The T-cell repertoire of Spanish patients with COVID-19 as a strategy to link T-cell characteristics to the severity of the disease.

BACKGROUND: The architecture and dynamics of T cell populations are critical in orchestrating the immune response to SARS-CoV-2. In our study, we used T Cell Receptor sequencing (TCRseq) to investigate TCR repertoires in 173 post-infection COVID-19 patients. METHODS: The cohort included 98 mild and 75 severe cases with a median age of 53. We amplified and sequenced the TCR ß chain Complementary Determining Region 3 (CDR3b) and performed bioinformatic analyses to assess repertoire diversity, clonality, and V/J allelic usage between age, sex and severity groups. CDR3b amino acid sequence inference was performed by clustering structural motifs and filtering validated reactive CDR3b to COVID-19. RESULTS: Our results revealed a pronounced decrease in diversity and an increase in clonal expansion in the TCR repertoires of severe COVID-19 patients younger than 55 years old. These results reflect the observed trends in patients older than 55 years old (both mild and severe). In addition, we identified a significant reduction in the usage of key V alleles (TRBV14, TRBV19, TRBV15 and TRBV6-4) associated with disease severity. Notably, severe patients under 55 years old had allelic patterns that resemble those over 55 years old, accompanied by a skewed frequency of COVID-19-related motifs. CONCLUSIONS: Present results suggest that severe patients younger than 55 may have a compromised TCR repertoire contributing to a worse disease outcome.

East meets west: integrating Yin-Yang theory with immunology teaching.

This perspective article delves into a novel integration of Yin-Yang theory-an ancient Chinese philosophical cornerstone-with the sophisticated realm of immunology. Given the intricate concepts inherent in immunology, many students find it challenging to comprehend the delicate mechanisms governing immune equilibrium and regulation. Given the deep-rooted understanding of Yin-Yang theory among Chinese students, we advocate for an educational strategy that contextualizes the concept of immune equilibrium within the framework of Yin-Yang, thereby offering a more intuitive and engaging learning experience. This method not only capitalizes on the cultural significance of Yin-Yang, but also corresponds to its principles of equilibrium and harmony, thus mirroring the homeostatic essence of immune responses. This article critically assesses this technique's capacity to bolster immune comprehension amongst Chinese students, while also considering its limitations. Despite these limitations, the fusion of these seemingly divergent fields holds substantial promise for augmenting immunology education, promoting critical thinking, and advancing cross-cultural academic discourse. The amalgamation of age-old philosophical insights with modern scientific exploration prompts a reassessment of educational methodologies within immunology, underscoring a novel pedagogical approach that bridges traditional wisdom with contemporary scientific education.

Acute hepatitis A with haemophagocytic lymphohistiocytosis: G-6PD deficiency-induced haemolytic anaemia and bile cast nephropathy.

Hepatitis A virus (HAV) infection typically presents as a self-limiting illness but it can cause debilitating symptoms and rarely fulminant hepatitis (acute liver failure), which is often fatal. WHO estimates that in 2016, 7134 persons died from hepatitis A worldwide (accounting for 0.5% of the mortality due to viral hepatitis). Fulminant hepatic failure is observed in less than 1% of cases of acute viral hepatitis A. Haemophagocytic lymphohistiocytosis (HLH) is a clinical syndrome of excessive inflammation and tissue destruction owing to abnormal immune activation. Acquired HLH due to viral infections (also known as virus-associated haemophagocytic syndrome) is most commonly associated with Epstein-Barr virus and cytomegalovirus (CMV). HAV-associated HLH has been rarely reported. Haemolysis of mild to moderate degree is not unheard of in cases of hepatitis A, which is often immune-mediated. Here, we present the case of a man in his 30s, with G6PD deficiency unmasked by acute viral hepatitis A, which later on progressed to hyperacute liver failure, HLH and renal failure.

Acquired Immunostimulatory Phenotype of Migratory CD103+ Dendritic Cells Promotes Alloimmunity Following Corneal Transplantation.

Post-transplantation, T helper 1 (Th1)-mediated immune rejection is the predominant cause of graft failure. Th1 cell sensitization occurs through complex and context-dependent interaction among antigen-presenting cell subsets, particularly CD11b+ dendritic cells (DC2) and CD103+ dendritic cells (DC1). This interaction necessitates further investigation in context of transplant immunity. We use a well-established pre-clinical models of corneal transplantation and identified distinct roles of migratory CD103+ DC1 in influencing the outcomes of the grafted tissue. In recipients with uninflamed corneal beds, migratory CD103+DC1 demonstrate a tolerogenic phenotype that modulate the immunogenic capacity of CD11b+DC2 primarily mediated by IL-10, suppressing alloreactive CD4+Th1 cells via the PD-L1/PD-1 pathway, and enhancing Treg-mediated tolerance via αvß8 integrin-activated TGFß1, thus facilitating graft survival. Conversely, in recipients with inflamed and vascularized corneal beds, IFN-γ produced by CD4+Th1 cells induces migratory CD103+DC1 to adopt an immunostimulatory phenotype, characterized by the downregulation of regulatory markers including αvß8 integrin and IL-10 and the upregulation of IL-12 and costimulatory molecules CD80/86, resulting in graft failure. The adoptive transfer of ex-vivo induced tolerogenic CD103+DC1(iDC1) effectively inhibits Th1 polarization and preserves the tolerogenic phenotype of their physiological counterparts. Collectively, our findings underscore the essential role played by CD103+DC1 in modulating host alloimmune responses.

Protocol for isolating high-purity natural killer cells from peripheral blood of septic patients using magnetic cell separation.

In human sepsis, myelocytosis and concomitant lymphopenia complicate the study of peripheral blood natural killer (NK) cells. Here, we present a protocol for isolating NK cells from peripheral blood of septic patients using magnetic cell separation. We describe steps for the depletion of non-NK cells and NK cell enrichment. We then detail procedures for comparing the results from this protocol to results obtained through the isolation procedures using two commercially available kits for NK cell isolation. For complete details on the use and execution of this protocol, please refer to Coulibaly et al.1.

Protocol to analyze 1D and 2D mass spectrometry data from glioblastoma tissues for cancer diagnosis and immune cell identification.

In context of cancer diagnosis-based mass spectrometry (MS), the classification model created is crucial. Moreover, exploration of immune cell infiltration in tissues can offer insights within the tumor microenvironment. Here, we present a protocol to analyze 1D and 2D MS data from glioblastoma tissues for cancer diagnosis and immune cells identification. We describe steps for training the most optimal model and cross-validating it, for discovering robust biomarkers and obtaining their corresponding boxplots as well as creating an immunoscore based on MS-imaging data. For complete details on the use and execution of this protocol, please refer to Zirem et al.1.

Acute and persistent responses after H5N1 vaccination in humans.

To gain insight into how an adjuvant impacts vaccination responses, we use systems immunology to study human H5N1 influenza vaccination with or without the adjuvant AS03, longitudinally assessing 14 time points including multiple time points within the first day after prime and boost. We develop an unsupervised computational framework to discover high-dimensional response patterns, which uncover adjuvant- and immunogenicity-associated early response dynamics, including some that differ post prime versus boost. With or without adjuvant, some vaccine-induced transcriptional patterns persist to at least 100 days after initial vaccination. Single-cell profiling of surface proteins, transcriptomes, and chromatin accessibility implicates transcription factors in the erythroblast-transformation-specific (ETS) family as shaping these long-lasting signatures, primarily in classical monocytes but also in CD8+ naive-like T cells. These cell-type-specific signatures are elevated at baseline in high-antibody responders in an independent vaccination cohort, suggesting that antigen-agnostic baseline immune states can be modulated by vaccine antigens alone to enhance future responses.

Myeloid-derived suppressor cells in cancer: Current knowledge and future perspectives.

MDSCs (myeloid-derived suppressor cells) are crucial for immune system evasion in cancer. They accumulate in peripheral blood and tumor microenvironment, suppressing immune cells like T-cells, natural killer cells and dendritic cells. They promote tumor angiogenesis and metastasis by secreting cytokines and growth factors and contribute to a tumor-promoting environment. The accumulation of MDSCs in cancer patients has been linked to poor prognosis and resistance to various cancer therapies. Targeting MDSCs and their immunosuppressive mechanisms may improve treatment outcomes and enhance immune surveillance by developing drugs that inhibit MDSC function, by preventing their accumulation and by disrupting the tumor-promoting environment. This review presents a detailed overview of the MDSC research in cancer with regulation of their development and function. The relevance of MDSC as a prognostic and predictive biomarker in different types of cancers, along with recent advancements on the therapeutic approaches to target MDSCs are discussed in detail.

Multi-omics Analysis to Identify Key Immune Genes for Osteoporosis based on Machine Learning and Single-cell Analysis.

OBJECTIVE: Osteoporosis is a severe bone disease with a complex pathogenesis involving various immune processes. With the in-depth understanding of bone immune mechanisms, discovering new therapeutic targets is crucial for the prevention and treatment of osteoporosis. This study aims to explore novel bone immune markers related to osteoporosis based on single-cell and transcriptome data, utilizing bioinformatics and machine learning methods, in order to provide novel strategies for the diagnosis and treatment of the disease. METHODS: Single cell and transcriptome data sets were acquired from Gene Expression Omnibus (GEO). The data was then subjected to cell communication analysis, pseudotime analysis, and high dimensional WGCNA (hdWGCNA) analysis to identify key immune cell subpopulations and module genes. Subsequently, ConsensusClusterPlus analysis was performed on the key module genes to identify different diseased subgroups in the osteoporosis (OP) training set samples. The immune characteristics between subgroups were evaluated using Cibersort, EPIC, and MCP counter algorithms. OP's hub genes were screened using 10 machine learning algorithms and 113 algorithm combinations. The relationship between hub genes and immunity and pathways was established by evaluating the immune and pathway scores of the training set samples through the ESTIMATE, MCP-counter, and ssGSEA algorithms. Real-time fluorescence quantitative PCR (RT-qPCR) testing was conducted on serum samples collected from osteoporosis patients and healthy adults. RESULTS: In OP samples, the proportions of bone marrow-derived mesenchymal stem cells (BM-MSCs) and neutrophils increased significantly by 6.73% (from 24.01% to 30.74%) and 6.36% (from 26.82% to 33.18%), respectively. We found 16 intersection genes and four hub genes (DND1, HIRA, SH3GLB2, and F7). RT-qPCR results showed reduced expression levels of DND1, HIRA, and SH3GLB2 in clinical blood samples of OP patients. Moreover, the four hub genes showed positive correlations with neutrophils (0.65-0.90), immature B cells (0.76-0.92), and endothelial cells (0.79-0.87), while showing negative correlations with myeloid-derived suppressor cells (negative 0.54-0.73), T follicular helper cells (negative 0.71-0.86), and natural killer T cells (negative 0.75-0.85). CONCLUSION: Neutrophils play a crucial role in the occurrence and development of osteoporosis. The four hub genes potentially inhibit metabolic activities and trigger inflammation by interacting with other immune cells, thereby significantly contributing to the onset and diagnosis of OP.

Epigenetic regulation of cell state by H2AFY governs immunogenicity in high-risk neuroblastoma.

Childhood neuroblastoma with MYCN-amplification is classified as high-risk and often relapses after intensive treatments. Immune checkpoint blockade therapy against the PD-1/L1 axis shows limited efficacy in neuroblastoma patients and the cancer intrinsic immune regulatory network is poorly understood. Here, we leverage genome-wide CRISPR/Cas9 screens and identify H2AFY as a resistance gene to the clinically approved PD-1 blocking antibody, nivolumab. Analysis of single-cell RNA sequencing datasets reveals that H2AFY mRNA is enriched in adrenergic cancer cells and is associated with worse patient survival. Genetic deletion of H2afy in MYCN-driven neuroblastoma cells reverts in vivo resistance to PD-1 blockade by eliciting activation of the adaptive and innate immunity. Mapping of the epigenetic and translational landscape demonstrates that H2afy deletion promotes cell transition to a mesenchymal-like state. With a multi-omics approach, we uncover H2AFY-associated genes that are functionally relevant and prognostic in patients. Altogether, our study elucidates the role of H2AFY as an epigenetic gatekeeper for cell states and immunogenicity in high-risk neuroblastoma.

Herpes zoster as the initial manifestation of varicella-zoster virus infection in a healthy toddler.

Herpes zoster (HZ), commonly known as shingles, is a painful blistering rash in dermatomal distribution, caused by the reactivation of varicella-zoster virus (VZV) that was acquired during a primary varicella infection. While commonly afflicting adults, cases of HZ in paediatric patients are infrequently reported. Such cases are predominantly reported in children who have had prior exposure to VZV, either during pregnancy, early childhood or have been vaccinated with live attenuated VZV. This report presents the first known case to our knowledge of HZ as the initial manifestation of a VZV infection in an immunocompetent toddler in the UK. The report details the chronology of the infection event and discusses the clinical context behind HZ presentations in paediatrics globally. It provides a compelling illustration of the uncommon presentation of VZV infection in an immunocompetent child devoid of antecedent virus exposure, thus meriting acknowledgement and potentially further investigation as to the cause.

Immune mediators in heart-lung communication.

It is often the case that serious, end-stage manifestations of disease result from secondary complications in organs distinct from the initial site of injury or infection. This is particularly true of diseases of the heart-lung axis, given the tight anatomical connections of the two organs within a common cavity in which they collectively orchestrate the two major, intertwined circulatory pathways. Immune cells and the soluble mediators they secrete serve as effective, and targetable, messengers of signals between different regions of the body but can also contribute to the spread of pathology. In this review, we discuss the immunological basis of interorgan communication between the heart and lung in various common diseases, and in the context of organ crosstalk more generally. Gaining a greater understanding of how the heart and lung communicate in health and disease, and viewing disease progression generally from a more holistic, whole-body viewpoint have the potential to inform new diagnostic approaches and strategies for better prevention and treatment of comorbidities.

Profiling migration of human monocytes in response to chemotactic and barotactic guidance cues.

Monocytes are critical to innate immunity, participating in chemotaxis during tissue injury, infection, and inflammatory conditions. However, the migration dynamics of human monocytes under different guidance cues are not well characterized. Here, we developed a microfluidic device to profile the migration characteristics of human monocytes under chemotactic and barotactic guidance cues while also assessing the effects of age and cytokine stimulation. Human monocytes preferentially migrated toward the CCL2 gradient through confined microchannels, regardless of donor age and migration pathway. Stimulation with interferon (IFN)-γ, but not granulocyte-macrophage colony-stimulating factor (GM-CSF), disrupted monocyte navigation through complex paths and decreased monocyte CCL2 chemotaxis, velocity, and CCR2 expression. Additionally, monocytes exhibited a bias toward low-hydraulic-resistance pathways in asymmetric environments, which remained consistent across donor ages, cytokine stimulation, and chemoattractants. This microfluidic system provides insights into the unique migratory behaviors of human monocytes and is a valuable tool for studying peripheral immune cell migration in health and disease.

A quadri-fluorescence SARS-CoV-2 pseudovirus system for efficient antigenic characterization of multiple circulating variants.

The ongoing co-circulation of multiple severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) strains necessitates advanced methods such as high-throughput multiplex pseudovirus systems for evaluating immune responses to different variants, crucial for developing updated vaccines and neutralizing antibodies (nAbs). We have developed a quadri-fluorescence (qFluo) pseudovirus platform by four fluorescent reporters with different spectra, allowing simultaneous measurement of the nAbs against four variants in a single test. qFluo shows high concordance with the classical single-reporter assay when testing monoclonal antibodies and human plasma. Utilizing qFluo, we assessed the immunogenicities of the spike of BA.5, BQ.1.1, XBB.1.5, and CH.1.1 in hamsters. An analysis of cross-neutralization against 51 variants demonstrated superior protective immunity from XBB.1.5, especially against prevalent strains such as "FLip" and JN.1, compared to BA.5. Our finding partially fills the knowledge gap concerning the immunogenic efficacy of the XBB.1.5 vaccine against current dominant variants, being instrumental in vaccine-strain decisions and insight into the evolutionary path of SARS-CoV-2.

The histone methyltransferase mixed-lineage-leukemia-1 drives T cell phenotype via notch signaling in diabetic tissue repair.

Immune cell mediated inflammation is important in normal tissue regeneration but can be pathologic in diabetic wounds. Limited literature exists on the role of CD4+T cells in normal or diabetic wound repair, however, the imbalance of CD4+TH17/Treg cells has been found to promote inflammation in other diabetic tissues. Here, using human tissue and murine transgenic models, we identified that the histone methyltransferase MLL1 directly regulates the TH17 transcription factor RORγ via an H3K4me3 mechanism and increases expression of Notch receptors and downstream Notch signaling. Further, we found that Notch receptor signaling regulates CD4+TH cell differentiation and is critical for normal wound repair, and loss of upstream Notch pathway mediators or receptors in CD4+T cells resulted in the loss of CD4+TH cell differentiation in wounds. In diabetes, MLL1 and Notch-receptor signaling were upregulated in wound CD4+TH cells, driving CD4+ T cells towards the TH17 cell phenotype. Treatment of diabetic wound CD4T cells with a small molecule inhibitor of MLL1 (MI-2) yielded a significant reduction in CD4+TH17 cells and IL17A. This is the first study to identify the MLL1-mediated mechanisms responsible for regulating the TH17/Treg balance in normal and diabetic wounds and define the complex role of Notch signaling in CD4+T cells in wounds, where increased or decreased Notch signaling both result in pathologic wound repair. Therapeutic targeting of MLL1 in diabetic CD4+TH cells may decrease pathologic inflammation through regulation of CD4+T cell differentiation.