Fatima König

Relation between humoral pathological changes in multiple sclerosis and response to therapeutic plasma exchange

Early, active multiple sclerosis lesions show four immunopathological patterns of demyelination. Although these patterns differ between patients, multiple active lesions from a given patient have an identical pattern, which suggests pathogenic heterogeneity. Therapeutic plasma exchange (TPE) has been successfully used to treat fulminant demyelinating attacks unresponsive to steroids. We postulated that patients with pattern II would be more likely to improve after TPE than those with other patterns since pattern II lesions are distinguished by prominent immunoglobulin deposition and complement activation. We retrospectively studied 19 patients treated with TPE for an attack of fulminant CNS inflammatory demyelinating disease. All patients with pattern II (n=10), but none with pattern I (n=3) or pattern III (n=6), achieved moderate to substantial functional neurological improvement after TPE (p<0.0001). Patients with multiple sclerosis with pattern II pathology are more likely to respond favourably to TPE than are patients with patterns I or III.

Clinical and radiographic spectrum of pathologically confirmed tumefactive multiple sclerosis

Atypical imaging features of multiple sclerosis lesions include size >2 cm, mass effect, oedema and/or ring enhancement. This constellation is often referred to as ‘tumefactive multiple sclerosis’. Previous series emphasize their unifocal and clinically isolated nature, however, evolution of these lesions is not well defined. Biopsy may be required for diagnosis. We describe clinical and radiographic features in 168 patients with biopsy confirmed CNS inflammatory demyelinating disease (IDD). Lesions were analysed on pre- and post-biopsy magnetic resonance imaging (MRI) for location, size, mass effect/oedema, enhancement, multifocality and fulfilment of Barkhof criteria. Clinical data were correlated to MRI. Female to male ratio was 1.2 : 1, median age at onset, 37 years, duration between symptom onset and biopsy, 7.1 weeks and total disease duration, 3.9 years. Clinical course prior to biopsy was a first neurological event in 61%, relapsing–remitting in 29% and progressive in 4%. Presentations were typically polysymptomatic, with motor, cognitive and sensory symptoms predominating. Aphasia, agnosia, seizures and visual field defects were observed. At follow-up, 70% developed definite multiple sclerosis, and 14% had an isolated demyelinating syndrome. Median time to second attack was 4.8 years, and median EDSS at follow-up was 3.0. Multiple lesions were present in 70% on pre-biopsy MRI, and in 83% by last MRI, with Barkhof criteria fulfilled in 46% prior to biopsy and 55% by follow-up. Only 17% of cases remained unifocal. Median largest lesion size on T2-weighted images was 4 cm (range 0.5–12), with a discernible size of 2.1 cm (range 0.5–7.5). Biopsied lesions demonstrated mass effect in 45% and oedema in 77%. A strong association was found between lesion size, and presence of mass effect and/or oedema (P < 0.001). Ring enhancement was frequent. Most tumefactive features did not correlate with gender, course or diagnosis. Although lesion size >5 cm was associated with a slightly higher EDSS at last follow-up, long-term prognosis in patients with disease duration >10 years was better (EDSS 1.5) compared with a population-based multiple sclerosis cohort matched for disease duration (EDSS 3.5; P < 0.001). Given the retrospective nature of the study, the precise reason for biopsy could not always be determined. This study underscores the diagnostically challenging nature of CNS IDDs that present with atypical clinical or radiographic features. Most have multifocal disease at onset, and develop RRMS by follow-up. Although increased awareness of this broad spectrum may obviate need for biopsy in many circumstances, an important role for diagnostic brain biopsy may be required in some cases.

Safety limits of cathodal transcranial direct current stimulation in rats

OBJECTIVE The aim of this rat study was to investigate the safety limits of extended transcranial direct current stimulation (tDCS). tDCS may be of therapeutic value in several neuro-psychiatric disorders. For its clinical applicability, however, more stable effects are required, which may be induced by intensified stimulations. METHODS Fifty-eight rats received single cathodal stimulations at 1-1000 microA for up to 270 min through an epicranial electrode (3.5 mm(2)). Histological evaluation (H&E) was performed 48 h later. A threshold estimate was calculated from volumes of DC-induced lesions. RESULTS Brain lesions occurred at a current density of 142.9 A/m(2) for durations greater than 10 min. For current densities between 142.9 and 285.7 A/m(2), lesion size increased linearly with charge density; with a calculated zero lesion size intercept of 52,400 C/m(2). Brains stimulated below either this current density or charge density threshold, including stimulations over 5 consecutive days, were morphologically intact. CONCLUSION The experimentally determined threshold estimate is two orders of magnitude higher than the charge density currently applied in humans (171-480 C/m(2)). In relation to transcranial DC stimulation in humans the rat epicranial electrode montage may provide for an additional safety margin. SIGNIFICANCE Although these results cannot be directly transferred to humans, they encourage the development intensified tDCS protocols. Further animal studies are required, before such protocols can be applied in humans.

Wallerian degeneration: a major component of early axonal pathology in multiple sclerosis.

Axonal loss is a major component of the pathology of multiple sclerosis (MS) and the morphological basis of permanent clinical disability. It occurs in demyelinating plaques but also in the so‐called normal‐appearing white matter (NAWM). However, the contribution of Wallerian degeneration to axonal pathology is not known. Here, we analyzed the extent of Wallerian degeneration and axonal pathology in periplaque white matter (PPWM) and lesions in early multiple sclerosis biopsy tissue from 63 MS patients. Wallerian degeneration was visualized using an antibody against the neuropeptide Y receptor Y1 (NPY‐Y1R). The number of SMI‐32‐positive axons with non‐phosphorylated neurofilaments was significantly higher in both PPWM and plaques compared to control white matter. APP‐positive, acutely damaged axons were found in significantly higher numbers in plaques compared to PPWM. Strikingly, the number of NPY‐Y1R‐positive axons undergoing Wallerian degeneration was significantly higher in PPWM and plaques than in control WM. NPY‐Y1R‐positive axons in PPWM were strongly correlated to those in the lesions. Our results show that Wallerian degeneration is a major component of axonal pathology in the periplaque white matter in early MS. It may contribute to radiological changes observed in early MS and most likely plays a major role in the development of disability.

Intracerebral Human Regulatory T Cells: Analysis of CD4+CD25+FOXP3+ T Cells in Brain Lesions and Cerebrospinal Fluid of Multiple Sclerosis Patients

Impaired suppressive capacity of CD4+CD25+FOXP3+ regulatory T cells (Treg) from peripheral blood of patients with multiple sclerosis (MS) has been reported by multiple laboratories. It is, however, currently unresolved whether Treg dysfunction in MS patients is limited to reduced control of peripheral T cell activation since most studies analyzed peripheral blood samples only. Here, we assessed early active MS lesions in brain biopsies obtained from 16 patients with MS by FOXP3 immunohistochemistry. In addition, we used six-color flow cytometry to determine numbers of Treg by analysis of FOXP3/CD127 expression in peripheral blood and cerebrospinal fluid (CSF) of 17 treatment-naïve MS patients as well as quantities of apoptosis sensitive CD45ROhiCD95hi cells in circulating and CSF Treg subsets. Absolute numbers of FOXP3+ and CD4+ cells were rather low in MS brain lesions and Treg were not detectable in 30% of MS biopsies despite the presence of CD4+ cell infiltrates. In contrast, Treg were detectable in all CSF samples and Treg with a CD45ROhiCD95hi phenotype previously shown to be highly apoptosis sensitive were found to be enriched in the CSF compared to peripheral blood of MS patients. We suggest a hypothetical model of intracerebral elimination of Treg by CD95L-mediated apoptosis within the MS lesion.

Clinical course, pathological correlations, and outcome of biopsy proved inflammatory demyelinating disease

Background: A pathological classification has been developed of early active multiple sclerosis (MS) lesions that reveals four patterns of tissue injury: I—T cell/macrophage associated; II—antibody/complement associated; III—distal oligodendrogliopathy, and IV—oligodendrocyte degeneration in the periplaque white matter. Mechanisms of demyelination in early MS may differ among the subgroups. Previous studies on biopsied MS have lacked clinicopathological correlation and follow up. Critics argue that observations are not generalisable to prototypic MS. Objective: To describe the clinicopathological characteristics of the MS Lesion Project biopsy cohort. Methods: Clinical characteristics and disability of patients with pathologically confirmed inflammatory demyelinating disease (excluding ADEM) classified immunopathologically (n = 91) and patients from the Olmsted County MS prevalence cohort (n = 218) were determined. Results: Most patients who underwent biopsy and had pathologically proved demyelinating disease ultimately developed definite (n = 70) or probable (n = 12) MS (median follow up 4.4 years). Most had a relapsing remitting course and 73% were ambulatory (EDSS ⩽4) at last follow up. Nine patients remained classified as having an isolated demyelinating syndrome at last follow up. Patients with different immunopathological patterns had similar clinical characteristics. Although presenting symptoms and sex ratios differed, the clinical course in biopsy patients was similar to the prevalence cohort. Median EDSS was <4.0 in both cohorts when matched for disease duration, sex, and age. Conclusions: Most patients undergoing biopsy, who had pathologically confirmed demyelinating disease, were likely to develop MS and remain ambulatory after a median disease duration of 4.4 years. The immunopathological patterns lacked specific clinical correlations and were not related to the timing of the biopsy. These data suggest that pathogenic implications derived largely from MS biopsy studies may be extrapolated to the general MS population.

Neuroaxonal regeneration is more pronounced in early multiple sclerosis than in traumatic brain injury lesions.

The extent of irreversible neuroaxonal damage is the key determinant of permanent disability in traumatic and inflammatory conditions of the central nervous system (CNS). Structural damage is nevertheless in part compensated by neuroplastic events. However, it is unknown whether the same kinetics and mechanisms of neuroaxonal de‐ and regeneration take place in inflammatory and traumatic conditions. We analyzed neuroaxonal degeneration and plasticity in early multiple sclerosis (MS) lesions and traumatic brain injury (TBI). Neuroaxonal degeneration identified by the presence of SMI31+ chromatolytic neurons and SMI32+ axonal profiles were characteristic features of leukocortical TBI lesions. Axonal transport disturbances as determined by amyloid precursor protein (APP)+ spheroids were present in both TBI and MS lesions to a similar degree. Neurons expressing growth‐associated protein 43 (GAP43) and synaptophysin (Syn) were found under both pathological conditions. However, axonal swellings immunopositive for GAP43 and Syn clearly prevailed in subcortical MS lesions, suggesting a higher regenerative potential in MS. In this context, GAP43+/APP+ axonal spheroid ratios correlated with macrophage infiltration in TBI and MS lesions, supporting the idea that phagocyte activation might promote neuroplastic events. Furthermore, axonal GAP43+ and Syn+ swellings correlated with prolonged survival after TBI, indicating a sustained regenerative response.

Myelin oligodendrocyte glycoprotein antibodies in pathologically proven multiple sclerosis : frequency, stability and clinicopathologic correlations

Controversy exists regarding the pathogenic or predictive role of anti-myelin oligodendrocyte glycoprotein (MOG) antibodies in patients with multiple sclerosis (MS). Four immunopathological patterns (IP) have been recognized in early active MS lesions, suggesting heterogeneous pathogenic mechanisms. Whether MOG antibodies contribute to this pathological heterogeneity and potentially serve as biomarkers to identify specific pathological patterns is unknown. Here we report the frequencies of antibodies to human recombinant MOG (identified by Western blot and enzymelinked immunoabsorbent assay (ELISA)) in patients with pathologically proven demyelinating disease, and investigate whether antibody status is associated with clinical course, HLA-DR2 genotype, IP or treatment response to plasmapheresis. The biopsy cohort consisted of 72 patients: 12 pattern I, 43 pattern II and 17 pattern III. No association was found between MOG antibody status and conversion to clinically definite MS, DR-2 status, IP or response to plasmapheresis. There was poor agreement between Western blot and ELISA (kappa=0.07 for MOG IgM). Fluctuations in antibody seropositivity were seen for 3/4 patients tested serially by Western blot. This study does not support a pathologic pattern-specific role for MOG-antibodies. Variable MOG-antibody status on serial measurements, coupled with the lack of Western blot and ELISA correlations, raises concern regarding the use of MOG-antibody as an MS biomarker and underscores the need for methodological consensus.

Screening for MOG-IgG and 27 other anti-glial and anti-neuronal autoantibodies in ‘pattern II multiple sclerosis’ and brain biopsy findings in a MOG-IgG-positive case:

Background: Histopathological studies have revealed four different immunopathological patterns of lesion pathology in early multiple sclerosis (MS). Pattern II MS is characterised by immunoglobulin and complement deposition in addition to T-cell and macrophage infiltration and is more likely to respond to plasma exchange therapy, suggesting a contribution of autoantibodies. Objective: To assess the frequency of anti-myelin oligodendrocyte glycoprotein (MOG), anti-M1-aquaporin-4 (AQP4), anti-M23-AQP4, anti-N-methyl-d-aspartate-type glutamate receptors (NMDAR) and 25 other anti-neural antibodies in pattern II MS. Methods: Thirty-nine serum samples from patients with MS who had undergone brain biopsy (n = 24; including 13 from patients with pattern II MS) and from histopathologically non-classified MS patients (n = 15) were tested for anti-MOG, anti-M1-AQP4, anti-M23-AQP4, anti-NMDAR, anti-α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor-type glutamate receptors (AMPAR), anti-gamma-aminobutyric acid receptors (GABABR), anti-leucine-rich, glioma-activated protein 1 (LGI1), anti-contactin-associated protein 2 (CASPR2), anti-dipeptidyl-peptidase-like protein-6 (DPPX), anti-Tr/Delta/notch-like epidermal growth factor–related receptor (DNER), anti-Hu, anti-Yo, anti-Ri, anti-Ma1/Ma2, anti-CV2/collapsin response mediator protein 5 (CRMP5), anti-glutamic acid decarboxylase (GAD), anti-amphiphysin, anti-Ca/RhoGTPase-activating protein 26 (ARHGAP26), anti-Sj/inositol-1,4,5-trisphosphate receptor 1 (ITPR1), anti-Homer3, anti-carbonic anhydrase–related protein (CARPVIII), anti-protein kinase gamma (PKCgamma), anti-glutamate receptor delta 2 (GluRdelta2), anti-metabotropic glutamate receptor 1 (mGluR1) and anti-mGluR5, as well as for anti-glial nuclei antibodies (AGNA) and Purkinje cell antibody 2 (PCA2). Results: Antibodies to MOG belonging to the complement-activating immunoglobulin G1 (IgG1) subclass were detected in a patient with pattern II MS. Detailed brain biopsy findings are shown. Conclusion: This is the largest study on established anti-neural antibodies performed in MS so far. MOG-IgG may play a role in a small percentage of patients diagnosed with pattern II MS.

CCR5 expression on macrophages/microglia is associated with early remyelination in multiple sclerosis lesions

Remyelination in multiple sclerosis (MS) occurs spontaneously and extensively. The underlying mechanisms, however, are only partly understood. Findings in experimental animal settings suggest that inflammation promotes remyelination and repair. Here, we characterized the chemokine receptor expression profiles of macrophages/microglia in early remyelinating and completely remyelinated lesions compared with active demyelinating and inactive demyelinated MS lesions obtained in the early disease course. Biopsy material consisting of 16 MS cases was available for this study. We found that macrophages/microglia within early remyelinating lesions expressed predominantly CCR5. Our findings implicate a possible role of CCR5+ cells in initiating remyelination.