Antibody signatures in patients with histopathologically defined multiple sclerosis patterns.

Early active multiple sclerosis (MS) lesions can be classified histologically into three main immunopathological patterns of demyelination (patterns I-III), which suggest pathogenic heterogeneity and may predict therapy response. Patterns I and II show signs of immune-mediated demyelination, but only pattern II is associated with antibody/complement deposition. In pattern III lesions, which include Baló's concentric sclerosis, primary oligodendrocyte damage was proposed. Serum antibody reactivities could reflect disease pathogenesis and thus distinguish histopathologically defined MS patterns. We established a customized microarray with more than 700 peptides that represent human and viral antigens potentially relevant for inflammatory demyelinating CNS diseases, and tested sera from 66 patients (pattern I n = 12; II n = 29; III n = 25, including 8 with Baló's), healthy controls, patients with Sjögren's syndrome and stroke patients. Cell-based assays were performed for aquaporin 1 (AQP1) and AQP4 antibody detection. No single peptide showed differential binding among study cohorts. Because antibodies can react with different peptides from one protein, we also analyzed groups of peptides. Patients with pattern II showed significantly higher reactivities to Nogo-A peptides as compared to patterns I (p = 0.02) and III (p = 0.02). Pattern III patients showed higher reactivities to AQP1 (compared to pattern I p = 0.002, pattern II p = 0.001) and varicella zoster virus (VZV, compared to pattern II p = 0.05). In patients with Baló's, AQP1 reactivity was also significantly higher compared to patients without Baló's (p = 0.04), and the former revealed distinct antibody signatures. Histologically, Baló's patients showed loss of AQP1 and AQP4 in demyelinating lesions, but no antibodies binding conformational AQP1 or AQP4 were detected. In summary, higher reactivities to Nogo-A peptides in pattern II patients could be relevant for enhanced axonal repair and remyelination. Higher reactivities to AQP1 peptides in pattern III patients and its subgroup of Baló's patients possibly reflect astrocytic damage. Finally, latent VZV infection may cause peripheral immune activation.

Myelinoclastic diffuse sclerosis (Schilder's disease) is immunologically distinct from multiple sclerosis: results from retrospective analysis of 92 lumbar punctures.

BACKGROUND: Myelinoclastic diffuse sclerosis (MDS; also termed Schilder's disease) is a rare inflammatory demyelinating disorder of the central nervous system characterised by demyelination of vast areas of the white matter. It is unclear whether MDS is a variant of multiple sclerosis (MS) or a disease entity in its own right. OBJECTIVE: To compare the cerebrospinal fluid (CSF) features of MDS with those of MS. METHODS: Retrospective analysis of the CSF profile of all patients with MDS reported in the medical literature between 1960 and 2018. RESULTS: The most striking finding was a substantial lack of oligoclonal bands (OCBs) in MDS, which were absent in at least 77% (30/39) of all lumbar punctures (LP) in the total cohort and in 86% in the subgroup of patients with normal very long-chain fatty acid serum ratios (VLCFA). Almost all cases published in the past 15 years were negative for OCBs. These findings are in contrast to MS, in which OCBs are present in up to 98% of cases (p < 0.00001 when compared with reference works in MS; both in adult and in pediatric patients). CSF pleocytosis was absent in at least 79% (46/58) of all LP (p < 0.0001 vs. MS) and in 92% (24/26) of LPs in the VLCFA-tested subgroup. CSF total protein levels were elevated in 56% of all LPs (p < 0.0001 vs. MS) and in 63% of LPs in the VLCFA-tested subgroup and were often higher than in typical MS (> 100 mg/dL in 13/22; up to 220 mg/dL). EBV serum antibodies, which are present in virtually all patients with MS, and the so-called MRZ (measles/rubella/zoster) reaction, a highly specific marker of MS, were absent in all of the few patients tested. In addition, we discuss further differences between MS and MDS, taking into account also Schilder's original comprehensive case description from 1912. CONCLUSION: In the majority of patients diagnosed with MDS, CSF features differ significantly from those typically found in MS and are more similar to those previously reported in patients with myelin oligodendrocyte glycoprotein-immunoglobulin G (IgG)-positive encephalomyelitis, aquaporin-4-IgG-positive neuromyelitis optica spectrum disorders or Baló's concentric sclerosis. Our data suggest that MDS and MS are immunopathologically distinct entities in the majority of cases.

[Clinical and biochemical characteristics of atypical variants of multiple sclerosis]. / Kliniko-biokhimicheskie kharakteristiki atipichnykh variantov rasseiannogo skleroza.

AIM: To study the clinical and biochemical features of atypical variants of multiple sclerosis (MS) (tumefactive demyelination (TD), Balo's concentric sclerosis (BCS)) and acute disseminated encephalomyelitis (ADEM)). MATERIAL AND METHODS: Forty-two patients were studied, including 32 patients with atypical variants of MS (6 patients with BCS and 26 patients with TD) and 10 patients with ADEM. The control group included 20 healthy volunteers. Clinical characteristics and EDSS scores were evaluated. Antibodies to aquaporin 1 (AQP1-IgG), aquaporin 4 (AQP4-IgG), antibodies to myelin oligodendrocyte glycoprotein (MOG-IgG) and aquaporin 1 (AQP1) in serum and cerebrospinal fluid (CSF) were detected using ELISA. RESULTS AND CONCLUSION: BCS and TD occurred both in isolation and comorbid with MS (in 50% of cases with BCS, 50% of cases with TD). Atypical symptoms of MS were detected in 50% of cases of CFS, 15.4% of cases of PD. The levels of CSF cytosis and CSF protein were not significantly different between the groups. The levels of AQP1-IgG, AQP4-IgG, AQP1, MOG-IgG in serum with BCS, TD and ADEM were significantly higher than in the control group. No significant differences were found between atypical variants of MS. A correlation between a high level of MOG-IgG and the EDSS score in BCS was shown. MOG-IgG may have a pathogenetic significance in BCS. Further studies of AQP1-IgG, AQP4-IgG and MOG-IgG in patients with atypical variants of MS are needed.

Baló's concentric sclerosis is immunologically distinct from multiple sclerosis: results from retrospective analysis of almost 150 lumbar punctures.

BACKGROUND: Baló's concentric sclerosis (BCS) is a rare inflammatory demyelinating disorder of the central nervous system characterised by concentric layers of demyelination. It is unclear whether BCS is a variant of multiple sclerosis (MS) or a disease entity in its own right. OBJECTIVE: To compare the cerebrospinal fluid (CSF) features of BCS to those of MS. METHODS: Retrospective analysis of the CSF profile of all patients with BCS reported in the medical literature between 1980 and 2017. RESULTS: In total, the results of 146 lumbar punctures (LP) in 132 patients were analysed. The most striking finding was a lack of CSF-restricted oligoclonal bands (OCB) in 66% (56/85) of all LP in the total BCS group, in 74% (14/19) in the subgroup of patients with both MRI and histological evidence for BCS, and in 82% (18/22) in the subgroup of patients with highest radiological confidence (high MRI quality, ≥ 3 layers of demyelination). OCB disappeared in 1/2 initially OCB-positive patients. These findings are in stark contrast to MS, in which OCB are present in ≥ 95% of patients and are thought to remain stably detectable over the entire course of disease (p < 0.000001). OCB frequency was low both in 'historic' patients (1980-2009; 37%) and in more recent patients (2010-2017; 31%). OCB-positive and OCB-negative patients did not differ significantly with regard to age, sex, disease duration, number of Baló-like lesions on MRI, number of relapses, treatment or final outcome. In accordance with the high rate of OCB negativity, Link's IgG index was negative in 63% of all tested samples (p < 0.000001 vs. MS). CSF pleocytosis was present in 28% (27/96; p < 0.000001 vs. MS) and elevated CSF total protein levels in 41% (31/76) of samples. CONCLUSION: OCB and IgG index frequencies in BCS are much more similar to those reported in neuromyelitis optica or myelin oligodendrocyte glycoprotein antibody-associated encephalomyelitis than to those in MS. Our findings suggest that in most cases BCS-like lesions denote the presence of a disease entity immunologically distinct from MS. In addition, we provide data on the demographics, clinical course and radiological features of BCS based on the largest cohort analysed to date.

Baló's concentric sclerosis and tumefactive demyelination: a shared immunopathogenesis?

Baló's concentric sclerosis (BCS) and tumefactive demyelination (TD) are considered atypical forms of multiple sclerosis (MS). Baló lesions are characterized by concentric rings corresponding to alternating bands of demyelination and relatively preserved myelin (Hu and Lucchinetti, 2009). Tumefactive lesions are pseudotumoural demyelinating lesions of >2 cm and may have an open ring-enhancing magnetic resonance imaging appearance (Hu and Lucchinetti, 2009; Lucchinetti et al., 2008; Altintas et al., 2012). We present a patient who developed limb weakness and focal seizures secondary to a lesion radiologically and histopathologically consistent with BCS who, six months later, developed a tumefactive demyelinating lesion. This is the first description of BCS and TD occurring in the same patient and is particularly notable because of the lack of any other more typical demyelinating lesions on the MRIs. The nature of BCS and TD in relation to more typical multiple sclerosis is discussed.

Baló's concentric sclerosis.

Baló's concentric sclerosis is often regarded as a rare variant of multiple sclerosis. Patients with this disorder present with acute or subacute neurological deterioration, with MRI showing one or more concentrically multilayered ring-like lesions usually in the cerebral white matter. Historically, Baló's concentric sclerosis was thought fatal in all cases. However, the availability of MRI has led to a better appreciation of the variable natural history of patients presenting with radiologically evident Baló lesions and the clinical association with multiple sclerosis and, less often, with other neurological disorders. Important advances have increased understanding of the immunopathogenic mechanisms associated with the formation of Baló lesions. However, how to treat an acute lesion and when or whether to start treatment are less well understood, although for patients with Baló lesions who also fulfil standard diagnostic criteria for multiple sclerosis, our opinion is that treatment with multiple sclerosis disease-modifying therapy would seem reasonable.

Extensive loss of connexins in Baló's disease: evidence for an auto-antibody-independent astrocytopathy via impaired astrocyte-oligodendrocyte/myelin interaction.

Extensive aquaporin-4 (AQP4) loss without perivascular deposition of either activated complement or immunoglobulins is a characteristic of Baló's disease. Our aim in this study was to investigate the relationship between astrocytopathy and demyelination in Baló's disease, focusing on connexins (Cx), which form gap junctions among glial cells and myelin. Autopsied specimens from four cases that provided seven actively demyelinating concentric lesions infiltrated with numerous CD68(+) macrophages were immunohistochemically examined for the astrocyte markers glial fibrillary acidic protein (GFAP), AQP4, Cx43, Cx30 and megalencephalic leukoencephalopathy with subcortical cyst 1 (MLC1). Specimens were also stained for oligodendrocyte/myelin markers, namely Cx32, Cx47, myelin-associated glycoprotein (MAG), myelin oligodendrocyte glycoprotein (MOG), oligodendrocyte-specific protein (OSP) and Nogo-A. Serum samples from six patients that had undergone magnetic resonance imaging, confirming a diagnosis of Baló's disease, were assayed for the presence of anti-Cx43, -Cx32 and -AQP4 antibodies. Despite the presence of numerous GFAP- and MLC1-positive astrocytes, there was a marked decrease in the levels of Cx43, Cx32 and Cx47. At the leading edges, Cx43 and AQP4 were mostly absent despite positive GFAP, MLC1, Cx32, Cx47, MOG, MAG, and OSP immunoreactivity. Of the six Baló's disease patients, none were positive for anti-Cxs or -AQP4 antibodies. Baló's disease is characterized by extensive loss of Cxs and AQP4, and a lack of auto-antibodies to Cxs and AQP4. Loss of Cx43 and AQP4 in the presence of other oligodendrocyte/myelin proteins at the leading edges suggests the possibility that auto-antibody-independent astrocytopathy may contribute to disease pathology via the disruption of astrocyte-oligodendrocyte/myelin interactions.

Pathology of demyelinating diseases.

There has been significant progress in our understanding of the pathology and pathogenesis of central nervous system inflammatory demyelinating diseases. Neuropathological studies have provided fundamental new insights into the pathogenesis of these disorders and have led to major advances in our understanding of multiple sclerosis (MS) heterogeneity, the substrate of irreversible progressive disability in MS, the relationship between inflammation and neurodegeneration in MS, the neuroimaging correlates of MS lesions, and the pathogenesis of other central nervous system inflammatory disorders, including neuromyelitis optica, acute disseminated encephalomyelitis, and Balo's concentric sclerosis. Herein, we review the pathological features of these central nervous system inflammatory demyelinating disorders and discuss neuropathological studies that have yielded novel insights into potential mechanisms involved in the formation of the demyelinated lesion.

Astrocytopathy in Balo's disease.

Baló's disease is characterized by alternating rings of demyelination and preserved myelin. As additional multiple sclerosis (MS)-like lesions often coexist in Baló's cases, Baló's disease is regarded as a variant of MS. In demyelinated areas, many hypertrophic astrocytes are present in close contact with oligodendrocytes, which often show apoptotic features. In the outermost layer of preserved myelin, stress proteins involved in tissue preconditioning are abundant in oligodendrocytes. The peri-plaque perimeter is thus assumed resistant to subsequent attack, thereby leaving a layer of preserved myelin. In some cases, Baló's concentric rings develop step by step in a centrifugal direction, whereas many other cases show simultaneous enhancement of multiple rings. Therefore tissue preconditioning and successive ring formation does not fully describe the mechanism of the disease. We recently reported that in four Filipino Baló's patients, aquaporin-4 (AQP4) was extensively lost in glial fibrillary acidic protein-positive hypertrophic astrocytes, both in demyelinated and myelinated layers of all actively demyelinating lesions. None of six further patients with MRI-confirmed Baló's disease were seropositive for anti-AQP4 antibody. I propose that AQP4 astrocytopathy, in the absence of anti-AQP4 antibody, is characteristic of Baló's disease. This hypothesis should be tested in future experimental studies.

Reappraisal of aquaporin-4 astrocytopathy in Asian neuromyelitis optica and multiple sclerosis patients.

Selective aquaporin-4 (AQP4) loss and vasculocentric complement and immunoglobulin deposition are characteristic of neuromyelitis optica (NMO). We recently reported extensive AQP4 loss in demyelinated and myelinated layers of Baló's lesions without perivascular immunoglobulin and complement deposition. We aimed to reappraise AQP4 expression patterns in NMO and multiple sclerosis (MS). We evaluated AQP4 expression relative to glial fibrillary acidic protein, extent of demyelination, lesion staging (CD68 staining for macrophages), and perivascular deposition of complement and immunoglobulin in 11 cases with NMO and NMO spectrum disorders (NMOSD), five with MS and 30 with other neurological diseases. The lesions were classified as actively demyelinating (n = 66), chronic active (n = 86), chronic inactive (n = 48) and unclassified (n = 12). Six NMO/NMOSD and two MS cases showed preferential AQP4 loss beyond the demyelinated areas, irrespective of lesion staging. Five NMO and three MS cases showed AQP4 preservation even in actively demyelinating lesions, despite grave tissue destruction. Vasculocentric deposition of complement and immunoglobulin was detected only in NMO/NMOSD patients, with less than 30% of actively demyelinating lesions showing AQP4 loss. Our present and previous findings suggest that antibody-independent AQP4 loss can occur in heterogeneous demyelinating conditions, including NMO, Baló's disease and MS.

[Recent progress in multiple sclerosis research: astrocytopathy in demyelinating diseases].

Multiple sclerosis (MS) is a demyelinating disease of the central nervous system (CNS) while neuromyelitis optica (NMO) is an inflammatory disease of the CNS that selectively affects the optic nerves and spinal cord. Recently, a specific IgG against NMO, designated NMO-IgG, was discovered, and the relevant antigen was found to be aquaporin 4 (AQP4), one of the major water channel proteins in the CNS. The sensitivity of NMO-IgG/anti-AQP4 antibodies for NMO varies from 30% to 80%, while specificity is 90-100%. Pathological studies on NMO patients have revealed perivascular immune complex (IgM, IgG and C9neo) deposition and extensive loss of AQP4 in active lesions, while myelin basic protein (MBP) staining was relatively preserved. IgG from NMO-IgG-seropositive NMO patients induces astrocyte death in culture in the presence of complement, and reproduces astrocyte loss in vivo when MBP-specific T cells are co-transferred to cause experimental autoimmune encephalomyelitis. Therefore, it is postulated that the complement-activating anti-AQP4 antibodies have a pivotal role in the development of NMO lesions through astrocyte necrosis, and that demyelination is a secondary event. Baló's disease is characterized by alternating rings of demyelination and preserved myelin. As additional MS-like lesions often coexist in Baló's cases, Baló's disease is regarded as a variant of MS. However, Baló's concentric rings are also observed in NMO cases and in Asian opticospinal MS patients in the cerebral white matter, spinal cord and optic chiasm. In demyelinated areas, many hypertrophic astrocytes are present, in close contact with oligodendrocytes that often show apoptotic features. In the outermost layer of preserved myelin, stress proteins involved in tissue preconditioning are abundant in oligodendrocytes. The peri-plaque white matter is thus assumed resistant to subsequent attack, thereby leaving a layer of preserved myelin. In some patients, Baló's concentric rings develop systematically in a centrifugal direction, while other patients show simultaneous enhancement of multiple rings. Therefore, tissue preconditioning and successive ring formation does not fully explain the mechanism of the disease. We recently reported that AQP4 was extensively lost in glial fibrillary acidic protein-positive hypertrophic astrocytes, both in demyelinated and myelinated layers of all actively demyelinating lesions in four Filipino Baló's patients. None of six other patients with magnetic resonance imaging-confirmed Baló's disease was seropositive for anti-AQP4 antibodies. I therefore propose that AQP4 astrocytopathy, in the absence of anti-AQP4 antibodies, is characteristic of Baló's disease. Since a similar loss of AQP4 without perivascular deposition of immunoglobulin and complement is also observed in autopsied CNS tissues from NMO and MS cases, I consider that autoantibody-independent astrocytopathy may widely occur in human CNS demyelinating diseases, including Baló's disease, MS and NMO.

Alpers syndrome with prominent white matter changes.

Alpers syndrome is a fatal neurogenetic disorder caused by the mutations in POLG1 gene encoding the mitochondrial DNA polymerase gamma (polgamma). Two missense variants, c.248T > C (p.L83P), c.2662G > A (p.G888S) in POLG1 were detected in a 10-year-old Chinese girl with refractory seizures, acute liver failure after exposure to valproic acid, cortical blindness, and psychomotor regression. The pathology of left occipital lobe showed neuronal loss, spongiform degeneration, astrocytosis, and demyelination. In addition, there were prominent white matter changes in a series of brain magnetic resonance imaging (MRI) and increased immunological factors in CSF.

Immunohistochemical analysis of brain macrophages in adrenoleukodystrophy.

Using a panel of monoclonal antibodies directed against antigenic determinants present at the surface of mononuclear cells, we characterized the macrophage infiltration in frozen brain specimens from a patient with adrenoleukodystrophy by immunohistochemical staining. This study demonstrated that macrophages were the main infiltrating cells in the white matter and that there was a wide variability in their phenotype according to their location: they stained very strongly with Leu-M5, EBM11, Leu-M3, To5 and 2LPM 19 C in the perivascular cuffs, whereas they stained principally with Leu-M5 and EBM11 and to a lesser extent with To5 and 2LPM19c in the white matter. In addition to the expression of MHC class II and CD4 molecules, macrophages exhibited strong labelling with 7G7B6, a monoclonal antibody raised against IL2 receptors. These results attest that macrophages, which infiltrate the brain parenchyma have various phenotypes, and very likely different states of activation, and suggest that interleukin-2 plays an important role during this activation.

Clinical improvement of adrenoleukodystrophy following intravenous gammaglobulin therapy.

A patient with adrenoleukodystrophy was successfully treated by means of intravenous gammaglobulin injections. The clinical symptoms, especially visual loss, were apparently relieved and no neurological deterioration was observed during a 18-month period following the start of the gammaglobulin treatment.