Opportunistic infections and other risks with newer multiple sclerosis therapies

Long-term prognosis and overall mortality in patients with progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is a rare but fatal opportunistic infection and mainly occurs in patients with immunosuppressive conditions. Despite the increasing number of patients receiving immunosuppressive treatments, studies on PML are still lacking due to its low prevalence and incidence. We retrospectively reviewed patients diagnosed with PML in two tertiary hospitals in South Korea from 1999 to 2021. Total of 47 PML patients were included. Of 27 patients (57.4%) were diagnosed with human immunodeficiency virus (HIV). Median last follow-up modified Rankin Scale (mRS) score was higher in the non-HIV PML group than that in the HIV group (5 vs. 4, p = 0.020). Median survival duration was lower in the non-HIV group (184 vs. 1,564 days). The 1-year and overall mortality rates of PML patients were significantly higher in the non-HIV group than that in HIV group (60.0% vs. 25.9%, p = 0.019; 80.0% vs. 40.7%, p = 0.007). Initial mRS score (HR 1.685, p = 0.038) and highly active antiretroviral therapy (HAART) in HIV patients (HR 0.374, p = 0.013) had a significant effect on overall mortality. Our findings suggest that early detection of PML with low mRS score and early initiation of HAART in patients with HIV may improve prognosis.

Exploiting Rational Assembly to Map Distinct Roles of Regulatory Cues during Autoimmune Therapy

Autoimmune diseases like multiple sclerosis (MS), type 1 diabetes, and lupus occur when the immune system attacks host tissue. Immunotherapies that promote selective tolerance without suppressing normal immune function are of tremendous interest. Here, nanotechnology was used for rational assembly of peptides and modulatory immune cues into immune complexes. Complexes containing self-peptides and regulatory nucleic acids reverse established paralysis in a preclinical MS model. Importantly, mice responding to immunotherapy maintain healthy, antigen-specific B and T cell responses during a foreign antigen challenge. A therapeutic library isolating specific components reveals that regulatory nucleic acids suppress inflammatory genes in innate immune cells, while disease-matched peptide sequences control specificity of tolerance. Distinct gene expression profiles in cells and animals are associated with the immune signals administered in particulate and soluble forms, highlighting the impact of biophysical presentation of signals. This work provides insight into the rational manipulation of immune signaling to drive tolerance.

Natalizumab-associated progressive multifocal leukoencephalopathy (PML) in multiple sclerosis (MS): "a case report from Ireland with review of literature, clinical pitfalls and future direction"

Background

Progressive multifocal leukoencephalopathy (PML) is one of the most serious treatment-related complications that is encountered in patients with multiple sclerosis (MS). PML is a serious complication of MS treatment which is most commonly related to natalizumab.

Case presentation

We report clinical course of progressive multifocal leukoencephalopathy (PML) in a 40-year-old man who was on treatment for highly active relapsing-remitting multiple sclerosis with natalizumab (Nz). He was treated with steroids, cidofovir, and mirtazapine and went on to develop long-term disability. The case describes the evolution of PML from diagnosis up till 5 months with changes on sequential brain scans and clinical symptoms in our patient.

Conclusion

Patients who are on natalizumab should be aware and consented for the risk of PML. They should be periodically re-assessed for their relative PML risk. There is a growing body of evidence that suggests switching patients from natalizumab who have a higher risk of PML to other safer treatment options.

Cerebrospinal fluid analysis in 108 patients with progressive multifocal leukoencephalopathy

BACKGROUND

Progressive multifocal leukoencephalopathy (PML) is caused by an opportunistic infection with JC polyoma virus (JCPyV) and mainly affects immunocompromised patients. It leads to pronounced demyelination of the central nervous system (CNS) resulting in severe disability or even death. Detection of JCPyV DNA in the cerebrospinal fluid (CSF) is usually accepted as proof for the diagnosis of PML. Routine CSF parameters, like CSF cell count, protein concentration, Qalbumin, or intrathecal immunoglobulin synthesis are mostly considered normal. However, this has not been investigated systematically.

METHODS

We analyzed routine CSF parameters in a cohort of 108 PML patients that were treated at four different neurological centers in Germany. The patients exhibited different underlying conditions with natalizumab-treated multiple sclerosis (n = 54) and human immunodeficiency virus (HIV)-infection (n = 25) being the most frequent. The data were collected at the respective centers in accordance with local requirements and then jointly analyzed. The total PML cohort was compared with a control group of patients with normal pressure hydrocephalus (NPH) and idiopathic intracranial hypertension (IIH). Multiple sclerosis and HIV patients were additionally compared with their own non-PML control groups.

RESULTS

The PML group showed an elevated cell count (p < 0.001) compared to the control group, however, this effect was mainly driven by HIV-PML patients. This subgroup also demonstrated a significantly higher proportion of patients with a disturbed blood-CSF-barrier function.

CONCLUSIONS

This comprehensive, retrospective study on CSF diagnostic analysis in PML patients provides insight into the CSF of those patients. It demonstrates that CSF composition in PML patients may be specific for the underlying condition that predisposes for the development of PML and thus data have to be interpreted in this context.

Progressive multifocal leukoencephalopathy: A 25-year retrospective cohort study

OBJECTIVE

To characterize the risk factors, clinical course, and treatment of patients with progressive multifocal leukoencephalopathy (PML) diagnosed and followed over a 25-year epoch at 2 academic hospitals.

METHODS

Patients with a definite diagnosis of PML were identified by positive CSF PCR for JC virus or histopathology between January 1, 1994, and January 1, 2019. Demographic and PML-specific variables were recorded on symptomatic presentation and at follow-up, including risk factors, clinical outcome, neuroimaging findings, and modified Rankin Scale (mRS) score at last follow-up.

RESULTS

There were 91 patients with confirmed PML. HIV infection was the most common risk factor, identified in 49% (n = 45). Other frequent risk factors included lymphoma, leukemia, or myelodysplasia, identified in 31% of patients (n = 28); exposure to chemotherapeutic medications (30%, n = 27); and exposure to monoclonal antibody therapies (19%, n = 17). Thirty percent of the cohort was alive at the time of censoring, with a median mRS of 2 points, indicating slight disability at last follow-up. Median survival following PML diagnosis in HIV-infected patients was longer than in HIV-uninfected patients (1,992 vs 101 days, p = 0.024). Forty patients survived more than 1 year after PML symptom onset, of whom 24 were HIV infected (60%). Thirteen patients survived more than 10 years after PML symptom onset, all HIV infected, of the 59 patients diagnosed before June 1, 2009, and eligible for 10-year survivor status (22%).

CONCLUSIONS

We add to the limited literature on PML by reporting its epidemiology in a large observational cohort. These parameters may be useful for future clinical trials that measure survival and clinical outcomes.

Lymphopenia, Infectious Complications, and Outcome in Spontaneous Intracerebral Hemorrhage

BACKGROUND

Lymphopenia is increasingly recognized as a consequence of acute illness and may predispose to infections. We investigated whether admission lymphopenia (AL) is associated with increased risk of infectious complications and poor outcome in patients with spontaneous intracerebral hemorrhage (ICH).

METHODS

We retrospectively analyzed a prospectively collected cohort of ICH patients ascertained between 1994 and 2015. We identified subjects with lymphocyte count obtained within 24 h from onset, and AL was defined as lymphocyte count <1000/μL. Infectious complications were assessed through retrospective chart review. Association between AL, infections, and mortality was investigated using multivariable logistic regression.

RESULTS

Of the 2014 patients meeting inclusion criteria, 548 (27.2%) had AL and 605 (30.0%) developed an infectious complication. Case-fatality at 90 days was 36.9%. Patients with AL had larger hematoma volumes, higher frequency of intraventricular hemorrhage, and lower Glasgow Coma Scale score on presentation (all p < 0.001). AL was independently associated with increased risk of pneumonia [odds ratio (OR) 1.97, 95% confidence interval (CI) 1.50-2.58, p < 0.001] and multiple infections (OR 1.84, 95% CI 1.24-2.71, p = 0.003). AL was also an independent predictor of 90-day mortality (OR 1.55, 95% CI 1.18-2.04, p = 0.002) after adjusting for confounders.

CONCLUSIONS

AL is common in ICH patients and independently associated with increased risk of infectious complications and poor outcome. Further studies will be needed to determine whether prophylactic antibiotics in ICH patients with AL can improve outcome.

Pathologic Findings of Chronic PML-IRIS in a Patient with Prolonged PML Survival Following Natalizumab Treatment

Immune reconstitution inflammatory syndrome (IRIS) is a common complication during treatment for natalizumab-associated progressive multifocal leukoencephalopathy (PML). Although severe IRIS can result in acute worsening of disability and is associated with poor prognosis, effective immune reconstitution may account for the high survival rate of this cohort of PML patients. We present pathological evidence of chronic IRIS 3.5 years after diagnosis with natalizumab-associated PML. Our case showed that the IRIS initially developed after plasma exchange therapy and resolved clinically and radiologically following a combination treatment with corticosteroids, maraviroc, and cidofovir. Autopsy 3.5 years later revealed evidence of grey-white matter junction demyelinating lesions characteristic of PML and perivascular leukocyte infiltrates predominated by CD8⁺ T-lymphocytes, and polymerase chain reaction analysis demonstrated the presence of JC viral DNA in this tissue, indicative of persistent PML-IRIS. While clinical symptoms of PML-IRIS typically stabilize within 6 months, our case report suggests that prolonged low-grade inflammation may persist in some patients. Better assays are needed to determine the prevalence of prolonged low-grade IRIS among PML survivors.

Circulating lymphocyte levels and relationship with infection status in patients with relapsing-remitting multiple sclerosis treated with daclizumab beta

BACKGROUND

Reversible lymphocyte count reductions have occurred following daclizumab beta treatment for relapsing-remitting multiple sclerosis.

OBJECTIVE

To analyse total and differential lymphocyte levels and relationship with infection status.

METHODS

In DECIDE, blood samples were collected at 12-week intervals from daclizumab beta- ( n = 919) or intramuscular interferon beta-1a-treated ( n = 922) patients. Infections/serious infections were assessed proximate to grade 2/3 lymphopenia or low CD4⁺/CD8⁺ T-cell counts. Total safety population (TSP) data were additionally analysed from the entire clinical development programme ( n = 2236).

RESULTS

Over 96 weeks in DECIDE, mean absolute lymphocyte count (ALC), CD4⁺ and CD8⁺ T-cell counts decreased <10% (7.1% vs 1.6%, 9.7% vs 2.0%, 9.3% vs 5.9%: daclizumab beta vs interferon beta-1a, respectively); shifts to ALC below lower limit of normal occurred in 13% versus 15%, respectively. Grade 3 lymphopenia was uncommon (TSP: <1%) and transient. Lymphocyte changes generally occurred within 24 weeks after treatment initiation and were reversible within 12 weeks of discontinuation. In DECIDE, mean CD4⁺/CD8⁺ T-cell counts were similar regardless of infection status. TSP data were consistent with DECIDE.

CONCLUSION

When observed, ALC and CD4⁺/CD8⁺ T-cell count decreases in daclizumab beta-treated patients were generally mild-to-modest, reversible upon treatment discontinuation and not associated with increased risk of infections, including opportunistic infections.

Human herpes virus-6 encephalitis causing severe anterograde amnesia associated with rituximab, azathioprine and prednisolone combination therapy for dermatomyositis

Human herpes virus-6 (HHV-6) reactivation is a well-recognised complication following haematological stem cell transplantation, but it is novel in the context of combination immunomodulatory therapy for autoimmune disease. We report a case of severe anterograde amnesia caused by HHV-6 encephalitis in a young female patient on rituximab, azathioprine and prednisolone for dermatomyositis (DM). The use of targeted biologic treatments for systemic autoimmune connective tissue diseases (CTDs) is increasing, particularly when refractory to conventional management. The anti-CD20 B cell depleting monoclonal antibody, rituximab is now increasingly used, often in combination with conventional immunomodulatory treatments, in certain autoimmune neurological conditions and systemic CTDs including DM. Physicians should be aware of the possibility of HHV-6 in those who develop encephalitis while CD20 B cell deplete, especially in the presence of additional immunomodulatory therapies. Prompt diagnosis and treatment of HHV-6 encephalitis with evidence-based anti-viral therapy may help reduce the extent of irreversible morbidity such as amnesia.

Disease-modifying therapies and infectious risks in multiple sclerosis

Immunomodulatory and immunosuppressive treatments for multiple sclerosis (MS) are associated with an increased risk of infection, which makes treatment of this condition challenging in daily clinical practice. Use of the expanding range of available drugs to treat MS requires extensive knowledge of treatment-associated infections, risk-minimizing strategies and approaches to monitoring and treatment of such adverse events. An interdisciplinary approach to evaluate the infectious events associated with available MS treatments has become increasingly relevant. In addition, individual stratification of treatment-related infectious risks is necessary when choosing therapies for patients with MS, as well as during and after therapy. Determination of the individual risk of infection following serial administration of different immunotherapies is also crucial. Here, we review the modes of action of the available MS drugs, and relate this information to the current knowledge of drug-specific infectious risks and risk-minimizing strategies.

Dimethyl fumarate in the management of multiple sclerosis: appropriate patient selection and special considerations

Delayed-release dimethyl fumarate (DMF), also known as gastroresistant DMF, is the most recently approved oral disease-modifying treatment (DMT) for relapsing multiple sclerosis. Two randomized clinical trials (Determination of the Efficacy and Safety of Oral Fumarate in Relapsing-Remitting MS [DEFINE] and Comparator and an Oral Fumarate in Relapsing-Remitting Multiple Sclerosis [CONFIRM]) demonstrated significant efficacy in reducing relapse rate and radiological signs of disease activity, as seen on magnetic resonance imaging. The DEFINE study also indicated a significant effect of DMF on disability worsening, while the low incidence of confirmed disability worsening in the CONFIRM trial rendered an insignificant reduction among the DMF-treated groups when compared to placebo. DMF also demonstrated a good safety profile and acceptable tolerability, since the most common side effects (gastrointestinal events and flushing reactions) are usually transient and mild to moderate in severity. Here, we discuss the place in therapy of DMF for individuals with relapsing multiple sclerosis, providing a tentative therapeutic algorithm to manage newly diagnosed patients and those who do not adequately respond to self-injectable DMTs. Literature data supporting the potential role of DMF as a first-line therapy are presented. The possibility of using DMF as switching treatment or even as an add-on strategy in patients with breakthrough disease despite self-injectable DMTs will also be discussed. Lastly, we argue about the role of DMF as an exit strategy from natalizumab-treated patients who are considered at risk for developing multifocal progressive leukoencephalopathy.

[Immunotherapy and infectious issues in multiple sclerosis. Self-injectable and oral drugs for immunotherapy]

Immunotherapy is generally associated with an increased risk for the development of infections. Due to the continuously expanding spectrum of new and potent immunotherapy treatment options for multiple sclerosis (MS), this article describes the currently known risks for treatment-related infections and the current recommendations for prevention of corresponding problems with drugs used in treatment strategies for MS and their mechanisms of action. The new treatment options in particular are linked to specific and severe infections; therefore, intensive and long-lasting monitoring is required before, during and after treatment and multidisciplinary surveillance of patients is needed. This article gives a detailed review of drug-specific red flags and current recommendations for the prophylaxis of infections associated with treatment of relapsing-remitting MS and when using self-injectable and oral disease-modifying immunotherapeutic drugs.

Human polyomavirus JC replication and non-coding control region analysis in multiple sclerosis patients under natalizumab treatment

In the last years, the treatment of multiple sclerosis (MS) patients with natalizumab has been associated with the occurrence of progressive multifocal leukoencephalopathy (PML) caused by human polyomavirus JC (JCV). Here, we have shown a significant correlation between patients with JC viruria and positive JC-specific antibody response and patients without JCV-specific antibodies after 1 year of natalizumab (p = 0.0006). Furthermore, JCV-specific quantitative PCR on urine and plasma samples, collected at the enrollment (t0) and every 4 months (t1, t2, t3) in the first year and at two time points (t4 and t5) in the second year of natalizumab treatment, indicated the prevalence of JC viremia rather than JC viruria only in the second year of treatment (p = 0.04). Moreover, the analysis of JCV non-coding control region (NCCR) sequences in peripheral blood mononuclear cells of patients with JC-specific antibodies after 12 natalizumab infusions (t3) revealed the presence of rearranged sequences, whereas the prevalence of genotypes 1A, 1B, and 4 was detected in these patients by VP1 sequence analysis. In summary, JC viruria evaluation seems to be useful to identify early those patients who do not already develop a humoral immune response against JCV. It may also be interesting to study the JCV NCCR rearrangements since they could give us new insights on the onset of neuro-invasive viral variants.

Acute retinal necrosis and immune reconstitution inflammatory syndrome in a natalizumab-treated patient with multiple sclerosis

PURPOSE

To describe a case of acute retinal necrosis and subsequent immune reconstitution inflammatory syndrome in a patient with multiple sclerosis treated with natalizumab.

METHODS

Case report.

RESULTS

A 51-year-old man with multiple sclerosis developed acute retinal necrosis during treatment with natalizumab. The patient was successfully managed with natalizumab discontinuation, oral valacyclovir, and prophylactic laser retinal photocoagulation. A few months after natalizumab interruption and 1 month after valacyclovir completion, the patient presented with an episode of presumed noninfectious anterior and intermediate uveitis, which responded well to oral steroid mini-pulse therapy.

CONCLUSION

Natalizumab is a potent immune suppressor used in the treatment of multiple sclerosis and Crohn disease. It has already been linked to herpetic infections and immune reconstitution inflammatory syndrome in the central nervous system. These complications may also affect ocular tissues.

Therapeutic uses of anti-α4-integrin (anti-VLA-4) antibodies in multiple sclerosis

Multiple sclerosis (MS) is a disorder of putative autoimmune origin, where immune cells invade the central nervous system and cause damage by attacking the myelin sheath of nerve cells. The blockade of the integrin very late antigen-4 (VLA-4) with the monoclonal antibody natalizumab has become the most effective therapy against MS since its approval in 2004. It is assumed that the inhibition of VLA-4-mediated immune cell adhesion to the endothelium of the blood-brain barrier (BBB) alleviates pathogenic processes of MS and, therefore, reduces disease severity and burden. Not all approaches to treat additional immune-mediated disorders (e.g. Rasmussen encephalitis and neuromyelitis optica) with natalizumab have been successful, but allowed researchers to gain additional insight into mechanisms of specific immune cell subsets' migration through the BBB in the human system. While the long-term efficacy and general tolerability of natalizumab in MS are clear, the over 400 cases of natalizumab-associated progressive multifocal leukoencephalopathy (PML) have been of great concern and methods of risk stratification in patients have become a major area of research. Modern risk stratification includes established factors such as treatment duration, previous immune-suppressive therapy, and anti-John Cunningham virus (JCV) antibody seropositivity, but also experimental factors such as anti-JCV antibody titers and levels of L-selectin. Today, anti-VLA-4 therapy is reserved for patients with highly active relapsing-remitting MS and patients are monitored closely for early signs of potential PML.

The good and the bad of neuroinflammation in multiple sclerosis

Multiple sclerosis (MS) is the most common inflammatory, demyelinating, neurodegenerative disorder of the central nervous system (CNS). It is widely considered a T-cell mediated autoimmune disease that develops in genetically susceptible individuals, possibly under the influence of certain environmental trigger factors. The invasion of autoreactive CD4+ T-cells into the CNS is thought to be a central step that initiates the disease. Several other cell types, including CD8+ T-cells, B-cells and phagocytes appear to be involved in causing inflammation and eventually neurodegeneration. But inflammation is not entirely deleterious in MS. Evidence has accumulated in the recent years that show the importance of regulatory immune mechanisms which restrain tissue damage and initiate regeneration. More insight into the beneficial aspects of neuroinflammation might allow us to develop new treatment strategies for this enigmatic disease.

Human Polyomavirus JC monitoring and noncoding control region analysis in dynamic cohorts of individuals affected by immune-mediated diseases under treatment with biologics: an observational study

BACKGROUND

Progressive multifocal leukoencephalopathy (PML) onset, caused by Polyomavirus JC (JCPyV) in patients affected by immune-mediated diseases during biological treatment, raised concerns about the safety profile of these agents. Therefore, the aims of this study were the JCPyV reactivation monitoring and the noncoding control region (NCCR) and viral protein 1 (VP1) analysis in patients affected by different immune-mediated diseases and treated with biologics.

METHODS

We performed JCPyV-specific quantitative PCR of biological samples collected at moment of recruitment (t0) and every 4 months (t1, t2, t3, t4). Subsequently, rearrangements' analysis of NCCR and VP1 was carried out. Data were analyzed using χ2 test.

RESULTS

Results showed that at t0 patients with chronic inflammatory rheumatic diseases presented a JCPyV load in the urine significantly higher (p≤0.05) than in patients with multiple sclerosis (MS) and Crohn's disease (CD). It can also be observed a significant association between JC viruria and JCPyV antibodies after 1 year of natalizumab (p=0.04) in MS patients. Finally, NCCR analysis showed the presence of an archetype-like sequence in all urine samples, whereas a rearranged NCCR Type IR was found in colon-rectal biopsies collected from 2 CD patients after 16 months of infliximab. Furthermore, sequences isolated from peripheral blood mononuclear cells (PBMCs) of 2 MS patients with JCPyV antibody at t0 and t3, showed a NCCR Type IIR with a duplication of a 98 bp unit and a 66 bp insert, resulting in a boxB deletion and 37 T to G transversion into the Spi-B binding site. In all patients, a prevalence of genotypes 1A and 1B, the predominant JCPyV genotypes in Europe, was observed.

CONCLUSIONS

It has been important to understand whether the specific inflammatory scenario in different immune-mediated diseases could affect JCPyV reactivation from latency, in particular from kidneys. Moreover, for a more accurate PML risk stratification, testing JC viruria seems to be useful to identify patients who harbor JCPyV but with an undetectable JCPyV-specific humoral immune response. In these patients, it may also be important to study the JCPyV NCCR rearrangement: in particular, Spi-B expression in PBMCs could play a crucial role in JCPyV replication and NCCR rearrangement.

Th1-mediated experimental autoimmune encephalomyelitis is CXCR3 independent

Drugs that block leukocyte trafficking ameliorate multiple sclerosis (MS). Occurrences of opportunistic infection, however, highlight the need for novel drugs that modulate more restricted subsets of T cells. In this context, chemokines and their receptors are attractive therapeutic targets. CXCR3, a Th1-associated chemokine receptor, is preferentially expressed on T cells that accumulate in MS lesions and central nervous system (CNS) infiltrates of mice with experimental autoimmune encephalomyelitis (EAE). Surprisingly, mice genetically deficient in either CXCR3 or CXCL10 succumb to EAE following active immunization with myelin antigens. EAE is mediated by a heterogeneous population of T cells in myelin-immunized mice. Hence, disease might develop in the absence of CXCR3 secondary to the compensatory action of encephalitogenic CCR6(+) Th17 cells. However, in the current study, we show for the first time that blockade or genetic deficiency of either CXCR3 or of its primary ligand has no impact on clinical EAE induced by the adoptive transfer of highly polarized Th1 effector cells. Our data illustrate the fact that, although highly targeted immunotherapies might have more favorable side effect profiles, they are also more likely to be rendered ineffective by inherent redundancies in chemokine and cytokine networks that arise at sites of neuroinflammation.

Immune evasion and the evolution of molecular mimicry in parasites

Parasites that are molecular mimics express proteins which resemble host proteins. This resemblance facilitates immune evasion because the immune molecules with the specificity to react with the parasite also cross-react with the host's own proteins, and these lymphocytes are rare. Given this advantage, why are not most parasites molecular mimics? Here we explore potential factors that can select against molecular mimicry in parasites and thereby limit its occurrence. We consider two hypotheses: (1) molecular mimics are more likely to induce autoimmunity in their hosts, and hosts with autoimmunity generate fewer new infections (the "costly autoimmunity hypothesis"); and (2) molecular mimicry compromises protein functioning, lowering the within-host replication rate and leading to fewer new infections (the "mimicry trade-off hypothesis"). Our analysis shows that although both hypotheses may select against molecular mimicry in parasites, unique hallmarks of protein expression identify whether selection is due to the costly autoimmunity hypothesis or the mimicry trade-off hypothesis. We show that understanding the relevant selective forces is necessary to predict how different medical interventions will affect the proportion of hosts that experience the different infection types, and that if parasite evolution is ignored, interventions aimed at reducing infection-induced autoimmunity may ultimately fail.

Progressive multifocal leukoencephalopathy

PURPOSE OF REVIEW

Progressive multifocal leukoencephalopathy (PML) is an opportunistic viral infection of the human CNS that has gained new importance because of AIDS and newer immunosuppressive therapies. It destroys oligodendrocytes, leading to neurologic deficits associated with demyelination.

RECENT FINDINGS

PML most commonly occurs in patients who are HIV infected, but increasing numbers of patients are being recognized in the context of immunosuppressive therapies for autoimmune diseases. The precise pathogenesis of infection by JC virus, the etiologic human papovavirus, remains elusive, but much has been learned since the original description of the pathologic entity PML in 1958. Detection and diagnosis of this disorder have become more sophisticated with MRI of the brain and spinal fluid analysis using PCR detection. Immune reconstitution inflammatory syndrome complicates reversal of immunosuppression when PML has established a foothold in the brain.

SUMMARY

No effective therapy exists, but there is hope for better management of patients by withdrawing exogenous immunosuppression and reconstituting the immune system, with a projection of better long-term survival.

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.

Clinical utility of glatiramer acetate in the management of relapse frequency in multiple sclerosis

Glatiramer acetate (GA) represents one of the most common disease-modifying therapies for multiple sclerosis. GA is currently approved for patients at high risk of developing clinically definite multiple sclerosis (CDMS) after having experienced a well-defined first clinical episode (clinically isolated syndrome or CIS) and for patients with relapsing-remitting multiple sclerosis (RRMS). GA’s efficacy and effectiveness to reduce relapse frequency have been proved in placebo-controlled and observational studies. Comparative trials have also confirmed the lack of significant differences over other choices of treatment in the management of relapse frequency, and long-term studies have supported its effect at extended periods of time. Additionally, RRMS patients with suboptimal response to interferon β may benefit from reduced relapse rate after switching to GA, and those with clinically isolated syndrome may benefit from delayed conversion to CDMS. All these results, together with its proven long-term safety and positive effect on patients’ daily living, support the favorable risk-benefit of GA for multiple sclerosis treatment.

Fatal PML associated with efalizumab therapy: insights into integrin αLβ2 in JC virus control

OBJECTIVES

Progressive multifocal leukoencephalopathy (PML) has become much more common with monoclonal antibody treatment for multiple sclerosis and other immune-mediated disorders.

METHODS

We report 2 patients with severe psoriasis and fatal PML treated for ≥3 years with efalizumab, a neutralizing antibody to αLβ2-leukointegrin (LFA-1). In one patient, we conducted serial studies of peripheral blood and CSF including analyses of leukocyte phenotypes, migration ex vivo, and CDR3 spectratypes with controls coming from HIV-infected patients with PML. Extensive pathologic and histologic analysis was done on autopsy CNS tissue of both patients.

RESULTS

Both patients developed progressive cognitive and motor deficits, and JC virus was identified in CSF. Despite treatment including plasma exchange (PE) and signs of immune reconstitution, both died of PML 2 and 6 months after disease onset. Neuropathologic examination confirmed PML. Efalizumab treatment was associated with reduced transendothelial migration by peripheral T cells in vitro. As expression levels of LFA-1 on peripheral T cells gradually rose after PE, in vitro migration increased. Peripheral and CSF T-cell spectratyping showed CD8+ T-cell clonal expansion but blunted activation, which was restored after PE.

CONCLUSIONS

From these data we propose that inhibition of peripheral and intrathecal T-cell activation and suppression of CNS effector-phase migration both characterize efalizumab-associated PML. LFA-1 may be a crucial factor in homeostatic JC virus control.

The occurrence and prevention of foodborne disease in vulnerable people

In developed countries, such as the United Kingdom and the United States, between 15% and 20% of the population show greater susceptibility than the general population to foodborne disease. This proportion includes people with primary immunodeficiency, patients treated with radiation or with immunosuppressive drugs for cancer and diseases of the immune system, those with acquired immune-deficiency syndrome and diabetics, people suffering from liver or kidney disease or with excessive iron in the blood, pregnant women, infants, and the elderly. Malnutrition and use of antacids, particularly proton-pump inhibitors, also increase susceptibility. We review the occurrence of infection by foodborne pathogens in these groups of people and measures to prevent infection. The nature and use of low microbial diets to reduce the risk of foodborne disease in immunocompromised patients are very variable. Diets for vulnerable people in care should exclude higher-risk foods, and vulnerable people in the community should receive clear advice about food safety, in particular avoidance of higher-risk foods and substitution of safer, nutritious foods.

A one-year prospective, randomized, placebo-controlled, quadruple-blinded, phase II safety pilot trial of combination therapy with interferon beta-1a and mycophenolate mofetil in early relapsing-remitting multiple sclerosis (TIME MS)

BACKGROUND

Mycophenolate mofetil (MMF) is an oral DNA base synthesis inhibitor with immunomodulatory effects on B cells, T cells, and macrophages.

OBJECTIVE

To conduct a safety and tolerability pilot study of interferon beta-1a (IFN-b1a) in combination with either placebo or oral MMF in multiple sclerosis (MS).

METHODS

Twenty-four treatment-naïve R-RMS patients participated in a one-year prospective, placebo-controlled, blinded, safety pilot clinical trial. Every patient injected weekly intramuscular interferon beta-1a. The cohort was then randomized (1 : 1) to either active oral MMF or identical-appearing placebo tablets. Clinical evaluations were assessed every 3 months, along with brain MRI scans performed at baseline and repeated every 60 days for one year. Comprehensive laboratory assessments were monitored for safety, along with adverse events.

RESULTS

In this small pilot investigation, no differences were identified between the two treatment groups with respect to patient-reported adverse events, MRI metrics, or laboratory abnormalities. Notwithstanding these observations, and the limited number of patients treated, trends appeared to favor the combination therapy regimen.

CONCLUSIONS

The combination treatment regimen of interferon beta-1a and MMF appeared to be well tolerated in this pilot study. Despite the small sample size, therapeutic trends were observed in favor of combination therapy. An adequately powered controlled trial of MMF in MS appears warranted.

A randomized, blinded, parallel-group, pilot trial of mycophenolate mofetil (CellCept) compared with interferon beta-1a (Avonex) in patients with relapsing-remitting multiple sclerosis

BACKGROUND

Mycophenolate mofetil (MMF, CellCept®) has been utilized as an antirejection agent in transplant recipients and in patients with myriad autoimmune disorders including multiple sclerosis (MS).

OBJECTIVE

To investigate radiographic and clinical safety involving monotherapy use of daily oral MMF (1 g b.i.d.) versus weekly intramuscular interferon beta 1a (Avonex® at 30 mcg) in relapsing-remitting MS (RRMS).

METHODS

We organized a randomized, serial, 6-monthly, MRI-blinded, parallel-group multicenter pilot study to determine the safety of MMF versus interferon beta monotherapy in 35 untreated patients with RRMS, all of whom exhibited evidence of gadolinium (Gd) enhancement on a screening MRI of the brain. The primary outcome was the reduction in the cumulative mean number of combined active lesions (CAL), new Gd-enhancing lesions, and new T2 lesions on MRI analyses.

RESULTS

Both interferon beta and MMF appeared safe and well tolerated in the majority of patients. There was no difference between MMF therapy and the standard regimen of interferon beta therapy on the primary safety MRI endpoints of the study. However, the MMF group showed a trend toward a lower accumulation of combined active lesions, CAL, Gd and T2 lesions when compared with interferon beta treated patients.

CONCLUSIONS

The results from this pilot study suggest that the application of MMF monotherapy in MS deserves further exploration.

Progressive multifocal leukoencephalopathy

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

Causes of death among patients with multiple sclerosis

BACKGROUND

Several studies show a high mortality risk among patients with multiple sclerosis (MS).

OBJECTIVES

In this study, mortality and underlying causes of death were analysed among patients with MS diagnosed between 1964-1993 in Finland (n = 1595).

METHODS

Standardized mortality ratios (SMRs) were calculated for both genders. The follow-up was based on linkage to the national computerized Cause-of-Death Register of Statistics Finland.

RESULTS

Altogether, 464 deaths were recorded by the end of 2006. The SMR as compared with the general population among females was 3.4 (95% confidence interval 3.0-3.9) and among males 2.2 (1.9-2.6). In total, 270 patients (58%) died from MS; only one of these deaths occurred during the first 2 years after the MS diagnosis. Mortality was also increased for other natural causes of death (n = 160) in patients followed for more than 10 years (SMR 1.4, 1.2-1.7), with a significant increase in deaths from influenza (29, 6.0-85), pneumonia (4.7, 2.5-8.0) and gastrointestinal causes (4.4, 2.3-7.7). The SMR for violent causes was 1.2 (0.7-1.9) and for alcohol-related deaths 0.2 (0.02-0.7). The SMR for suicides was 1.7 (0.9-2.7).

CONCLUSIONS

The MS population has an increased disease mortality, while the increase in the risk of accidents and suicides is not significantly increased among patients with MS in Finland.

Demyelination as a complication of new immunomodulatory treatments

PURPOSE OF REVIEW

This review discusses demyelinating events of the nervous system that have been associated with new immunomodulatory treatments, in particular monoclonal antibodies (mAbs).

RECENT FINDINGS

Natalizumab, a mAb targeting the alpha-4 integrins, which is efficient in relapsing-remitting multiple sclerosis, has been associated with progressive multifocal leukoencephalopathy (PML). We will review the putative mechanisms linking natalizumab with JC virus, the agent of PML. Efalizumab, a mAb targeting a member of the integrin family, CD11a, was approved for the treatment of psoriasis, but had to be withdrawn in 2009 because of the occurrence of three cases of PML. Rituximab, an anti-CD20 mAb, is used in different neoplastic and autoimmune diseases and may soon enter the pharmacopeia of multiple sclerosis. It has been suggested that rituximab is a risk factor for PML; however, evidence of such a link is unclear. Antitumor necrosis factor-alpha agents are used in several autoimmune diseases. Several cases of demyelinating events of the nervous system have been reported, prompting a heightened surveillance of treated patients. Recent data are reassuring, suggesting that the incidence of such events is relatively low.

SUMMARY

Neurologists must become familiar with neurological complications of new immunomodulatory treatments, a field situated at the interface of neurology, immunology and infection.

Risks vs benefits of glatiramer acetate: a changing perspective as new therapies emerge for multiple sclerosis

An understanding of the risks, benefits, and relative value of glatiramer acetate (GA) in multiple sclerosis (MS) has been evolving based on recently completed head-to-head studies: REGARD (REbif vs Glatiramer Acetate in Relapsing MS Disease); BEYOND (Betaseron Efficacy Yielding Outcomes of a New Dose); and BECOME (BEtaseron vs COpaxone in Multiple Sclerosis with Triple-Dose Gadolinium and 3-Tesla MRI Endpoints). Outcomes in the primary endpoints of these trials showed no significant differences between GA and high-dose beta-interferons (IFNβs). Results of the PreCISe (Early GA Treatment in Delaying Conversion to Clinically Definite Multiple Sclerosis [CDMS] in Subjects Presenting With a Clinically Isolated Syndrome [CIS]) trial led to the US Food and Drug Administration approval of GA in patients with a CIS. Furthermore, the ongoing follow-up study to the original pivotal GA trial, now extending beyond 15 years, continues to support the safety of GA. Currently, GA and IFNβs are no longer the only immunomodulators available for MS. Introduction of the monoclonal antibody, natalizumab (Tysabri^®; Biogen Idec, Inc., Cambridge, MA, USA) provides an alternative immunomodulator for MS and has changed the therapeutic landscape dramatically. However, the rare but serious cases of progressive multifocal leukoencephalopathy that have occurred with natalizumab have raised concerns among clinicians and patients about using this agent and some of the emerging agents. The potential risks and benefits of the emerging therapies (cladribine, alemtuzumab, rituximab, fingolimod, laquinimod, teriflunomide, and dimethyl fumarate) based on phase II/III trials, as well as their use for indications other than MS, will be presented. This review provides available data on GA, natalizumab, and the emerging agents to support new developments in our understanding of GA and how its long-standing role as a first-line therapy in MS will evolve within the increasingly complex MS therapeutic landscape.

Natalizumab-associated progressive multifocal leukoencephalopathy in patients with multiple sclerosis: lessons from 28 cases

BACKGROUND

Treatment of multiple sclerosis with natalizumab is complicated by rare occurrence of progressive multifocal leukoencephalopathy (PML). Between July, 2006, and November, 2009, there were 28 cases of confirmed PML in patients with multiple sclerosis treated with natalizumab. Assessment of these clinical cases will help to inform future therapeutic judgments and improve the outcomes for patients.

RECENT DEVELOPMENTS

The risk of PML increases with duration of exposure to natalizumab over the first 3 years of treatment. No new cases occurred during the first two years of natalizumab marketing but, by the end of November, 2009, 28 cases had been confirmed, of which eight were fatal. The median treatment duration to onset of symptoms was 25 months (range 6-80 months). The presenting symptoms most commonly included changes in cognition, personality, and motor performance, but several cases had seizures as the first clinical event. Although PML has developed in patients without any previous use of disease-modifying therapies for multiple sclerosis, previous therapy with immunosuppressants might increase risk. Clinical diagnosis by use of MRI and detection of JC virus in the CSF was established in all but one case. Management of PML has routinely used plasma exchange (PLEX) or immunoabsorption to hasten clearance of natalizumab and shorten the period in which natalizumab remains active (usually several months). Exacerbation of symptoms and enlargement of lesions on MRI have occurred within a few days to a few weeks after PLEX, indicative of immune reconstitution inflammatory syndrome (IRIS). This syndrome seems to be more common and more severe in patients with natalizumab-associated PML than it is in patients with HIV-associated PML. WHERE NEXT?: Diagnosis of natalizumab-associated PML requires optimised clinical vigilance, reliable and sensitive PCR testing of the JC virus, and broadened criteria for recognition of PML lesions by use of MRI, including contrast enhancement. Optimising the management of IRIS reactions will be needed to improve outcomes. Predictive markers for patients at risk for PML must be sought. It is crucial to monitor the risk incurred during use of natalizumab beyond 3 years.

Progressive multifocal leukoencephalopathy in patients on immunomodulatory therapies

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the white matter of the human brain caused by lytic infection of oligodendrocytes with the human polyomavirus JCV. Although the majority of PML cases occur in severely immune-suppressed individuals, with HIV-1 infection as the predominant factor, PML has been increasingly diagnosed in patients treated with biological therapies such as monoclonal antibodies that modulate immune system functions. Monoclonal antibodies that target the cell adhesion molecules VLA-4 (natalizumab; Tysabri for multiple sclerosis and Crohn's disease) or LFA-1 (efalizumab; Raptiva for severe forms of plaque psoriasis) to prevent extravasation of inflammatory T cells into tissues, or target the cell surface marker CD20 (rituximab; Rituxan for hematologic malignancies and rheumatoid arthritis) to deplete peripheral circulating B cells, have all been associated with PML. The link between the effects of these therapies on the immune system and the occurrence of PML has prompted investigations on JCV sites of latency in the bone marrow, the migration of bone marrow derived cells into the circulation, and intracellular virus entry into the brain.