratory-confirmed," with detection of JCV DNA in cerebrospinal fluid (CSF), or "possible," in the presence of typical clinical and radiological picture, but no demonstration of JCV infection. Disease outcome should be defined by the evidence or lack of evidence of disease activity, rather than using survival or other variables. Disease activity should be based on clinical (scored neurological examination), radiological (magnetic resonance imaging), and virological (JCV DNA levels in CSF) indicators, to be assessed regularly, e.g., every 3 months until evidence of disease arrest or death. Furthermore, parallel assessments of other HIV-associated manifestations, including CD4+ cell counts and viral load, are required. A standard patient classification would be helpful for clinical management of PML patients, for their inclusion in clinical studies, and also will increase our current knowledge of PML and its evolution in relation with HAART.