Progressive multifocal leukoencephalopathy in common variable immunodeficiency: mitigated course under mirtazapine and mefloquine

Revisiting JC virus and progressive multifocal leukoencephalopathy

Since its definition 65 years ago, progressive multifocal leukoencephalopathy (PML) has continued to devastate a growing population of immunosuppressed patients despite major advances in our understanding of the causative JC virus (JCV). Unless contained by the immune system, JCV lyses host oligodendrocytes collateral to its life cycle, leading to demyelination, neurodegeneration, and death. Novel treatments have stagnated in the absence of an animal model while current antiviral agents fail to address the now ubiquitous polyomavirus. In this review, we highlight the established pathogenesis by which JCV infection progresses to PML, highlighting major challenges that must be overcome to eliminate the underlying virus and, therefore, the debilitating disease.

An Elusive Target: Inhibitors of JC Polyomavirus Infection and Their Development as Therapeutics for the Treatment of Progressive Multifocal Leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is a rare demyelinating disease caused by infection with JC Polyomavirus (JCPyV). Despite the identification of the disease and isolation of the causative pathogen over fifty years ago, no antiviral treatments or prophylactic vaccines exist. Disease onset is usually associated with immunosuppression, and current treatment guidelines are limited to restoring immune function. This review summarizes the drugs and small molecules that have been shown to inhibit JCPyV infection and spread. Paying attention to historical developments in the field, we discuss key steps of the virus lifecycle and antivirals known to inhibit each event. We review current obstacles in PML drug discovery, including the difficulties associated with compound penetrance into the central nervous system. We also summarize recent findings in our laboratory regarding the potent anti-JCPyV activity of a novel compound that antagonizes the virus-induced signaling events necessary to establish a productive infection. Understanding the current panel of antiviral compounds will help center the field for future drug discovery efforts.

Progressive multifocal leukoencephalopathy successfully treated with mefloquine and literature review

Progressive multifocal leukoencephalopathy (PML) is an opportunistic infection due to reactivation of John Cunningham virus (JCV). The diagnosis depends on evidence from clinical, imaging, and virologic studies. When the cerebrospinal fluid shows a negative polymerase chain reaction result, brain biopsy is required to confirm the diagnosis. PML has no standard treatment except for immune reconstitution. The anti-JCV effect of mefloquine, however, is supported by some studies, and if brain biopsy is difficult, a mefloquine trial can be considered. We describe a case of possible PML successfully treated with mefloquine.

Antivirals against human polyomaviruses: Leaving no stone unturned

Human polyomaviruses (HPyVs) encompass more than 10 species infecting 30%-90% of the human population without significant illness. Proven HPyV diseases with documented histopathology affect primarily immunocompromised hosts with manifestations in brain, skin and renourinary tract such as polyomavirus-associated nephropathy (PyVAN), polyomavirus-associated haemorrhagic cystitis (PyVHC), polyomavirus-associated urothelial cancer (PyVUC), progressive multifocal leukoencephalopathy (PML), Merkel cell carcinoma (MCC), Trichodysplasia spinulosa (TS) and pruritic hyperproliferative keratinopathy. Although virus-specific immune control is the eventual goal of therapy and lasting cure, antiviral treatments are urgently needed in order to reduce or prevent HPyV diseases and thereby bridging the time needed to establish virus-specific immunity. However, the small dsDNA genome of only 5 kb of the non-enveloped HPyVs only encodes 5-7 viral proteins. Thus, HPyV replication relies heavily on host cell factors, thereby limiting both, number and type of specific virus-encoded antiviral targets. Lack of cost-effective high-throughput screening systems and relevant small animal models complicates the preclinical development. Current clinical studies are limited by small case numbers, poorly efficacious compounds and absence of proper randomized trial design. Here, we review preclinical and clinical studies that evaluated small molecules with presumed antiviral activity against HPyVs and provide an outlook regarding potential new antiviral strategies.

Long-Term Survival after Progressive Multifocal Leukoencephalopathy in a Patient with Primary Immune Deficiency and NFKB1 Mutation

PURPOSE

To describe the development of progressive multifocal leukoencephalopathy (PML) in a patient with primary immune deficiency (PID) due to a NFKB1 (nuclear factor kB subunit 1) mutation, who was treated successfully with a combination of mirtazapine and mefloquine.

METHODS

We've based the treatment of our patient on literature research and provide a review of PML in CVID patients.

RESULTS

Only a few reports have been published on the occurrence of PML in PID. PML is mainly observed in patients with reduced cellular immunity, which was not the case in our patient. Successful treatment options in this population are limited. Though severely disabled, our patient still survives, more than 4 years after symptom onset and shows consistent improvement on MRI (magnetic resonance imaging) and CSF (cerebrospinal fluid) analysis.

CONCLUSION

We conclude that some patients with PML might be treatable and can show long-term survival although neurological deficits remain. Involvement of humoral immunity in the pathogenesis of PML as well as the possible role of NFKB1 mutations in response to specific pathogens deserves further investigation.

The Use of Antimalarial Drugs against Viral Infection

In recent decades, drugs used to treat malaria infection have been shown to be beneficial for many other diseases, including viral infections. In particular, they have received special attention due to the lack of effective antiviral drugs against new emerging viruses (i.e., HIV, dengue virus, chikungunya virus, Ebola virus, etc.) or against classic infections due to drug-resistant viral strains (i.e., human cytomegalovirus). Here, we reviewed the in vitro/in vivo and clinical studies conducted to evaluate the antiviral activities of four classes of antimalarial drugs: Artemisinin derivatives, aryl-aminoalcohols, aminoquinolines, and antimicrobial drugs.

Structural Noninfectious Manifestations of the Central Nervous System in Common Variable Immunodeficiency Disorders

BACKGROUND

Central nervous system (CNS) disease in adult common variable immunodeficiency (CVID) is rare, and therefore diagnostic and therapeutic protocols are lacking.

OBJECTIVE

To provide clinical information aiming to establish awareness and first experience-based recommendations.

METHODS

We reviewed clinical manifestations, genetic and immunological characteristics, diagnostic evaluation, and treatment of patients with CVID with abnormal magnetic resonance imaging (MRI) of the CNS disease in our cohort.

RESULTS

Seventeen patients with CNS manifestation and a previous diagnosis of CVID were identified. Presenting symptoms of the CNS disease included loss of sensory or motoric function, headache, or epilepsy. Contrast-enhancing lesions of the brain or solely the spinal cord were the most common findings on MRI. The prevalence of splenomegaly, lymphadenopathy, interstitial lung disease, and autoimmune cytopenia was significantly increased compared with control CVID patients. In 8 patients, a molecular defect was identified, including mutations in CTLA4, NFKB1, and CECR1. Patients with CVID with CNS involvement generally displayed lymphopenia, skewed CD4⁺ T-cell subsets, and increased proportions of CD21^low B cells in the peripheral blood. CNS involvement usually responded well to high-dose steroids, but regularly required maintenance therapy to prevent relapse.

CONCLUSION

CNS disease is a severe but rare complication in CVID disorders, particularly affecting patients with other noninfectious disease symptoms. Diagnostic evaluation needs to rule out infectious causes by all means; a genetic evaluation is recommended given the high probability of an underlying monogenic disorder. Possible treatment consists of steroids with yet to be determined optimal maintenance therapy in case of relapse.

Managing the side effects of multiple sclerosis therapy: pharmacotherapy options for patients

INTRODUCTION

Multiple sclerosis (MS) is an immune-mediated and neurodegenerative disease with an unpredictable outcome. Immune-modulatory treatment aims at decreasing long-term disability. With the increasing number of treatment options, it is essential to fully digest the possible side effects of the available therapeutics and to monitor patients is essential.

AREAS COVERED

All approved disease-modifying drugs (DMD) for MS are discussed in this review. Mode of action, adverse effects, reported risks for infections and malignancies, and pregnancy related issues are discussed in the review. The authors also provide suggestions for monitoring therapy. For all approved DMDs the pivotal studies have been included for possible side effects, as well as reports by health authorities. For this manuscript, PubMed was checked for reports on side effects for various drugs.

EXPERT OPINION

Treatment options in MS are manifold, each carrying different risks. The safety-risk profile for approved agents is favorable. Knowing and monitoring these possible side effects is essential to minimize risks associated with treatment. Presently, the long-term experience for some of these therapies is missing and this must be addressed.

T cell deficiencies as a common risk factor for drug associated progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is a disease of the central nervous system caused by neuropathogenic prototypes of ubiquitous community-acquired JC virus (JCV). The disease became of particular concern following its association with certain therapies that modulate immune system function without heavy immunosuppression. Due to lack of prophylactic/treatment options and poor outcomes, which often include severe disability or death, PML is a considerable concern for development of new drugs that interfere with immune system functions. In this review of clinical and research findings, we discuss the evidence that deficiencies in CD4⁺ T helper cells, cytotoxic CD8⁺ T cells, and interferon gamma are of crucial importance for development of PML under a variety of circumstances, including those associated with use of various drugs, regardless of differences in their mechanisms of action. These deficiencies apparently enable transformation of the harmless JCV archetype into neuropathogenic prototypes, but the site(s), and the mechanisms, of this transformation are yet to be elucidated. Here we discuss the evidence for brain as one of the sites of this transformation, and propose a model of PML pathogenesis that emphasizes the central role of T cell deficiencies in the two life cycles of the JCV, one non-pathogenic and one neuropathogenic. Finally, we conclude that the development of clinical grade T cell functional tests and more consistent use of already available laboratory tests for T cell subset analysis would greatly aid the effort to more accurately predict and assess the magnitude of PML risk for concerned therapeutic interventions.

JC Polyomavirus Attachment and Entry: Potential Sites for PML Therapeutics

PURPOSE OF REVIEW

JC polyomavirus (JCPyV) is a significant human pathogen that causes an asymptomatic infection in the kidney in the majority of the population. In immunosuppressed individuals, the virus can become reactivated and spread to the brain, causing the fatal, demyelinating disease progressive multifocal leukoencephalopathy (PML). There are currently limited treatment options for this fatal disease. Attachment to receptors and entry into host cells are the initiating events in JCPyV infection and therefore an attractive target for therapeutics to prevent or treat PML. This review provides the current understanding of JCPyV attachment and entry events and the potential therapeutics to target these areas.

RECENT FINDINGS

JCPyV attachment and entry to host cells is mediated by α2,6-linked lactoseries tetrasaccharide c (LSTc) and 5-hydroxytryptamine receptors (5-HT₂Rs), respectively, and subsequent trafficking to the endoplasmic reticulum is required for infection. Recently, vaccines, monoclonal antibodies, and small molecules have shown promise as anti-viral and PML therapies.

SUMMARY

This review summarizes our current understanding of JCPyV attachment, entry, and trafficking and the development of potential PML therapeutics that inhibit these critical steps in JCPyV infection.

Progressive Multifocal Leukoencephalopathy: Endemic Viruses and Lethal Brain Disease

In 1971, the first human polyomavirus was isolated from the brain of a patient who died from a rapidly progressing demyelinating disease known as progressive multifocal leukoencephalopathy. The virus was named JC virus after the initials of the patient. In that same year a second human polyomavirus was discovered in the urine of a kidney transplant patient and named BK virus. In the intervening years it became clear that both viruses were widespread in the human population but only rarely caused disease. The past decade has witnessed the discovery of eleven new human polyomaviruses, two of which cause unusual and rare cancers. We present an overview of the history of these viruses and the evolution of JC polyomavirus-induced progressive multifocal leukoencephalopathy over three different epochs. We review what is currently known about JC polyomavirus, what is suspected, and what remains to be done to understand the biology of how this mostly harmless endemic virus gives rise to lethal disease.

2,8-bis(trifluoromethyl)quinoline analogs show improved anti-Zika virus activity, compared to mefloquine

Zika virus (ZIKV), an arthropod-born Flavivirus, has been associated with a wide range of neurological diseases in adults, foetuses and neonates. Since no vaccine is available, repurposing of antiviral drugs currently in medical use is necessary. Mefloquine has confirmed anti-ZIKV activity. We used medicinal chemistry-driven approaches to synthesize and evaluate the ability of a series of new 2,8-bis(trifluoromethyl)quinoline derivatives to inhibit ZIKV replication in vitro, in order to improve the potency of mefloquine. We found that quinoline derivatives 3a and 4 were the most potent compounds within this series, both with mean EC₅₀ values of 0.8 μM, which represents a potency 5 times that of mefloquine. These results indicate that new 2,8-bis(trifluoromethyl)quinoline chemical structures may be promising for the development of novel anti-ZIKV drugs.

Neurologic Complications of Common Variable Immunodeficiency

Common variable immunodeficiency is a rare disorder of immunity associated with a myriad of clinical manifestations including recurrent infections, autoimmunity, and malignancy. Though rare, neurologic complications have been described in a small number of case reports and case series of CVID patients. In this article, we present a patient with CVID who suffered significant neurologic morbidity and categorize the reported range of neurologic complications associated with CVID. Our case highlights the complex nature of neurologic manifestations in CVID patients, and our review of the current database suggests that infection and inflammatory neurologic disorders are the cause of most neurologic presentations.

Progressive Multifocal Leukoencephalopathy in Primary Immune Deficiencies: Stat1 Gain of Function and Review of the Literature

BACKGROUND

Progressive multifocal leukoencephalopathy (PML) is a rare, severe, otherwise fatal viral infection of the white matter of the brain caused by the polyomavirus JC virus, which typically occurs only in immunocompromised patients. One patient with dominant gain-of-function (GOF) mutation in signal transducer and activator of transcription 1 (STAT1) with chronic mucocutaneous candidiasis and PML was reported previously. We aim to identify the molecular defect in 3 patients with PML and to review the literature on PML in primary immune defects (PIDs).

METHODS

STAT1 was sequenced in 3 patients with PML. U3C cell lines were transfected with STAT1 and assays to search for STAT1 phosphorylation, transcriptional response, and target gene expression were performed.

RESULTS

We identified 3 new unrelated cases of PML in patients with GOF STAT1 mutations, including the novel STAT1 mutation, L400Q. These STAT1 mutations caused delayed STAT1 dephosphorylation and enhanced interferon-gamma-driven responses. In our review of the literature regarding PML in primary immune deficiencies we found 26 cases, only 54% of which were molecularly characterized, the remainder being syndromically diagnosed only.

CONCLUSIONS

The occurrence of PML in 4 cases of STAT1 GOF suggests that STAT1 plays a critical role in the control of JC virus in the central nervous system.

Progressive multifocal leukoencephalopathy and immune reconstitution inflammatory syndrome (IRIS)

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

Progressive multifocal leukoencephalopathy associated to natalizumab extended dosing regimen

A risk for developing progressive multifocal leukoencephalopathy is a major barrier to natalizumab use. Extended dosing intervals have been proposed as a way to maintain therapeutic efficacy and reduce progressive multifocal leukoencephalopathy incidence. This is the first reported case of progressive multifocal leukoencephalopathy in a patient using an extended dosing regimen (300 mg/6 weeks). A close clinical and imaging monitoring allowed early detection, which is a major prognostic factor. A favorable outcome was seen with a therapy comprising plasma exchange therapy, mirtazapine, mefloquine and cidofovir. Further studies will be needed to assess the potential role of extended dosing intervals to improve prognosis in patients receiving natalizumab and also to measure its impact clinically and/or radiologically.