Epidemiology of NMOSD in Catalonia: Influence of the new 2015 criteria in incidence and prevalence estimates.

BACKGROUND: Population-based studies on neuromyelitis optica spectrum disorders (NMOSD) are limited, and it is unclear whether the rates have changed with the implementation of the new 2015 criteria. OBJECTIVES: To estimate the incidence and prevalence of NMOSD in Catalonia (Spain), using both the 2006 and the 2015 criteria. METHODS: In this clinic-based retrospective study, patients diagnosed with NMOSD between 2006 and 2015 were identified using multiple sources, including direct contact to all Catalan hospitals, identification of cases through the Catalan Health Surveillance System, and registry of antibodies to aquaporin-4 (AQP4-IgG) and myelin oligodendrocyte glycoprotein (MOG-IgG) in a reference laboratory. The incidence rate was calculated for the period 1 January 2006-1 January 2016 and prevalence for the date 1 January 2016. RESULTS: We identified 74 patients (by the 2015 criteria). Most patients were Caucasian (81%), and female (76%) with a median age at disease onset of 42 years (range, 10-76 years). In total, 54 (73%) patients were positive for AQP4-IgG, 11 (15%) double-seronegative, and 9 (12%) MOG-IgG-positive. Rates of incidence and prevalence (0.63/1,000,000 person-years and 0.89/100,000, respectively) were 1.5-fold higher than those reported by the 2006 criteria. Lowest rates were seen in children and elder people and highest in women and middle-aged people (40-59 years). The female predominance was lost in incident AQP4-IgG-seronegative children and AQP4-IgG-positive elder people. MOG-IgG and double-seronegativity contributed similarly but did not influence the long-term outcome. CONCLUSION: The new criteria increase the estimates, but NMOSD remains as a rare disease. The differences in age- and sex-specific estimates highlight the importance of the serologic classification.

Leukocyte adhesion molecule dynamics after Natalizumab withdrawal in Multiple Sclerosis.

Cell-adhesion molecules (CAMs) dynamics in Multiple Sclerosis (MS) patients have been widely studied after Natalizumab (NTZ) introduction. However, their temporal dynamics after NTZ withdrawal (NTZ-W) has not been described. We prospectively evaluate changes in the expression levels of CAMs (CD49d, CD29, L-Selectin and CD11a) involved in T cell migration of 22 MS patients after NTZ-W. CD49d, CD29 and CD11a expression experienced a continuous increase expression two months after NTZ-W and Cd49d expression at month six after NTZ-W correlated to NTZ treatment duration, both in CD45+CD4+ and CD45+CD8+. CD49d expression up to month three after NTZ-W was related to MS activity in CD45+CD8+ at the end of the study. Results from this study suggest that patients with a longer NTZ treatment are more susceptible to present a "molecular rebound" after NTZ-W. CD49d determination may be a useful tool to closely monitor MS activity in patients who interrupt NTZ.

Assessing Blood-Based Biomarkers to Define a Therapeutic Window for Natalizumab.

Natalizumab is a monoclonal antibody that binds CD49d. Although it is one of the most effective treatments for Relapsing-Remitting Multiple Sclerosis (RRMS), a dosing regimen has not been optimized for safety and efficacy in individual patients. We aimed to identify biomarkers to monitor Natalizumab treatment and to establish a personalized dose utilizing an ongoing longitudinal study in 29 RRMS patients under Natalizumab with standard interval dose (SD) of 300 mg/4wks or extended interval dose (EID) of 300 mg/6wks. Blood samples were analyzed by flow cytometry to determine CD49d saturation and expression in several T and B lymphocytes subpopulations. Each patient was analyzed at two different timepoints separated by 3 Natalizumab administrations. Natalizumab and sVCAM-1 levels in serum were also analyzed using ELISA. To determine the reproducibility of various markers, two different timepoints were compared and no significant differences were observed for CD49d expression nor for saturation; SD patients had higher saturation levels (~80%) than EID patients (~60%). A positive correlation exists between CD49d saturation and Natalizumab serum levels. CD49d expression and saturation are stable parameters that could be used as biomarkers in the immunomonitoring of Natalizumab treatment. Moreover, Natalizumab and sVCAM-1 serum levels could be used to optimize an individual's dosing schedule.

Absence of MxA induction is related to a poor clinical response to interferon beta treatment in multiple sclerosis patients.

The aim of this study is to investigate whether induction of myxovirus resistance protein A (MxA) mRNA after 3 months of interferon-ß administration is related to the treatment response in multiple sclerosis (MS) patients. In this prospective study, MS patients were enrolled before starting treatment. Demographic, clinical and radiological variables were recorded. Blood samples were obtained before, and at 3 and 12 months after interferon-ß treatment. Real-time PCR was used to analyze MxA mRNA expression. Patients were classified as MxA-low or -high depending on MxA levels at baseline, and as MxA-induced or -non-induced according to whether an increase in MxA expression was detected at month 3. Time to the next relapse was investigated using Cox proportional hazards regression analysis. One hundred and four patients were selected and followed for a median of 2.2 years (IQR 1.6-3.5). On Cox regression analysis, a higher EDSS score before treatment (HR 1.57; 95 % CI 1.02-2.40; p = 0.039), MxA-high status at baseline (HR 2.71; 95 % CI 1.26-5.81; p = 0.010), and MxA-non-induced at month 3 (HR 2.49; 95 % CI 1.08-5.68; p = 0.031), were predictors of poor response to interferon-ß in naïve MS patients. Patients showing a lower capacity for MxA induction following 3 months of interferon-ß treatment are more likely to be non-responders to this therapy.