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Objective: To identify biomarkers associated with the development of progressive multifocal leukoencephalopathy (PML) in multiple sclerosis (MS) patients treated with natalizumab (NTZ). Methods: Relapsing-remitting MS (RRMS) patients who developed PML under NTZ therapy (pre-PML) and non-PML natalizumab-treated patients (NTZ-ctr) were included in the study. Cryopreserved peripheral blood mononuclear cells (PBMC) and serum samples collected at baseline, at one- and two-year treated time points, and during PML were analyzed for gene expression by RNA-sequencing and for serum protein levels by LUMINEX and ELISA assays respectively. Results: Among top differentially expressed genes in the RNA-sequencing between pre-PML and NTZ-ctr patients, pathway analysis revealed a high representation of genes belonging to the following categories: pro-angiogenic factors (MMP9, VEGFA), chemokines (CXCL1, CXCL5, IL8, CCL2), cytokines (IL1B, IFNG), and plasminogen- and coagulation-related molecules (SERPINB2, PLAU, PLAUR, TFPI, THBD). Serum protein levels for these candidates were measured in a two-step manner in a screening cohort and a validation cohort of pre-PML and NTZ-ctr patients. Only MMP9 was validated and, in pre-PML patients MMP9 protein levels were significantly reduced at baseline compared with NTZ-ctr patients and levels remained lower at later time points during NTZ treatment. Interpretation: The results from this study suggest that the pro-angiogenic factor MMP9 may play a role as biomarker associated with the development of PML in MS patients treated with NTZ. This article is protected by copyright. All rights reserved.

Objective Using positron emission tomography (PET) with [11C]flumazenil ([11C]FMZ), an antagonist of the central benzodiazepine site located within the GABAA receptor, we quantified and mapped neuronal damage in the gray matter (GM) of patients with multiple sclerosis (MS) at distinct disease stages. We investigated the relationship between neuronal damage and white matter (WM) lesions and evaluated the clinical relevance of this neuronal PET metric. Methods A cohort of 18 MS patients (9 progressive and 9 relapsing-remitting) was compared to healthy controls and underwent neurological and cognitive evaluations, high-resolution dynamic [11C]FMZ PET imaging and brain magnetic resonance imaging. [11C]FMZ binding was estimated using the partial saturation protocol providing voxel-wise absolute quantification of GABAA receptor concentration. PET data were evaluated using a region of interest (ROI) approach as well as on a vertex-by-vertex basis. Results [11C]FMZ binding was significantly decreased in the cortical GM of MS patients, compared to controls (–10%). Cortical mapping of benzodiazepine receptor concentration ([11C]FMZ Bmax) revealed significant intergroup differences in the bilateral parietal cortices and right frontal areas. ROI analyses taking into account GM volume changes showed extensive decrease in [11C]FMZ binding in bilateral parietal, cingulate, and insular cortices as well as in the thalami, amygdalae, and hippocampi. These changes were significant in both progressive and relapsing-remitting forms of the disease and correlated with WM T2-weighted lesion load. [11C]FMZ cortical binding correlated with cognitive performance. Interpretation This pilot study showed that PET with [11C]FMZ could be a promising and sensitive quantitative marker to assess and map the neuronal substrate of GM pathology in MS. Ann Neurol 2015;78:554–567

To identify biomarkers associated with the development of progressive multifocal leukoencephalopathy (PML) in multiple sclerosis (MS) patients treated with natalizumab (NTZ).Relapsing-remitting MS patients who developed PML under NTZ therapy (pre-PML) and non-PML NTZ-treated patients (NTZ-ctr) were included in the study. Cryopreserved peripheral blood mononuclear cells and serum samples collected at baseline, at 1- and 2-year treated time points, and during PML were analyzed for gene expression by RNA sequencing and for serum protein levels by Luminex and enzyme-linked immunosorbent assays, respectively.Among top differentially expressed genes in the RNA sequencing between pre-PML and NTZ-ctr patients, pathway analysis revealed a high representation of genes belonging to the following categories: proangiogenic factors (MMP9, VEGFA), chemokines (CXCL1, CXCL5, IL8, CCL2), cytokines (IL1B, IFNG), and plasminogen- and coagulation-related molecules (SERPINB2, PLAU, PLAUR, TFPI, THBD). Serum protein levels for these candidates were measured in a 2-step manner in a screening cohort and a validation cohort of pre-PML and NTZ-ctr patients. Only matrix metalloproteinase 9 (MMP9) was validated; in pre-PML patients, MMP9 protein levels were significantly reduced at baseline compared with NTZ-ctr patients, and levels remained lower at later time points during NTZ treatment.The results from this study suggest that the proangiogenic factor MMP9 may play a role as a biomarker associated with the development of PML in MS patients treated with NTZ. Ann Neurol 2017;82:186-195.

Using positron emission tomography (PET) with [(11) C]flumazenil ([(11) C]FMZ), an antagonist of the central benzodiazepine site located within the GABAA receptor, we quantified and mapped neuronal damage in the gray matter (GM) of patients with multiple sclerosis (MS) at distinct disease stages. We investigated the relationship between neuronal damage and white matter (WM) lesions and evaluated the clinical relevance of this neuronal PET metric.A cohort of 18 MS patients (9 progressive and 9 relapsing-remitting) was compared to healthy controls and underwent neurological and cognitive evaluations, high-resolution dynamic [(11) C]FMZ PET imaging and brain magnetic resonance imaging. [(11) C]FMZ binding was estimated using the partial saturation protocol providing voxel-wise absolute quantification of GABAA receptor concentration. PET data were evaluated using a region of interest (ROI) approach as well as on a vertex-by-vertex basis.[(11) C]FMZ binding was significantly decreased in the cortical GM of MS patients, compared to controls (-10%). Cortical mapping of benzodiazepine receptor concentration ([(11) C]FMZ Bmax) revealed significant intergroup differences in the bilateral parietal cortices and right frontal areas. ROI analyses taking into account GM volume changes showed extensive decrease in [(11) C]FMZ binding in bilateral parietal, cingulate, and insular cortices as well as in the thalami, amygdalae, and hippocampi. These changes were significant in both progressive and relapsing-remitting forms of the disease and correlated with WM T2-weighted lesion load. [(11) C]FMZ cortical binding correlated with cognitive performance.This pilot study showed that PET with [(11) C]FMZ could be a promising and sensitive quantitative marker to assess and map the neuronal substrate of GM pathology in MS.