Frontiers in Immunology

Cell-mediated immunity (CMI), which includes T-cells (both T helper and cytotoxic), is critical for effective antiviral defenses against coronavirus disease-2019 (COVID-19). To better understand the immunological characteristics of CD markers on T-cells in post-COVID-19 patients, we investigated the expression of differential CD markers in the patient groups in this study. Flow cytometry was used to quantify total lymphocyte count and assess the levels of expression of CD markers in the samples...

The World Health Organization has declared SARS-CoV-2 virus outbreak a world-wide pandemic. Individuals infected by the virus exhibited different degrees of symptoms, the basis of which remains largely unclear. Currently, though convalescent individuals have been shown with both cellular and humoral immune responses, there is very limited understanding on the immune responses, especially adaptive immune responses, in patients with severe COVID-19. Here, we examined 10 blood samples from COVID-19...

In mid-2021, the SARS-CoV-2 Delta variant caused the third wave of the COVID-19 pandemic in several countries worldwide. The pivotal studies were aimed at studying changes in the efficiency of neutralizing antibodies to the spike protein. However, much less attention was paid to the T-cell response and the presentation of virus peptides by MHC-I molecules. In this study, we compared the features of the HLA-I genotype in symptomatic patients with COVID-19 in the first and third waves of the pande...

Antigen (ag)-specific T cell analysis is an important step for investigation of cellular immunity in many settings, such as infectious diseases, cancer and vaccines. Multiparameter flow cytometry has advantages in studying both the rarity and heterogeneity of these cells. In the cellular immunologists toolbox, the expression of activation-induced markers (AIM) following antigen exposure has made possible the study and sorting of ag-specific T cells without using human leukocyte antigen (HLA)-mul...

Long-COVID (LC) is a serious clinical condition characterised by debilitating fatigue together with a wide array of symptoms that significantly reduce the quality of life of patients. Currently no holistic or even symptom specific treatment options are available, likely due to both a lack of insight into the disease processes that drive LC symptoms and an extreme heterogeneity in patients profiles. We characterised patients and post infection controls, with respect to their immunological profile...

Pemphigus vulgaris (PV) is a life-threatening autoimmune blistering disease caused by pathogenic autoantibodies targeting the desmosomal cadherins desmoglein 3 (DSG3) and desmoglein 1 (DSG1), essential for cell-cell adhesion. Although the role of these autoantibodies in disease pathogenesis is well established, the mechanisms initiating the autoimmune response remain unclear. A strong genetic association has been identified between PV and specific HLA class II alleles, particularly HLA-DRB1*04:0...

Multisystem Inflammatory Syndrome in Children associated with COVID-19 (MIS-C) is a late complication of pediatric COVID-19, which follows weeks after original SARS-CoV-2 infection, regardless of its severity. It is characterized by hyperinflammation, neutrophilia, lymphopenia and activation of T cells with elevated IFN-{gamma}. Observing production of autoantibodies and parallels with systemic autoimmune disorders, such as systemic lupus erythematodes (SLE), we explored B cell phenotype and ser...

A novel pneumonia-associated respiratory syndrome named coronavirus disease-2019 (COVID-19), which caused by SARS-CoV-2 and broken in Wuhan, China in the end of 2019. Unfortunately, there is no specific antiviral agent or vaccine available to treat SARS-CoV-2 infections. Also, information regarding the immunological characteristics in COVID-19 patients remains limited. Here we collected the blood samples from 18 healthy donors (HD) and 38 COVID-19 patients to analyze changes in {gamma}{delta} T ...

BackgroundImmunocompromised people, including those with Inborn Errors of Immunity (IEI), are at increased risk of severe disease from viral infections. Therefore, regular booster vaccinations are recommended for SARS-CoV-2 and influenza, but it is unclear if these elicit protective immunity. ObjectiveComprehensive evaluation of adaptive immune responses, including SARS-COV-2 specific antibodies, memory B-(Bmem) and memory T-cells (Tmem), to COVID-19 vaccination in IEI patients. MethodsBlood s...

SARS-CoV-2 is a novel coronavirus, not encountered before by humans. The wide spectrum of clinical expression of SARS-CoV-2 illness suggests that individual immune responses to SARS-CoV-2 play a crucial role in determining the clinical course after first infection. Immunological studies have focussed on patients with moderate to severe disease, demonstrating excessive inflammation in tissues and organ damage. In order to understand the basis of the protective immune response in COVID-19, we per...

A complex and tissue-specific network of cells including T lymphocytes maintains intestinal homeostasis. To address disease and tissue-specific alterations, we performed a T cell-centric mass cytometry analysis of peripheral and intestinal lymphocytes from patients with Crohns disease (CD) and healthy donor PBMCs. We compared inflamed and not inflamed tissue areas of bowel resections. Chronic inflammation enforced activation, exhaustion and terminal differentiation of CD4+ and CD8+ T cells and a...

Multisystem inflammatory syndrome in children (MIS-C or PIMS) is a rare but serious complication after an infection with SARS-CoV-2. A possible involvement of pathogenetically relevant autoantibodies has been discussed. Recently neutralizing autoantibodies against anti-inflammatory receptor antagonists progranulin (PGRN) and IL-1-receptor antagonist (IL-1-Ra) were discovered in adult patients with critical COVID-19. Plasma of an index case with severe PIMS/MIS-C was analyzed for autoantibodies ...

Coronavirus disease-2019 (COVID-19), caused by SARS-CoV-2, has rapidly spread to most of countries in the world, threatening the health and lives of many people. Unfortunately, information regarding the immunological characteristics in COVID-19 patients remains limited. Here we collected the blood samples from 18 healthy donors (HD) and 38 COVID-19 patients to analyze changes in the adaptive immune cell populations and phenotypes. In comparison to HD, the lymphocyte percentage was slightly decre...

Post-COVID syndrome (PCS) has emerged as a significant health concern with persisting symptoms. A subset of PCS patients develops severe myalgic encephalomyelitis/chronic fatigue syndrome (pcME/CFS). Dysregulated autoantibodies (AABs) have been implicated in PCS, contributing to immune dysregulation, impairment of autonomous nerve and vascular function. As recently shown in autoimmune diseases, IgG fractions translate disease-specific pathways into various cells. Therefore, we asked whether IgG ...

A better understanding of the innate and adaptive cells in the COVID-19 disease caused by the SARS-CoV-2 coronavirus is a necessity for the development of effective treatment methods and vaccines. We studied phenotypic features of innate and adaptive immune cells, oxidative burst, phagocytosis and apoptosis. One hundred and three patients with COVID-19 grouped according to their clinical features as mild (35%), moderate (40.8%), and severe (24.3%) were included in the study. Monocytes from all C...

Initial symptoms of COVID-19 infection depend on viral replication, while hyperinflammation is a hallmark of critical illness and may drive severe pneumonia and death. Among the mechanisms potentially involved in the hyperinflammatory state, we focused on the unfolded protein response, because the IRE1-XBP1 branch can be activated as result of the endoplasmic reticulum stress produced by the overwhelming synthesis of viral components and synergizes with Toll-like receptor signaling to induce cyt...

Immunization with mRNA SARS-CoV-2 vaccines has been highly recommended and prioritized in fragile categories with higher risk of mortality after COVID-19 disease compared to healthy people, including patients with myelofibrosis (MF). Available data on the vaccine immune response developed by MF patients, and the impact of the treatment with the inhibitor of JAK-STAT signaling ruxolitimib, are still fragmented to support an informed decision for a third dose for this category of subjects. Here, w...

BackgroundLymphopenia is a typical symptom in the COVID-19 patients. While millions of patients are clinical recovered, little is known about the immune status of lymphocytes in these individuals. MethodsA clinical recovered cohort (CR) of 55 COVID-19 individuals (discharged from hospital 4 to 11 weeks), and 55 age and sex matched healthy donors cohort (HD) were recruited. Detailed analysis on phenotype of the lymphocytes in peripheral blood mononuclear cells (PBMCs) was performed by flow cytom...

The WHO has declared SARS-CoV-2 outbreak a public health emergency of international concern. However, to date, there was hardly any study in characterizing the immune responses, especially adaptive immune responses to SARS-CoV-2 infection. In this study, we collected blood from COVID-19 patients who have recently become virus-free and therefore were discharged, and analyzed their SARS-CoV-2-specific antibody and T cell responses. We observed SARS-CoV-2-specific humoral and cellular immunity in t...

BackgroundSARS-CoV-2 infection causes an abrupt response by the host immune system, which is largely responsible for the pathogenesis and outcome of COVID-19. We aimed to investigate which specific responses from either cellular or humoral immunity associate to severity and progression of COVID-19. MethodsA cohort of 276 patients classified in mild, moderate and severe, was studied. Peripheral blood lymphocyte subpopulations were quantified by flow cytometry, and immunoglobulins and complement ...