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.

Gut microbiota in centenarians: A potential metabolic and aging regulator in the study of extreme longevity.

Centenarians, those aged 100 years or older, are considered the most successful biological aging model in humans. This population is commonly characterized by a low prevalence of chronic diseases, with favorable maintenance of functionality and independence, thus determining a health phenotype of successful aging. There are many factors usually associated with extreme longevity: genetics, lifestyles, diet, among others. However, it is most likely a multifactorial condition where protective factors contribute individually to some extent. The gut microbiota (GM) has emerged as a potential factor associated with the establishment of a favorable health phenotype that allows for extreme longevity, as seen in centenarians. To understand the possible impact generated by the GM, its changes, and the probable causes for successful aging, the aim of this review was to synthesize evidence on the role of the GM as a potential protective factor for achieving extreme longevity, using its relationship with centenarians.

Global Research on Centenarians: A Historical and Comprehensive Bibliometric Analysis from 1887 to 2023.

BACKGROUND: Centenarians are considered the most successful human biological aging model. However, the characteristics and patterns of research among centenarians have not been described or analyzed. Thus, this study aimed to disclose the historical landscape of global research on centenarians. METHODS: This bibliometric study investigated historical evidence on centenarian research published in the Scopus database. The bibliometrix package in R was used to perform visual and quantitative analyses of research metrics, trends, and patterns. RESULTS: Of the 2,061 documents included between 1887 and 2023, 84.2% (n=1,736) were published as articles with primary data. We identified international collaboration and annual growth rates of 21.4% and 3.15%, respectively. The United States published the highest number of papers on centenarians (n=786), whereas the publications from Italy had the highest impact (h-index of 90). Based on the frequency of keywords, mortality, genetics, dementia, Alzheimer's disease, and immunosenescence are a few of the most studied topics among centenarians, with emerging research related to mitochondrial DNA and comparison of results between nonagenarians and centenarians. Italy, the United States, and China lead the global research collaboration network, collaborating most frequently with Japan and European countries. CONCLUSION: Global research on centenarians has grown over the last 20 years, primarily led by Italy, the United States, and China. Latin American and African countries have conducted little or no research on centenarians. The most widely studied topics include mortality, cognition, immunosenescence, and genetics.

Autoimmunity in centenarians. A paradox.

Autoimmune diseases (ADs) are one of the groups of chronic illnesses that impose a significant burden of disease and health costs worldwide. Age is a crucial risk factor for the onset of ADs. Theoretically, it is inferred that with organic and immune system aging, the loss of immune tolerance and specificity of immune activity becomes more intense, the probability of autoimmunity is increasing. However, there is a group of individuals whose prevalence of ADs is very low or non-existent, despite the biological aging. This paradox in autoimmunity raises questions. Centenarians, individuals who are over 100 years old, are possibly the most successful model of biological aging in humans. Most of these individuals exhibit a favorable health phenotype. To date, primary data evidence and potential hypotheses explaining this phenomenon are lacking globally, even though this paradox could provide valuable, original, and relevant information regarding the understanding of risk or protective factors, biological drivers, and biomarkers related to autoimmunity. Herein we discuss some hypothesis that may explain the absence of ADs in centenarians, including inflammaging, immunosenescence and immune resilience, immune system hyperstimulation, proteodynamics, and genetics.

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.

Factors associated with mental health outcomes after COVID-19: A 24-month follow-up longitudinal study.

OBJECTIVE: Investigate the proportion of mental health outcomes (MHOs) and associated factors in COVID-19 survivors during a 24-month follow-up period. METHOD: An observational, prospective study was performed in a teaching hospital in Barranquilla, Colombia, from April 1, 2020, to August 30, 2022. A cohort of 1565 COVID-19 survivors was recruited after discharge from the emergency room (ER), inpatient floor (IF), and intensive care unit (ICU) services and followed for 24 -months. The clinical assessment included screening scales for symptoms of anxiety, depressive, post-traumatic stress disorder (PTSD), and insomnia. Sociodemographic and clinical factors were also collected to identify possible associated factors. Descriptive, bivariate and mixed random-effect linear models were performed. RESULTS: A total of 1565 patients were included, of whom 785 (50.35%) were men. A large proportion of patients with mental symptoms were identified. After 24-months, the proportions of anxiety, depression, PTSD, and insomnia symptoms remained high at 16.55%, 21.79%, 35.27%, and 23.86%, respectively. Social factors, location of hospital stays, physical comorbidities, and the severity of COVID-19 were significantly associated with anxiety, depression, PTSD, and insomnia symptoms. CONCLUSIONS: COVID-19's 2-year deleterious impacts on mental health, as well as the variables influencing these findings, have been documented. These results should aid in the development of public health initiatives to reduce morbidity rates in post-COVID-19 patients.

Immunological Evaluation of Pediatric Patients with Polyautoimmunity.

BACKGROUND: Autoimmunity can be the first or predominant manifestation in patients with primary immunodeficiency disorder, also referred to as inborn errors of immunity (IEI). This study aims to evaluate the immune status of pediatric patients with polyautoimmunity to identify those with underlying immune defects. METHODS: In this cross-sectional study, pediatric patients with polyautoimmunity including at least one confirmed autoimmune endocrine disease were enrolled. Demographic and clinical data were collected using a questionnaire based on medical records and direct family interviews. For each patient, a basic immunologic evaluation was performed. The clinical diagnosis was established according to the criteria of the European Society for Immunodeficiencies (ESID). Based on the presence or absence of a history of severe and/or recurrent infections, patients were divided into two groups for comparison. RESULTS: Thirty-nine patients, 18 males (46.2%) and 21 females (53.8%), were included. Fourteen patients (35.9%) had consanguineous parents. Fifteen patients (38.5%) had a history of severe and/or recurrent infections. The median (interquartile range: IQR) age of our patients at the time of evaluation was 11.1 (9-16) years. The median (IQR) age at the onset of infections and autoimmunities were 3 (1-10.8) and 5 (2.6-8) years, respectively. The most common infectious complications reported were pneumonia and candidiasis, each in 12.8% of the patients. The most prevalent autoimmune disorders were type 1 diabetes (74.3%) and autoimmune thyroiditis (58.9%). IEI was diagnosed in six patients (15.38%), five of which were from the group with severe or recurrent infections: three with selective IgA deficiency, two with common variable immunodeficiency (CVID), and one with immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX), but without a history of infections. CONCLUSION: The occurrence of early onset polyautoimmunity in association with severe and/or recurrent infections or in patients with a positive family history should be a warning sign for physicians to initiate an evaluation for possible immunodeficiency disorders to prevent complications through early treatment.

Increased incidence of rheumatoid arthritis after COVID-19.

An increase in the incidence of inflammatory arthritis after COVID-19 has been reported. Since many diseases exhibit population-specific causal effect sizes, we aimed to evaluate the incidence trends of inflammatory arthritis, including rheumatoid arthritis (RA), after COVID-19 in a large admixed Colombian population. Data analysis for this retrospective, population-based cohort study was carried out using the COOSALUD EPS registry. The following codes were selected for analyses: M059, seropositive RA, M069, unspecified RA, M060 seronegative RA, and other RA-related diagnoses: M064, M139, M068, M058, M130 and M053. The study period was limited to January 01, 2018, through December 31, 2022. Incidence rates (IRs) and incidence rate ratios (IRRs) were assessed. A Cox survival model was built to evaluate the influence of age, gender, and COVID-19 vaccination status on the development of inflammatory arthritis. A bioinformatic analysis was performed to evaluate the homology between SARS-CoV-2 and autoantigen peptides related to RA. The entire population study comprised 3,335,084 individuals. During the pandemic period (2020-2022) the total IIR for seropositive and unspecified RA were 1.60 (95% CI, 1.16-2.22) and 2.93 (95% CI, 2.04-4.19), respectively, and the IIR for overall RA-related diagnosis was 2.01 (95% CI 1.59-2.53). The age groups hazard ratios (HRs) were increased until the age group of 51-60 years (HR: 9.16; 95% CI, 7.24-11.59) and then decreased slightly in the age group 61 years or older (HR: 5.364; 95% CI, 4.24-6.78) compared to those within 18-30 years. Men were less at risk than women to develop inflammatory arthritis (HR: 0.21; 95% CI, 0.18-0.24). The greater time since COVID-19 diagnosis was associated with a lower likelihood of developing inflammatory arthritis (HR: 0.99; 95% CI:0.998-0.999). Vaccination (all types of COVID-19 vaccines included) did not prevent the development of inflammatory arthritis after COVID-19. Low identity was found between the SARS-CoV-2 ORF1ab antigen and the human antigens Poly ADP-ribose polymerase 14 and Protein mono-ADP-ribosyltransferase PARP9 isoform D (39% and 29%, respectively). In conclusion, our study confirms increased incidence of inflammatory arthritis, including RA, after COVID-19, with the greatest increase occurring before the first year post-covid. Women in their fifties were more susceptible. Further research is required to examine the effectiveness of vaccination in preventing post-COVID inflammatory arthritis and the mechanisms implicated in the development of RA after COVID-19.

Molecular mimicry and autoimmunity in the time of COVID-19.

Infectious diseases are commonly implicated as potential initiators of autoimmune diseases (ADs) and represent the most commonly known factor in the development of autoimmunity in susceptible individuals. Epidemiological data and animal studies on multiple ADs suggest that molecular mimicry is one of the likely mechanisms for the loss of peripheral tolerance and the development of clinical disease. Besides molecular mimicry, other mechanisms such as defects in central tolerance, nonspecific bystander activation, epitope-determinant spreading, and/or constant antigenic stimuli, may also contribute for breach of tolerance and to the development of ADs. Linear peptide homology is not the only mechanism by which molecular mimicry is established. Peptide modeling (i.e., 3D structure), molecular docking analyses, and affinity estimation for HLAs are emerging as critical strategies when studying the links of molecular mimicry in the development of autoimmunity. In the current pandemic, several reports have confirmed an influence of SARS-CoV-2 on subsequent autoimmunity. Bioinformatic and experimental evidence support the potential role of molecular mimicry. Peptide dimensional analysis requires more research and will be increasingly important for designing and distributing vaccines and better understanding the role of environmental factors related to autoimmunity.

Post-COVID Syndrome in Adults-An Overview.

This article provides an overview of various aspects related to post-COVID syndrome. Apart from its prevalence, symptoms and sequelae, risk determinants, and psychosocial implications, the pathogenesis of post-COVID condition is discussed in more detail. A focus on thrombo-inflammation in SARS-CoV-2 infection, the role of neutrophil extracellular traps, and the prevalence of venous thromboembolism is made. Moreover, COVID-19 and post-COVID syndrome in immunocompromising conditions, and the impact of vaccination on the prevention and treatment of post-COVID symptoms are reviewed. Autoimmunity is a hallmark of post-COVID syndrome, and, therefore, is another focus of this article. Thus, misdirected cellular and humoral immune responses can enhance the risk of latent autoimmunity in post-COVID syndrome. Facing the high prevalence of COVID-19 cases worldwide, it can be assumed that autoimmune disorders will increase globally over the next few years. Recent advances in identifying genetically determined variants may open the avenue for a better understanding of the susceptibility to and severity of SARS-CoV-2 infection and post-COVID syndrome.

Guillain-Barré Syndrome Following Zika Virus Infection Is Associated With a Diverse Spectrum of Peripheral Nerve Reactive Antibodies.

BACKGROUND AND OBJECTIVES: Recent outbreaks of Zika virus (ZIKV) in South and Central America have highlighted significant neurologic side effects. Concurrence with the inflammatory neuropathy Guillain-Barré syndrome (GBS) is observed in 1:4,000 ZIKV cases. Whether the neurologic symptoms of ZIKV infection are immune mediated is unclear. We used rodent and human live cellular models to screen for anti-peripheral nerve reactive IgG and IgM autoantibodies in the sera of patients with ZIKV with and without GBS. METHODS: In this study, 52 patients with ZIKV-GBS were compared with 134 ZIKV-infected patients without GBS and 91 non-ZIKV controls. Positive sera were taken forward for target identification by immunoprecipitation and mass spectrometry, and candidate antigens were validated by ELISA and cell-based assays. Autoantibody reactions against glycolipid antigens were also screened on an array. RESULTS: Overall, IgG antibody reactivities to rat Schwann cells (SCs) (6.5%) and myelinated cocultures (9.6%) were significantly higher, albeit infrequent, in the ZIKV-GBS group compared with all controls. IgM antibody immunoreactivity to dorsal root ganglia neurones (32.3%) and SCs (19.4%) was more frequently observed in the ZIKV-GBS group compared with other controls, whereas IgM reactivity to cocultures was as common in ZIKV and non-ZIKV sera. Strong axonal-binding ZIKV-GBS serum IgG antibodies from 1 patient were confirmed to react with neurofascin 155 and 186. Serum from a ZIKV-infected patient without GBS displayed strong myelin-binding and putative antilipid antigen reaction characteristics. There was, however, no significant association of ZIKV-GBS with any known antiglycolipid antibodies. DISCUSSION: Autoantibody responses in ZIKV-GBS target heterogeneous peripheral nerve antigens suggesting heterogeneity of the humoral immune response despite a common prodromal infection.

Variants in the DDX6-CXCR5 autoimmune disease risk locus influence the regulatory network in immune cells and salivary gland.

Fine mapping and bioinformatic analysis of the DDX6-CXCR5 genetic risk association in Sjögren's Disease (SjD) and Systemic Lupus Erythematosus (SLE) identified five common SNPs with functional evidence in immune cell types: rs4938573, rs57494551, rs4938572, rs4936443, rs7117261. Functional interrogation of nuclear protein binding affinity, enhancer/promoter regulatory activity, and chromatin-chromatin interactions in immune, salivary gland epithelial, and kidney epithelial cells revealed cell type-specific allelic effects for all five SNPs that expanded regulation beyond effects on DDX6 and CXCR5 expression. Mapping the local chromatin regulatory network revealed several additional genes of interest, including lnc-PHLDB1-1. Collectively, functional characterization implicated the risk alleles of these SNPs as modulators of promoter and/or enhancer activities that regulate cell type-specific expression of DDX6, CXCR5, and lnc-PHLDB1-1, among others. Further, these findings emphasize the importance of exploring the functional significance of SNPs in the context of complex chromatin architecture in disease-relevant cell types and tissues.

Kawasaki disease in Colombia: A systematic review and contrast with multisystem inflammatory syndrome in children associated with COVID-19

Introduction: Kawasaki disease (KD) is an acute vasculitis with multisystem involvement. Recently, the increasing incidence of a condition that closely resembles KD in many cases, named multisystem inflammatory syndrome in children (MIS-C), has set off alarms amid the current worldwide coronavirus disease-19 (COVID-19) pandemic. Hence, the aim is to conduct a systematic review of the literature about KD in Colombia and contrast it with COVID-19-related MIS-C. Materials and methods: A search was carried out in both international and Latin American electronic databases for publications concerning patients with KD in the Colombian population. Records were then screened by titles and/or abstracts, assessed for eligibility, and reviewed. Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines were followed. The search included studies reporting MIS-C associated with COVID-19, and compared these patients with our findings of KD in Colombia. Results: Out of 36 publications retrieved, 17 were included, representing 120 individuals. Male to female ratio was 1.6, and most patients (90.4%) were aged 5 years or less. Among the main features of KD, fever was the most frequent (96.2% of the patients), while cervical lymphadenopathy was present in only 40.6%. Intravenous immunoglobulin was administered in 91.4% cases and 6.2% were resistant. Cardiac involvement was found in around 30%, and 20% had coronary artery lesions. Comparison between MIS-C associated with COVID-19 and KD in Colombia indicates that patients affected by MIS-C were older (72.2% of MIS-C patients > 5 years), had higher rates of cardiac involvement, and required critical care more often. Conclusions: Our findings of KD in Colombia are consistent with the available descriptions of KD in the scientific literature. Given the increasing rate of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection in Colombia and Latin America, our study raises awareness about MIS-C in pediatric patients with COVID-19 and its relationship with KD.

Introducción: La enfermedad de Kawasaki (EK) es una vasculitis aguda con compromiso multisistémico. Recientemente, la incidencia creciente de una condición que se asemeja en forma considerable a la EK en muchos casos, denominada síndrome inflamatorio multisistémico (SIMS) en niños, ha encendido las alarmas en medio de la actual pandemia mundial de la enfermedad COVID-19. Por consiguiente, nos propusimos realizar una revisión sistemática de la literatura acerca de la EK en Colombia y contrastarla con el SIMS relacionado con COVID-19 en niños. Materiales y métodos: Buscamos publicaciones respecto a pacientes con EK en población colombiana, en bases de datos electrónicas tanto internacionales como latinoamericanas. Los registros hallados fueron tamizados por títulos o resúmenes, evaluados para elegibilidad y revisados. Se siguieron las guías Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). Posteriormente, buscamos estudios que reportaran SIMS temporalmente asociado con COVID-19 en niños y comparamos estos pacientes con nuestros hallazgos de EK en Colombia. Resultados: De 36 publicaciones encontradas se incluyeron 17, las cuales representaron 120 individuos. La razón hombre a mujer fue de 1,6 y la mayoría de los pacientes (90,4%) tenía 5 anos o menos. Entre las principales características de EK, la fiebre fue la más frecuente (96,2%), mientras que la linfadenopatía cervical estuvo presente solo en el 40,6%. La inmunoglobulina intravenosa se administró en el 91,4% de los casos y 6,2% presentaron resistencia. Se encontró compromiso cardiaco en alrededor del 30% de los pacientes, en tanto que el 20% tuvo lesiones de arterias coronarias. La comparación entre las características clínicas de la EK y el SIMS asociado a COVID-19 mostró que los individuos afectados por el SIMS eran mayores (72,2% con SIMS tenían más de cinco anos), tuvieron mayores índices de compromiso cardiaco y requirieron cuidado crítico con mayor frecuencia. Conclusiones: Nuestros hallazgos de EK en Colombia son consistentes con las descripciones disponibles de esta enfermedad en la literatura científica. Debido al aumento de infección por SARS-CoV-2 en Colombia y Latinoamérica, nuestro estudio busca crear conciencia sobre el SIMS en pacientes pediátricos con COVID-19 y su relación con la EK.

Gonococcal arthritis in a healthy adult. Is it that possible?

A case report is presented of a 50-year-old woman who was seen in Accident and Emergency because of pain in the lumbar area. She was subsequently diagnosed with septic arthritis of the left hip due to being Neisseria gonorrhoeae positive for beta-lactamase. She responded to treatment with ceftriaxone, but later required a total hip replacement.

Presentamos el caso de una mujer de 50 arios, sin antecedentes de importancia, a quien se le diagnosticó inicialmente lumbago e infección de vías urinarias. Por persistencia del dolor y limitación de la movilidad en la cadera izquierda se inicia el estudio de artritis séptica, que fue provocada por Neisseria gonorrhoeae betalactamasa positiva, sensible a tratamiento con ceftriaxona, con posterior deterioro articular, el cual requirió reemplazo total de cadera.

Autoimmune and autoinflammatory conditions after COVID-19 vaccination. New case reports and updated literature review.

Autoimmunity linked to COVID-19 immunization has been recorded throughout the pandemic. Herein we present six new patients who experienced relapses of previous autoimmune disease (AD) or developed a new autoimmune or autoinflammatory condition following vaccination. In addition, we documented additional cases through a systematic review of the literature up to August 1st, 2022, in which 464 studies (928 cases) were included. The majority of patients (53.6%) were women, with a median age of 48 years (IQR: 34 to 66). The median period between immunization and the start of symptoms was eight days (IQR: 3 to 14). New-onset conditions were observed in 81.5% (n: 756) of the cases. The most common diseases associated with new-onset events following vaccination were immune thrombocytopenia, myocarditis, and Guillain-Barré syndrome. In contrast, immune thrombocytopenia, psoriasis, IgA nephropathy, and systemic lupus erythematosus were the most common illnesses associated with relapsing episodes (18.5%, n: 172). The first dosage was linked with new-onset events (69.8% vs. 59.3%, P = 0.0100), whereas the second dose was related to relapsing disease (29.5% vs. 59.3%, P = 0.0159). New-onset conditions and relapsing diseases were more common in women (51.5% and 62.9%, respectively; P = 0.0081). The groups were evenly balanced in age. No deaths were recorded after the disease relapsed, while 4.7% of patients with new-onset conditions died (P = 0.0013). In conclusion, there may be an association between COVID-19 vaccination and autoimmune and inflammatory diseases. Some ADs seem to be more common than others. Vaccines and SARS-CoV-2 may induce autoimmunity through similar mechanisms. Large, well-controlled studies are warranted to validate this relationship and assess additional variables such as genetic and other environmental factors.