Black holes and high levels of neurofilaments in glial fibrillary acidic protein - astrocytopathy: a case report.

BACKGROUND AND PURPOSE: Glial fibrillary acidic protein (GFAP) is an intracellular protein of the astrocytic cytoskeleton. Recently, autoantibodies to GFAP detected by cell-based assay in cerebrospinal fluid (CSF) or serum have been implicated in cerebral astrocytopathy, presenting predominantly with autoimmune meningoencephalomyelitis. However, the phenotypic spectrum, prognosis and therapeutics of this new entity remain to be elucidated. METHODS: Herein, we report radiological, CSF and serological findings during disease exacerbation and remission, from a patient with autoimmune GFAP astrocytopathy, presenting as an immunotherapy responsive GFAP IgG-associated meningoencephalomyelitis. RESULTS: Brain and spine magnetic resonance imaging revealed meningeal enhancement, T2 hyperintensities, black holes, significant sulci widening and spinal atrophy. In addition, high levels of neurofilaments (NfL) and GFAP were also identified during disease exacerbation, consistent with the appearance of the black holes. CONCLUSIONS: To date, black holes and atrophy have never been reported before in autoimmune GFAP astrocytopathy. These findings, combined with the high levels of GFAP and NfL, suggest the existence of an underlying neurodegenerative mechanism in addition to the known inflammatory response. Further studies are needed to elucidate the pathomechanism of GFAP-astrocytopathies.

Heterogeneity of Baló's concentric sclerosis: a study of eight cases with different therapeutic concepts.

BACKGROUND: Baló's Concentric Sclerosis (BCS) is a rare heterogeneous demyelinating disease with a variety of phenotypes on Magnetic Resonance Imaging (MRI). Existing literature lacks data especially on the therapeutic approach of the disease which we intended to elucidate by means of suggesting a new possible BCS classification and introducing different therapeutic concepts based on each BCS-subgroup characteristics. METHODS: We present a retrospective study of eight treated patients with BCS-type lesions, emphasizing on MRI characteristics and differences on therapeutic maneuvers. RESULTS: Data analysis showed: at disease onset the BCS-type lesion was tumefactive (size ≥2 cm) in 6 patients, with a mean size of 2.7 cm (± 0.80 SD); a coexistence of MS-like plaques on brain MRI was identified in 7 patients of our cohort. The mean age was 26.3 years (±7.3 SD) at disease onset and the mean follow-up period was 56.8 months (range 9-132 months). According to radiological characteristics and response to therapies, we further categorized them into 3 subgroups: a) Group-1; BCS with or without coexisting nonspecific white matter lesions; poor response to intravenous methylprednisolone (IVMP); treated with high doses of immunosuppressive agents (4 patients), b) Group-2; BCS with typical MS lesions; good response to IVMP; treated with MS-disease modifying therapies (2 patients), c) Group-3; BCS with typical MS lesions; poor response to IVMP; treated with rituximab (2 patients). CONCLUSIONS: Our study introduces a new insight regarding the categorization of BCS into three subgroups depending on radiological features at onset and during the course of the disease, in combination with the response to different immunotherapies. Immunosuppressive agents such as cyclophosphamide are usually effective in BCS. However, therapeutic alternatives like anti-CD20 monoclonal antibodies or more classical disease-modifying MS therapies can be considered when BCS has also mixed lesions similar to MS. Future studies with a larger sample size are necessary to further establish these findings, thus leading to better treatment algorithms and improved clinical outcomes.

Translational Mini-Review Series on B cell subsets in disease. B cells in multiple sclerosis: drivers of disease pathogenesis and Trojan horse for Epstein-Barr virus entry to the central nervous system?

The recent success of therapies directed at B cells has highlighted their potential as central players in multiple sclerosis (MS) pathogenesis. Exciting new data showed that B cell depletion led to reduced clinical and magnetic resonance imaging (MRI) evidence of disease activity. However, the mechanisms of action remain unknown, but could involve autoantibody production, antigen presentation and/or cytokine production by B cells. Another exciting line of investigation in the field of MS comes from latent infection of memory B cells by Epstein-Barr virus (EBV). These cells are hijacked as 'Trojan horses' and 'smuggle' the virus into the central nervous system (CNS). Thus, these new anti B cell treatments will also be likely to have anti-viral effects. We briefly review recent findings in the field of MS pathogenesis, and highlight promising new targets for therapeutic intervention in MS.

Monoclonal antibodies against the acetylcholine receptor gamma-subunit as site specific probes for receptor tyrosine phosphorylation.

Tyrosine phosphorylation of the nicotinic acetylcholine receptor (AChR) may be involved in AChR desensitization and clustering. Torpedo AChR gamma-subunit is phosphorylated at Tyr365. Using overlapping synthetic peptides, we have precisely mapped the epitopes of five anti-gamma-subunit monoclonal antibodies (mAbs) and found that the epitope(s) for the mAbs 154, 165 and 168 (gamma 365-370) all contain Tyr365. mAb 168 is a known blocker of AChR channel function. Using peptide analogues, Tyr365 was found to be indispensable for mAb165 binding; furthermore its binding was selectively inhibited by in vitro AChR tyrosine phosphorylation. The possible connection between gamma-subunit phosphorylation and regulation of AChR function and the proven usefulness of these mAbs as tools should facilitate functional studies of AChR gamma-subunit phosphorylation.

Association of innate immune activation with latent Epstein-Barr virus in active MS lesions.

OBJECTIVE: To determine whether the activation of innate immune responses, which can be elicited by pathogenic and endogenous triggers, is associated with the presence of Epstein-Barr virus (EBV) infection in the multiple sclerosis (MS) brain. METHODS: White matter postmortem MS (n = 10) and control tissue (n = 11) was analyzed for the expression of the proinflammatory cytokine interferon α (IFNα) by immunohistochemistry and for EBV by using the highly sensitive method of EBV-encoded RNA (EBER) in situ hybridization. RESULTS: We detected overexpression of IFNα in active areas of white matter MS lesions but not in inactive MS lesions, normal-appearing white matter, or normal brains. The presence of IFNα in macrophages and microglia (expressing human leukocyte antigen class II) is suggestive of local production as part of an acute inflammatory process. Interestingly, EBERs were also specifically detected in areas where IFNα was overexpressed in these preselected active MS lesions. EBER+ cells were also found in CNS lymphoma and stroke cases, but were absent in other control brains. We next addressed a potential mechanism, e.g., the role of EBERs in eliciting IFNα production, and transfected EBERs into human embryonic kidney (HEK) cells. We used HEK cells that stably expressed Toll-like receptor-3, which recognizes double-stranded RNAs, associated with many viral infections. EBERs elicited IFNα production in vitro. CONCLUSION: These findings suggest that latent EBV infection may contribute to the inflammatory milieu in active MS lesions by activating innate immune responses, e.g., IFNα production. Unraveling the underlying mechanisms may help in uncovering causal pathways and developing better treatment strategies for MS and other neuroinflammatory diseases.