Progressive multifocal leukoencephalopathy following treatment for Wegener's granulomatosis

Drug-associated progressive multifocal leukoencephalopathy: a clinical, radiological, and cerebrospinal fluid analysis of 326 cases

The implementation of a variety of immunosuppressive therapies has made drug-associated progressive multifocal leukoencephalopathy (PML) an increasingly prevalent clinical entity. The purpose of this study was to investigate its diagnostic characteristics and to determine whether differences herein exist between the multiple sclerosis (MS), neoplasm, post-transplantation, and autoimmune disease subgroups. Reports of possible, probable, and definite PML according to the current diagnostic criteria were obtained by a systematic search of PubMed and the Dutch pharmacovigilance database. Demographic, epidemiologic, clinical, radiological, cerebrospinal fluid (CSF), and histopathological features were extracted from each report and differences were compared between the disease categories. In the 326 identified reports, PML onset occurred on average 29.5 months after drug introduction, varying from 14.2 to 37.8 months in the neoplasm and MS subgroups, respectively. The most common overall symptoms were motor weakness (48.6 %), cognitive deficits (43.2 %), dysarthria (26.3 %), and ataxia (24.1 %). The former two also constituted the most prevalent manifestations in each subgroup. Lesions were more often localized supratentorially (87.7 %) than infratentorially (27.4 %), especially in the frontal (64.1 %) and parietal lobes (46.6 %), and revealed enhancement in 27.6 % of cases, particularly in the MS (42.9 %) subgroup. Positive JC virus results in the first CSF sample were obtained in 63.5 %, while conversion after one or more negative outcomes occurred in 13.7 % of cases. 52.2 % of patients died, ranging from 12.0 to 83.3 % in the MS and neoplasm subgroups, respectively. In conclusion, despite the heterogeneous nature of the underlying diseases, motor weakness and cognitive changes were the two most common manifestations of drug-associated PML in all subgroups. The frontal and parietal lobes invariably constituted the predilection sites of drug-related PML lesions.

Experience with rituximab in the treatment of antineutrophil cytoplasmic antibody associated vasculitis

Prior to the 1970s, severe cases of antineutrophil cytoplasmic antibody associated vasculitis (AAV) were thought to be invariably fatal. However, the use of cyclophosphamide-based treatment regimens fundamentally altered disease outcomes, transforming AAV into a manageable, chronic illness. Despite the tremendous success of cyclophosphamide in the treatment of AAV, there remained a need for alternative therapies, due to high rates of treatment failures and significant toxicities. In recent years, with the introduction of targeted biologic response modifiers into clinical practice, many have hoped that the treatment options for AAV could be expanded. Rituximab, a chimeric monoclonal antibody directed against the B-lymphocyte protein CD20, has been the most successful biologic response modifier to be used in AAV. Following the first report of its use in AAV in 2001, experience with rituximab for treatment of AAV has rapidly expanded. Rituximab, in combination with glucocorticosteroids, is now well established as a safe and effective alternative to cyclophosphamide for remission induction for severe manifestations of granulomatosis with polyangiitis and microscopic polyangiitis. In addition, initial experiences with rituximab for remission maintenance in these diseases have been favorable, as have experiences for remission induction in eosinophilic granulomatosis with polyangiitis.

Treatment of ANCA-associated vasculitis: new therapies and a look at old entities

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a small-vessel vasculitis that primarily comprises 2 clinical syndromes: granulomatosis with polyangiitis and microscopic polyangiitis. Cyclophosphamide and glucocorticoids have traditionally been used for induction of remission. However, more recent studies have shown that rituximab is as effective as cyclophosphamide for induction therapy in patients with newly diagnosed severe AAV and superior for patients with relapsing AAV. There is also accumulating evidence indicating a potential role of rituximab for maintenance therapy in AAV. In this article, we will review the evidence supporting the various treatment choices for patients with AAV.

JC virus agnoprotein inhibits in vitro differentiation of oligodendrocytes and promotes apoptosis

Productive infection of oligodendrocytes, which are responsible for the formation of myelin sheath in the central nervous system, with the human neurotropic virus JC virus (JCV) causes the fatal demyelinating disease progressive multifocal leukoencephalopathy (PML). In addition to encoding T antigen and the capsid proteins, which are produced at the early and late phases of the infection cycle, respectively, JCV encodes a small regulatory protein named agnoprotein that is important for successful completion of the virus life cycle. Here we used bipotential CG-4 cells to examine the impact of agnoprotein on oligodendrocyte differentiation and survival in the absence of JCV lytic infection. We demonstrate that the expression of agnoprotein delayed the formation of complex outgrowth networks of the cells during oligodendrocyte differentiation. These alterations were accompanied by high levels of DNA damage, induction of proapoptotic proteins, and suppression of prosurvival signaling. Accordingly, apoptosis was significantly increased upon the induction of CG-4 cells toward differentiation in cells expressing agnoprotein. These observations provide the first evidence for the possible involvement of agnoprotein, independent from its role in viral replication, in a series of biological events that may contribute to the pathological features seen in PML lesions.

The safety profile of cyclophosphamide in multiple sclerosis therapy

Cyclophosphamide (Cyc) is an alkylating agent used to treat malignancies and autoimmune diseases, such as lupus nephritis, rheumatoid arthritis and immune-mediated neuropathies. Over the past 40 years, Cyc has also been applied to treat multiple sclerosis (MS) and the effective stabilisation of rapidly progressive forms of MS has been demonstrated in several studies. Cyc has a dose-dependent bimodal effect on the immune system. High doses have been demonstrated to induce an anti-inflammatory immune deviation (i.e., suppression of T helper 1 and enhancement of T helper 2 activity), affect CD4CD25(high) regulatory T cells and establish a state of marked immunosuppression. Data from the literature suggest that Cyc is particularly indicated in the treatment of young MS patients, suffering from a very active inflammatory disease characterised by frequent relapses and rapid accumulation of disability and displaying gadolinium-enhancing lesions on brain magnetic resonance. The most common Cyc-based therapeutic protocol applied in MS consists of monthly intravenous pulses for 1 year followed by bimonthly pulses for the second year, with or without prior infusion of corticosteroids. This protocol is usually well tolerated by the patients. Indeed, most of the side effects (mild alopecia, nausea and vomiting, cystitis) are dose dependent, transient and completely reversible. Definitive amenorrhoea is observed only in older female patients (aged > 40 years). Cyc has a safety and efficacy profile similar to that of mitoxantrone and can be used in patients whose disease is not controlled by IFN-beta or glatiramer acetate. Short course (6-12 months) of Cyc therapy can precede the initiation of immunomodulatory treatment in selected patients with an aggressive MS onset.

Central nervous system infections - a potential complication of systemic immunotherapy

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Central nervous system involvement in Wegener granulomatosis

Wegener granulomatosis (WG) is an antineutrophil cytoplasmic antibody (ANCA)-associated granulomatous vasculitis of small and medium-sized vessels. This vasculitis involves mainly the upper and lower respiratory tracts and kidneys, although WG may affect any organ. Central nervous system (CNS) involvement is an uncommon manifestation of WG, reported in 7%-11% of patients. Three major mechanisms have been incriminated as causing CNS disease in WG: contiguous invasion of granuloma from extracranial sites, remote intracranial granuloma, and CNS vasculitis. Herein we describe 6 patients with WG-related CNS involvement, 2 of whom had chronic hypertrophic pachymeningitis, 3 with pituitary involvement, and 1 with cerebral vasculitis. CNS involvement was present at disease onset in 2 patients and occurred 5-18 years after WG diagnosis in the remaining 4. Based on these observations and a review of the literature, we discuss the pathogenic mechanisms, clinical features, imaging findings, treatment, and outcome of meningeal, pituitary, and vascular involvement, with an emphasis on differential diagnoses, prognosis, and therapeutic management of WG-related CNS involvement.

Infectious CNS disease as a differential diagnosis in systemic rheumatic diseases: three case reports and a review of the literature

BACKGROUND

Immunosuppressive treatment of rheumatic diseases may be associated with several opportunistic infections of the brain. The differentiation between primary central nervous system (CNS) involvement and CNS infection may be difficult, leading to delayed diagnosis.

OBJECTIVE

To differentiate between CNS involvement and CNS infection in systemic rheumatic diseases.

METHODS AND RESULTS

Three patients with either longstanding or suspected systemic rheumatic diseases (systemic lupus erythematodes, Wegener's granulomatosis, and cerebral vasculitis) who presented with various neuropsychiatric symptoms are described. All three patients were pretreated with different immunosuppressive drugs (leflunomide, methotrexate, cyclophosphamide) in combination with corticosteroids. Magnetic resonance imaging of the brain was suggestive of infectious disease, which was confirmed by cerebrospinal fluid analysis or stereotactic brain biopsy (progressive multifocal leucoencephalopathy (PML) in two and nocardiosis in one patient).

DISCUSSION

More than 20 cases of PML or cerebral nocardiosis in patients receiving corticosteroids and cytotoxic drugs for rheumatic disease have been reported. The clinical aspects of opportunistic CNS infections and the role of brain imaging, cerebrospinal fluid analysis and stereotactic brain biopsy in the differential diagnosis are reviewed.