Loss of Bcl-6-Expressing T Follicular Helper Cells and Germinal Centers in COVID-19.

Humoral responses in coronavirus disease 2019 (COVID-19) are often of limited durability, as seen with other human coronavirus epidemics. To address the underlying etiology, we examined post mortem thoracic lymph nodes and spleens in acute SARS-CoV-2 infection and observed the absence of germinal centers and a striking reduction in Bcl-6+ germinal center B cells but preservation of AID+ B cells. Absence of germinal centers correlated with an early specific block in Bcl-6+ TFH cell differentiation together with an increase in T-bet+ TH1 cells and aberrant extra-follicular TNF-α accumulation. Parallel peripheral blood studies revealed loss of transitional and follicular B cells in severe disease and accumulation of SARS-CoV-2-specific "disease-related" B cell populations. These data identify defective Bcl-6+ TFH cell generation and dysregulated humoral immune induction early in COVID-19 disease, providing a mechanistic explanation for the limited durability of antibody responses in coronavirus infections, and suggest that achieving herd immunity through natural infection may be difficult.

Anti-apoptotic Protein BIRC5 Maintains Survival of HIV-1-Infected CD4+ T Cells.

HIV-1 infection of CD4+ T cells leads to cytopathic effects and cell demise, which is counter to the observation that certain HIV-1-infected cells possess a remarkable long-term stability and can persist lifelong in infected individuals treated with suppressive antiretroviral therapy (ART). Using quantitative mass spectrometry-based proteomics, we showed that HIV-1 infection activated cellular survival programs that were governed by BIRC5, a molecular inhibitor of cell apoptosis that is frequently overexpressed in malignant cells. BIRC5 and its upstream regulator OX40 were upregulated in productively and latently infected CD4+ T cells and were functionally involved in maintaining their viability. Moreover, OX40-expressing CD4+ T cells from ART-treated patients were enriched for clonally expanded HIV-1 sequences, and pharmacological inhibition of BIRC5 resulted in a selective decrease of HIV-1-infected cells in vitro. Together, these findings suggest that BIRC5 supports long-term survival of HIV-1-infected cells and may lead to clinical strategies to reduce persisting viral reservoirs.

Safety and Immunogenicity of mRNA-1010, an Investigational Seasonal Influenza Vaccine, in Healthy Adults: Final Results From a Phase 1/2 Randomized Trial.

BACKGROUND: Seasonal influenza remains a global public health concern. A messenger RNA (mRNA)-based quadrivalent seasonal influenza vaccine, mRNA-1010, was investigated in a 3-part, first-in-human, phase 1/2 clinical trial. METHODS: In Parts 1-3 of this stratified, observer-blind study, adults aged ≥18 years old were randomly assigned to receive a single dose (6.25 µg to 200 µg) of mRNA-1010 or placebo (Part 1) or an active comparator (Afluria; Parts 2-3). Primary study objectives were assessment of safety, reactogenicity, and humoral immunogenicity of mRNA-1010, placebo (Part 1), or active comparator (Parts 2-3). Exploratory endpoints included assessment of cellular immunogenicity (Part 1) and antigenic breadth against vaccine heterologous (A/H3N2) strains (Parts 1-2). RESULTS: In all study parts, solicited adverse reactions were reported more frequently for mRNA-1010 than placebo or Afluria and most were grade 1 or 2 in severity. No vaccine-related serious adverse events or deaths were reported. In Parts 1-2, a single dose of mRNA-1010 (25 µg to 200 µg) elicited robust Day 29 hemagglutination inhibition (HAI) titers that persisted through 6 months. In Part 3, lower doses of mRNA-1010 (6.25 µg to 25 µg) elicited Day 29 HAI titers that were higher or comparable to Afluria for influenza A strains. Compared with Afluria, mRNA-1010 (50 µg) elicited broader A/H3N2 antibody responses (Part 2). mRNA-1010 induced greater T-cell responses than placebo at Day 8 that were sustained or stronger at Day 29 (Part 1). CONCLUSIONS: Data support the continued development of mRNA-1010 as a seasonal influenza vaccine. CLINICALTRIALS.GOV IDENTIFIER: NCT04956575 (https://clinicaltrials.gov/study/NCT04956575).

Temporal changes in T cell subsets and expansion of cytotoxic CD4+ T cells in the lungs in severe COVID-19.

Many studies have been performed in severe COVID-19 on immune cells in the circulation and on cells obtained by bronchoalveolar lavage. Most studies have tended to provide relative information rather than a quantitative view, and it is a combination of approaches by various groups that is helping the field build a picture of the mechanisms that drive severe lung disease. Approaches employed to date have not revealed information on lung parenchymal T cell subsets in severe COVID-19. Therefore, we sought to examine early and late T cell subset alterations in the lungs and draining lymph nodes in severe COVID-19 using a rapid autopsy protocol and quantitative imaging approaches. Here, we have established that cytotoxic CD4+ T cells (CD4 + CTLs) increase in the lungs, draining lymph nodes and blood as COVID-19 progresses. CD4 + CTLs are prominently expanded in the lung parenchyma in severe COVID-19. In contrast CD8+ T cells are not prominent, exhibit increased PD-1 expression, and no obvious increase is seen in the number of Granzyme B+ CD8+ T cells in the lung parenchyma in severe COVID-19. Based on quantitative evidence for re-activation in the lung milieu, CD4 + CTLs may be as likely to drive viral clearance as CD8+ T cells and may also be contributors to lung inflammation and eventually to fibrosis in severe COVID-19.

Blood and Lymph Node Dissemination of Clonal Genome-Intact Human Immunodeficiency Virus 1 DNA Sequences During Suppressive Antiretroviral Therapy.

The majority of cells with latent human immunodeficiency virus 1 infection are located in lymphoid tissues that are difficult to access. In the current study, we used single-genome near-full-length proviral sequencing to evaluate intact and defective proviruses in blood and lymph node CD4 T cells enriched for specific functional polarizations. We observed minor variations between the frequencies of proviral sequences within individual CD4 T-cell subsets and across tissue compartments. However, we noted multiple clonal clusters of identical intact or defective proviral sequences from distinct compartments and CD4 T-cell subpopulations, suggesting frequent interchanges between viral reservoir cells in blood and tissues.

[Managing the Adverse Effects Related to Immune Checkpoint Inhibitors].

Immune checkpoint inhibitors (ICIs) have become the new posterchild of cancer treatment in recent years largely due to their impressive clinical efficacy. Drugs targeting cytotoxic T- lymphocyte-associated antigen 4 (CTLA-4) and programmed cell death-1 (PD-1) antibodies, e.g., ipilimumab (Yervoy®), pembrolizumab (Keytruda®), and nivolumab (Opdivo®), reinvigorate cytotoxic T cells to kill cancer cells in patients. Despite the impressive clinical benefits, ICIs may induce immune-related adverse events (irAE) of the skin, gastrointestinal tract, liver, endocrine, and lung with a wide spectrum of severity. Rare but severe irAEs of critical organs such as the heart and central nervous system have also been reported. Clinical practitioners must recognize the early signs and symptoms of irAE as well as related management strategies.

Platelets in early antibody-mediated rejection of renal transplants.

Antibody-mediated rejection is a major complication in renal transplantation. The pathologic manifestations of acute antibody-mediated rejection that has progressed to functional impairment of a renal transplant have been defined in clinical biopsy specimens. However, the initial stages of the process are difficult to resolve with the unavoidable variables of clinical studies. We devised a model of renal transplantation to elucidate the initial stages of humoral rejection. Kidneys were orthotopically allografted to immunodeficient mice. After perioperative inflammation subsided, donor-specific alloantibodies were passively transferred to the recipient. Within 1 hour after a single transfer of antibodies, C4d was deposited diffusely on capillaries, and von Willebrand factor released from endothelial cells coated intravascular platelet aggregates. Platelet-transported inflammatory mediators platelet factor 4 and serotonin accumulated in the graft at 100- to 1000-fold higher concentrations compared with other platelet-transported chemokines. Activated platelets that expressed P-selectin attached to vascular endothelium and macrophages. These intragraft inflammatory changes were accompanied by evidence of acute endothelial injury. Repeated transfers of alloantibodies over 1 week sustained high levels of platelet factor 4 and serotonin. Platelet depletion decreased platelet mediators and altered the accumulation of macrophages. These data indicate that platelets augment early inflammation in response to donor-specific antibodies and that platelet-derived mediators may be markers of evolving alloantibody responses.

[New Hope for HER2-Positive Metastatic Breast Cancer Treatment: Trastuzumab Emtansine (T-DM1) From the Perspective of Nursing Care].

Human epidermal growth factor receptor (HER2)-positive breast cancer is associated with a more aggressive disease and poor prognosis. The development of trastuzumab, a HER2-targeted agent, has changed the paradigm of HER2-positive breast cancer treatment and improved survival rates dramatically. However, metastatic HER2-positive breast cancer patients eventually develop resistance to this treatment regimen eventually. A new anti-HER2 antibody-drug conjugate, Trastuzumab emtansine (T-DM1), has been shown to improve treatment efficacy. However, side effects that differ from trastuzumab, including thrombocytopenia, liver dysfunction, fatigue, cardiotoxicity, pneumonitis, and peripheral neuropathy, may occur. Clinical nurses must understand the mechanism of this new agent and be aware of the symptoms and signs related to its side effects. Furthermore, clinical nurses should understand the varying degrees of these side effects, their probable causes, and the potential approaches to their management. Finally, clinical nurses must understand how to administer this agent in order to ensure patient safety. Understanding the side effects of T-DM1 and their management will help elevate nursing quality and caring efficacy.

Extrafollicular IgD-CD27-CXCR5-CD11c- DN3 B cells infiltrate inflamed tissues in autoimmune fibrosis and in severe COVID-19.

Although therapeutic B cell depletion dramatically resolves inflammation in many diseases in which antibodies appear not to play a central role, distinct extrafollicular pathogenic B cell subsets that accumulate in disease lesions have hitherto not been identified. The circulating immunoglobulin D (IgD)-CD27-CXCR5-CD11c+ DN2 B cell subset has been previously studied in some autoimmune diseases. A distinct IgD-CD27-CXCR5-CD11c- DN3 B cell subset accumulates in the blood both in IgG4-related disease, an autoimmune disease in which inflammation and fibrosis can be reversed by B cell depletion, and in severe COVID-19. These DN3 B cells prominently accumulate in the end organs of IgG4-related disease and in lung lesions in COVID-19, and double-negative B cells prominently cluster with CD4+ T cells in these lesions. Extrafollicular DN3 B cells may participate in tissue inflammation and fibrosis in autoimmune fibrotic diseases, as well as in COVID-19.

Platelets: versatile modifiers of innate and adaptive immune responses to transplants.

PURPOSE OF REVIEW: Over the last decade there has been mounting experimental data demonstrating that platelets contribute to acute vascular inflammation and atherosclerosis. This review focuses on recent findings that link platelets to inflammatory responses of relevance to transplants. RECENT FINDINGS: Although it has been known that platelets modify vascular inflammation by secretion of soluble mediators and release of microparticles, new aspects of these mechanisms are being defined. For example, platelet-derived CCL5 not only functions in homomers, but also forms more potent heteromers with platelet factor 4 (PF4; CXCL4). This heteromer formation can be inhibited with small molecules. New findings also demonstrate heterologous interactions of platelet microparticles with leukocytes that may increase their range of impact. By attaching to neutrophils, platelet microparticles appear to migrate out of blood vessels and into other compartments where they stimulate secretion of cytokines. Contact of platelets with extracellular matrix also can result in cleavage of hyaluronan into fragments that serve as an endogenous danger signal. SUMMARY: Recent findings have expanded the range of interactions by which platelets can modify innate and adaptive immune responses to transplants.

Expansion of Cytotoxic CD4+ T cells in the lungs in severe COVID-19.

The contributions of T cells infiltrating the lungs to SARS-CoV-2 clearance and disease progression are poorly understood. Although studies of CD8+ T cells in bronchoalveolar lavage and blood have suggested that these cells are exhausted in severe COVID-19, CD4+ T cells have not been systematically interrogated within the lung parenchyma. We establish here that cytotoxic CD4+ T cells (CD4+CTLs) are prominently expanded in the COVID-19 lung infiltrate. CD4+CTL numbers in the lung increase with disease severity and progression is accompanied by widespread HLA-DR expression on lung epithelial and endothelial cells, increased apoptosis of epithelial cells and tissue remodeling. Based on quantitative evidence for re-activation in the lung milieu, CD4+ CTLs are as likely to drive viral clearance as CD8+ T cells and may also be contributors to lung inflammation and eventually to fibrosis in severe COVID-19. IN BRIEF: In severe COVID-19 cytotoxic CD4+ T cells accumulate in draining lymph nodes and in the lungs during the resolving phase of the disease. Re-activated cytotoxic CD4+ T cells and cytotoxic CD8+ T cells are present in roughly equivalent numbers in the lungs at this stage and these cells likely collaborate to eliminate virally infected cells and potentially induce fibrosis. A large fraction of epithelial and endothelial cells in the lung express HLA class II in COVID-19 and there is temporal convergence between CD4+CTL accumulation and apoptosis in the lung. HIGHLIGHTS: In severe COVID-19, activated CD4+ CTLs accumulate in the lungs late in diseaseThese cells likely participate in SARS-CoV-2 clearance, collaborating with CD8+ T cells many of which exhibit an exhausted phenotypeT cells likely contribute to the late exacerbation of inflammationCD4+CTLs have been linked to fibrosis in many disorders and could also be responsible for the eventual induction of fibrosis in a subset of COVID-19 patients. SUMMARY: The contributions of T cells infiltrating the lungs to SARS-CoV-2 clearance and disease progression are poorly understood. Although studies of CD8+ T cells in bronchoalveolar lavage and blood have suggested that these cells are exhausted in severe COVID-19, CD4+ T cells have not been systematically interrogated within the lung parenchyma. We establish here that cytotoxic CD4+ T cells (CD4+CTLs) are prominently expanded in the COVID-19 lung infiltrate. CD4+CTL numbers in the lung increase with disease severity and progression is accompanied by widespread HLA-DR expression on lung epithelial and endothelial cells, increased apoptosis of epithelial cells and tissue remodeling. Based on quantitative evidence for re-activation in the lung milieu, CD4+ CTLs are as likely to drive viral clearance as CD8+ T cells and may also be contributors to lung inflammation and eventually to fibrosis in severe COVID-19.

The Loss of Bcl-6 Expressing T Follicular Helper Cells and the Absence of Germinal Centers in COVID-19.

Humoral responses in COVID-19 disease are often of limited durability, as seen with other human coronavirus epidemics. To address the underlying etiology, we examined postmortem thoracic lymph nodes and spleens in acute SARS-CoV-2 infection and observed the absence of germinal centers, a striking reduction in Bcl-6+ germinal center B cells but preservation of AID+ B cells. Absence of germinal centers correlated with an early specific block in Bcl-6+TFH cell differentiation together with an increase in T-bet+TH1 cells and aberrant extra-follicular TNF-a accumulation.  Parallel peripheral blood studies revealed loss of transitional and follicular B cells in severe disease and accumulation of SARS-CoV-2-specific "disease-related" B cell populations. These data identify defective Bcl-6+TFH cell generation and dysregulated humoral immune induction early in COVID-19 disease, providing a mechanistic explanation for the limited durability of antibody responses in coronavirus infections and suggest that achieving herd immunity through natural infection may be difficult. Funding: This work was supported by NIH U19 AI110495 to SP, NIH R01 AI146779 to AGS, NIH R01AI137057 and DP2DA042422 to DL, BMH was supported by NIGMS T32 GM007753, TMC was supported by T32 AI007245. Funding for these studies from the Massachusetts Consortium of Pathogen Readiness, the Mark and Lisa Schwartz Foundation and Enid Schwartz is also acknowledged. Conflict of Interest: None. Ethical Approval: This study was performed with the approval of the Institutional Review Boards at the Massachusetts General Hospital and the Brigham and Women's Hospital.

Recent progress in understanding HIV reservoirs.

PURPOSE OF REVIEW: Reservoirs of HIV-1-infected cells persist long-term despite highly effective antiretroviral suppression therapy and represent the main barrier against a cure for HIV-1. This review summarizes recent advances in understanding the complexity and diversity of viral reservoir cells. RECENT FINDINGS: Latently infected memory CD4 T cells are the predominant cell compartment responsible for viral persistence, but some studies suggest that myeloid cells, and possibly hematopoietic progenitors, can also serve as long-term viral reservoirs. Specific phenotypic markers, including T-cell activation and exhaustion molecules, may denote CD4 T cells enriched for replication-competent proviruses. Clonal proliferation of infected CD4 T cells in vivo represents an important mechanism responsible for the remarkable long-term stability of the viral reservoir. Multiple new assays, including near full-genome proviral sequencing and simplified versions of viral outgrowth assays, are being developed to analyze and quantify persisting reservoirs of HIV-1-infected cells. SUMMARY: Recent technological advances allow to profile the molecular structure and composition of viral reservoir cells in great detail. Continuous progress in understanding phenotypic and functional properties of viral reservoir cells provides clues for novel clinical interventions to destabilize viral persistence during antiretroviral therapy.

Clonal expansion of genome-intact HIV-1 in functionally polarized Th1 CD4+ T cells.

HIV-1 causes a chronic, incurable disease due to its persistence in CD4+ T cells that contain replication-competent provirus, but exhibit little or no active viral gene expression and effectively resist combination antiretroviral therapy (cART). These latently infected T cells represent an extremely small proportion of all circulating CD4+ T cells but possess a remarkable long-term stability and typically persist throughout life, for reasons that are not fully understood. Here we performed massive single-genome, near-full-length next-generation sequencing of HIV-1 DNA derived from unfractionated peripheral blood mononuclear cells, ex vivo-isolated CD4+ T cells, and subsets of functionally polarized memory CD4+ T cells. This approach identified multiple sets of independent, near-full-length proviral sequences from cART-treated individuals that were completely identical, consistent with clonal expansion of CD4+ T cells harboring intact HIV-1. Intact, near-full-genome HIV-1 DNA sequences that were derived from such clonally expanded CD4+ T cells constituted 62% of all analyzed genome-intact sequences in memory CD4 T cells, were preferentially observed in Th1-polarized cells, were longitudinally detected over a duration of up to 5 years, and were fully replication- and infection-competent. Together, these data suggest that clonal proliferation of Th1-polarized CD4+ T cells encoding for intact HIV-1 represents a driving force for stabilizing the pool of latently infected CD4+ T cells.

Quality of sleep and related factors during chemotherapy in patients with stage I/II breast cancer.

BACKGROUND: Insomnia causes severe distress in patients with breast cancer who receive chemotherapy. Few studies have focused on using objective methods to assess sleep. This study explored the quality of sleep and related factors in patients with breast cancer during chemotherapy. METHODS: The participants were 16 women with stage I or II breast cancer receiving their third cycle of chemotherapy with cyclophosphamide, epirubicin and fluorouracil, or cyclophosphamide, methotrexate and fluorouracil. The effects of chemotherapy on sleep were assessed on the 8th and 9th days of the third cycle, i.e. the active phase in terms of side effects, and the last 2 days before the start of the fourth cycle for comparison. Instruments used to assess sleep quality and related factors included actigraphy, the Hospital Anxiety and Depression Scale (HADS), the Symptom Distress Scale (SDS), the Fatigue Visual Analogue Scale (FVAS), the Epworth Sleepiness Scale (ESS), and sleep logs. RESULTS: During the active phase, patients showed an anxiety tendency with an average HADS score of 7.8 +/- 3.8. The average FVAS score was 4 +/- 2, indicative of mild fatigue, and SDS score (1.8 +/- 0.3) also indicated mild symptom distress. The number of awakenings each night was 2.2 +/- 1.6 by sleep logs, and the total time spent awake during these episodes was 47.8 +/- 26.1 minutes by Actiwatch. Sleep efficiency measured by Actiwatch in the active phase was 82.1 +/- 9.4% below the normal limit. Daytime sleepiness assessed by ESS showed mild sleepiness (6.0 +/- 3.5) in the active phase. CONCLUSION: The study showed poor sleep quality and daytime sleepiness in patients with breast cancer during the active phase of chemotherapy. Chemotherapy may bring symptom distress to patients and adversely influence sleep quality.

A platelet-inspired paradigm for nanomedicine targeted to multiple diseases.

Platelets are megakaryocyte-derived anucleated cells found in the blood. They are mainly responsible for rendering hemostasis or clotting to prevent bleeding complications. Decreased platelet numbers or deficiencies in platelet functions can lead to various acute or chronic bleeding conditions and hemorrhage. On the other hand, dysregulated hyperactivity of the clotting process can lead to thrombosis and vascular occlusion. There is significant evidence that beyond hemostasis and thrombosis, platelets play crucial mechanistic roles in other disease scenarios such as inflammation, immune response and cancer metastasis by mediating several cell-cell and cell-matrix interactions, as well as aiding the disease microenvironment via secretion of multiple soluble factors. Therefore, elucidating these mechanistic functions of platelets can provide unique avenues for developing platelet-inspired nanomedicine strategies targeted to these diseases. To this end, the current review provides detailed mechanistic insight into platelets' disease-relevant functions and discusses how these mechanisms can be utilized to engineer targeted nanomedicine systems.

Alloantibody induced platelet responses in transplants: potent mediators in small packages.

The early histological studies of organ allografts noted platelets attached to vascular endothelium. Platelets adhere to vessels before any morphological evidence of endothelial injury. Subsequently, in vitro and in vivo experiments have demonstrated that alloantibodies can induce exocytosis of von Willebrand factor and P-selectin from endothelial cells and attachment of platelets within minutes. Platelets also adhere to and stimulate leukocytes. These interactions are increased by complement activation. After attachment platelets degranulate, releasing preformed mediators. Some chemokines stored together in platelet granules can form heteromers with synergistic functions. Heteromers containing platelet factor 4 (PF4; CXCL4) are specific to platelets and provide insights to unique platelet functions and opportunities for therapeutic intervention.