Antigen-specific T cells and autoimmunity.

Autoimmune diseases (ADs) showcase the intricate balance between the immune system's protective functions and its potential for self-inflicted damage. These disorders arise from the immune system's erroneous targeting of the body's tissues, resulting in damage and disease. The ability of T cells to distinguish between self and non-self-antigens is pivotal to averting autoimmune reactions. Perturbations in this process contribute to AD development. Autoreactive T cells that elude thymic elimination are activated by mimics of self-antigens or are erroneously activated by self-antigens can trigger autoimmune responses. Various mechanisms, including molecular mimicry and bystander activation, contribute to AD initiation, with specific triggers and processes varying across the different ADs. In addition, the formation of neo-epitopes could also be implicated in the emergence of autoreactivity. The specificity of T cell responses centers on the antigen recognition sequences expressed by T cell receptors (TCRs), which recognize peptide fragments displayed by major histocompatibility complex (MHC) molecules. The assortment of TCR gene combinations yields a diverse array of T cell populations, each with distinct affinities for self and non-self antigens. However, new evidence challenges the traditional notion that clonal expansion solely steers the selection of higher-affinity T cells. Lower-affinity T cells also play a substantial role, prompting the "two-hit" hypothesis. High-affinity T cells incite initial responses, while their lower-affinity counterparts perpetuate autoimmunity. Precision treatments that target antigen-specific T cells hold promise for avoiding widespread immunosuppression. Nevertheless, detection of such antigen-specific T cells remains a challenge, and multiple technologies have been developed with different sensitivities while still harboring several drawbacks. In addition, elements such as human leukocyte antigen (HLA) haplotypes and validation through animal models are pivotal for advancing these strategies. In brief, this review delves into the intricate mechanisms contributing to ADs, accentuating the pivotal role(s) of antigen-specific T cells in steering immune responses and disease progression, as well as the novel strategies for the identification of antigen-specific cells and their possible future use in humans. Grasping the mechanisms behind ADs paves the way for targeted therapeutic interventions, potentially enhancing treatment choices while minimizing the risk of systemic immunosuppression.

The polygenic implication of clopidogrel responsiveness: Insights from platelet reactivity analysis and next-generation sequencing.

Clopidogrel is widely used worldwide as an antiplatelet therapy in patients with acute coronary disease. Genetic factors influence interindividual variability in response. Some studies have explored the polygenic contributions in the drug response, generating pharmacogenomic risk scores (PgxPRS). Importantly, these factors are less explored in underrepresented populations, such as Latin-American countries. Identifying patients at risk of high-on-treatment platelet reactivity (HTPR) is highly valuable in translational medicine. In this study we used a custom next-generation sequencing (NGS) panel composed of 91 single nucleotide polymorphisms (SNPs) and 28 genes related to clopidogrel metabolism, to analyze 70 patients with platelet reactivity values, assessed through closure time (CT). Our results demonstrated the association of SNPs with HTPR and non-HTPR, revealing the strongest associations with rs2286823 (OR: 5,0; 95% CI: 1,02-24,48; p: 0,03), rs2032582 (OR: 4,41; 95% CI: 1,20-16,12; p: 0,019), and rs1045642 (OR: 3,38; 95% CI: 0,96-11,9; p: 0,05). Bivariate regression analysis demonstrated the significant association of several SNPs with the CT value, a "surrogate" biomarker of clopidogrel response. Exploratory results from the LASSO regression model showed a high discriminatory capacity between HTPR and non-HTPR patients (AUC: 0,955), and the generated PgxPRS demonstrated a significant negative association between the risk score, CT value, and the condition of HTPR and non-HTPR. To our knowledge, our study addresses for the first time the analysis of the polygenic contribution in platelet reactivity using NGS and establishes PgxPRS derived from the LASSO model. Our results demonstrate the polygenic implication of clopidogrel response and offer insights applicable to the translational medicine of antiplatelet therapy in an understudied population.

Prevalence of latent and overt polyautoimmunity in type 1 diabetes: A systematic review and meta-analysis.

BACKGROUND: Patients afflicted by type 1 diabetes (T1D) exhibit polyautoimmunity (PolyA). However, the frequency and distribution of PolyA in T1D is still unknown. OBJECTIVE: We conducted a systematic review and meta-analysis to define the prevalence of latent and overt PolyA in individuals with T1D. METHODS: Following PRISMA guidelines, a comprehensive search across medical databases identified studies on latent and overt PolyA in T1D. Two researchers independently screened, extracted data, and assessed study quality. A random effects model was utilized to calculate the pooled prevalence, along with its corresponding 95 % confidence interval (CI), for latent PolyA and overt PolyA. Meta-regression analysis was conducted to study the effect of study designs, age, sex, and duration of disease on pooled prevalence. RESULTS: A total of 158 articles, encompassing a diverse composition of study designs were scrutinized. The analysis included 270,890 individuals with a confirmed diagnosis of T1D. The gender was evenly distributed (50.30 % male). Notably, our analysis unveiled an overt PolyA prevalence rate of 8.50 % (95 % CI, 6.77 to 10.62), with North America having the highest rates (14.50 %, 95 % CI, 7.58 to 24.89). This PolyA profile was further characterized by a substantial incidence of concurrent autoimmune thyroid disease (7.44 %, 95 % CI, 5.65 to 9.74). Moreover, we identified a notable prevalence of latent PolyA in the T1D population, quantified at 14.45 % (95 % CI, 11.17 to 18.49) being most frequent in Asia (23.29 %, 95 % CI, 16.29 to 32.15) and Oceania (21.53 %, 95 % CI, 16.48 to 27.62). Remarkably, this latent PolyA phenomenon primarily featured an array of autoantibodies, including rheumatoid factor, followed by Ro52, thyroid peroxidase antibodies, and thyroglobulin antibodies. Duration of the disease was associated with a highest frequency of latent (ß: 0.0456, P-value: 0.0140) and overt PolyA (ß: 0.0373, P-value: 0.0152). No difference in the pooled prevalence by study design was observed. CONCLUSION: This meta-analysis constitutes a substantial advancement in the realm of early detection of PolyA in the context of T1D. Individuals with T1D should regularly undergo assessments to identify potential concurrent autoimmune diseases, especially as they age.

Early detection of optic nerve head changes using optical coherence tomography after using mesenchymal stromal cells as intravitreal therapy in rabbit models of ocular hypertension.

Background and Aim: Stem cell therapy is considered a promising treatment for several neurodegenerative diseases. However, there are very few studies on the use of this therapy in glaucoma models. By detecting the changes produced by glaucoma early, cell therapy could help prevent the events that lead to blindness. In this study, early changes in the optic nerve head (ONH) as detected by optical coherence tomography (OCT) after the application of human Wharton's jelly-derived mesenchymal stromal cells (hWJ-MSCs) in an experimental model of ocular hypertension (OH) were evaluated. Materials and Methods: Fifteen New Zealand rabbits were randomly divided into the following three groups: G1: OH, G2: hWJ-MSCs, and G3: OH + hWJ-MSCs. An OH model was constructed, and the intraocular pressure (IOP) was measured regularly. At week 7, 105/100 µL hWJ-MSCs were intravitreally injected. Retinography and OCT were used to evaluate structural changes in ONH. Results: IOP increased significantly in G1 and G3 from week 3 onward. Retinography revealed more significant optic nerve changes, that is, papillary asymmetry suggestive of optic nerve excavation, vascular alterations, and irregular hypopigmentation peripheral to the optic disk margin, in G1 compared with G3. OH locates the hWJ-MSCs solution in the vitreous in front of the optic nerve. OCT revealed retinal nerve fiber layer (RNFL) reduction in all groups, reduced optic cup volume in G2 and G3 between weeks 1 and 9, and significant ganglion cell layer thickness reduction in G1 and a slight increase in G3. Conclusion: Intravitreal hWJ-MSCs injection produced changes in optic cup volume, which were detected early on by OCT; however, RNFL could not be restored in this OH model.

Mesenchymal Stromal Cells from Human Wharton's Jelly Modulate the Intraocular Immune Response in a Glucocorticoid Hypertension Model: An Exploratory Analysis.

INTRODUCTION: Glaucoma is a neurodegenerative disease characterized by the loss of retinal ganglion cells. Recent research suggests immunological changes such as cytokine imbalance may affect its pathophysiology. This implies that immunomodulation, like that of mesenchymal cells, could be a potential therapeutic avenue for this disease. However, the effects of intravitreal injections of human Wharton's jelly-derived mesenchymal stromal cells (hWJ-MSCs) on intraocular immune response have not been assessed in ocular hypertension (OH) models. METHODS: We explored this by measuring cytokine levels and expression of other markers, such as glial fibrillary acidic protein (GFAP) and T cells, in 15 randomly divided New Zealand rabbits: G1: OH, G2: hWJ-MSCs, and G3: OH+hWJ-MSCs. We analyzed the aqueous humor (IL-6, IL-8, and TNF-α) and vitreous humor (IFN-γ, IL-10, and TGF-ß) using ELISA and flow cytometry (cell populations), as well as TCD3+, TCD3+/TCD4+, and TCD3+/TCD8+ lymphocytes, and GFAP in the retina and optic nerve through immunohistochemistry. RESULTS: We found a decrease in TNF-α, IL-6, IFN-γ, IL-10, and IL-8 in G3 compared to G1 and an increase in TGF-ß in both G2 and G3. TCD3+ retinal infiltration in all groups was primarily TCD8+ rather than TCD4+ cells, and strong GFAP expression was observed in both the retina and optic nerves in all groups. CONCLUSION: Our results suggest that cellular and humoral immune responses may play a role in glaucomatous optic neuropathy and that intravitreal hWJ-MSCs can induce an immunosuppressive environment by inhibiting proinflammatory cytokines and enhancing regulatory cytokines.

Predictors of mortality in hospitalised patients with COVID-19: a 1-year case-control study.

BACKGROUND: A paucity of predictive models assessing risk factors for COVID-19 mortality that extend beyond age and gender in Latino population is evident in the current academic literature. OBJECTIVES: To determine the associated factors with mortality, in addition to age and sex during the first year of the pandemic. DESIGN: A case-control study with retrospective revision of clinical and paraclinical variables by systematic revision of clinical records was conducted. Multiple imputations by chained equation were implemented to account for missing variables. Classification and regression trees (CART) were estimated to evaluate the interaction of associated factors on admission and their role in predicting mortality during hospitalisation. No intervention was performed. SETTING: High-complexity centre above 2640 m above sea level (masl) in Colombia. PARTICIPANTS: A population sample of 564 patients admitted to the hospital with confirmed COVID-19 by PCR. Deceased patients (n=282) and a control group (n=282), matched by age, sex and month of admission, were included. MAIN OUTCOME MEASURE: Mortality during hospitalisation. MAIN RESULTS: After the imputation of datasets, CART analysis estimated 11 clinical profiles based on respiratory distress, haemoglobin, lactate dehydrogenase, partial pressure of oxygen to inspired partial pressure of oxygen ratio, chronic kidney disease, ferritin, creatinine and leucocytes on admission. The accuracy model for prediction was 80.4% (95% CI 71.8% to 87.3%), with an area under the curve of 78.8% (95% CI 69.63% to 87.93%). CONCLUSIONS: This study discloses new interactions between clinical and paraclinical features beyond age and sex influencing mortality in COVID-19 patients. Furthermore, the predictive model could offer new clues for the personalised management of this condition in clinical settings.

Neutrophil extracellular traps in autoimmune diseases / Trampas extracelulares de neutrófilos en enfermedades autoinmunes

ABSTRACT Neutrophils play an important role in immune defence against several pathogens. These cells actively participate in the innate immune response through different functions, such as chemotaxis, phagocytosis, oxidative burst and degranulation, which have been widely studied. However, in the last few years, a new function has been described; activated neutrophils are able to release web-like chromatin structures known as neutrophil extracellular traps (NETs). These structures formed by DNA, histones, and proteins, immobilize and kill microorganisms. Disruption in NET formation is associated with the pathophysiology of several disorders, including the autoimmune diseases. NETs are an important source of the autoantigens involved in the production of autoantibodies and maintenance of the inflammatory milieu. This review provides a summary of the contribution of NETs to the pathogenesis of anti-neutrophil cytoplasmic antibodies-associated vasculitis, systemic lupus erythematosus, and rheumatoid arthritis. The preliminary findings on NETs components in Sjögren.'s syndrome will also be described.

RESUMEN Los neutrófilos juegan un papel muy importante en la defensa inmune contra diferentes patógenos. Estas células participan activamente en la respuesta inmune innata a través de diferentes funciones como quimiotaxis, fagocitosis, estallido oxidativo y degranulación, las cuales han sido estudiadas ampliamente. Sin embargo, en los últimos años se ha descrito una nueva función; los neutrófilos activados son capaces de liberar redes de cromatina llamadas trampas extracelulares de neutrófilos (NETs). Estas estructuras están formadas por ADN, histonas y proteínas capaces de inmovilizar y matar microorganismos. Alteraciones en la formación de estas NETs están asociadas con la fisiopatología de varios trastornos, incluyendo las enfermedades autoinmunes (EAI). Las NETs son consideradas una fuente de autoantígenos que ayudan a la producción de autoanticuerpos y al mantenimiento de un ambiente inflamatorio. Esta revisión resume la contribución de las NETs a la patogénesis de vasculitis asociada a anticuerpos contra el citoplasma de los neutrófilos, lupus eritematoso sistémico y artritis reumatoide. Adicionalmente, se describirán los resultados preliminares de la detección de componentes de las NETs en pacientes con síndrome de Sjögren.

Respuesta autoinmune en individuos infectados por el virus ZIKA (RAIZ) / Autoinmune response in people infected with ZIKA viruS (RAIZ)

En el presente artículo se presenta una revisión de los principales resultados del proyecto RAIZ, acrónimo de "Respuesta autoinmune en individuos infectados por el virus Zika", originado por dos eventos mutuamente relacionados, la asociación entre un virus emergente en el continente, el virus Zika (vZika), y una enfermedad neuromuscular poco prevalente en Colombia, el síndrome de Guillain-Barré. Después de la llegada del virus al país se observó que las zonas donde se reportaban brotes del virus, se documentaba un aumento en los casos de síndrome de Guillain-Barré y otros síndromes neurológicos, que generó un gran interés para entender los mecanismos subyacentes de la infección asociados con autoinmunidad neurológica. Mediante la realización del primer estudio de casos y controles de Zika, Guillain-Barré y otros síndromes neurológicos, se comprobó dicha asociación en Colombia. A lo largo del proyecto, además, se investigaron los principales mecanismos asociados, mediante estudios de seroprevalencia de otras infecciones, inmunológicos y genéticos

This article presents a review of the main results of the RAIZ project, acronym of "Autoimmune response in individuals infected with the Zika virus", originated by two mutually related events: the association between an emerging virus on the continent, the Zika virus (vZika), and a neuromuscular disease not very prevalent in Colombia, the Guillain-Barré syndrome. After the arrival of the virus in the country it was observed that in the areas of outbreaks an increase of cases of Guillain-Barré syndrome and other neurological syndromes was documented, which generated a great interest in the understanding of the underlying mechanisms of the infection associated with neurological autoimmunity. By conducting the first case-control study on Zika, Guillain-Barré and other neurological syndromes in Colombia, the association was verified. Throughout the project, the main associated mechanisms were addressed through analyses of other infections, immunological analysis and the first genome-wide association study

Ecología autoinmune en mujeres / Autoimmune ecology in women

Introducción: La exposición ambiental puede influenciar el desarrollo de enfermedades autoinmunes (EAI). El medio ambiente junto con la predisposición genética influyen en el desarrollo y severidad de estas enfermedades. Objetivo: Evaluar las exposiciones ambientales en pacientes con 4 EAI. Métodos: Se realizó un estudio exploratorio en 188 mujeres con 4 EAI: artritis reumatoide (AR) n= 51, lupus eritematoso sistémico (LES) n= 70, esclerosis sistémica (ES) n= 35 y síndrome de Sjögren (SS) n= 32. Los datos fueron recolectados mediante un cuestionario que evaluó características demográficas, clínicas, y exposición a factores ambientales. Además, se midieron 14 autoanticuerpos.

Discordancia entre métodos de detección de autoanticuerpos / Discrepancy between methods of detection of autoantibodies

Introducción: Las enfermedades autoinmunes sistémicas se caracterizan por la producción de diferentes autoanticuerpos contra antígenos intracelulares. En lupus eritematoso sistémico (LES) los autoanticuerpos son principalmente contra antígenos nucleares, los más frecuentes son los anti-ADN de doble cadena (anti-dsDNA) seguido de los antígenos nucleares extractables (ENAs) los cuales son componentes citoplasmáticos y nucleares solubles con más de 100 antígenos. Los ENAs están presentes también en el síndrome de Sjögren (SS) siendo más frecuentes los anti-Ro y anti-La. Contar con métodos fiables de detección de autoanticuerpos es necesario para el diagnóstico de estas enfermedades. Objetivo: Evaluar la concordancia de tres métodos de detección de anticuerpos antinucleares.

Interacciones entre citoquinas y resiliencia en pacientes con esclerosis sistémica / Interactions between Cytokines and resilience in patients with systemic sclerosis

Introducción: Resiliencia es la habilidad de responder de manera positiva a eventos adversos. Ésta puede ser influenciada por factores como el estrés crónico, la actividad física y afeccio-nes autoinmunes y/o inflamatorias como la esclerosis sistémica (ES) (1). Objetivo: Evaluar un panel de citoquinas y su asociación con resiliencia, severidad de los síntomas y actividad física en pacientes con ES. Métodos: Este fue un estudio exploratorio que incluyó 35 mujeres con ES. Las características clínicas, incluidas la severidad de los síntomas, la actividad física, la resiliencia así como un panel de 15 citoquinas fueron evaluados simultáneamente.

Plausibilidad genética de la infección por el virus del Zika y el síndrome de Guillain-Barré / Genetic plausibility of infection by the Zika virus syndrome Guillain - Barré Syndrome

Introducción: La infección por el virus del Zika (ZIKV) es, en la mayoría de los casos, asinto-mática o se presenta como una enfermedad leve y auto-limitada, principalmente con erupción cutánea, fiebre, artralgias y conjuntivitis. Sin embargo, en algunos pacientes puede producir efectos graves en el sistema nervioso, entre los cuales se destaca el síndrome de Guillain-Ba-rré (SGB), una polirradiculoneuropatía aguda, con características autoinmunes y, por lo ge-neral, desmielinizante. Objetivo: Realizar el primer estudio de asociación del genoma com-pleto en pacientes con infección por ZIKV y en aquellos que desarrollaron SGB post-viral.