Massive exacerbation of multiple sclerosis after withdrawal and early restart of treatment with natalizumab

Immunopathogenesis of multiple sclerosis: molecular and cellular mechanisms and new immunotherapeutic approaches

BACKGROUND

Multiple sclerosis (MS) is a central nervous system (CNS) demyelinating autoimmune disease with increasing global prevalence. It predominantly affects females, especially those of European descent. The interplay between environmental factors and genetic predisposition plays a crucial role in MS etiopathogenesis.

METHODS

We searched recent relevant literature on reputable databases, which include, PubMed, Embase, Web of Science, Scopus, and ScienceDirect using the following keywords: multiple sclerosis, pathogenesis, autoimmunity, demyelination, therapy, and immunotherapy.

RESULTS

Various animal models have been employed to investigate the MS etiopathogenesis and therapeutics. Autoreactive T cells within the CNS recruit myeloid cells through chemokine expression, leading to the secretion of inflammatory cytokines driving the MS pathogenesis, resulting in demyelination, gliosis, and axonal loss. Key players include T cell lymphocytes (CD4+ and CD8+), B cells, and neutrophils. Signaling dysregulation in inflammatory pathways and the immunogenetic basis of MS are essential considerations for any successful therapy to MS. Data indicates that B cells and neutrophils also have significant roles in MS, despite the common belief that T cells are essential. High neutrophil-to-lymphocyte ratios correlate with MS severity, indicating their contribution to disease progression. Dysregulated signaling pathways further exacerbate MS progression.

CONCLUSION

MS remains incurable, but disease-modifying therapies, monoclonal antibodies, and immunomodulatory drugs offer hope for patients. Research on the immunogenetics and immunoregulatory functions of gut microbiota is continuing to provide light on possible treatment avenues. Understanding the complex interplay between genetic predisposition, environmental factors, and immune dysregulation is critical for developing effective treatments for MS.

Multiple faces of multiple sclerosis in the era of highly efficient treatment modalities: Lymphopenia and switching treatment options challenges daily practice

The expanded treatment landscape in relapsing-remitting multiple sclerosis (MS) has resulted in highly effective treatment options and complexity in managing disease- or drug-related events during disease progression. Proper decision-making requires thorough knowledge of the immunobiology of MS itself and an understanding of the main principles behind the mechanisms that lead to secondary autoimmunity affecting organs other than the central nervous system as well as opportunistic infections. The immune system is highly adapted to both environmental and disease-modifying agents. Immune reconstitution following cell depletion or cell entrapment therapies eliminates pathogenic aspects of the disease but can also lead to distorted immune responses with harmful effects. Atypical relapses occur with second-line treatments or after their discontinuation and require appropriate clinical decisions. Lymphopenia is a result of the mechanism of action of many drugs used to treat MS. However, persistent lymphopenia and cell-specific lymphopenia could result in disease exacerbation, secondary autoimmunity, or the emergence of opportunistic infections. Clinicians treating patients with MS should be aware of the multiple faces of MS under novel, efficient treatment modalities and understand the intricate brain-immune cell interactions in the context of an altered immune system. MS relapses and disease progression still occur despite the current treatment modalities and are mediated either by failure to control effector mechanisms inherent to MS pathophysiology or by new drug-related mechanisms. The multiple faces of MS due to the highly adapted immune system of patients impose the need for appropriate switching therapies that safeguard disease remission and further clinical improvement.

Immunopathology of Tumefactive Demyelinating Lesions-From Idiopathic to Drug-Related Cases

Tumefactive demyelinating lesions (TDL) represent a diagnostic dilemma for clinicians, and in rare atypical cases a collaboration of a neuroradiologist, a neurologist, and a neuropathologist is warranted for accurate diagnosis. Recent advances in neuropathology have shown that TDL represent an umbrella under which many different diagnostic entities can be responsible. TDL can emerge not only as part of the spectrum of classic multiple sclerosis (MS) but also can represent an idiopathic monophasic disease, a relapsing disease with recurrent TDL, or could be part of the myelin oligodendrocyte glycoprotein (MOG)- and aquaporin-4 (AQP4)-associated disease. TDL can appear during the MS disease course, and increasingly cases arise showing an association with specific drug interventions. Although TDL share common features with classic MS lesions, they display some unique features, such as extensive and widespread demyelination, massive and intense parenchymal infiltration by macrophages along with lymphocytes (mainly T but also B cells), dystrophic changes in astrocytes, and the presence of Creutzfeldt cells. This article reviews the existent literature regarding the neuropathological findings of tumefactive demyelination in various disease processes to better facilitate the identification of disease signatures. Recent developments in immunopathology of central nervous system disease suggest that specific pathological immune features (type of demyelination, infiltrating cell type distribution, specific astrocyte pathology and complement deposition) can differentiate tumefactive lesions arising as part of MS, MOG-associated disease, and AQP4 antibody-positive neuromyelitis optica spectrum disorder. Lessons from immunopathology will help us not only stratify these lesions in disease entities but also to better organize treatment strategies. Improved advances in tissue biomarkers should pave the way for prompt and accurate diagnosis of TDL leading to better outcomes for patients.

A Review of Clinical and Imaging Findings in Tumefactive Demyelination

OBJECTIVE. Tumefactive demyelination mimics primary brain neoplasms on imaging, often necessitating brain biopsy. This article reviews the literature for the clinical and radiologic findings of tumefactive demyelination in various disease processes to facilitate identification of tumefactive demyelination on imaging. CONCLUSION. Both clinical and radiologic findings must be integrated to distinguish tumefactive demyelinating lesions from similarly appearing lesions on imaging. Further research on the immunopathogenesis of tumefactive demyelination and associated conditions will elucidate their interrelationship.

Acute Multiple Sclerosis Relapse

PURPOSE OF REVIEW

This article discusses acute exacerbations (relapses) of multiple sclerosis (MS). Relapses are a hallmark of MS and are often associated with significant functional impairment and decreased quality of life. This review discusses the proposed pathophysiology of MS relapses, triggering factors, associated markers, variants of clinical presentation, and diagnostic recommendations.

RECENT FINDINGS

Most MS exacerbations are followed by a period of repair leading to clinical remission; however, residual deficits may persist after MS relapse and contribute to the stepwise progression of disability. Treatment of MS relapses is important as it helps to shorten the duration of disability associated with their course. Successful treatment of relapse helps patients with MS obtain a vital sense of being able to gain control over the disease. Patients with relapsing MS who receive treatment report better outcomes than those who are simply observed. This article discusses treatment options for MS relapse, including systemic corticosteroids, adrenocorticotropic hormone, and plasma exchange. Recent findings related to the mechanisms of action of steroids and adrenocorticotropic hormone are also reviewed, and other potential therapies are assessed. A proposed algorithm for MS relapse management is presented, including strategies for steroid-resistant MS exacerbations.

SUMMARY

MS relapses need to be recognized in a timely manner and treated using recommended therapeutic methods.

[Immune reconstitution inflammatory syndrome and rebound syndrome in multiple sclerosis patients who stopped disease modification therapy: current understanding and a case report]

More and more multiple sclerosis patients have been receiving treatment with new immunomodulatory drugs. Its discontinuation because of side-effects, lack of efficacy or pregnancy has been increasing as well. This paper reviews such severe complications of natalizumab and fingolimod cessation as immune reconstitution inflammatory syndrome (IRIS) and rebound. The short history, immunopathogenesis and diagnostic criteria of IRIS in individuals with human immunodeficiency virus infection are covered. Clinical and radiological presentations as well as possible pathogenic mechanisms of IRIS in patients treated with natalizumab and fingolimod are discussed. The authors also report the case of a woman with multiple sclerosis treated with fingolimod, who experienced a severe relapse when she stopped treatment. Diagnostic criteria and prognostic factors for IRIS and rebound are needed in patients with multiple sclerosis who discontinue the new disease modification therapy.

Catastrophic outcome of patients with a rebound after Natalizumab treatment discontinuation

INTRODUCTION

Natalizumab (NTZ) is an effective drug for the treatment of relapsing-remitting multiple sclerosis. In some patients discontinuation is mandatory due to the risk of progressive multifocal leukoencephalopathy. However, severe clinical and radiological worsening has been described after drug cessation. Our aim was to describe the clinical and radiological features of the rebound phenomenon.

MATERIAL AND METHODS

Patients switched from NTZ to Fingolimod (FTY) who had presented a rebound after discontinuation were selected. Clinical and magnetic resonance imaging (MRI) data were collected.

RESULTS

Four JC virus positive patients were included. The mean disease duration was 9.5 years (SD: 4.12) with a mean time of 3.1 years on NTZ. All patients started FTY within 3-4 months. Neurological deterioration started in a mean time of 3.5 months (SD: 2.08) with multifocal involvement: 75% motor disturbances, 50% cognitive impairment, 25% seizures. The average worsening in Expanded Disability Status Scale [EDSS] was of 3.25 points (SD: 2.33). The MRI showed a very large increase in T2 and gadolinium-enhanced lesions (mean: 23.67, SD: 18.58). All patients received 5 days of IV methylprednisolone, one patient required plasma exchange. All the patients presented neurological deterioration with an EDSS worsening of 1.13 points (SD: 0.48). After the rebound three patients continued treatment with FTY, only one patient restarted NTZ.

CONCLUSION

Discontinuation of NTZ treatment may trigger a severe rebound with marked clinical and radiological worsening. A very careful evaluation of benefit-risk should be considered before NTZ withdrawal, and a close monitoring and a short washout period is recommended after drug withdrawal.

Massive intracerebral Epstein-Barr virus reactivation in lethal multiple sclerosis relapse after natalizumab withdrawal

Rebound of disease activity in multiple sclerosis patients after natalizumab withdrawal is a potentially life-threatening event. To verify whether highly destructive inflammation after natalizumab withdrawal is associated with Epstein-Barr virus (EBV) reactivation in central nervous system infiltrating B-lineage cells and cytotoxic immunity, we analyzed post-mortem brain tissue from a patient who died during a fulminating MS relapse following natalizumab withdrawal. Numerous EBV infected B cells/plasma cells and CD8+ T cells infiltrated all white matter lesions; the highest frequency of EBV lytically infected cells and granzyme B+ CD8+ T cells was observed in actively demyelinating lesions. These results may encourage switching to B-cell depleting therapy after natalizumab discontinuation.

Natalizumab-associated PML

Progressive multifocal leukoencephalopathy (PML) associated with natalizumab treatment continues to be a severe problem of clinically successful therapy. This is an update of risk stratification developments and discusses the current approach to depict and calculate PML incidence and PML risk. (1) PML incidence and resulting risk used in today's clinical practice are potentially outdated and the risk for patients with prior immunosuppression might have been underestimated. (2) Risk stratification according to treatment duration epochs likely suggests lower risk due to patients stopping treatment within a given epoch. PML incidence within the complete treatment epoch is statistically lowered due to the fact that patients at the beginning of an epoch presumably have a lower PML risk than the patients at the end. Periodic risk is not accurate in assessing risk for long treatment durations. (3) The JC virus (JCV) serostatus risk factor has low specificity concerning PML prediction and anti-JCV seroconversion during treatment with natalizumab further lowers its specificity over time. Specificity of the risk factor treatment duration varies depending on the average treatment duration and the number of short-term patients. These short-term patients reduce overall average treatment duration and thus enhance the specificity of the risk factor and reduce overall PML incidence. It is also suggested that short-term natalizumab patients are exclusively non-PML, even though they might still develop PML. Clinicians have to consider the cumulative risk of patients to stratify efficiently.

Natalizumab treatment of multiple sclerosis: new insights

Natalizumab is a monoclonal antibody directed against the α4 chain of the very late activating antigen 4 and α4β7 integrins, present on the leukocytes surface, used as monotherapy for the treatment of relapsing-remitting multiple sclerosis. It substantially reduces relapse rate and the accumulation of disability, but its use is associated with a very adverse event, that is the development of progressive multifocal leukoencephalopathy, a fatal demyelinating disease of the CNS, due to the lytic replication of the human polyomavirus JC. The main focus of the review is to describe the newest insights on natalizumab, its current use in the clinical practice, the natalizumab-treated patients' management and the risk stratification related to the progressive multifocal leukoencephalopathy development.

Immunological and pathological characterization of fatal rebound MS activity following natalizumab withdrawal

BACKGROUND

Severe rebound multiple sclerosis (MS) activity is a life-threatening complication of natalizumab (NTZ) withdrawal, for which pathogenesis and treatment are still unclear. We report the immunological and pathological characterization of a case of central nervous system (CNS) inflammatory demyelination after NTZ discontinuation.

OBJECTIVE

To understand the pathophysiology of this neuroinflammatory condition.

METHODS

Antemortem blood and cerebrospinal fluid (CSF) analysis was compared with postmortem pathological studies, as well as with novel flow cytometry characterization of immune cells isolated from the CNS parenchyma.

RESULTS

Pathological analysis of the brain revealed the presence of innumerable active inflammatory demyelinating lesions typical of immunopathological pattern II. Monocytes/macrophages and B cells were enriched in the CNS parenchyma compared to the CSF. Numerous plasma cells were present in the lesions, but CD8 T lymphocytes were predominant in the parenchyma, as opposed to CD4 in the CSF. CNS-infiltrating lymphocytes expressed high levels of adhesion molecules, granzyme B (GzB), interferon-gamma (IFN-γ), and interleukin (IL)-17.

CONCLUSIONS

Our results underline the differences in immune cell populations between the CSF and the CNS parenchyma, and suggest that aggressive immunosuppressive therapy targeting both T and B lymphocytes is warranted to control the overwhelming CNS inflammation.

Dysregulation of sphingosine 1 phosphate receptor-1 (S1P1) signaling and regulatory lymphocyte-dependent immunosuppression in a model of post-fingolimod MS rebound

Fingolimod affords protection from MS by sequestering lymphocytes in secondary lymphoid organs via down regulation of their sphingosine 1 phosphate receptor (S1P1). Unexpectedly, accumulating evidence indicates that patients who discontinue fingolimod treatment may be at risk of rehearsal of magnetic resonance (MR) and clinical disease activity, sometimes featuring dramatic rebound. We therefore developed in vivo and in vitro models of post-fingolimod MS rebound to unravel its cellular and molecular mechanisms. The impact of fingolimod withdrawal on T regulatory lymphocytes was also investigated by means of cytofluorimetric analysis and antigen-specific lymphocyte proliferation assays. We show that mice with relapsing-remitting experimental autoimmune encephalomyelitis (EAE) undergo extremely severe, chronic disease rebound upon discontinuation of fingolimod. Remarkably, rebound is preceded by a burst of S1P1 overexpression in lymph node-entrapped lymphocytes that correlates with subsequent massive lymphocyte egress and widespread CNS immune infiltration. Also, consistent with the ability of S1P1 to counteract polarization and function of T regulatory lymphocytes their number and suppression of effector T cells is reduced by fingolimod suspension. Data disclose the first pathogenic mechanisms of post-fingolimod rebound that may be targeted for therapeutic intervention.

Neuroimaging of Natalizumab Complications in Multiple Sclerosis: PML and Other Associated Entities

Natalizumab (Tysabri) is a monoclonal antibody (α4 integrin antagonist) approved for treatment of multiple sclerosis, both for patients who fail therapy with other disease modifying agents and for patients with aggressive disease. Natalizumab is highly effective, resulting in significant decreases in rates of both relapse and disability accumulation, as well as marked decrease in MRI evidence of disease activity. As such, utilization of natalizumab is increasing, and the presentation of its associated complications is increasing accordingly. This review focuses on the clinical and neuroimaging features of the major complications associated with natalizumab therapy, focusing on the rare but devastating progressive multifocal leukoencephalopathy (PML). Associated entities including PML associated immune reconstitution inflammatory syndrome (PML-IRIS) and the emerging phenomenon of rebound of MS disease activity after natalizumab discontinuation are also discussed. Early recognition of neuroimaging features associated with these processes is critical in order to facilitate prompt diagnosis, treatment, and/or modification of therapies to improve patient outcomes.