Extracellular vesicles (EVs) are membrane-bound particles involved in intercellular communication. They carry proteins, lipids, and nucleotides such as microRNAs (miRNAs) from the secreting cell that can modulate target cells. We and others have previously described the presence of EVs in peripheral blood of multiple sclerosis (MS) patients and postulated them as novel biomarkers. However, their immune function in MS pathogenesis and the effect during the onset of new immunomodulatory therapies on EVs remain elusive. Here, we isolated plasma EVs from fingolimod-treated MS patients in order to assess whether EVs are affected by the first dose of the treatment. We quantified EVs, analyzed their miRNA cargo, and checked their immune regulatory function. Results showed an elevated EV concentration with a dramatic change in their miRNA cargo 5 h after the first dose of fingolimod. Besides, EVs obtained prior to fingolimod treatment showed an increased immune regulatory activity compared to EVs obtained 5 h post-treatment. This work suggests that EVs are implicated in the mechanism of action of immunomodulatory treatments from the initial hours and opens a new avenue to explore a potential use of EVs for early treatment monitoring.

The presence of anti-myelin lipid-specific oligoclonal IgM bands (LS-OCMBs) has been defined as an accurate predictor of an aggressive evolution of multiple sclerosis. However, the detection of this biomarker is performed in cerebrospinal fluid, a quite invasive liquid biopsy. In the present study we aimed at studying the expression profile of miRNA, snoRNA, circRNA and linearRNA in peripheral blood mononuclear cells (PBMCs) from patients with lipid-specific oligoclonal IgM band characterization. We included a total of 89 MS patients, 47 with negative LS-OCMB status and 42 with positive status. Microarray (miRNA and snoRNA) and RNA-seq (circular and linear RNAs) were used to perform the profiling study in the discovery cohort and candidates were validated by RT-qPCR in the whole cohort. The biomarker potential of the candidates was evaluated by ROC curve analysis. RNA-seq and RT-qPCR validation revealed that two circular (hsa_circ_0000478 and hsa_circ_0116639) and two linear RNAs (IRF5 and MTRNR2L8) are downregulated in PBMCs from patients with positive LS-OCMBs. Finally, those RNAs show a performance of a 70% accuracy in some of the combinations. The expression of hsa_circ_0000478, hsa_circ_0116639, IRF5 and MTRNR2L8 might serve as minimally invasive biomarkers of highly active disease.

Objective: This study aimed to unravel the single tetraspanin pattern of extracellular vesicles (EVs), L1CAM⁺ and GLAST⁺ EV levels as diagnostic biomarkers to stratify people with multiple sclerosis (pwMS), specifically relapsing–remitting (RRMS) and primary progressive (PPMS). Methods: The ExoView platform was used to directly track single EVs using a clinically feasible volume of cerebrospinal fluid (CSF) and serum samples. This technology allowed us to examine the patterns of classical tetraspanin and quantify the levels of L1CAM and GLAST proteins, commonly used to immunoisolate putative neuron- and astrocyte-derived EVs. Results: The tetraspanin EV pattern does not allow us to differentiate RRMS, PPMS and non-MS donors neither in CSF nor serum, but this was associated with the type of biofluid. L1CAM⁺ and GLAST⁺ EVs showed a very low presence of tetraspanin proteins. Additionally, a significant decrease in the particle count of L1CAM⁺ EVs was detected in L1CAM-captured spots, and L1CAM⁺ and GLAST⁺ EVs decreased in GLAST-captured spots in the CSF from PPMS subjects compared to RRMS. Interestingly, only GLAST⁺ EVs exhibited a lower quantity in the CSF from PPMS compared to both MS and non-MS samples. Finally, GLAST⁺ EVs demonstrated a medium negative and significative correlation with GFAP levels—a biomarker of MS progression, astrocyte damage and neurodegenerative processes. Conclusions: ExoView technology could track neural EV biomarkers and be potentially useful in the diagnostic evaluation and follow-up of pwMS. GLAST⁺ EVs might provide insights into the etiology of PPMS and could offer small windows to elucidate the molecular mechanisms behind its clinical presentation.

Background: Emerging evidence suggests that SARS-CoV-2 infection and vaccines may trigger autoimmune responses in predisposed individuals. Idiopathic inflammatory myopathies (IIMs) are diseases with diverse clinical manifestations, often associated with myositis autoantibodies (MAs). Diagnosing IIM is challenging due to limitations in classification criteria and diagnostic assays. This study aimed to describe the incidence of IIM following SARS-CoV-2 infection or vaccination and compare rates between exposures. Methods: A multicenter observational study was conducted with 788 patients from 11 Spanish referral centers. A total of 1209 autoantibodies including myositis-specific autoantibodies (MSAs) and myositis-associated autoantibodies (MAAs), were analyzed using line blot immunoassay (LIA). Results: The study identified distinct patterns in aminoacyl-tRNA synthetase (ARS) antibody frequencies compared to pre-pandemic periods. Anti-PL-7 was the most prevalent ARS antibody (14.85%), while anti-Jo-1 was less frequent (7.23%). Anti-MDA5, commonly linked to SARS-CoV-2 infection, was detected in 11.68%. ANA positivity was observed in 60.66%, suggesting an autoimmune background. The most frequent diagnoses were anti-synthetase syndrome (ASSD) or IIM-non-ASSD (21.31%), followed by other systemic autoimmune diseases (SAIDs) (13.57%). Among the cohort, 91.13% received at least one dose of a messenger RNA (mRNA) COVID-19 vaccine, with a median of three doses per patient. Patients with prior SARS-CoV-2 infection or heterologous vaccination showed a higher frequency of multiple autoantibody positivity (p < 0.05), reflecting distinct immune signatures. Conclusions: This study provides valuable insights into the autoimmune risks and phenotypes associated with SARS-CoV-2 infection and vaccination, establishing a basis for further research on IIM and its link to MSAs and MAAs.

ABO blood groups have been related to COVID19 infection. ABO blood groups are slightly differently distributed in the populations and therefore these results should be replicated in the specific areas with a proper control population. In this work, we present data from 412 COVID19 patients and 17796 blood donors from Gipuzkoa, a region in Northern Spain. Our data shows the importance of group O as a protective factor.

Emerging evidence suggests that the severe-acute-respiratory-syndrome-related coronavirus (SARS- CoV-2) infection and anti-SARS-CoV-2 vaccines may trigger autoimmune responses in genetically predisposed individuals. Idiopathic inflammatory myopathies (IIMs) are a group of diseases with a broad spectrum of clinical manifestations featured by the presence of myositis autoantibodies (MAs). The diagnosis of IIM is challenging due to the limitations of current classification criteria and diagnostic assays. We conducted a multicenter observational study, whose main goal was to describe the incidence of IIM following exposure to SARS-CoV-2 infection and/or its specific vaccination, and to compare the rates of both. A total of 788 patients belonging to 11 different Spanish referral centers were analyzed, with a cumulative count of 1,209 MAs measured by line blot immunoassays (LIA). The study identified distinct patterns in the frequency of aminoacyl-tRNA synthetase (ARS) antibodies compared to pre-pandemic periods. Notably, the most prevalent ARS antibody identified associated to IIM was anti-PL-7 (14.85%), whereas anti-Jo1, traditionally the most frequent antibody documented, had a frequency of 7.23% in our cohort. Anti- MDA5, the most commonly described antibody in the literature associated with the SARS-CoV-2 infection, was identified in 11.68% of our patients. Our cohort displayed positive antinuclear antibodies (ANA) result in 61% of patients, which suggests an underlying autoimmune background. The most prevalent final diagnoses were anti- synthetase syndrome (ASSD) or IIM-non-ASSD (21.31% of total cases) and other systemic autoimmune diseases (SAID) with 13.57% of cases. 91.13% of patients received at least one dose of a messenger RNA (mRNA) coronavirus disease 2019 (COVID-19) vaccine, with a median of three doses per patient. It is noteworthy that patients with prior SARS-CoV-2 infection or heterologous vaccination demonstrated a higher frequency of multiple autoantibody positivity (p<0.05), which could reflect different humoral and cellular immune signatures. This collaborative work enhances our understanding of IIM and may facilitate the optimization of care through the implementation of standardized approaches. Further investigation is required to fully characterize the autoimmune risks and phenotypes following a diagnosis of SARS-CoV-2 infection or vaccination.Emerging evidence suggests that the severe-acute-respiratory-syndrome-related coronavirus (SARS- CoV-2) infection and anti-SARS-CoV-2 vaccines may trigger autoimmune responses in genetically predisposed individuals. Idiopathic inflammatory myopathies (IIMs) are a group of diseases with a broad spectrum of clinical manifestations featured by the presence of myositis autoantibodies (MAs). The diagnosis of IIM is challenging due to the limitations of current classification criteria and diagnostic assays. We conducted a multicenter observational study, whose main goal was to describe the incidence of IIM following exposure to SARS-CoV-2 infection and/or its specific vaccination, and to compare the rates of both. A total of 788 patients belonging to 11 different Spanish referral centers were analyzed, with a cumulative count of 1,209 MAs measured by line blot immunoassays (LIA). The study identified distinct patterns in the frequency of aminoacyl-tRNA synthetase (ARS) antibodies compared to pre-pandemic periods. Notably, the most prevalent ARS antibody identified associated to IIM was anti-PL-7 (14.85%), whereas anti-Jo1, traditionally the most frequent antibody documented, had a frequency of 7.23% in our cohort. Anti- MDA5, the most commonly described antibody in the literature associated with the SARS-CoV-2 infection, was identified in 11.68% of our patients. Our cohort displayed positive antinuclear antibodies (ANA) result in 61% of patients, which suggests an underlying autoimmune background. The most prevalent final diagnoses were anti- synthetase syndrome (ASSD) or IIM-non-ASSD (21.31% of total cases) and other systemic autoimmune diseases (SAID) with 13.57% of cases. 91.13% of patients received at least one dose of a messenger RNA (mRNA) coronavirus disease 2019 (COVID-19) vaccine, with a median of three doses per patient. It is noteworthy that patients with prior SARS-CoV-2 infection or heterologous vaccination demonstrated a higher frequency of multiple autoantibody positivity (p<0.05), which could reflect different humoral and cellular immune signatures. This collaborative work enhances our understanding of IIM and may facilitate the optimization of care through the implementation of standardized approaches. Further investigation is required to fully characterize the autoimmune risks and phenotypes following a diagnosis of SARS-CoV-2 infection or vaccination.