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1.  Inclusion of Rituximab in Treatment Protocols for Non-Hodgkin's Lymphomas and Risk for Progressive Multifocal Leukoencephalopathy 
The Oncologist  2010;15(11):1214-1219.
Reported is a retrospective, monocentric cohort study of the incidence of progressive multifocal leukoencephalopathy (PML) in non-Hodgkin's lymphoma patients treated with rituximab. Clinical surveillance of PML-related symptoms in these patients is recommended based on the number of PML cases seen in these individuals.
Learning Objectives
After completing this course, the reader will be able to: Evaluate the application of risk estimates of progressive multifocal leukoencephalopathy to your patients with non-Hodgkin's lymphoma previously treated with rituximab.Include progressive multifocal leukoencephalopathy in the differential diagnosis for neurological symptoms in your patients with non-Hodgkin's lymphoma previously treated with rituximab.
This article is available for continuing medical education credit at
Rituximab is an anti-CD20 monoclonal antibody that promotes better treatment outcomes in patients with non-Hodgkin's lymphoma (NHL). Case series of progressive multifocal leukoencephalopathy (PML) in patients receiving rituximab within polychemotherapy regimens have led to the introduction of a black box warning, but no risk estimation has ever been provided.
We performed a retrospective, monocentric cohort study on 976 NHL patients diagnosed in 1994–2008, including 517 patients who received at least one dose of rituximab.
Inclusion of rituximab into standard chemotherapy regimens for NHL caused a significantly higher incidence of PML cases (rate difference, 2.2 every 1,000 patient-years; 95% confidence interval, 0.1–4.3).
Based on this finding, clinical surveillance of PML-related symptoms is recommended in NHL patients exposed to rituximab.
PMCID: PMC3227905  PMID: 21041380
Rituximab; Progressive multifocal leukoencephalopathy; JCV; Monoclonal antibody; Non-Hodgkin's lymphoma
2.  Incidence and Risk Factors for Progressive Multifocal Leukoencephalopathy among Patients with Selected Rheumatic Diseases 
Arthritis care & research  2012;64(4):612-615.
We conducted a large, population-based study to describe the incidence and risk factors for progressive multifocal leukoencephalopathy (PML) among patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA), psoriasis (PsO), juvenile idiopathic arthritis (JIA), inflammatory bowel disease (IBD), and ankylosing spondylitis (AS) using national inpatient and outpatient administrative data from the entire Center for Medicare and Medicaid Services (CMS) from 2000–2009. Suspected PML cases were identified using hospital discharge diagnosis codes. Risk factors for PML were evaluated using outpatient data >= 6 months prior to PML diagnosis.
Among 2,030,578 patients with autoimmune diseases of interest, a total of 53 PML cases were identified (2.6/100,000 patients). Most PML cases had HIV and/or cancer. Nine PML cases had evidence for biologic use prior to PML hospitalization, of which 3 had neither HIV nor malignancy and were exposed to biologics within 12 (rituximab) or 6 months(all other biologics) prior to PML diagnosis. PML occurred at an estimated incidence of 0.2/100,000 patients with autoimmune diseases who did not have HIV or malignancy. PML occurs at a very low incidence among patients with rheumatic diseases but can occur even in the absence of HIV or malignancy.
PMCID: PMC3310319  PMID: 22162369
rheumatoid arthritis; infliximab; progressive multifocal leukoencephalopathy; JC virus
3.  PML-IRIS in patients with HIV infection 
Neurology  2009;72(17):1458-1464.
Progressive multifocal leukoencephalopathy (PML) is an opportunistic infection that develops in immunosuppressed patients with HIV infection. Paradoxically, some of these patients may develop PML during combined antiretroviral therapy in the setting of immune reconstitution. We describe the types of PML in relation to immune reconstitution inflammatory syndrome (IRIS) and the effects of steroid use in these patients.
We performed a retrospective review of the literature (1998 to 2007) and of all HIV-infected patients diagnosed with PML-IRIS at Johns Hopkins Hospital (2004 to 2007). We recorded information on clinical features, microbiologic and virological analysis, neuroimaging, pathology, treatment, and outcome.
Of 54 patients with PML-IRIS, 36 developed PML and IRIS simultaneously (PML-s-IRIS) and 18 had worsening of preexisting PML (PML-d-IRIS) after the initiation of combined antiretroviral therapy. PML-IRIS developed between 1 week and 26 months after initiation of antiretroviral therapy. PML-d-IRIS patients developed IRIS earlier, had higher lesion loads on MRI of the brain, had shorter durations of survival, and had higher mortality rate compared to PML-s-IRIS patients. Twelve patients received treatment with steroids, of which five died and seven showed good neurologic recovery. Patients who survived had received steroids early after IRIS diagnosis for longer durations and had contrast enhancement on IRIS neuroimaging.
Immune reconstitution following initiation of combined antiretroviral therapy may lead to activation of an inflammatory response to detectable or latent JC virus infection. Early and prolonged treatment with steroids may be useful in these patients but requires further investigation.
= fluid-attenuated inversion recovery;
= highly active antiretroviral therapy;
= immune reconstitution inflammatory syndrome;
= JC virus;
= Johns Hopkins Hospital;
= progressive multifocal leukoencephalopathy;
= worsening of preexisting PML;
= PML and IRIS simultaneously.
PMCID: PMC2677476  PMID: 19129505
4.  Evaluation of Patients Treated with Natalizumab for Progressive Multifocal Leukoencephalopathy 
The New England journal of medicine  2006;354(9):924-933.
Progressive multifocal leukoencephalopathy (PML) was reported to have developed in three patients treated with natalizumab. We conducted an evaluation to determine whether PML had developed in any other treated patients.
We invited patients who had participated in clinical trials in which they received recent or long-term treatment with natalizumab for multiple sclerosis, Crohn's disease, or rheumatoid arthritis to participate. The clinical history, physical examination, brain magnetic resonance imaging (MRI), and testing of cerebrospinal fluid for JC virus DNA were used by an expert panel to evaluate patients for PML. We estimated the risk of PML in patients who completed at least a clinical examination for PML or had an MRI.
Of 3417 patients who had recently received natalizumab while participating in clinical trials, 3116 (91 percent) who were exposed to a mean of 17.9 monthly doses underwent evaluation for PML. Of these, 44 patients were referred to the expert panel because of clinical findings of possible PML, abnormalities on MRI, or a high plasma viral load of JC virus. No patient had detectable JC virus DNA in the cerebrospinal fluid. PML was ruled out in 43 of the 44 patients, but it could not be ruled out in one patient who had multiple sclerosis and progression of neurologic disease because data on cerebrospinal fluid testing and follow-up MRI were not available. Only the three previously reported cases of PML were confirmed (1.0 per 1000 treated patients; 95 percent confidence interval, 0.2 to 2.8 per 1000).
A detailed review of possible cases of PML in patients exposed to natalizumab found no new cases and suggested a risk of PML of roughly 1 in 1000 patients treated with natalizumab for a mean of 17.9 months. The risk associated with longer treatment is not known.
PMCID: PMC1934511  PMID: 16510746
5.  Immune reconstitution inflammatory syndrome in natalizumab-associated PML 
Neurology  2011;77(11):1061-1067.
To study the outcome of patients with multiple sclerosis (MS) and with natalizumab-associated progressive multifocal leukoencephalopathy (PML) and immune reconstitution inflammatory syndrome (IRIS).
MedWatch reports from Biogen-Idec (manufacturer of natalizumab, Tysabri®) were reviewed which comprised all 42 cases of natalizumab-related PML cases since its reintroduction until March 2010.
All except 2 patients with natalizumab-related PML were managed by discontinuation of natalizumab and plasmapheresis/immunoadsorption (PLEX/IA). Seventeen patients had contrast enhancement of PML lesions on neuroimaging at the time of diagnosis before withdrawal/removal of natalizumab (early-PML-IRIS) and 23 patients developed contrast enhancement only after withdrawal/removal of natalizumab (late-PML-IRIS). All patients developed IRIS. IRIS was defined as worsening of neurologic deficits during the immune reconstitution following discontinuation of natalizumab, corroborated by inflammatory changes on neuroimaging. Following PLEX/IA, JC viral load in CSF increased by >10 fold in those with early-PML-IRIS but <2 fold in late-PML-IRIS. IRIS developed earlier and was more severe in early-PML-IRIS (p < 0.05). At the last follow-up, all patients had worse EDSS scores but this was higher in patients with early-PML-IRIS compared to those with late-PML-IRIS (p > 0.05). Mortality was comparable between the 2 groups, 29.4 ± 11% vs 21.7 ± 8.8%. Corticosteroid therapy during IRIS was associated with better Expanded Disability Status Scale outcome, p < 0.05.
Early immunologic rebound in natalizumab-associated PML has worse survival and neurologic outcome. PLEX/IA may accelerate IRIS and its impact on the final outcome is unclear. Corticosteroid therapy provides a modest benefit and needs to be systemically studied in a controlled manner in the management of natalizumab-associated PML-IRIS.
PMCID: PMC3174071  PMID: 21832229
6.  Disease course and outcome of 15 monocentrically treated natalizumab-associated progressive multifocal leukoencephalopathy patients 
Although the prognosis of natalizumab-associated progressive multifocal leukoencephalopathy (PML) seems to be better than HIV-associated PML, little is known about the long-term functional outcome in multiple sclerosis (MS) patients and the subsequent return of MS disease activity. We evaluated retrospectively 15 patients with natalizumab-associated PML treated at our centre.
Patients and methods
Fifteen MS-PML patients (nine women, six men) were referred to us from adjacent local centres. The patients had a median natalizumab exposure of 34 months at PML diagnosis. They received standardised treatment as described in previous work. Expanded Disability Status Scale (EDSS) and Karnofsky score in the year pre-PML, at PML-diagnosis (pre-immune reconstitution inflammatory syndrome (IRIS)) and post-PML were determined in 3–6 monthly intervals.
The median follow-up of these 15 patients was 21.5 months. None of the 15 patients died. Three patients had a Karnofsky score of 80 or higher, nine patients between 50–70 and three patients of 40 or lower at latest examination. Eight of the 15 patients developed seizures during acute PML phase. Fifty percent of those patients were not seizure-free one year post PML, despite continuation of antiepileptic treatment. The median EDSS in the year pre-PML was 2.5, 4.5 at PML diagnosis, 6.5 post-IRIS and 5.5 at latest examination. CSF became virus-free in eight of the 15 patients after a median time of 4.5 months. In nine patients, disease reappeared after a median time of seven months from PML diagnosis.
Although the clinical outcome of natalizumab-treated PML patients is much better than in patients with HIV-associated PML, this may be further improved by treatment at reference centres using standardised therapy regimens and transient intensive care if needed. Systematic studies of appropriate MS immunotherapies after PML are critically needed.
PMCID: PMC3786662  PMID: 23606731
Multiple Sclerosis; Neurovirology
7.  From Clinical Presentation to the Outcome: the Natural History of PML in a Portuguese Population of HIV Infected Patients 
Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system, associated with immunosuppression states. As there are only some non-published documents concerning PML in HIV infected patients in Portugal, we pretend to characterize natural history of PML infection in a population of HIV patients.
We retrospectively reviewed, from 1992 to 2009, PML cases in a population of 724 HIV infected patients followed in our institution. Clinical, biological, imagery features and outcomes were characterized.
Twenty-five (3.45%) patients were identified as having PML. The mean time between HIV and PML diagnosis was 20.4 months. PML was the presentation of HIV infection in 40% of the patients, and 92% had CD4 T cell count lower than 200/mm3. Paresis was the most common clinical presentation. No specific characteristics were found in cerebrospinal fluid and JCV DNA was positive in 3 of 7 patients. MRI revealed characteristic findings. Combined antiretroviral therapy was started or changed in 96% of the patients. Neurological condition got worse in 12 patients. From the 14 deaths, 5 were directly attributed to PML progression. Follow-up was lost in 8 patients.
PML was the presentation of HIV infection in more than 1/3 of patients, frequently associated with advanced immunocompromise. MRI sensitivity to PML is high, and JCV DNA determination in CSF was not revealed to be sensible. PML diagnosis should be taken into account in HIV patients presenting any neurological symptoms, and HIV infection should be suspected when radiological findings suggest PML lesions even in previously healthy individuals.
Progressive multifocal leukoencephalopathy; JC virus; Human immunodeficiency virus; Demyelinating disease
PMCID: PMC3194021  PMID: 22043267
8.  Treatment-related progressive multifocal leukoencephalopathy: current understanding and future steps 
Progressive multifocal leukoencephalopathy (PML) is a rare demyelinating disorder of the brain caused by a ubiquitous polyomavirus, JC virus. PML is almost always associated with some underlying immunosuppression and acquired immune deficiency syndrome has been the most common predisposing disorder. Recently, different pharmacological agents have been demonstrated to increase the risk of PML. Therapies that predispose people to PML can be classified into three categories: therapies that uniquely increase the risk for the disorder, such as the monoclonal antibodies natalizumab and efalizumab; therapies that appear to increase the risk in individuals already at risk of PML due to pre-existing conditions, such as rituximab and mycophenolate mofetil; and therapies with a mechanism of action that might suggest a potential for increased PML risk and/or with which rare cases of PML have been observed. Unlike the latter two classes, therapeutic agents uniquely increasing the risk of PML are associated with a much greater prevalence of the disorder and a latent interval from the time of drug initiation to the development of PML. PML development with pharmacological agents has provided new insight into the pathogenesis of this devastating disorder. This review focuses on the risks of PML with multiple pharmacological agents, the proposed pathogenesis with these agents, and potential risk mitigation strategies.
PMCID: PMC4110869  PMID: 25083238
alemtuzumab; efalizumab; JC virus; multiple sclerosis; mycophenolate mofetil; natalizumab; progressive multifocal leukoencephalopathy; rituximab
9.  Monoclonal antibodies and progressive multifocal leukoencephalopathy 
mAbs  2009;1(6):583-589.
Since their introduction, monoclonal antibodies have found an ever expanding role in the treatment of a wide number of disorders. However, the perturbation of the immune system that attends their use may also increase the risk for the development of disorders that arise in the setting of immunosuppressive conditions, such as, opportunistic infection and malignancy. In this paper, we address the association between some monoclonal antibodies and the development of a rare demyelinating disease of the brain, progressive multifocal leukoencephalopathy (PML). PML results from infection with a ubiquitous polyoma virus, JC virus, and typically occurs in the setting of impaired immunity, most commonly, AIDS. It was first recognized as a potential complication of monoclonal antibody therapy in patients with multiple sclerosis and Crohn disease being treated with natalizumab, an α4β1 and α4β7 integrin inhibitor. Subsequently, efalizumab, a monoclonal antibody used in the treatment of psoriasis, was also demonstrated to be associated with PML. An increased risk has been suggested for rituximab, although most of the patients developing PML with that monoclonal antibody have been treated for B-cell disorders that predispose to the development of PML. Based on our current understanding of the biology of JC virus and the pathogenesis of PML, we propose an explanation for the increased risk for PML that is observed with natalizumab and certain other monoclonal antibodies.
PMCID: PMC2791316  PMID: 20073129
progressive multifocal leukoencephalopathy; JC virus; natalizumab; efalizumab; rituximab; alemtuzumab; multiple sclerosis; crohn disease
10.  Changes in JC Virus-Specific T Cell Responses during Natalizumab Treatment and in Natalizumab-Associated Progressive Multifocal Leukoencephalopathy 
PLoS Pathogens  2012;8(11):e1003014.
Progressive multifocal leukoencephalopathy (PML) induced by JC virus (JCV) is a risk for natalizumab-treated multiple sclerosis (MS) patients. Here we characterize the JCV-specific T cell responses in healthy donors and natalizumab-treated MS patients to reveal functional differences that may account for the development of natalizumab-associated PML. CD4 and CD8 T cell responses specific for all JCV proteins were readily identified in MS patients and healthy volunteers. The magnitude and quality of responses to JCV and cytomegalovirus (CMV) did not change from baseline through several months of natalizumab therapy. However, the frequency of T cells producing IL-10 upon mitogenic stimulation transiently increased after the first dose. In addition, MS patients with natalizumab-associated PML were distinguished from all other subjects in that they either had no detectable JCV-specific T cell response or had JCV-specific CD4 T cell responses uniquely dominated by IL-10 production. Additionally, IL-10 levels were higher in the CSF of individuals with recently diagnosed PML. Thus, natalizumab-treated MS patients with PML have absent or aberrant JCV-specific T cell responses compared with non-PML patients, and changes in T cell-mediated control of JCV replication may be a risk factor for developing PML. Our data suggest further approaches to improved monitoring, treatment and prevention of PML in natalizumab-treated patients.
Author Summary
Progressive multifocal leukoencephalopathy (PML) is a complication of treatment with natalizumab in patients with multiple sclerosis (MS) and Crohn's disease. PML results from a failure of the immune system to control replication of JC virus (JCV) in the brain. We studied the T cell responses of 8 patients with MS who were starting treatment with natalizumab, 10 healthy volunteers, and 4 patients with natalizumab-associated PML. The magnitude and quality of JCV-specific immune responses remained unchanged after starting natalizumab. However, applying the same methods and antigens, we found that immune responses in the individuals who developed PML differed from those in the MS patients and healthy volunteers. In the four patients with PML from whom the laboratory had identified JCV DNA in the cerebrospinal fluid (CSF), two had no measurable T cell response to JCV and two had T cells that produced IL-10, an anti-inflammatory mediator. Furthermore, we studied the CSF of 10 patients with natalizumab-associated PML and 10 patients on natalizumab who had similar symptoms but did not have PML. We found that IL-10 was detectable in the CSF of half of the individuals with PML but none of the control group. These findings shed light on the mechanisms that lead to PML in a subset of patients treated with natalizumab and have implications for therapeutic and preventative measures.
PMCID: PMC3493478  PMID: 23144619
11.  Changes to anti-JCV antibody levels in a Swedish national MS cohort 
The anti-JC virus (JCV) antibody status has been introduced to stratify patients with multiple sclerosis (MS) for higher or lower risk of progressive multifocal leukoencephalopathy (PML).
To assess the potential utility of anti-JCV antibody levels for earlier diagnosis or prediction of PML.
An analytically validated antibody assay was used to determine serological status, normalised optical density values, and dilution titres for anti-JCV antibodies. The method was applied to stored sera of 1157 patients with MS including five cases of PML, all enrolled in the Swedish pharmacovigilance study for natalizumab (NAT). Anticytomegalovirus (CMV) and antivaricella-zoster (VZV) antibody levels served as controls.
Prior to treatment with NAT, anti-JCV antibody levels were stable in the anti-JCV positive patients. During therapy, a slight decrease in anti-JCV and anti-VZV antibody levels, but not anti-CMV antibody levels, was observed. All five patients who developed PML showed a mild to moderate increase in anti-JCV antibody levels at time of PML diagnosis; pre-PML samples suggested that this increase might start already prior to diagnosis of PML.
Treatment initiation with NAT may lead to a slight decrease in anti-JCV and anti-VZV antibody levels, suggestive of a mild suppressive effect of NAT on antibody levels. Our findings in five cases of PML demonstrate that the onset of PML can be accompanied by increasing anti-JCV antibodies in serum. Monitoring of anti-JCV antibody levels could potentially be used as a tool for prediction or earlier diagnosis of PML during NAT treatment for MS. Further studies are warranted.
PMCID: PMC3812878  PMID: 23463870
12.  Reduced concentrations of HIV-RNA and TNF-α coexist in CSF of AIDS patients with progressive multifocal leukoencephalopathy 
OBJECTIVES—To confirm reduced human immunodeficiency virus type-1 (HIV-1) burden in the CSF of patients with progressive multifocal leukoencephalopathy (PML) and to verify whether this viral load coincides with the absence of inflammatory changes in the CSF.
METHODS—Paired CSF and plasma samples from 17 patients with PML, 26 with non-PML cerebral opportunistic infections, nine with HIV-1 leukoencephalopathy (HIVE), and 12 neurologically asymptomatic AIDS patients were subjected to HIV-RNA titration. Tumour necrosis factor (TNF)-α was also measured and the CSF albumin: serum albumin ratio (QAlb) was calculated.
RESULTS—The CSF HIV-1 burden of patients with PML did not differ from that of neurologically asymptomatic patients (p=0.21), but was significantly lower than CSF burden of the remaining patients (non-PML opportunistic infections, p<0.001; HIVE, p<0.001). QAlb was normal for all neurologically asymptomatic patients, for 86.6% patients with PML, and 62.5% patients with HIVE (p=0.09). QAlb was altered in 91.6% patients with non-PML opportunistic infections. TNF-α in CSF was higher in patients with non-PML opportunistic infections (p<0.001) and those with HIVE (p<0.001) than in patients with PML who consistently had TNF-α concentrations<10 pg/ml.
CONCLUSIONS—These results, while indicating a reduced HIV replication in CSF of patients with PML which might serve as a disease marker, emphasise the increased CSF HIV-RNA concentration in patients with HIVE and patients with non-PML opportunistic infections. Low concentrations of HIV-RNA in CSF coincide with reduced TNF-α concentrations, possibly due to particular features of PML compared with other opportunistic infections as it develops without detectable inflammatory changes in the CSF.

PMCID: PMC1736519  PMID: 10449561
13.  Detection of human herpesviruses in the cerebrospinal fluid from patients diagnosed with or suspected of having progressive multifocal leukoencephalopathy 
BMC Neurology  2013;13:200.
Progressive multifocal leukoencephalopathy (PML), a fatal demyelinating disease caused by JC virus (JCV), occurs mainly in immunocompromised patients. While JCV DNA is detected in the cerebrospinal fluid (CSF) from a certain proportion of patients suspected of having PML, JCV-negative patients may also develop brain lesions due to other infectious agents. This study assessed the prevalence of six herpesviruses in the CSF from patients diagnosed with or suspected of PML.
Two hundred and ninety-nine CSF specimens and clinical data were collected from 255 patients, including 31 confirmed PML cases. Quantitative PCR assays were carried out to detect the genomic DNA of JCV, herpes simplex virus (HSV), varicella-zoster virus (VZV), cytomegalovirus (CMV), Epstein-Barr virus (EBV), and human herpesvirus 6 (HHV-6).
Herpesvirus DNAs were detected in the CSF specimens from 29 of 255 patients (11.4%). HSV-1 and CMV were detected in JCV-negative patients, whereas VZV and EBV were detected in both CSF JCV-positive and -negative individuals. The herpesvirus-positive patients had underlying disorders that caused immunosuppression, such as HIV infection, congenital immunodeficiencies, and hematologic malignancies, and presented with neurologic symptoms and MRI lesions, mainly in the cerebral white matter. The median values of CSF cell counts and protein levels in the herpesvirus-positive patients were slightly higher than those in the PML patients.
The results demonstrate that herpesviruses are occasionally detected in the CSF from PML patients and immunocompromised individuals suspected of having PML. Thus, this study provides a significant basis for the diagnosis and treatment of neurological disorders in immunocompromised patients.
PMCID: PMC3878787  PMID: 24330281
Cerebrospinal fluid; Human herpesvirus; JC virus; Progressive multifocal leukoencephalopathy; Quantitative PCR testing
14.  Functional Energetics of CD4+-Cellular Immunity in Monoclonal Antibody-Associated Progressive Multifocal Leukoencephalopathy in Autoimmune Disorders 
PLoS ONE  2011;6(4):e18506.
Progressive multifocal leukoencephalopathy (PML) is an opportunistic central nervous system- (CNS-) infection that typically occurs in a subset of immunocompromised individuals. An increasing incidence of PML has recently been reported in patients receiving monoclonal antibody (mAb) therapy for the treatment of autoimmune diseases, particularly those treated with natalizumab, efalizumab and rituximab. Intracellular CD4+-ATP-concentration (iATP) functionally reflects cellular immunocompetence and inversely correlates with risk of infections during immunosuppressive therapy. We investigated whether iATP may assist in individualized risk stratification for opportunistic infections during mAb-treatment.
Methodology/Principal Findings
iATP in PHA-stimulated, immunoselected CD4+-cells was analyzed using an FDA-approved assay. iATP of mAb-associated PML (natalizumab (n = 8), rituximab (n = 2), efalizumab (n = 1)), or other cases of opportunistic CNS-infections (HIV-associated PML (n = 2), spontaneous PML, PML in a psoriasis patient under fumaric acids, natalizumab-associated herpes simplex encephalitis (n = 1 each)) was reduced by 59% (194.5±29 ng/ml, mean±SEM) in comparison to healthy controls (HC, 479.9±19.8 ng/ml, p<0.0001). iATP in 14 of these 16 patients was at or below 3rd percentile of healthy controls, similar to HIV-patients (n = 18). In contrast, CD4+-cell numbers were reduced in only 7 of 15 patients, for whom cell counts were available. iATP correlated with mitochondrial transmembrane potential (ΔΨm) (iATP/ΔΨm−correlation:tau = 0.49, p = 0.03). Whereas mean iATP of cross-sectionally analysed natalizumab-treated patients was unaltered (448.7±12 ng/ml, n = 150), iATP was moderately decreased (316.2±26.1 ng/ml, p = 0.04) in patients (n = 7) who had been treated already during the pivotal phase III trials and had received natalizumab for more than 6 years. 2/92 (2%) patients with less than 24 months natalizumab treatment revealed very low iATP at or below the 3rd percentile of HC, whereas 10/58 (17%) of the patients treated for more than 24 months had such low iATP-concentrations.
Our results suggest that bioenergetic parameters such as iATP may assist in risk stratification under mAb-immunotherapy of autoimmune disorders.
PMCID: PMC3080364  PMID: 21533133
15.  Pre-Existing T- and B-Cell Defects in One Progressive Multifocal Leukoencephalopathy Patient 
PLoS ONE  2012;7(4):e34493.
Progressive multifocal leukoencephalopathy (PML) usually occurs in patients with severe immunosuppression, hematological malignancies, chronic inflammatory conditions or receiving organ transplant. Recently, PML has also been observed in patients treated with monoclonal antibodies. By taking advantage of the availability of samples from a multiple sclerosis (MS) patient treated with natalizumab, the antibody anti-α4 integrin, who developed PML and was monitored starting before therapy initiation, we investigated the fate of T and B lymphocytes in the onset of PML. Real-time PCR was used to measure new T- and B-cell production by means of T-cell receptor excision circle (TREC) and K-deleting recombination excision circle (KREC) analysis and to quantify transcripts for CD34, terminal-deoxynucleotidyltransferase, and V pre-B lymphocyte gene 1. T- and B-cell subsets and T-cell heterogeneity were measured by flow cytometry and spectratyping. The data were compared to those of untreated and natalizumab-treated MS patients and healthy donors. Before therapy, a patient who developed PML had a low TREC and KREC number; TRECs remained low, while KRECs and pre-B lymphocyte gene 1 transcripts peaked at 6 months of therapy and then decreased at PML diagnosis. Flow cytometry confirmed the deficient number of newly produced T lymphocytes, counterbalanced by an increase in TEMRA cells. The percentage of naive B cells increased by approximately 70% after 6 months of therapy, but B lymphocyte number remained low for the entire treatment period. T-cell heterogeneity and immunoglobulins were reduced.
Although performed in a single patient, all results showed that an immune deficit, together with an increase in newly produced B cells a few months after therapy initiation, may predispose the patient to PML. These findings indicate the TREC/KREC assay is a potential tool to identify patients at risk of developing PML and may provide insights into the immunological involvement of monoclonal antibody-associated therapies.
PMCID: PMC3319584  PMID: 22496817
16.  Characteristics of progressive multifocal leukoencephalopathy clarified through internet-assisted laboratory surveillance in Japan 
BMC Neurology  2012;12:121.
Progressive multifocal leukoencephalopathy (PML), a rare but fatal demyelinating disease caused by JC virus (JCV), occurs mainly in immunocompromised patients. As PML develops in individuals with various underlying disorders sporadically and infrequently, a nationwide survey of PML is difficult. This study was conducted to elucidate the characteristics of PML in Japan through an internet-assisted laboratory surveillance program.
A diagnostic support system for PML was established using a real-time PCR assay of JCV DNA in cerebrospinal fluid (CSF), and requests for testing were received from clinicians via specialized websites. Medical histories of patients were collected through standardized questionnaires, and a database of CSF JCV loads and clinical information was created and analyzed.
For 4 years from April 2007 to March 2011, CSF specimens from 419 patients were tested. Forty-eight individuals were found positive for JCV DNA in their CSF and were diagnosed with PML. PML primarily occurred not only in HIV-positive patients (33.3%) but also in patients with hematologic disorders after receiving stem cell transplantation, chemotherapy, and/or immunosuppressive treatment (39.6%). The frequencies of PML cases among the subjects in these two categories were 20.3% and 23.5%, respectively. Although no significant features were observed with respect to CSF JCV loads in PML patients with an HIV infection or hematologic disorder, males were predominant in both groups (100% and 89.5%, respectively). The proportion of PML cases with autoimmune disorders (6.3%) or solid-organ transplants (2.1%) was smaller than those with HIV infection or hematologic disorders, probably due to the limited availability of therapeutic monoclonal antibodies and transplantation from brain dead donors.
The results suggest that the internet-assisted laboratory surveillance program might be a useful strategy for collecting precise real-time information on PML on a national level. The current database provides important background information for the diagnosis and treatment of patients with risk factors for PML.
PMCID: PMC3495800  PMID: 23066763
Cerebrospinal fluid; Surveillance; Japan; JC virus; Progressive multifocal leukoencephalopathy
17.  Monoclonal antibody therapy in multiple sclerosis 
mAbs  2010;2(6):670-681.
Therapeutic approaches to multiple sclerosis (MS) are based on altering the functions of the immune system, either by using broad immunosuppressive drugs used for transplantation rejection and rheumatology, or by modulating them more discreetly with beta interferon and synthetic amino-acid copolymers. These strategies are only partially successful, have important safety and tolerability limitations, and have shown to be mostly effective in earlier stages of the disease, in which acute relapses dominate the clinical picture. For progressive phenotypes of MS there are currently no effective therapeutic options. As very specific and potent immunosuppressive agents, monoclonal antibodies (mAbs) may offer considerable advantages over other therapies for MS. During the last decade, anti-a4 integrin natalizumab became the first approved mAb for treatment of relapsing MS, after convincingly demonstrating clinically significant effects on two large Phase 3 trials. Moreover, the concept of disease remission was introduced for the first time to describe patients who show no signs of clinical or imaging markers of disease activity during therapy with natalizumab. Of the mAbs under development for MS, alemtuzumab and rituximab have also shown promising evidence of effectiveness and potentially expanded the therapeutic horizon to reversal of disease progression in early relapsing patients and progressive patients who previously had not been studied. However, the appearance of progressive multifocal leukoencephalopathy (PML) in natalizumab-treated MS patients, as well as in patients with lymphoma, lupus and rheumatoid arthritis, treated with rituximab and autoimmune-type complications in alemtuzumab-treated MS patients underlines the fact that extended efficacy comes with significant clinical risks. The challenge is then how best to utilize therapies that have evidently superior efficacy in a chronic disease of young adults to obtain the best benefit-risk ratio and how to monitor and prevent emergent safety concerns.
PMCID: PMC3011221  PMID: 21124072
monoclonal; antibody; multiple sclerosis; therapy; natalizumab; rituximab; alemtuzumab
18.  HIV-associated progressive multifocal leukoencephalopathy: longitudinal study of JC virus non-coding control region rearrangements and host immunity 
Journal of Neurovirology  2013;19(3):274-279.
John Cunningham virus (JCV), the etiological agent of progressive multifocal leukoencephalopathy (PML), contains a hyper-variable non-coding control region usually detected in urine of healthy individuals as archetype form and in the brain and cerebrospinal fluid (CSF) of PML patients as rearranged form. We report a case of HIV-related PML with clinical, immunological and virological data longitudinally collected. On admission (t0), after 8-week treatment with a rescue highly active antiretroviral therapy (HAART), the patient showed a CSF-JCV load of 16,732 gEq/ml, undetectable HIV-RNA and an increase of CD4+ cell count. Brain magnetic resonance imaging (MRI) showed PML-compatible lesions without contrast enhancement. We considered PML-immune reconstitution inflammatory syndrome as plausible because of the sudden onset of neurological symptoms after the effective HAART. An experimental JCV treatment with mefloquine and mirtazapine was added to steroid boli. Two weeks later (t1), motor function worsened and MRI showed expanded lesions with cytotoxic oedema. CSF JCV-DNA increased (26,263 gEq/ml) and JCV viremia was detected. After 4 weeks (t2), JCV was detected only in CSF (37,719 gEq/ml), and 8 weeks after admission (t3), JC viral load decreased in CSF and JCV viremia reappeared. The patient showed high level of immune activation both in peripheral blood and CSF. He died 4 weeks later. Considering disease progression, combined therapy failure and immune hyper-activation, we finally classified the case as classical PML. The archetype variant found in CSF at t0/t3 and a rearranged sequence detected at t1/t2 suggest that PML can develop from an archetype virus and that the appearance of rearranged genotypes contribute to faster disease progression.
PMCID: PMC3695672  PMID: 23715894
PML; JCV-NCCR; HIV; IRIS; Immune activation
19.  Progressive Multifocal Leukoencephalopathy Complicating HIV-1 Infection 
The Lancet infectious diseases  2009;9(10):625-636.
Progressive multifocal leukoencephalopathy (PML) caused by the polyomavirus, JC virus (JCV), is one of the most dreaded complications of HIV-1 infection. Unlike other opportunistic infections, PML may present while blood CD4+ T cells remain above AIDS-defining levels and while patients receive combined antiretroviral therapy (cART), either shortly after starting or, more rarely, during chronic successful treatment. PML can be suspected by typical presentation with focal neurological deficits and corresponding demyelinating lesions at magnetic resonance imaging (MRI), while definitive diagnosis requires identification of JCV in cerebrospinal fluid (CSF) or brain tissue. While there is no specific treatment, reversal of immunosuppression by cART leads to clinical and MRI stabilization in 50-60% of PML patients and JCV clearance from CSF. A proportion of cART-treated patients develop inflammatory lesions, which may either accompany a favorable outcome or associate with clinical worsening. The reasons for variability in PML natural history and treatment responses are largely undefined, and more specific and rational approaches to management are sorely needed.
PMCID: PMC2919371  PMID: 19778765
HIV-1; progressive multifocal leukoencephalopathy; PML; JC virus; JCV; brain; central nervous system; CNS; antiretroviral treatment; ART; cART; HAART
20.  Unmasking of PML by HAART: Unusual Clinical Features and the Role of IRIS 
Journal of neuroimmunology  2009;219(1-2):100-104.
For patients with HIV/AIDS, highly active antiretroviral therapy (HAART) is currently the only effective therapy for progressive multifocal leukoencephalopathy (PML), a viral-induced demyelinating disease caused by polyomavirus JC. Immune reconstitution inflammatory syndrome (IRIS) following initiation of HAART can cause paradoxical clinical deterioration in patients with established PML. Because the onset of PML follows soon after initiation of HAART in some cases (unmasking), we investigated the role IRIS plays in unmasked PML. We reviewed records of 20 PML cases seen from 1997–2006 at the UCSD HIV primary care clinic. Eight cases presented with PML symptoms within 6 months of initiating HAART (referred to hereafter as unmasked PML), six patients were diagnosed with PML before initiating HAART, and six were diagnosed more than 6 months after starting HAART. Patients with unmasked PML constituted forty percent of our series, had relatively long survival, and commonly (50%) had lesions exclusively in the posterior fossa, a localization not previously reported with such a high prevalence. Only 3 of the 8 patients with unmasked PML had IRIS reactions as evidenced by contrast enhancement around lesions on MRI, suggesting that IRIS is not necessary for the pathogenesis of this syndrome.
PMCID: PMC2825275  PMID: 19962769
HIV; PML; HAART; IRIS; immune reconstitution
21.  Beyond progressive multifocal leukoencephalopathy: expanded pathogenesis of JC virus infection in the central nervous system 
Lancet neurology  2010;9(4):425-437.
Progressive multifocal leukoencephalopathy (PML) is a rare but often fatal brain disease caused by the reactivation of the polyomavirus JC (JCV). Characteristics of PML have expanded considerably since the onset of the HIV epidemic with the advent of combination antiretroviral therapy (cART), and the development of immune reconstitution inflammatory syndrome in PML lesions (PML-IRIS). Recently, the monoclonal antibodies natalizumab, efalizumab and rituximab used for treatment of multiple sclerosis, psoriasis, hematologic malignancies, Crohn’s and rheumatic diseases, have been associated with PML. In addition, JCV can also infect neurons, leading to novel neurological disorders JC virus granule cell neuronopathy (JCV GCN) and JC virus encephalopathy (JCVE), and it may also cause meningitis. The newly observed features of PML, the increasingly diverse populations at risk, and the recently discovered grey matter involvement by JCV invite us to reappraise the expanded pathogenesis of this virus in the central nervous system.
PMCID: PMC2880524  PMID: 20298966
22.  Pathology of immune reconstitution inflammatory syndrome in multiple sclerosis with natalizumab-associated progressive multifocal leukoencephalopathy 
Acta Neuropathologica  2011;123(2):235-245.
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.
PMCID: PMC3259335  PMID: 22057786
IRIS; Natalizumab; PML; MS; Pathology; MRI
23.  Investigation of pre-diagnostic virological markers for progressive multifocal leukoencephalopathy in human immunodeficiency virus-infected patients 
Journal of medical virology  2009;81(7):1140-1150.
Progressive multifocal leukoencephalopathy (PML) is a severe neurological disorder due to JC virus (JCV) infection. Pre-diagnostic biological markers and risk factors for PML are not well understood. We conducted a case-control study nested within the Multicenter AIDS Cohort Study to examine the association between JCV viruria and viremia and serum antibody to JCV capsids, in relation to subsequent PML diagnoses, 5 months to 12 years later. Other demographic and immunologic factors were examined also. The study population included 28 incident cases of PML, 26 matched HIV-positive controls, and 50 HIV-negative controls. Prevalence of JCV viruria was 37% in cases, 42% in HIV-positive controls, and 28% in HIV-negative controls (p = 0.43). Among persons with JCV viruria, persistent viruria was more common in cases (89%) than in HIV- positive controls (33%) (p = 0.02). Presence of JCV viruria was not related to the time to PML diagnosis (OR: 1.03, 95% CI: 0.8 – 1.4); however, the urinary concentration of JCV DNA increased with proximity to the date of PML diagnosis in cases. JCV seropositivity did not differ between cases or controls (p = 0.42). Four cases tested JCV seronegative, including one case only 5 months prior to diagnosis with PML. JCV DNA was detected in the serum of one HIV-positive control. Smoking was the only demographic variable analyzed associated with an increased risk for PML (MOR: 9.0, 95% CI: 1.2–394.5). The results suggest that persistent JCV viruria and increasing urinary concentration of JCV DNA may be predictive of PML for some patients.
PMCID: PMC2969173  PMID: 19475619
24.  Progressive Multifocal Leukoencephalopathy in a HIV-Negative Patient with Small Lymphocytic Leukemia following Treatment with Rituximab 
Case Reports in Oncology  2011;4(1):136-142.
We describe a case of progressive multifocal leukoencephalopathy (PML) caused by infection with the human polyomavirus JC virus in a patient with B-cell small lymphocytic leukemia who was treated with rituximab. The first symptoms of PML appeared immediately following the last of five cycles of rituximab, cyclophosphamide and pentostatin. Magnetic resonance imaging revealed changes consistent with PML, although JC virus DNA was not detected by polymerase chain reaction assay of the cerebrospinal fluid. A stereotactic biopsy of the brain showed histological changes consistent with PML, while electron microscopy revealed JC virus particles attached to the nuclei of astrocytes. The patient was treated supportively but died 53 days after the initial onset of symptoms.
PMCID: PMC3114618  PMID: 21691572
Progressive multifocal leukoencephalopathy; Rituximab; Small lymphocytic leukemia; JC virus
25.  Progressive multifocal leukoencephalopathy during treatment with rituximab and CHOP chemotherapy in a patient with a diffuse large B-cell lymphoma 
BMJ Case Reports  2013;2013:bcr2012008142.
A 74-year-old woman with a diffuse large B-cell lymphoma was treated with rituximab and CHOP chemotherapy. After three cycles of chemotherapy she developed progressive symptoms of motor imbalance, fatigue, weight loss and impaired cognitive function, which was interpreted as toxicity of the CHOP chemotherapy. The sixth cycle CHOP chemotherapy was withheld and three additional cycles of rituximab were given. Two weeks later, neurological symptoms appeared, including abducens nerve palsy of her left eye, ataxia and hemiparesis of her right body. MRI of the brain revealed two hyperintense lesions on T2-weighted and fluid-attenuated inversion recovery images without oedema or gadolinium enhancement. A PCR on John Cunningham (JC) virus DNA in cerebrospinal fluid was negative, but subsequent brain biopsy diagnosed progressive multifocal leukoencephalopathy (PML). She rapidly deteriorated and died. Awareness of PML during immunosuppressive therapy can be lifesaving, since only immune reconstitution can prevent mortality in these patients.
PMCID: PMC3604000  PMID: 23355583

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