Neuromyelitis Optica (NMO) is an autoimmune disease with a higher prevalence in non-European populations. Because the Mexican population resulted from the admixture between mainly Native American and European populations, we used genome-wide microarray, HLA high-resolution typing and AQP4 gene sequencing data to analyze genetic ancestry and to seek genetic variants conferring NMO susceptibility in admixed Mexican patients. A total of 164 Mexican NMO patients and 1,208 controls were included. On average, NMO patients had a higher proportion of Native American

Patients with multiple sclerosis (MS) who present coronavirus disease 2019 (COVID-19) are of particular interest to neurologists. These patients have a neuroimmune disease and receive immunomodulatory or immunosuppressive therapies in the long-term. We present here data from 73 patients with MS and a confirmed diagnosis of COVID-19 from five Latin American countries. Fifteen patients (20.5%) were hospitalized and two patients died. The use of anti-CD20 therapies was the only risk factor associated to hospitalization and death. Despite the small sample size, this study highlights the awareness regarding therapeutic options for MS during the pandemic.

Background: Regulatory CD4+ T cells (Tregs) exhibit functional alterations in patients with multiple sclerosis (MS). Transforming growth factor (TGF)-β is a key regulator of Treg development and function. Objective: The objective of this study is to determine whether the expression of functionally relevant TGF-β-regulated molecules is altered in Tregs from patients with MS. Methods: Expression of nine Treg markers was analyzed by multi-color flow cytometry in CD4+ T cells and Treg subpopulations of 31 untreated MS patients and age- and sex-matched healthy donors (HDs). Correlations between Treg marker expression and clinical variables were sought. Results: Expression of the transcription factor Helios, which defines thymic-derived Tregs, was decreased in this Treg subpopulation. The frequency of peripherally generated Tregs was increased in patients with MS, particularly in patients with progressive MS. Low frequencies of thymic-derived Tregs were associated with magnetic resonance imaging (MRI) lesion-burden and a high relapse rate. Four surface markers associated with TGF-β signaling (ABCA1, BTLA, DNAM-1, and GARP) were differentially expressed on Tregs from patients with MS and HDs. Expression levels of CD73, CD103, ABCA1, and PAR2 showed strong correlations with disease severity. Conclusion: We have identified novel markers abnormally expressed on Tregs from patients with MS that could detect patients with severe disease.

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