CD8+ T cells contribute to survival in patients with COVID-19 and hematologic cancer

Limitations of neutralizing antibody titers in COVID-19 vaccine efficacy trials and a call for additional correlates of protection

The coronavirus disease (COVID-19) pandemic accelerated development of various vaccine platforms. Among them, mRNA vaccines played a crucial role in controlling the pandemic due to their swift development and efficacy against virus variants. Despite the success of these vaccines, recent studies highlight challenges in evaluating vaccine efficacy, especially in individuals with prior COVID-19 infection. Weakened neutralizing antibody responses after additional doses are observed in these populations, raising concerns about using neutralizing antibody titers as the sole immune correlate of protection. While neutralizing antibodies remain the primary endpoint in immunogenicity trials, they may not fully capture the immune response in populations with widespread prior infection or vaccination. This review explores reduced neutralizing antibody responses in previously infected individuals, and their impact on vaccine efficacy evaluation. It also offers recommendations for improving efficacy assessment, stressing incorporation of additional immune markers such as cell-mediated immunity to enable more comprehensive understanding of vaccine-induced immunity.

Discovery of a pan anti-SARS-CoV-2 monoclonal antibody with highly efficient infected cell killing capacity for novel immunotherapeutic approaches

Unlocking the potential of broadly reactive coronavirus monoclonal antibodies (mAbs) and their derivatives offers a transformative therapeutic avenue against severe COVID-19, especially crucial for safeguarding high-risk populations. Novel mAb-based immunotherapies may help address the reduced efficacy of current vaccines and neutralizing mAbs caused by the emergence of variants of concern (VOCs). Using phage display technology, we discovered a pan-SARS-CoV-2 mAb (C10) that targets a conserved region within the receptor-binding domain (RBD) of the virus. Noteworthy, C10 demonstrates exceptional efficacy in recognizing all assessed VOCs, including recent Omicron variants. While C10 lacks direct neutralization capacity, it efficiently binds to infected lung epithelial cells and induces their lysis via natural killer (NK) cell-mediated antibody-dependent cellular cytotoxicity (ADCC). Building upon this pan-SARS-CoV-2 mAb, we engineered C10-based, Chimeric Antigen Receptor (CAR)-T cells endowed with efficient killing capacity against SARS-CoV-2-infected lung epithelial cells. Notably, NK and CAR-T-cell mediated killing of lung infected cells effectively reduces viral titers. These findings highlight the potential of non-neutralizing mAbs in providing immune protection against emerging infectious diseases. Our work reveals a pan-SARS-CoV-2 mAb effective in targeting infected cells and demonstrates the proof-of-concept for the potential application of CAR-T cell therapy in combating SARS-CoV-2 infections. Furthermore, it holds promise for the development of innovative antibody-based and cell-based therapeutic strategies against severe COVID-19 by expanding the array of therapeutic options available for high-risk populations.Trial registration: ClinicalTrials.gov identifier: NCT04093596.

Severe Acute Respiratory Syndrome Coronavirus 2 Immunology and Coronavirus Disease 2019 Clinical Outcomes

The humoral and cellular immune response are the key players in preventing viral infection and limiting disease severity, particular in the context of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and coronavirus disease 2019. In this review, we discuss how immune responses generated by prior infection and vaccination influence the outcomes of SARS-CoV-2 infection. We aim to provide an overview of the role of humoral and cellular immunity, with a particular focus on CD8+ T cell responses, to delineate how different immune compartments contribute to the control of infection and modulation of disease outcomes.

Optimized tacrolimus dosing strategy in kidney transplant recipients receiving nirmatrelvir-ritonavir for COVID-19

Kidney transplantation recipients (KTRs) represent a vulnerable population for COVID-19 infection and severe disease. Nirmatrelvir-ritonavir has demonstrated efficacy in treating COVID-19 among KTRs, and interacts with tacrolimus leading to a precipitous increase in tacrolimus blood levels when co-administered, which may potentially result in toxicity. To explore a safe strategy for the combination of nirmatrelvir-ritonavir and tacrolimus, we established a new administration strategy to restore tacrolimus after the discontinuation of nirmatrelvir-ritonavir and conducted a real-world retrospective observational cohort study to evaluate its clinical efficacy. In the experimental group, tacrolimus was initiated at 20-25% of the baseline dose 48 hours after the discontinuation of nirmatrelvir-ritonavir, with daily increments of 20-25% until the baseline dose was restored. The patients who did not follow the experimental protocol were included in the control group. Results showed that withholding tacrolimus 12 hours before starting nirmatrelvir-ritonavir maintained tacrolimus blood levels above 83% of the baseline throughout the nirmatrelvir-ritonavir treatment period. Compared with the control group, the experimental group achieved target trough concentrations of tacrolimus more quickly and maintained a higher proportion within the therapeutic range (p = 0.029), and had significantly lower rates of adverse events (p = 0.002, OR = 0.308, 95%CI:0.136-0.695). This study provides a safe and effective pharmacological strategy for KTRs infected with COVID-19, allowing the safe co-administration of nirmatrelvir-ritonavir and tacrolimus.

In-depth analysis of the risk factors for persistent severe acute respiratory syndrome coronavirus 2 infection and construction of predictive models: an exploratory research study

BACKGROUND

Persistent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection differs from long coronavirus disease (COVID-19) (acute symptoms ≥ 12 weeks post-clearance). The Omicron BA.5 variant has a shorter median clearance time (10-14 days) than the Delta variant, suggesting that the traditional 20-day diagnostic threshold may delay interventions in high-risk populations. This study integrated multi-threshold analysis (14/20/30 days), whole-genome sequencing, and machine learning to investigate diagnostic thresholds for persistent SARS-CoV-2 infection and developed a generalizable risk prediction model.

METHODS

This retrospective study analyzed data from 1,216 patients with COVID-19 hospitalized at Aerospace Center Hospital between January 2021 and October 2024. We used whole-genome sequencing to genotype all COVID-19 cases and to identify major variants (such as Omicron BA. 5, Delta). The outcome, "persistent SARS-CoV-2 infection," was defined as viral nucleic acid positivity ≥ 14 days. Risk factors associated with persistent infection were identified through subgroup analysis with multiple logistic regression (adjusted for age, comorbidities, vaccination status, and virus strain) and machine learning models (70% training, 30% testing dataset).

RESULTS

Persistent SARS-CoV-2 infection was identified in 15.5% (188/1,216) of hospitalized COVID-19 patients. Key predictors included comorbidities-hypertension, diabetes, and active malignancy-and immune dysfunction, marked by reduced B-cell and CD4 + T-cell counts. Unvaccinated patients exhibited an 82% higher risk of persistent infection. Elevated inflammatory markers (C-reactive protein and interleukin-6) and bilateral lung infiltrates on computed tomography further distinguished persistent cases. The predictive model demonstrated strong discrimination with an area under the curve (AUC) of 0.847 (95% confidence interval: 0.815-0.879) and an AUC of 0.81 externally in external validation, underscoring its clinical utility for risk stratification.

CONCLUSIONS

Hypertension, diabetes, malignancy, immunosuppression (low B/CD4 + cells), and non-vaccination are independent risk factors for persistent SARS-CoV-2 infection. Integrating these factors into clinical risk stratification may optimize management of high-risk populations.

Dysregulated Adaptive Immune Responses to SARS-CoV-2 in Immunocompromised Individuals

The SARS-CoV-2 virus poses a significant risk to immunocompromised patients, who display weakened immunity and reduced seroconversion following infection and vaccination. In this study, we recruited 19 hospitalized patients with immune disorders (ImCo) and 4 immunocompetent controls (ICC) with COVID-19. We evaluated their serological, humoral, and cellular immune responses at <30 days and >90 days post-symptom onset. ICC patients showed robust B and T cell responses against SARS-CoV-2, indicated by detectable antibody levels, memory antibody-secreting cells (mASCs) towards the spike protein and spike-specific CD4+ and CD8+ T cells. ImCo patients showed impaired immune responses, with lower levels of B cell responses. Further subdivision of the ImCo patients demonstrates that solid organ transplant (SOT) patients generated B cell responses similar to ICC patients, whereas the other ImCo patients, including patients with hematological malignancies and anti-CD20 therapy, did not. Absolute T cell numbers and spike-specific CD4+ and CD8+ T cell responses were low in the ImCo patients at <30 days but increased at later time points. Our findings suggest that even when B cell responses were reduced, patients could present a T cell response, suggesting a more successful line of passive immunization for immunocompromised individuals focusing on boosting T cell responses.

Influence of polyfunctional Tbet+ T cells on specific clinical events in chronic lymphocytic leukaemia

Introduction

T-cell dysfunction is a hallmark of chronic lymphocytic leukemia (CLL), but the extent to which individual CD4+ or CD8+ T-cell subpopulations influence specific clinical events remains unclear. To address this knowledge gap, we utilised high-dimensional mass cytometry to profile circulating CD4+ and CD8+ T-cells in pre-treatment samples from a well-defined cohort of CLL patients undergoing initial therapy as part of a clinical trial.

Methods

Pre-treatment blood samples from 138 CLL patients receiving initial chemoimmunotherapy containing bendamustine or chlorambucil in the NCRI RIAltO trial (NCT01678430; EudraCT 2011-000919-22) were subjected to deep immunophenotyping by mass cytometry using a bespoke panel of 37 antibodies. T-cell clusters were identified through unsupervised clustering and related to treatment outcomes. Additionally, a randomly selected cohort of 30 CLL patients underwent T-cell stimulation with anti-CD3/CD28 microbeads, followed by cytokine analysis using a separate 36-antibody panel, which included seven cytokines.

Results

Seventeen CD4+ and 22 CD8+ T-cell clusters were identified in a discovery cohort of 79 patients. Three of these clusters, measured as a proportion of their parental CD4+ or CD8+ populations, correlated with a reduced risk of grade ≥3 infection, grade ≥3 second primary malignancy (SPM) and death, respectively. Three corresponding T-cell subpopulations prospectively defined by non-redundant markers and Boolean gating (ICOS+HLA-DR+PD1+TIGIT+Tbet+CD4+ T-helper cells; CD27+CD28-PD1+Tbet+Eomes+CD8+ cells; and CD27+CD28-GrymB+Tbet+Eomes+CD8+ terminal effector cells) showed the same clinical correlations as the clusters on which they were based. With the exception of SPM for which there were insufficient events, these correlations were confirmed in a separate validation cohort of 59 patients. In-vitro stimulation of a subset of CLL patients in the discovery cohort showed an enrichment of primed and polyfunctional cells in all three Tbet+ T-cell subpopulations of interest.

Conclusion

Our study provides new insights into the potential for Tbet+ T-cell subpopulations to influence and predict specific clinical events in CLL. This, in turn, raises the possibility that these respective subpopulations could play an important role in controlling infection, solid tumours and CLL itself.

Clinical Trial Registration

https://www.clinicaltrials.gov/, identifier NCT01678430; https://www.isrctn.com/ISRCTN09988575, identifier EudraCT 2011-000919-22.

The T-cell response to SARS-CoV- 2 vaccination persists beyond six months in rheumatoid arthritis patients treated with rituximab

BACKGROUND

The spike protein-specific humoral response observed after SARS-CoV- 2 vaccination is decreased in rheumatoid arthritis (RA) patients treated with rituximab (RTX). However, when analyzed immediately after vaccination, the spike-specific T-cell immune response appears to be preserved. The possible persistence of specific T cells over the long term is underexplored and could be a useful decision-making tool for deciding when to perform revaccination. This study aimed to assess the persistence of T-cell-mediated immunity after the last SARS-CoV- 2 vaccination or infection (named "SARS-CoV- 2 boost" in this study) in RA patients treated with RTX. Clinical and biological parameters that can influence this immune system were also explored.

METHODS

Our observational study cohort included 51 RA patients treated with RTX and 24 RA patients treated with other disease-modifying antirheumatic drugs (DMARDs) who had received at least one dose of the SARS-CoV- 2 mRNA vaccine. The T-cell immune response was assessed by flow cytometry, which focused on antigen-specific T-cell characterization between 3 and 18 months after the last SARS-CoV- 2 boost. T-cell activation was assessed by measuring CD69, CD154, CD137 and CD107a surface expression.

RESULTS

As expected, even if a lower mean antibody titer was measured in RA patients receiving RTX (RA RTX) than in RA patients treated with therapies other than RTX (p = 0.034), all patients exhibited CD4 + and CD8 + T-cell spike protein-specific responses, with an even greater spike-specific CD8 + T-cell response in RA RTX patients (p < 0.001). The main finding of our study was that the T-cell response remarkably persisted up to 18 months after the last SARS-CoV- 2 boost and no difference was found in COVID- 19 severity between RTX- and non-RTX-treated patients (p = 0.770).

CONCLUSIONS

Even if RTX treatment prevented the SARS-CoV- 2 vaccine-dependent antibody response in RA patients, a strong spike protein-specific T-cell-mediated response that persisted for up to 18 months after the last SARS-CoV- 2 boost was found in RA RTX patients. With respect to personalized medicine, analyzing the spike protein-specific T-cell response might be a valuable strategy for deciding when revaccination is necessary.

Role of antiviral CD8+ T cell immunity to SARS-CoV-2 infection and vaccination

The COVID-19 pandemic has greatly enhanced our understanding of CD8+ T cell immunity and their role in natural infection and vaccine-induced protection. Rapid and early SARS-CoV-2-specific CD8+ T cell responses have been associated with efficient viral clearance and mild disease. Virus-specific CD8+ T cell responses can compensate for waning, morbidity-related, and iatrogenic reduction of humoral immunity. After infection or vaccination, SARS-CoV-2-specific memory CD8+ T cells are formed, which mount an efficient recall response in the event of breakthrough infection and help to protect from severe disease. Due to their breadth and ability to target mainly highly conserved epitopes, SARS-CoV-2-specific CD8+ T cells are also able to cross-recognize epitopes of viral variants, thus maintaining immunity even after the emergence of viral evolution. In some cases, however, CD8+ T cells may contribute to the pathogenesis of severe COVID-19. In particular, delayed and uncontrolled, e.g., nonspecific and hyperactivated, cytotoxic CD8+ T cell responses have been linked to poor COVID-19 outcomes. In this minireview, we summarize the tremendous knowledge about CD8+ T cell responses to SARS-CoV-2 infection and COVID-19 vaccination that has been gained over the past 5 years, while also highlighting the critical knowledge gaps that remain.

A systems biology approach to define SARS-CoV-2 correlates of protection

Correlates of protection (CoPs) for SARS-CoV-2 have yet to be sufficiently defined. This study uses the machine learning platform, SIMON, to accurately predict the immunological parameters that reduced clinical pathology or viral load following SARS-CoV-2 challenge in a cohort of 90 non-human primates. We found that anti-SARS-CoV-2 spike antibody and neutralising antibody titres were the best predictors of clinical protection and low viral load in the lung. Since antibodies to SARS-CoV-2 spike showed the greatest association with clinical protection and reduced viral load, we next used SIMON to investigate the immunological features that predict high antibody titres. It was found that a pre-immunisation response to seasonal beta-HCoVs and a high frequency of peripheral intermediate and non-classical monocytes predicted low SARS-CoV-2 spike IgG titres. In contrast, an elevated T cell response as measured by IFNγ ELISpot predicted high IgG titres. Additional predictors of clinical protection and low SARS-CoV-2 burden included a high abundance of peripheral T cells. In contrast, increased numbers of intermediate monocytes predicted clinical pathology and high viral burden in the throat. We also conclude that an immunisation strategy that minimises pathology post-challenge did not necessarily mediate viral control. This would be an important finding to take forward into the development of future vaccines aimed at limiting the transmission of SARS-CoV-2. These results contribute to SARS-CoV-2 CoP definition and shed light on the factors influencing the success of SARS-CoV-2 vaccination.

Global Research on the Treatment of Cancer Patients During the COVID-19 Pandemic: Visualisation and Bibliometric Analysis

AIMS

The COVID-19 threatened global health, especially for cancer patients. We conducted a bibliometric analysis of the Science Citation Index literature published from 2019 to 2023 on the treatment of cancer patients during the COVID-19 pandemic, and explored the research trends and public interest in this topic.

MATERIALS AND METHODS

A total of 4,941 articles in the Web of Science core collection on this topic were retrieved. The online analysis platforms of literature metrology were employed to do statistical analysis of the global annual volume of documents and citation frequency, perform cocitation analysis on authors, journals, and references, draw visual maps for countries or regions cooperation, institutional cooperation, author cooperation, and keyword cooccurrence, and then conduct keyword cluster analysis and keyword bursting.

RESULTS

A total of 298 authors from 103 institutions and 74 countries or regions carried out research in the field, and the number of publications reached a peak in 2022. The United States, China, and Italy were the countries with the highest number of publications. The institutions that published the most papers are universities and research institutions. Keyword analysis showed that the research mainly focused on risk factors, outcomes, mortality, and therapy of cancer patients caused by COVID-19. Breast cancer was the cluster with the widest research scope. In addition to COVID-19, the burst keywords mainly included vaccination, delays, identification, immune response, malignancy, immunogenicity, and efficacy.

CONCLUSION

The research on the treatment of cancer patients during the COVID-19 has shifted from laboratory research to clinical research, and the focus has gradually shifted from exploring the mechanism to improving the therapeutic effect. Developing vaccines and exploring treatment options that are more suitable for use in cancer patients, and investigating the relevance of the cytokine storms seem to concur with research priorities postpandemic. In the future, strengthening cooperation among countries or regions, institutions, and authors will be crucial for future pandemics.

The Impact of Vaccination Frequency on COVID-19 Public Health Outcomes: A Model-Based Analysis

Background: While the rapid deployment of SARS-CoV-2 vaccines had a significant impact on the ongoing COVID-19 pandemic, rapid viral immune evasion and waning neutralizing antibody titers have degraded vaccine efficacy. Nevertheless, vaccine manufacturers and public health authorities have a number of options at their disposal to maximize the benefits of vaccination. In particular, the effect of booster schedules on vaccine performance bears further study. Methods: To better understand the effect of booster schedules on vaccine performance, we used an agent-based modeling framework and a population pharmacokinetic model to simulate the impact of boosting frequency on the durability of vaccine protection against infection and severe acute disease. Results: Our work suggests that repeated dosing at frequent intervals (three or more times a year) may offset the degradation of vaccine efficacy, preserving the utility of vaccines in managing the ongoing pandemic. Conclusions: Given the practical significance of potential improvements in vaccine utility, clinical research to better understand the effects of repeated vaccination would be highly impactful. These findings are particularly relevant as public health authorities worldwide have reduced the frequency of boosters to once a year or less.

Proceedings of the 2023 Annual Scientific Meeting of the French Society of Toxicologic Pathology (SFPT) on Preclinical Development and Therapeutic Applications of mRNA-Based Technologies

The 2023 annual scientific meeting of the French Society of Toxicologic Pathology (Société Française de Pathologie Toxicologique, SFPT), entitled "mRNA-based technologies: preclinical development and therapeutic applications," was held in Lyon (France) on May 25 to 26, 2023. The aim of the meeting was to discuss the biology, immunology, and preclinical development of messenger RNA (mRNA)-based vaccines and therapeutics, including immuno-oncology and rare diseases, as well as the regulatory aspect of the COVID-19 vaccines and an overview of the principles and applications of in situ hybridization techniques. This article presents the summary of five lectures along with selected figures, tables, and key literature references on this topic.

Treatment patterns and clinical outcomes of immunocompromised patients with COVID-19 receiving remdesivir in the inpatient setting in Japan

INTRODUCTION

Remdesivir (RDV) was approved in Japan for the treatment of coronavirus disease 2019 (COVID-19) in May 2020. However, large-scale research describing the characterized use of RDV in the inpatient setting in Japan is limited. This study aimed to describe the treatment patterns and clinical outcomes of immunocompromised patients with COVID-19 treated with RDV.

METHODS

We used a secondary nationwide administrative claims database of acute care hospitals in Japan. The study period was from October 19, 2020, to September 30, 2022. Patients with COVID-19 treated with RDV during hospitalization were included, and the proportion of patients with death and disease progression were calculated.

RESULTS

The analysis included a total of 2171 immunocompromised patients treated with RDV. The mean (standard deviation) age at index date was 75.1 (13.6) years. The median time to RDV initiation from hospitalization was 1.0 days (Q1-Q3: 1.0-2.0), and the median duration of RDV treatment was 5.0 days (Q1-Q3: 3.0-5.0). At RDV initiation, 53.02% (n=1151) of patients required non-invasive positive pressure ventilation, nasal high-flow or low-flow oxygen, and 2.26% (n=49) required mechanical ventilation, extracorporeal membrane oxygenation, or intensive care unit admission. Inpatient mortality rate by day 28 was 8.98% (95% confidence interval, 7.81-10.26). By day 28, the rate of disease progression was 9.86% (n=214), and 76.83% (n=1668) were discharged.

CONCLUSION

This study presents practical information on outcomes and treatment patterns of RDV in immunocompromised inpatients diagnosed with COVID-19.

Molecular determinants of cross-strain influenza A virus recognition by αβ T cell receptors

Cross-reactive αβ T cell receptors (TCRs) recognizing multiple peptide variants can provide effective control of rapidly evolving viruses yet remain understudied. By screening 12 naturally occurring influenza-derived HLA-B*35:01-restricted nucleoprotein (NP)418-426 epitopes (B*35:01-NP418) that emerged since 1918 within influenza A viruses, including 2024 A/H5N1 viruses, we identified functional broadly cross-reactive T cells universally recognizing NP418 variants. Binding studies demonstrated that TCR cross-reactivity was concomitant with diminished antigen sensitivity. Primary human B*35:01/NP418+CD8+ T cell lines displayed reduced cross-reactivity in the absence of CD8 coreceptor binding, validating the low avidity of cross-reactive B*35:01-NP418+CD8+ T cell responses. Six TCR-HLA-B*35:01/NP418 crystal structures showed how cross-reactive TCRs recognized multiple B*35:01/NP418 epitope variants. Specific TCR interactions were formed with invariant and conserved peptide-HLA features, thus remaining distal from highly varied positions of the NP418 epitope. Our study defines molecular mechanisms associated with extensive TCR cross-reactivity toward naturally occurring viral variants highly relevant to universal protective immunity against influenza.

Comprehensive humoral and cellular immune responses to COVID-19 vaccination in adults with cancer

BACKGROUND

The COVID-19 pandemic has significantly impacted people with cancer. Initial vaccine studies excluded patients with malignancy. Immunocompromised individuals remain vulnerable to SARS-CoV-2, necessitating detailed understanding of vaccine response. The epidemiology of COVID-19 in Australia offered unique opportunities to study cancer populations with minimal community exposure to SARS-CoV-2.

METHODS

SerOzNET prospectively examined previously unvaccinated patients with solid and haematological malignancies receiving up to five COVID-19 vaccine doses. Antibody response was measured by live virus neutralisation assay (neutralising antibody (NAb); positive titre ≥1:20; study primary endpoint) and commercial assay. T cell response was measured by cytometric bead array; positive defined as interferon gamma (IFN-γ) ≥10 pg/mL in response to Spike antigen. Patient and physician-reported adverse events were secondary endpoints.

OUTCOMES

395 adults were enrolled prior to receiving mRNA vaccine (BNT162b2 = 347; mRNA-1273 = 1) or viral vector vaccine (ChadOx1-S = 43) for initial two-dose course, plus up to three additional doses. Median age was 58 years (range: 20-85); 60 % were female; 35 % had haematological malignancy, 2/395 (0.5 %) had baseline positive nucleocapsid antibody indicating prior SARS-CoV-2 exposure. NAb response post dose three was demonstrated in 84 % overall; 96 % of patients with solid cancers and 64 % with haematological cancer (p < 0·001). Risk factors for non-response were haematological cancer and anti B-cell therapies. Some patients with haematological cancer seroconverted for the first time after the fourth or fifth dose. IFN-γ response was seen in many patients with haematological cancer who lacked NAb response. Serious adverse events were rare. COVID-19 infection occurred in 29 % with no deaths.

INTERPRETATION

COVID-19 vaccination elicits B and T cell responses in patients with solid and haematological cancers, with an acceptable safety profile. A significant proportion of haematological cancer patients require >3 doses to elicit NAb, with many demonstrating T cell response, which may be an alternative pathway of immune protection.

mRNA vaccines with RBD mutations have broad-spectrum activity against SARS-CoV-2 variants in mice

The emergence of SARS-CoV-2 variants with defined mutations that enhance pathogenicity or facilitate immune evasion has resulted in a continual decline in the protective efficacy of existing vaccines. Therefore, there is a pressing need for a vaccine capable of combating future variants. In this study, we designed new mRNA vaccines, BSCoV05 and BSCoV06, and generated point mutations in the receptor-binding domain (RBD) of the original Wuhan strain to increase their broad-spectrum antiviral activity. Additionally, we used the BA.1 RBD as a control. Both vaccines elicited a robust immune response in BALB/c and K18-hACE2 mice, generating high levels of specific binding antibodies against the BA.2 RBD. Moreover, all three vaccines induced neutralizing antibodies against the prototype viral strain and relevant variants, including the Alpha and Beta strains and the Omicron variants BA.1, BA.2, BA.5, XBB.1.5, XBB.1.16, EG.5.1, and EG.5.1.1, with BSCoV06 demonstrating broader neutralizing antibody activity. Both BSCoV05 and BSCoV06 also elicited a cellular immune response. After the challenge, both BSCoV05 and BSCOV06 provided protection against the EG.5.1 strain in both mouse strains. Therefore, these two vaccines merit further evaluation in nonhuman primates, and this vaccine design strategy should be explored for its potential application in combating future SARS-CoV-2 variants, offering valuable insights into broad-spectrum vaccine development.

An Update on Anti-COVID-19 Vaccines and the Challenges to Protect Against New SARS-CoV-2 Variants

The COVID-19 pandemic has posed a significant threat to global health systems, with extensive impacts across many sectors of society. The pandemic has been responsible for millions of deaths worldwide since its first identification in late 2019. Several actions have been taken to prevent the disease, including the unprecedented fast development and global vaccination campaigns, which were pivotal in reducing symptoms and deaths. Given the impact of the pandemic, the continuous changes of the virus, and present vaccine technologies, this review analyzes how, so far, we have met the challenge posed by the emergence of new variants and discusses how next-generation pan-coronavirus vaccines, with enhanced longevity and breadth of immune responses, may be tackled with alternative administration routes and antigen delivery platforms. By addressing these critical aspects, this review aims to contribute to the ongoing efforts to achieve long-term control of COVID-19, stimulating the discussion and work on next-generation vaccines capable of facing future waves of infection.

Linking COVID-19 and cancer: Underlying mechanism

COVID-19 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), lead to a global health crisis with a spectrum of clinical manifestations. A potentially vulnerable category for SARS-CoV-2 infection was identified in patients with other medical conditions. Intriguingly, parallels exist between COVID-19 and cancer at the pathophysiological level, suggesting a possible connection between them. This review discusses all possible associations between COVID-19 and cancer. Expression of receptors like angiotensin-converting enzyme 2 (ACE2) and transmembrane protease serine 2 (TMPRSS2) increases COVID-19 susceptibility. SARS-CoV-2 infection might increase cancer susceptibility and accelerate cancer progression through mechanisms involving cytokine storm, tissue hypoxia, impaired T-cell responses, autophagy, neutrophil activation, and oxidative stress. These mechanisms collectively contribute to immune suppression, hindered apoptosis, and altered cellular signaling in the tumor microenvironment, creating conditions favorable for tumor growth, metastasis, and recurrence. Approved vaccines and their impact on cancer patients along-with new clinical trials are also described.

COVID-19 vaccines: Immune correlates and clinical outcomes

Severe disease due to COVID-19 has declined dramatically as a result of widespread vaccination and natural immunity in the population. With the emergence of SARS-CoV-2 variants that largely escape vaccine-elicited neutralizing antibody responses, the efficacy of the original vaccines has waned and has required vaccine updating and boosting. Nevertheless, hospitalizations and deaths due to COVID-19 have remained low. In this review, we summarize current knowledge of immune responses that contribute to population immunity and the mechanisms how vaccines attenuate COVID-19 disease severity.

The contributions of T cell-mediated immunity to protection from vaccine-preventable diseases: A primer

In the face of the ever-present burden of emerging and reemerging infectious diseases, there is a growing need to comprehensively assess individual- and population-level immunity to vaccine-preventable diseases (VPDs). Many of these efforts, however, focus exclusively on antibody-mediated immunity, ignoring the role of T cells. Aimed at clinicians, public health practioners, and others who play central roles in human vaccine research but do not have formal training in immunology, we review how vaccines against infectious diseases elicit T cell responses, what types of vaccines elicit T cell responses, and how T cell responses are measured. We then use examples to demonstrate six ways that T cells contribute to protection from VPD, including directly mediating protection, enabling antibody responses, reducing disease severity, increasing cross-reactivity, improving durability, and protecting special populations. We conclude with a discussion of challenges and solutions to more widespread consideration of T cell responses in clinical vaccinology.

Staggered immunization with mRNA vaccines encoding SARS-CoV-2 polymerase or spike antigens broadens the T cell epitope repertoire

Combining a T cell-targeting mRNA vaccine encoding the conserved SARS-CoV-2 RNA-dependent RNA polymerase, RdRp, with a Spike-encoding mRNA vaccine may offer an additional pathway toward COVID-19 protection. Here, we show that a nucleoside-modified RdRp mRNA vaccine raises robust and durable CD8+ T cell responses in mice. Immunization drives a CD8+ T cell response enriched toward a specific RdRp epitope. Unexpectedly, coadministration of mRNA vaccines encoding RdRp or the Spike Receptor Binding Domain (RBD) dampens RBD-specific immune responses. Contralateral administration reduces the suppression of RBD-specific T cell responses while type I interferon signaling blockade restores RBD-specific antibodies. A staggered immunization strategy maintains both RBD vaccine-mediated antibody and T cell responses as well as protection against lethal SARS-CoV-2 challenge in human ACE2 transgenic mice. In HLA-A2.1 transgenic mice, the RdRp vaccine elicits CD8+ T cell responses against HLA-A*02:01-restricted epitopes recognized by human donor T cells. These results highlight RdRp as a candidate antigen for COVID-19 vaccines. The findings also offer insights into crafting effective multivalent mRNA vaccines to broaden CD8+ T cell responses against SARS-CoV-2 and potentially other viruses with pandemic potential.

Autopsy findings in cancer patients infected with SARS-CoV-2 show a milder presentation of COVID-19 compared to non-cancer patients

COVID-19, caused by SARS-CoV-2, manifests with differing severity across distinct patient subgroups, with outcomes influenced by underlying comorbidities such as cancer, which may cause functional and compositional alterations of the immune system during tumor progression. We aimed to investigate the association of SARS-CoV-2 infection and its complications with cancer in a large autopsy series and the role of COVID-19 in the fatal sequence leading to death. A total of 2641 adult autopsies were investigated, 539 of these were positive for SARS-CoV-2. Among the total number of patients analyzed, 829 had active cancer. Overall, the cohort included 100 patients who simultaneously had cancer and SARS-CoV-2 infection. The course of COVID-19 was less severe in cancer patients, including a significantly lower incidence of viral and bacterial pneumonia, occurring more frequently as a contributory disease or coexisting morbidity, or as SARS-CoV-2 positivity without viral disease. SARS-CoV-2 positivity was more frequent among non-metastatic than metastatic cancer cases, and in specific tumor types including hematologic malignancies. COVID-19 was more frequently found to be directly involved in the fatal sequence in patients undergoing active anticancer therapy, but less frequently in perioperative status, suggesting that the underlying malignancy and consequent surgery are more important factors leading to death perioperatively than viral disease. The course of COVID-19 in cancer patients was milder and balanced during the pandemic. This may be due to relative immunosuppressed status, and the fact that even early/mild viral infections can easily upset their condition, leading to death from their underlying cancer or its complications.

Neutralizing antibody correlate of protection against severe-critical COVID-19 in the ENSEMBLE single-dose Ad26.COV2.S vaccine efficacy trial

Assessment of immune correlates of severe COVID-19 has been hampered by the low numbers of severe cases in COVID-19 vaccine efficacy (VE) trials. We assess neutralizing and binding antibody levels at 4 weeks post-Ad26.COV2.S vaccination as correlates of risk and of protection against severe-critical COVID-19 through 220 days post-vaccination in the ENSEMBLE trial (NCT04505722), constituting ~4.5 months longer follow-up than our previous correlates analysis and enabling inclusion of 42 severe-critical vaccine-breakthrough cases. Neutralizing antibody titer is a strong inverse correlate of severe-critical COVID-19, with estimated hazard ratio (HR) per 10-fold increase 0.35 (95% CI: 0.13, 0.90). In a multivariable model, HRs are 0.31 (0.11, 0.89) for neutralizing antibody titer and 1.22 (0.49, 3.02) for anti-Spike binding antibody concentration. VE against severe-critical COVID-19 rises with neutralizing antibody titer: 63.1% (95% CI: 40.0%, 77.3%) at unquantifiable [<4.8975 International Units (IU)50/ml], 85.2% (47.2%, 95.3%) at just-quantifiable (5.2 IU50/ml), and 95.1% (81.1%, 96.9%) at 90th percentile (30.2 IU50/ml). At the same titers, VE against moderate COVID-19 is 32.5% (11.8%, 48.4%), 33.9% (19.1%, 59.3%), and 60.7% (40.4%, 76.4%). Protection against moderate vs. severe disease may require higher antibody levels, and very low antibody levels and/or other immune responses may associate with protection against severe disease.

Long-Term Outcomes of COVID-19 and Risk Factors for Prolonged or Persistent COVID-19 in Lymphoma Patients: A Multicenter, Retrospective Cohort Study

BACKGROUND

Patients with hematologic malignancies exhibit persistent severe acute respiratory syndrome coronavirus 2 positivity over long periods after coronavirus disease 2019 (COVID-19) diagnosis. However, the frequency of, risk factors for, and prognosis of prolonged COVID-19 in immunocompromised patients remain unclear. Therefore, we investigated the long-term outcomes of COVID-19 in lymphoma patients and identified the associated factors and impact of prolonged COVID-19 on mortality.

METHODS

A multicenter retrospective cohort study of 583 lymphoma patients was conducted in 3 tertiary hospitals in South Korea. Patients receiving lymphoma treatment who were quarantined after obtaining a diagnosis of COVID-19 by polymerase chain reaction (PCR) or antigen test from August 2021 to September 2022 were examined.

RESULTS

Overall, 115 patients (19.7%) were diagnosed with COVID-19. Among 77 patients with clinical data, 24 had prolonged COVID-19. Patients in the prolonged COVID-19 group showed higher rates of receiving rituximab maintenance therapy following bendamustine and rituximab (BR) treatment for follicular lymphoma. This group did not show significant differences in clinical presentation within 30 days of COVID-19 diagnosis; however, it showed higher rates of re-admission due to COVID-19 pneumonia compared with the non-prolonged COVID-19 group. BR treatment followed by rituximab maintenance therapy is one of the risk factors for persistent PCR positivity, delayed or persistent pneumonia, and COVID-19 related admission after quarantine period. Prolonged COVID-19 was an independent risk factor for 1-year mortality.

CONCLUSION

Prolonged COVID-19 was more frequent in lymphoma patients who received BR treatment followed by rituximab maintenance therapy and associated with unfavorable long-term outcomes and higher 1-year mortality.

A phase I/II study of adoptive SARS-CoV-2-specific T cells in immunocompromised hosts with or at risk of severe COVID-19 infection

BACKGROUND

Post-transplant or hematological cancer patients have a higher risk of mortality after infection with ancestral and early variants of severe acute respiratory syndrome (SARS)-CoV-2. Adoptive cell therapy (ACT) with virus-specific T cells (VSTs) could augment endogenous T cell immunity to avoid disease deterioration before viral clearance.

METHODS

We established a third-party SARS-CoV-2-specific T cell (COVID-T) bank in 2020 (NCT04351659) using convalescent and/or vaccinated donors. In a phase I/II study (NCT04457726), 13 adult and pediatric patients, acutely positive for SARS-CoV-2 and predicted to have a high chance of mortality, were recruited from September 2021 to February 2022. Twelve patients received a single dose of COVID-T cells, matched on at least 1 HLA.

RESULTS

A dose of either 75,000 or 150,000 IFN-γ+CD3+ cells/m2 SARS-COV-2-specific T cells did not cause cytokine release syndrome, acute respiratory distress syndrome, or graft-versus-host disease. In the 8 patients who had detectable donor SARS-COV-2-specific T cells after ACT, none progressed to severe disease or died with COVID-19. In contrast, among the other four patients without evidence of donor micro-chimerism, two died of COVID-19.

CONCLUSIONS

Long-acting third-party VSTs from convalescent or vaccinated donors could be expediently produced and might be clinically useful in future pandemics, particularly before global vaccination is implemented.

T-Cell Immune Responses to SARS-CoV-2 Infection and Vaccination

The innate and adaptive immune systems collaborate to detect SARS-CoV-2 infection, minimize the viral spread, and kill infected cells, ultimately leading to the resolution of the infection. The adaptive immune system develops a memory of previous encounters with the virus, providing enhanced responses when rechallenged by the same pathogen. Such immunological memory is the basis of vaccine function. Here, we review the current knowledge on the immune response to SARS-CoV-2 infection and vaccination, focusing on the pivotal role of T cells in establishing protective immunity against the virus. After providing an overview of the immune response to SARS-CoV-2 infection, we describe the main features of SARS-CoV-2-specific CD4+ and CD8+ T cells, including cross-reactive T cells, generated in patients with different degrees of COVID-19 severity, and of Spike-specific CD4+ and CD8+ T cells induced by vaccines. Finally, we discuss T-cell responses to SARS-CoV-2 variants and hybrid immunity and conclude by highlighting possible strategies to improve the efficacy of COVID-19 vaccination.

SARS-CoV-2-Specific T-Cell as a Potent Therapeutic Strategy against Immune Evasion of Emerging COVID-19 Variants

Despite advances in vaccination and therapies for coronavirus disease, challenges remain due to reduced antibody longevity and the emergence of virulent variants like Omicron (BA.1) and its subvariants (BA.1.1, BA.2, BA.3, and BA.5). This study explored the potential of adoptive immunotherapy and harnessing the protective abilities using virus-specific T cells (VSTs). Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) VSTs were generated by stimulating donor-derived peripheral blood mononuclear cells with spike, nucleocapsid, and membrane protein peptide mixtures. Phenotypic characterization, including T-cell receptor (TCR) vβ and pentamer analyses, was performed on the ex vivo-expanded cells. We infected human leukocyte antigen (HLA)-partially matched human Calu-3 cells with various authentic SARS-CoV-2 strains in a Biosafety Level 3 facility and co-cultured them with VSTs. VSTs exhibited a diverse TCR vβ repertoire, confirming their ability to target a broad range of SARS-CoV-2 antigens from both the ancestral and mutant strains, including Omicron BA.1 and BA.5. These ex vivo-expanded cells exhibited robust cytotoxicity and low alloreactivity against HLA-partially matched SARS-CoV-2-infected cells. Their cytotoxic effects were consistent across variants, targeting conserved spike and nucleocapsid epitopes. Our findings suggest that third-party partial HLA-matching VSTs could counter immune-escape mechanisms posed by emerging variants of concern.

SARS-CoV-2-specific CD8+ T cells from people with long COVID establish and maintain effector phenotype and key TCR signatures over 2 years

Long COVID occurs in a small but important minority of patients following COVID-19, reducing quality of life and contributing to healthcare burden. Although research into underlying mechanisms is evolving, immunity is understudied. SARS-CoV-2-specific T cell responses are of key importance for viral clearance and COVID-19 recovery. However, in long COVID, the establishment and persistence of SARS-CoV-2-specific T cells are far from clear, especially beyond 12 mo postinfection and postvaccination. We defined ex vivo antigen-specific B cell and T cell responses and their T cell receptors (TCR) repertoires across 2 y postinfection in people with long COVID. Using 13 SARS-CoV-2 peptide-HLA tetramers, spanning 11 HLA allotypes, as well as spike and nucleocapsid probes, we tracked SARS-CoV-2-specific CD8+ and CD4+ T cells and B-cells in individuals from their first SARS-CoV-2 infection through primary vaccination over 24 mo. The frequencies of ORF1a- and nucleocapsid-specific T cells and B cells remained stable over 24 mo. Spike-specific CD8+ and CD4+ T cells and B cells were boosted by SARS-CoV-2 vaccination, indicating immunization, in fully recovered and people with long COVID, altered the immunodominance hierarchy of SARS-CoV-2 T cell epitopes. Meanwhile, influenza-specific CD8+ T cells were stable across 24 mo, suggesting no bystander-activation. Compared to total T cell populations, SARS-CoV-2-specific T cells were enriched for central memory phenotype, although the proportion of central memory T cells decreased following acute illness. Importantly, TCR repertoire composition was maintained throughout long COVID, including postvaccination, to 2 y postinfection. Overall, we defined ex vivo SARS-CoV-2-specific B cells and T cells to understand primary and recall responses, providing key insights into antigen-specific responses in people with long COVID.

COVID-19 in patients with haematologic malignancies: Effect of RNAemia on clinical outcome in vaccinated patients

OBJECTIVES

Patients with haematologic malignancies (HM) COVID-19 have more severe disease, with increased risk of mortality. Therefore, this study aimed to evaluate the effect of SARS-CoV-2 RNAemia and the specific humoral immune responses on the clinical outcomes of patients with HM and COVID-19.

METHODS

Interferon-α/γ (IFN-α/IFN-γ) serum levels, neutralizing antibodies and RNAemia at COVID-19 diagnosis, and persistent RNAemia during the follow-up were evaluated.

RESULTS

Overall, 63 (58.9%) out of 107 patients had RNAemia, which was persistent in 26 (41.3%) patients. RNAemia at diagnosis and persistent RNAemia were associated with the need for high-flow nasal oxygen therapy during admission. Persistent RNAemia, age >70 years, and CURB-65 score ≥2 in patients with pneumonia were associated with increased 90-day mortality (P = 0.009, P = 0.030 and P = 0.001, respectively). The 90-day overall survival was lower (P = 0.006) in patients with persistent RNAemia. In addition, dexamethasone administration was associated with a COVID-19 episode with persistent RNAemia.

CONCLUSION

Our results suggest that in patients with HM, RNAemia at the time of COVID-19 diagnosis and during the follow-up can be used to stratify patients with HM according to their clinical evolution and to guide clinical decisions tailored to the specific needs of each patient.

Improved outcome of COVID-19 over time in patients treated with CAR T-cell therapy: Update of the European COVID-19 multicenter study on behalf of the European Society for Blood and Marrow Transplantation (EBMT) Infectious Diseases Working Party (IDWP) and the European Hematology Association (EHA) Lymphoma Group

COVID-19 has been associated with high mortality in patients treated with Chimeric Antigen Receptor (CAR) T-cell therapy for hematologic malignancies. Here, we investigated whether the outcome has improved over time with the primary objective of assessing COVID-19-attributable mortality in the Omicron period of 2022 compared to previous years. Data for this multicenter study were collected using the MED-A and COVID-19 report forms developed by the EBMT. One-hundred-eighty patients were included in the analysis, 39 diagnosed in 2020, 35 in 2021 and 106 in 2022. The median age was 58.9 years (min-max: 5.2-78.4). There was a successive decrease in COVID-19-related mortality over time (2020: 43.6%, 2021: 22.9%, 2022: 7.5%) and in multivariate analysis year of infection was the strongest predictor of survival (p = 0.0001). Comparing 2022 with 2020-2021, significantly fewer patients had lower respiratory symptoms (21.7% vs 37.8%, p = 0.01), needed oxygen support (25.5% vs 43.2%, p = 0.01), or were admitted to ICU (5.7% vs 33.8%, p = 0.0001). Although COVID-19-related mortality has decreased over time, CAR T-cell recipients remain at higher risk for complications than the general population. Consequently, vigilant monitoring for COVID-19 in patients undergoing B-cell-targeting CAR T-cell treatment is continuously recommended ensuring optimal prevention of infection and advanced state-of-the art treatment when needed.

SARS-CoV-2-Specific T Lymphocytes Analysis in mRNA-Vaccinated Patients with B-Cell Lymphoid Malignancies on Active Treatment

BACKGROUND

Patients with B-lymphocyte malignancies (BCMs) receiving B-lymphocyte-targeted therapies have increased risk of severe COVID-19 outcomes and impaired antibody response to SARS-CoV-2 mRNA vaccination in comparison to non-hematologic oncologic patients or general population. Consequently, it is vital to explore vaccine-induced T-lymphocyte responses in patients referred for the understanding of immune protection against SARS-CoV2 infections. The objective of the present study was to analyze the recall immune responses carried out by T lymphocytes after two COVID-19 mRNA vaccine doses.

METHODS

We enrolled 40 patients with BCMs and 10 healthy controls (HCs) after 4 weeks from the second mRNA vaccine dose. Spike (S)-specific T-lymphocyte responses were assessed in peripheral blood mononuclear lymphocytes (PBMCs) by intracellular IFN-γ staining combined with flow cytometry. Furthermore, the humoral response was assessed with the measurement of anti-spike antibodies.

RESULTS

From March to July 2021, 40 patients (median age 68) received mRNA vaccines. The overall antibody response for BCMs was 52.5% versus 100% for the healthy controls (p = 0.008). The antibody response was different across BCMs: 18.75% for non-Hodgkin lymphoma, 54.5% for chronic lymphocytic leukemia, and 92.3% for multiple myeloma. Responses varied by malignancy type and treatment, with anti-CD20 therapies showing the lowest response (6.7%). T-lymphocyte analysis revealed reduced numbers and altered differentiation stages in patients compared to the controls. However, the vaccine-induced T response was generally robust, with variations in specific T subpopulations.

CONCLUSIONS

mRNA vaccines induced significant humoral and cellular immune responses in B-cell lymphoid malignancy patients, although responses varied by treatment type and malignancy. Further research is needed to optimize vaccination strategies in this population.

Evaluation of inflammatory biomarkers and their association with anti-SARS-CoV-2 antibody titers in healthcare workers vaccinated with BNT162B2

Introduction

Vaccine-induced immunity against COVID-19 generates antibody and lymphocyte responses. However, variability in antibody titers has been observed after vaccination, and the determinants of a better response should be studied. The main objective of this investigation was to analyze the inflammatory biomarker response induced in healthcare workers vaccinated with BNT162b2, and its association with anti-Spike (a SARS-CoV-2 antigen) antibodies measured throughout a 1-year follow-up.

Methods

Anti-spike antibodies and 92 biomarkers were analyzed in serum, along with socio-demographic and clinical variables collected by interview or exploration.

Results

In our study, four biomarkers (ADA, IL-17C, CCL25 and CD8α) increased their expression after the first vaccine dose; and 8 others (uPA, IL-18R1, EN-RAGE, CASP-8, MCP-2, TNFβ, CD5 and CXCL10) decreased their expression. Age, body mass index (BMI), smoking, alcohol consumption, and prevalent diseases were associated with some of these biomarkers. Furthermore, higher baseline levels of T-cell surface glycoprotein CD6 and hepatocyte growth factor (HGF) were associated with lower mean antibody titers at follow-up, while levels of monocyte chemotactic protein 2 (MCP-2) had a positive association with antibody levels. Age and BMI were positively related to baseline levels of MCP-2 (β=0.02, 95%CI 0.00-0.04, p=0.036) and HGF (β=0.03, 95%CI 0.00-0.06, p=0.039), respectively.

Conclusion

Our findings indicate that primary BNT162b2 vaccination had a positive effect on the levels of several biomarkers related to T cell function, and a negative one on some others related to cancer or inflammatory processes. In addition, a higher level of MCP-2 and lower levels of HGF and CD6 were found to be associated with higher anti-Spike antibody titer following vaccination.

SARS-CoV-2 Vaccination in the First Year After Hematopoietic Cell Transplant or Chimeric Antigen Receptor T-Cell Therapy: A Prospective, Multicenter, Observational Study

BACKGROUND

The optimal timing of vaccination with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines after cellular therapy is incompletely understood. The objectives of this study are to determine whether humoral and cellular responses after SARS-CoV-2 vaccination differ if initiated <4 months versus 4-12 months after cellular therapy.

METHODS

We conducted a multicenter, prospective, observational study at 30 cancer centers in the United States. SARS-CoV-2 vaccination was administered as part of routine care. We obtained blood prior to and after vaccinations at up to 5 time points and tested for SARS-CoV-2 spike (anti-S) IgG in all participants and neutralizing antibodies for Wuhan D614G, Delta B.1.617.2, and Omicron B.1.1.529 strains, as well as SARS-CoV-2-specific T-cell receptors, in a subgroup.

RESULTS

We enrolled 466 allogeneic hematopoietic cell transplantation (HCT) (n = 231), autologous HCT (n = 170), and chimeric antigen receptor T-cell (CAR-T-cell) therapy (n = 65) recipients between April 2021 and June 2022. Humoral and cellular responses did not significantly differ among participants initiating vaccinations <4 months versus 4-12 months after cellular therapy. Anti-S IgG ≥2500 U/mL was correlated with high neutralizing antibody titers and attained by the last time point in 70%, 69%, and 34% of allogeneic HCT, autologous HCT, and CAR-T-cell recipients, respectively. SARS-CoV-2-specific T-cell responses were attained in 57%, 83%, and 58%, respectively. Pre-cellular therapy SARS-CoV-2 infection or vaccination and baseline B-cell count were key predictors of post-cellular therapy immunity.

CONCLUSIONS

These data support mRNA SARS-CoV-2 vaccination prior to, and reinitiation 3 to 4 months after, cellular therapies with allogeneic HCT, autologous HCT, and CAR-T-cell therapy.

Safety and feasibility of third-party cytotoxic T lymphocytes for high-risk patients with COVID-19

ABSTRACT

Cytotoxic T lymphocytes (CTLs) destroy virally infected cells and are critical for the elimination of viral infections such as those caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Delayed and dysfunctional adaptive immune responses to SARS-CoV-2 are associated with poor outcomes. Treatment with allogeneic SARS-CoV-2-specific CTLs may enhance cellular immunity in high-risk patients providing a safe, direct mechanism of treatment. Thirty high-risk ambulatory patients with COVID-19 were enrolled in a phase 1 trial assessing the safety of third party, SARS-CoV-2-specific CTLs. Twelve interventional patients, 6 of whom were immunocompromised, matched the HLA-A∗02:01 restriction of the CTLs and received a single infusion of 1 of 4 escalating doses of a product containing 68.5% SARS-CoV-2-specific CD8+ CTLs/total cells. Symptom improvement and resolution in these patients was compared with an observational group of 18 patients lacking HLA-A∗02:01 who could receive standard of care. No dose-limiting toxicities were observed at any dosing level. Nasal swab polymerase chain reaction testing showed ≥88% and >99% viral elimination from baseline in all patients at 4 and 14 days after infusion, respectively. The CTLs did not interfere with the development of endogenous anti-SARS-CoV-2 humoral or cellular responses. T-cell receptor β analysis showed persistence of donor-derived SARS-CoV-2-specific CTLs through the end of the 6-month follow-up period. Interventional patients consistently reported symptomatic improvement 2 to 3 days after infusion, whereas improvement was more variable in observational patients. SARS-CoV-2-specific CTLs are a potentially feasible cellular therapy for COVID-19 illness. This trial was registered at www.clinicaltrials.gov as #NCT04765449.

Immune dysfunction prior to and during vaccination in multiple myeloma: a case study based on COVID-19

Infection is the leading cause of death in multiple myeloma (MM). However, the cellular composition associated with immune dysfunction is not defined. We analyzed immune profiles in the peripheral blood of patients with MM (n = 28) and B-cell chronic lymphoproliferative disorders (n = 53) vs. health care practitioners (n = 96), using multidimensional and computational flow cytometry. MM patients displayed altered distribution of most cell types (41/56, 73%), particularly within the B-cell (17/17) and T-cell (20/30) compartments. Using COVID-19 as a case study, we compared the immune response to vaccination based on 64,304 data points generated from the analysis of 1099 longitudinal samples. MM patients showed limited B-cell expansion linked to lower anti-RBD and anti-S antibody titers after the first two doses and booster. The percentages of B cells and CD4+ T cells in the blood, as well as the absolute counts of B cells and dendritic cells, predicted vaccine immunogenicity at different time points. In contrast with the humoral response, the percentage and antigen-dependent differentiation of SARS-CoV-2-specific CD8+ T cells was not altered in MM patients. Taken together, this study defined the cellular composition associated with immune dysfunction in MM and provided biomarkers such as the B-cell percentage and absolute count to individualize vaccination calendars.

Inhibiting the NADase CD38 improves cytomegalovirus-specific CD8+ T cell functionality and metabolism

Cytomegalovirus (CMV) is one of the most common and relevant opportunistic pathogens in people who are immunocompromised, such as kidney transplant recipients (KTRs). The exact mechanisms underlying the disability of cytotoxic T cells to provide sufficient protection against CMV in people who are immunosuppressed have not been identified yet. Here, we performed in-depth metabolic profiling of CMV-specific CD8+ T cells in patients who are immunocompromised and show the development of metabolic dysregulation at the transcriptional, protein, and functional level of CMV-specific CD8+ T cells in KTRs with noncontrolled CMV infection. These dysregulations comprise impaired glycolysis and increased mitochondrial stress, which is associated with an intensified expression of the nicotinamide adenine dinucleotide nucleotidase (NADase) CD38. Inhibiting NADase activity of CD38 reinvigorated the metabolism and improved cytokine production of CMV-specific CD8+ T cells. These findings were corroborated in a mouse model of CMV infection under conditions of immunosuppression. Thus, dysregulated metabolic states of CD8+ T cells could be targeted by inhibiting CD38 to reverse hyporesponsiveness in individuals who fail to control chronic viral infection.

T-Cell Epitope Mapping of SARS-CoV-2 Reveals Coordinated IFN-γ Production and Clonal Expansion of T Cells Facilitates Recovery from COVID-19

BACKGROUND

T-cell responses can be protective or detrimental during severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection; however, the underlying mechanism is poorly understood.

METHODS

In this study, we screened 144 15-mer peptides spanning the SARS-CoV-2 spike, nucleocapsid (NP), M, ORF8, ORF10, and ORF3a proteins and 39 reported SARS-CoV-1 peptides in peripheral blood mononuclear cells (PBMCs) from nine laboratory-confirmed coronavirus disease 2019 (COVID-19) patients (five moderate and four severe cases) and nine healthy donors (HDs) collected before the COVID-19 pandemic. T-cell responses were monitored by IFN-γ and IL-17A production using ELISA, and the positive samples were sequenced for the T cell receptor (TCR) β chain. The positive T-cell responses to individual SARS-CoV-2 peptides were validated by flow cytometry.

RESULTS

COVID-19 patients with moderate disease produced more IFN-γ than HDs and patients with severe disease (moderate vs. HDs, p < 0.0001; moderate vs. severe, p < 0.0001) but less IL-17A than those with severe disease (p < 0.0001). A positive correlation was observed between IFN-γ production and T-cell clonal expansion in patients with moderate COVID-19 (r = 0.3370, p = 0.0214) but not in those with severe COVID-19 (r = -0.1700, p = 0.2480). Using flow cytometry, we identified that a conserved peptide of the M protein (Peptide-120, P120) was a dominant epitope recognized by CD8+ T cells in patients with moderate disease.

CONCLUSION

Coordinated IFN-γ production and clonal expansion of SARS-CoV-2-specific T cells are associated with disease resolution in COVID-19. Our findings contribute to a better understanding of T-cell-mediated immunity in COVID-19 and may inform future strategies for managing and preventing severe outcomes of SARS-CoV-2 infection.

Testing for SARS-CoV-2: lessons learned and current use cases

SUMMARYThe emergence and worldwide dissemination of SARS-CoV-2 required both urgent development of new diagnostic tests and expansion of diagnostic testing capacity on an unprecedented scale. The rapid evolution of technologies that allowed testing to move out of traditional laboratories and into point-of-care testing centers and the home transformed the diagnostic landscape. Four years later, with the end of the formal public health emergency but continued global circulation of the virus, it is important to take a fresh look at available SARS-CoV-2 testing technologies and consider how they should be used going forward. This review considers current use case scenarios for SARS-CoV-2 antigen, nucleic acid amplification, and immunologic tests, incorporating the latest evidence for analytical/clinical performance characteristics and advantages/limitations for each test type to inform current debates about how tests should or should not be used.

Managing and treating COVID-19 in patients with hematological malignancies: a narrative review and expert insights

Patients with hematologic malignancies (HMs) are at a significantly higher risk of contracting COVID-19 and experiencing severe outcomes compared to individuals without HMs. This heightened risk is influenced by various factors, including the underlying malignancy, immunosuppressive treatments, and patient-related factors. Notably, immunosuppressive regimens commonly used for HM treatment can lead to the depletion of B cells and T cells, which is associated with increased COVID-19-related complications and mortality in these patients. As the pandemic transitions into an endemic state, it remains crucial to acknowledge and address the ongoing risk for individuals with HMs. In this review, we aim to summarize the current evidence to enhance our understanding of the impact of HMs on COVID-19 risks and outcomes, identify particularly vulnerable individuals, and emphasize the need for specialized clinical attention and management. Furthermore, the impaired immune response to COVID-19 vaccination observed in these patients underscores the importance of implementing additional mitigation strategies. This may include targeted prophylaxis and treatment with antivirals and monoclonal antibodies as indicated. To provide practical guidance and considerations, we present two illustrative cases to highlight the real-life challenges faced by physicians caring for patients with HMs, emphasizing the need for individualized management based on disease severity, type, and the unique circumstances of each patient.

Dietary Inulin to Improve SARS-CoV-2 Vaccine Response in Kidney Transplant Recipients: The RIVASTIM-Inulin Randomised Controlled Trial

Kidney transplant recipients are at an increased risk of hospitalisation and death from SARS-CoV-2 infection, and standard two-dose vaccination schedules are typically inadequate to generate protective immunity. Gut dysbiosis, which is common among kidney transplant recipients and known to effect systemic immunity, may be a contributing factor to a lack of vaccine immunogenicity in this at-risk cohort. The gut microbiota modulates vaccine responses, with the production of immunomodulatory short-chain fatty acids by bacteria such as Bifidobacterium associated with heightened vaccine responses in both observational and experimental studies. As SCFA-producing populations in the gut microbiota are enhanced by diets rich in non-digestible fibre, dietary supplementation with prebiotic fibre emerges as a potential adjuvant strategy to correct dysbiosis and improve vaccine-induced immunity. In a randomised, double-bind, placebo-controlled trial of 72 kidney transplant recipients, we found dietary supplementation with prebiotic inulin for 4 weeks before and after a third SARS-CoV2 mRNA vaccine to be feasible, tolerable, and safe. Inulin supplementation resulted in an increase in gut Bifidobacterium, as determined by 16S RNA sequencing, but did not increase in vitro neutralisation of live SARS-CoV-2 virus at 4 weeks following a third vaccination. Dietary fibre supplementation is a feasible strategy with the potential to enhance vaccine-induced immunity and warrants further investigation.

Impaired immune responses and prolonged viral replication in lung allograft recipients infected with SARS-CoV-2 in the early phase after transplantation

PURPOSE

Lung transplant recipients are at increased risk of severe disease following infection with severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) due to high-dose immunosuppressive drugs and the lung is the main organ affected by Coronavirus disease 2019 (COVID-19). Several studies have confirmed increased SARS-CoV-2-related mortality and morbidity in patients living with lung allografts; however, detailed immunological studies of patients with SARS-CoV-2 infection in the early phase following transplantation remain scarce.

METHODS

We investigated patients who were infected with SARS-CoV-2 in the early phase (18-103 days) after receiving double-lung allografts (n = 4, LuTx) in comparison to immunocompetent patients who had not received solid organ transplants (n = 88, noTx). We analyzed SARS-CoV-2-specific antibody responses against the SARS-CoV-2 spike and nucleocapsid proteins using enzyme-linked immunosorbent assays (ELISA), chemiluminescence immunoassays (CLIA), and immunoblot assays. T cell responses were investigated using Elispot assays.

RESULTS

One LuTx patient suffered from persistent infection with fatal outcome 122 days post-infection despite multiple interventions including remdesivir, convalescent plasma, and the monoclonal antibody bamlanivimab. Two patients experienced clinically mild disease with prolonged viral shedding (47 and 79 days), and one patient remained asymptomatic. Antibody and T cell responses were significantly reduced or undetectable in all LuTx patients compared to noTx patients.

CONCLUSION

Patients in the early phase following lung allograft transplantation are vulnerable to infection with SARS-CoV-2 due to impaired immune responses. This patient population should be vaccinated before LuTx, protected from infection post-LuTx, and in case of infection treated generously with currently available interventions.

New variants of COVID-19 (XBB.1.5 and XBB.1.16, the "Arcturus"): A review of highly questioned concerns, a brief comparison between different peaks in the COVID-19 pandemic, with a focused systematic review on expert recommendations for prevention, vaccination, and treatment measures in the general population and at-risk groups

INTRODUCTION

The COVID-19 pandemic has taken many forms and continues to evolve, now around the Omicron wave, raising concerns over the globe. With COVID-19 being declared no longer a "public health emergency of international concern (PHEIC)," the COVID pandemic is still far from over, as new Omicron subvariants of interest and concern have risen since January of 2023. Mainly with the XBB.1.5 and XBB.1.16 subvariants, the pandemic is still very much "alive" and "breathing."

METHODS

This review consists of five highly concerning questions about the current state of the COVID Omicron peak. We searched four main online databases to answer the first four questions. For the last one, we performed a systematic review of the literature, with keywords "Omicron," "Guidelines," and "Recommendations."

RESULTS

A total of 31 articles were included. The main symptoms of the current Omicron wave include a characteristically high fever, coughing, conjunctivitis (with itching eyes), sore throat, runny nose, congestion, fatigue, body ache, and headache. The median incubation period of the symptoms is shorter than the previous peaks. Vaccination against COVID can still be considered effective for the new subvariants.

CONCLUSION

Guidelines recommend continuation of personal protective measures, third and fourth dose boosters, along with administration of bivalent messenger RNA vaccine boosters. The consensus antiviral treatment is combination therapy using Nirmatrelvir and Ritonavir, and the consensus for pre-exposure prophylaxis is Tixagevimab and Cilgavimab combination. We hope the present paper raises awareness for the continuing presence of COVID and ways to lower the risks, especially for at-risk groups.

Perturbations of the T-cell receptor repertoire in response to SARS-CoV-2 in immunocompetent and immunocompromised individuals

BACKGROUND

Functional T-cell responses are essential for virus clearance and long-term protection after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, whereas certain clinical factors, such as older age and immunocompromise, are associated with worse outcome.

OBJECTIVE

We sought to study the breadth and magnitude of T-cell responses in patients with coronavirus disease 2019 (COVID-19) and in individuals with inborn errors of immunity (IEIs) who had received COVID-19 mRNA vaccine.

METHODS

Using high-throughput sequencing and bioinformatics tools to characterize the T-cell receptor β repertoire signatures in 540 individuals after SARS-CoV-2 infection, 31 IEI recipients of COVID-19 mRNA vaccine, and healthy controls, we quantified HLA class I- and class II-restricted SARS-CoV-2-specific responses and also identified several HLA allele-clonotype motif associations in patients with COVID-19, including a subcohort of anti-type 1 interferon (IFN-1)-positive patients.

RESULTS

Our analysis revealed that elderly patients with COVID-19 with critical disease manifested lower SARS-CoV-2 T-cell clonotype diversity as well as T-cell responses with reduced magnitude, whereas the SARS-CoV-2-specific clonotypes targeted a broad range of HLA class I- and class II-restricted epitopes across the viral proteome. The presence of anti-IFN-I antibodies was associated with certain HLA alleles. Finally, COVID-19 mRNA immunization induced an increase in the breadth of SARS-CoV-2-specific clonotypes in patients with IEIs, including those who had failed to seroconvert.

CONCLUSIONS

Elderly individuals have impaired capacity to develop broad and sustained T-cell responses after SARS-CoV-2 infection. Genetic factors may play a role in the production of anti-IFN-1 antibodies. COVID-19 mRNA vaccines are effective in inducing T-cell responses in patients with IEIs.

SARS-CoV-2-specific immune responses converge in kidney disease patients and controls with hybrid immunity

Healthy individuals with hybrid immunity, due to a SARS-CoV-2 infection prior to first vaccination, have stronger immune responses compared to those who were exclusively vaccinated. However, little is known about the characteristics of antibody, B- and T-cell responses in kidney disease patients with hybrid immunity. Here, we explored differences between kidney disease patients and controls with hybrid immunity after asymptomatic or mild coronavirus disease-2019 (COVID-19). We studied the kinetics, magnitude, breadth and phenotype of SARS-CoV-2-specific immune responses against primary mRNA-1273 vaccination in patients with chronic kidney disease or on dialysis, kidney transplant recipients, and controls with hybrid immunity. Although vaccination alone is less immunogenic in kidney disease patients, mRNA-1273 induced a robust immune response in patients with prior SARS-CoV-2 infection. In contrast, kidney disease patients with hybrid immunity develop SARS-CoV-2 antibody, B- and T-cell responses that are equally strong or stronger than controls. Phenotypic analysis showed that Spike (S)-specific B-cells varied between groups in lymph node-homing and memory phenotypes, yet S-specific T-cell responses were phenotypically consistent across groups. The heterogeneity amongst immune responses in hybrid immune kidney patients warrants further studies in larger cohorts to unravel markers of long-term protection that can be used for the design of targeted vaccine regimens.

Evaluation of SARS-CoV-2 interferon gamma release assay in BNT162b2 vaccinated healthcare workers

To predict protective immunity to SARS-CoV-2, cellular immunity seems to be more sensitive than humoral immunity. Through an Interferon-Gamma (IFN-γ) Release Assay (IGRA), we show that, despite a marked decrease in total antibodies, 94.3% of 123 healthcare workers have a positive cellular response 6 months after inoculation with the 2nd dose of BNT162b2 vaccine. Despite the qualitative relationship found, we did not observe a quantitative correlation between IFN-γ and IgG levels against SARS-CoV-2. Using stimulated whole blood from a subset of participants, we confirmed the specific T-cell response to SARS-CoV-2 by dosing elevated levels of the IL-6, IL-10 and TNF-α. Through a 20-month follow-up, we found that none of the infected participants had severe COVID-19 and that the first positive cases were only 12 months after the 2nd dose inoculation. Future studies are needed to understand if IGRA-SARS-CoV-2 can be a powerful diagnostic tool to predict future COVID-19 severe disease, guiding vaccination policies.

Management of vaccinations in patients with non-Hodgkin lymphoma

Vaccinations are fundamental tools in preventing infectious diseases, especially in immunocompromised patients like those affected by non-Hodgkin lymphomas (NHLs). The COVID-19 pandemic made clinicians increasingly aware of the importance of vaccinations in preventing potential life-threatening SARS-CoV-2-related complications in NHL patients. However, several studies have confirmed a significant reduction in vaccine-induced immune responses after anti-CD20 monoclonal antibody treatment, thus underscoring the need for refined immunization strategies in NHL patients. In this review, we summarize the existing data about COVID-19 and other vaccine's efficacy in patients with NHL and propose multidisciplinary team-based recommendations for the management of vaccines in this specific group of patients.

Altered COVID-19 immunity in children with asthma by atopic status

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection causes a spectrum of clinical outcomes that may be complicated by severe asthma. Antiviral immunity is often compromised in patients with asthma; however, whether this is true for SARS-CoV-2 immunity and children is unknown.

Objective

We aimed to evaluate SARS-CoV-2 immunity in children with asthma on the basis of infection or vaccination history and compared to respiratory syncytial viral or allergen (eg, cockroach, dust mite)-specific immunity.

Methods

Fifty-three children from an urban asthma study were evaluated for medical history, lung function, and virus- or allergen-specific immunity using antibody or T-cell assays.

Results

Polyclonal antibody responses to spike were observed in most children from infection and/or vaccination history. Children with atopic asthma or high allergen-specific IgE, particularly to dust mites, exhibited reduced seroconversion, antibody magnitude, and SARS-CoV-2 virus neutralization after SARS-CoV-2 infection or vaccination. TH1 responses to SARS-CoV-2 and respiratory syncytial virus correlated with antigen-respective IgG. Cockroach-specific T-cell activation as well as IL-17A and IL-21 cytokines negatively correlated with SARS-CoV-2 antibodies and effector functions, distinct from total and dust mite IgE. Allergen-specific IgE and lack of vaccination were associated with recent health care utilization. Reduced lung function (forced expiratory volume in 1 second ≤ 80%) was independently associated with (SARS-CoV-2) peptide-induced cytokines, including IL-31, whereas poor asthma control was associated with cockroach-specific cytokine responses.

Conclusion

Mechanisms underpinning atopic and nonatopic asthma may complicate the development of memory to SARS-CoV-2 infection or vaccination and lead to a higher risk of repeated infection in these children.

COVID-19 in Lung Transplant Recipients: A Report on 10 Recent Cases

Due to immunosuppression, transplant recipients are at higher risk of infections with SARS-CoV-2 and worse clinical outcomes than immunocompetent hosts. Furthermore, lung transplant patients represent a special group among solid organ recipients, since pneumonia is the main manifestation of COVID-19. However, data on the course of disease and the changes in morbidity and mortality during the course of the pandemic are limited. In our pulmonary rehabilitation clinic, we treat patients shortly after lung transplant as well as long-term transplant patients. Over the last almost 4 years of pandemic, we witnessed several COVID-19 infections in lung transplant patients in our clinic as well as patients who acquired an infection beforehand. In this paper, we aim at retrospectively describing a series of recent COVID-19 cases in our clinic, looking at the clinical course of disease and outcomes in lung transplant patients.