Interactions of adenoviruses with platelets and coagulation and the vaccine-induced immune thrombotic thrombocytopenia syndrome

Association of human leucocyte antigen loci with vaccine-induced immune thrombotic thrombocytopenia: Potential role of the interaction between platelet factor 4-derived peptides and MHC-II

No risk factors have been identified for vaccine-induced immune thrombotic thrombocytopenia (VITT) so far. The aim of this study was to identify human leucocyte antigen (HLA) alleles potentially associated with VITT susceptibility. Specific HLA class II alleles were detected with significantly higher frequency in VITT patients compared with Italian controls: DPB1*17:01, DQA1*05:01, and DRB1*11:04. In silico analysis revealed increased affinity of DRB1*11:04 for a platelet factor 4 (PF4)-derived peptide, ITSLEVIKA, that contains two amino acids present in the specific binding site of anti-PF4 antibodies from VITT patients. Our findings show for the first time a genetic predisposition to developing anti-PF4 antibodies in response to Ad-vector vaccines.

Emerging Thrombotic Disorders Associated with Virus-Based Innovative Therapies: From VITT to AAV Gene Therapy-Related Thrombotic Microangiopathy

Gene therapy is a promising therapeutic approach for treating life-threatening disorders. Despite the clinical improvements observed with gene therapy, immune responses either innate or adaptive against the vector used for gene delivery, can affect treatment efficacy and lead to adverse reactions. Thrombotic microangiopathy (TMA) is a thrombosis with thrombocytopenia syndrome (TTS) characterized by microangiopathic hemolytic anemia, thrombocytopenia, and small vessel occlusion known to be elicited by several drugs, that has been recently reported as an adverse event of adeno-associated virus (AAV)-based gene therapy. TMA encompasses a heterogenous group of disorders, its classification and underlining mechanisms are still uncertain, and still lacks validated biomarkers. The identification of predictors of TMA, such as vector dose and patient characteristics, is a pressing need to recognize patients at risk before and after AAV-based gene therapy administration. This review aims to explore the literature on TMA associated with AAV-based gene therapy in the larger context of TMA (i.e., hemolytic-uremic syndrome, thrombotic thrombocytopenic purpura, and other drug-related TMAs). Considering the wide attention recently gained by another TTS associated with a non-gene therapy viral platform (adenovirus, AV COVID-19 vaccine), namely vaccine-induced immune thrombocytopenia and thrombosis (VITT), AAV gene therapy-related TMA mechanisms will be discussed and differentiated from those of VITT to avoid recency bias and favor a correct positioning of these two recently emerged syndromes within the heterogenous group of drug-related TTS. Finally, the review will discuss strategies for enhancing the safety and optimize the management of AAV-based gene therapy that is emerging as an efficacious therapeutic option for disparate, severe, and often orphan conditions.

Whole Exome Sequencing in Vaccine-Induced Thrombotic Thrombocytopenia (VITT)

Background: In February 2021, a few cases of unusual, severe thrombotic events associated with thrombocytopenia reported after vaccination with ChAdOx1 nCoV-19 (Vaxzevria) or with Johnson & Johnson's Janssen vaccine raise concern about safety. The vaccine-induced thrombotic thrombocytopenia (VITT) has been related to the presence of platelet-activating antibodies directed against platelet Factor 4. Objectives: We investigated VITT subject genetic background by a high-throughput whole exome sequencing (WES) approach in order to investigate VITT genetic predisposition. Methods: Six consecutive patients (females of Caucasian origin with a mean age of 64 years) were referred to the Atherothrombotic Diseases Center (Department of Experimental and Clinical Medicine, Azienda Ospedaliero-Universitaria Careggi, Florence) with a diagnosis of definite VITT underwent WES analysis. WES analysis was performed on the Illumina NextSeq500 platform. Results:WES analysis revealed a total of 140,563 genetic variants. Due to VITT's rare occurrence, we focused attention on rare variants. The global analysis of all high-quality rare variants did not reveal a significant enrichment of mutated genes in biological/functional pathways common to patients analyzed. Afterwards, we focused on rare variants in genes associated with blood coagulation and fibrinolysis, platelet activation and aggregation, integrin-mediated signaling pathway, and inflammation with particular attention to those involved in vascular damage, as well as autoimmune thrombocytopenia. According to ACMG criteria, 47/194 (24.2%) rare variants were classified as uncertain significance variants (VUS), whereas the remaining were likely benign/benign. Conclusion: WES analysis identifies rare variants possibly favoring the prothrombotic state triggered by the exposure to the vaccine. Functional studies and/or extensions to a larger number of patients might allow a more comprehensive definition of these molecular pathways.

Viruses and thrombocytopenia

Thrombocytopenia, characterized by a decrease in platelet count, is a multifaceted clinical manifestation that can arise from various underlying causes. This review delves into the intriguing nexus between viruses and thrombocytopenia, shedding light on intricate pathophysiological mechanisms and highlighting the pivotal role of platelets in viral infections. The review further navigates the landscape of thrombocytopenia in relation to specific viruses, and sheds light on the diverse mechanisms through which hepatitis C virus (HCV), measles virus, parvovirus B19, and other viral agents contribute to platelet depletion. As we gain deeper insights into these interactions, we move closer to elucidating potential therapeutic avenues and preventive strategies for managing thrombocytopenia in the context of viral infections.

Temporal changes in biomarkers of neutrophil extracellular traps and NET-promoting autoantibodies following adenovirus-vectored, mRNA, and recombinant protein COVID-19 vaccination

Neutrophil extracellular traps (NETs) play a role in innate pathogen defense and also trigger B-cell response by providing antigens. NETs have been linked to vaccine-induced thrombotic thrombocytopenia. We postulated a potential link between NET biomarkers, NET-promoting autoantibodies, and adverse events (AEs) after COVID-19 vaccine boosters. Healthy donors (HDs) who received ChAdOx1-S (A), mRNA-1273 (M), or recombinant protein (MVC-COV1901) vaccines at the National Taiwan University Hospital between 2021 and 2022 were recruited. We measured serial NET-associated biomarkers, citrullinated-histone3 (citH3), and myeloperoxidase (MPO)-DNA. Serum citH3 and MPO-DNA were significantly or numerically higher in HDs who reported AEs (n = 100, booster Day 0/Day 30, p = 0.01/p = 0.03 and p = 0.30/p = 0.35, respectively). We also observed a positive correlation between rash occurrence in online diaries and elevated citH3. A linear mixed model also revealed significantly higher citH3 levels in mRNA-1273/ChAdOx1-S recipients than MVC-COV1901 recipients. Significant positive correlations were observed between the ratios of anti-heparin platelet factor 4 and citH3 levels on Booster Day 0 and naïve and between the ratios of anti-NET IgM and citH3 on Booster Day 30/Day 0 in the AA-M and MM-M group, respectively. The increased levels of citH3/MPO-DNA accompanied by NET-promoting autoantibodies suggest a potential connection between mRNA-1273/ChAdOx1-S vaccines and cardiovascular complications. These findings provide insights for risk assessments of future vaccines.

Vaccine-Induced Immune Thrombotic Thrombocytopenia: Clinicopathologic Features and New Perspectives on Anti-PF4 Antibody-Mediated Disorders

INTRODUCTION

Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a rare yet severe adverse complication first identified during the global vaccination effort against SARS-CoV-2 infection, predominantly observed following administration of the ChAdOx1-S (Oxford-AstraZeneca) and Ad26.CoV2.S (Johnson & Johnson/Janssen) adenoviral vector-based vaccines. Unlike other anti-platelet factor 4 (PF4) antibody-mediated disorders, such as heparin-induced thrombocytopenia (HIT), VITT arises with the development of platelet-activating anti-PF4 antibodies 4-42 days post-vaccination, typically featuring thrombocytopenia and thrombosis at unusual sites.

AIM

To explore the unique properties, pathogenic mechanisms, and long-term persistence of VITT antibodies in patients, in comparison with other anti-PF4 antibody-mediated disorders.

DISCUSSION

This review highlights the complexity of VITT as it differs in antibody behavior and clinical presentation from other anti-PF4-mediated disorders, including the high incidence rate of cerebral venous sinus thrombosis (CVST) and the persistence of anti-PF4 antibodies, necessitating a re-evaluation of long-term patient care strategies. The nature of VITT antibodies and the underlying mechanisms triggering their production remain largely unknown.

CONCLUSION

The rise in awareness and subsequent prompt recognition of VITT is paramount in reducing mortality. As vaccination campaigns continue, understanding the role of adenoviral vector-based vaccines in VITT antibody production is crucial, not only for its immediate clinical implications, but also for developing safer vaccines in the future.

Delivery of nucleic acids using nanomaterials

The increasing number of approved nucleic acid therapeutics demonstrates the potential for the prevention and treatment of a broad spectrum of diseases. This trend underscores the significant impact and promise of nucleic acid-based treatments in the field of medicine. Nevertheless, employing nucleic acids as therapeutics is challenging due to their susceptibility to degradation by nucleases and their unfavorable physicochemical characteristics that hinder delivery into cells. Appropriate vectors play a pivotal role in improving nucleic acid stability and delivering nucleic acids into specific cells. The maturation of delivery systems has led to breakthroughs in the development of therapeutics based on nucleic acids such as DNA, siRNA, and mRNA. Non-viral vectors have gained prominence among the myriad of nanomaterials due to low immunogenicity, ease of manufacturing, and simplicity of cost-effective, large-scale production. Here, we provide an overview of the recent advancements in nanomaterials for nucleic acid delivery. Specifically, we give a detailed introduction to the characteristics of polymers, lipids, and polymer-lipid hybrids, and provide comprehensive descriptions of their applications in nucleic acid delivery. Also, biological barriers, administration routes, and strategies for organ-selective delivery of nucleic acids are discussed. In summary, this review offers insights into the rational design of next-generation delivery vectors for nucleic acid delivery.

Comparative analysis of the impact of 40 adenovirus types on dendritic cell activation and CD8+ T cell proliferation capacity for the identification of favorable immunization vector candidates

For the development of new adenovirus (AdV)-based vectors, it is important to understand differences in immunogenicity. In a side-by-side in vitro analysis, we evaluated the effect of 40 AdV types covering human AdV (HAdV) species A through G on the expression of 11 activation markers and the secretion of 12 cytokines by AdV-transduced dendritic cells, and the effect on CD8+ T cell proliferation capacity. We found that the expression of activation markers and cytokines differed widely between the different HAdV types, and many types were able to significantly impair the proliferation capacity of CD8+ T cells. Univariate and multivariate regression analyses suggested an important role of type I interferons in mediating this suppression of CD8+ T cells, which we confirmed experimentally in a proliferation assay using a type I interferon receptor blocking antibody. Using Bayesian statistics, we calculated a prediction model that suggests HAdV types HAdV-C1, -D8, -B7, -F41, -D33, -C2, -A31, -B3 and -D65 as the most favorable candidates for vaccine vector development.

From Immunogen to COVID-19 vaccines: Prospects for the post-pandemic era

The COVID-19 pandemic has affected millions of people and posed an unprecedented burden on healthcare systems and economies worldwide since the outbreak of the COVID-19. A considerable number of nations have investigated COVID-19 and proposed a series of prevention and treatment strategies thus far. The pandemic prevention strategies implemented in China have suggested that the spread of COVID-19 can be effectively reduced by restricting large-scale gathering, developing community-scale nucleic acid testing, and conducting epidemiological investigations, whereas sporadic cases have always been identified in numerous places. Currently, there is still no decisive therapy for COVID-19 or related complications. The development of COVID-19 vaccines has raised the hope for mitigating this pandemic based on the intercross immunity induced by COVID-19. Thus far, several types of COVID-19 vaccines have been developed and released to into financial markets. From the perspective of vaccine use in globe, COVID-19 vaccines are beneficial to mitigate the pandemic, whereas the relative adverse events have been reported progressively. This is a review about the development, challenges and prospects of COVID-19 vaccines, and it can provide more insights into all aspects of the vaccines.

COVID-19 vaccines adverse events: potential molecular mechanisms

COVID-19 is an infectious disease caused by a single-stranded RNA (ssRNA) virus, known as SARS-CoV-2. The disease, since its first outbreak in Wuhan, China, in December 2019, has led to a global pandemic. The pharmaceutical industry has developed several vaccines, of different vector technologies, against the virus. Of note, among these vaccines, seven have been fully approved by WHO. However, despite the benefits of COVID-19 vaccination, some rare adverse effects have been reported and have been associated with the use of the vaccines developed against SARS-CoV-2, especially those based on mRNA and non-replicating viral vector technology. Rare adverse events reported include allergic and anaphylactic reactions, thrombosis and thrombocytopenia, myocarditis, Bell's palsy, transient myelitis, Guillen-Barre syndrome, recurrences of herpes-zoster, autoimmunity flares, epilepsy, and tachycardia. In this review, we discuss the potential molecular mechanisms leading to these rare adverse events of interest and we also attempt an association with the various vaccine components and platforms. A better understanding of the underlying mechanisms, according to which the vaccines cause side effects, in conjunction with the identification of the vaccine components and/or platforms that are responsible for these reactions, in terms of pharmacovigilance, could probably enable the improvement of future vaccines against COVID-19 and/or even other pathological conditions.

Incubation Temperature and Period During Denarase Treatment and Microfiltration Affect the Yield of Recombinant Adenoviral Vectors During Downstream Processing

Adenoviral vectors (AV) are commonly used as vaccine and gene therapy vehicles because of their ease of construction, ability to grow to high titers in the large-scale production process, and safety for human applications. However, the efficiency rate of downstream processes for adenoviral vectors still varies greatly. In the current study, we aimed to investigate the effect of the downstream treatment protocol and microfiltration of the harvested upstream material on viral vector yield. We compared the performance of the repeated freeze-thaw (RFT) and the Tween-20 detergent lysis (DLT) methods. In addition, the effects of the cell lysis method, incubation temperature, and time on viral yield were investigated. The samples were incubated at either room temperature or 37 °C for 1-, 2-, and 4-h periods. Samples were filtered with PES and SFCA membrane. Virus yield and infectivity were assayed by qPCR and immuno-titration. In conclusion, our results suggest that 2-h incubation gives the best results when incubated at 37 °C for denarase activity when Tween-20 is used for virus recovery. If the room temperature is preferred, 4-h incubation could be preferred. A phase 1 clinical trial (NCT05526183, January 21, 2022) was started with the recombinant adenovirus used in the study.

Oncolytic virus: A catalyst for the treatment of gastric cancer

Gastric cancer (GC) is a leading contributor to global cancer incidence and mortality. According to the GLOBOCAN 2020 estimates of incidence and mortality for 36 cancers in 185 countries produced by the International Agency for Research on Cancer (IARC), GC ranks fifth and fourth, respectively, and seriously threatens the survival and health of people all over the world. Therefore, how to effectively treat GC has become an urgent problem for medical personnel and scientific workers at this stage. Due to the unobvious early symptoms and the influence of some adverse factors such as tumor heterogeneity and low immunogenicity, patients with advanced gastric cancer (AGC) cannot benefit significantly from treatments such as radical surgical resection, radiotherapy, chemotherapy, and targeted therapy. As an emerging cancer immunotherapy, oncolytic virotherapies (OVTs) can not only selectively lyse cancer cells, but also induce a systemic antitumor immune response. This unique ability to turn unresponsive 'cold' tumors into responsive 'hot' tumors gives them great potential in GC therapy. This review integrates most experimental studies and clinical trials of various oncolytic viruses (OVs) in the diagnosis and treatment of GC. It also exhaustively introduces the concrete mechanism of invading GC cells and the viral genome composition of adenovirus and herpes simplex virus type 1 (HSV-1). At the end of the article, some prospects are put forward to determine the developmental directions of OVTs for GC in the future.

Case report: An unusual case of multisite embolism in a patient with adenovirus pneumoniae

A 36-year-old previous healthy man presented with fever, cough, and dyspnea associated with adenovirus pneumonia. The patient developed left ventricular thrombus, pulmonary embolism and multisite embolism of undetermined etiology. Adenovirus is a rare cause of thrombotic events in immunocompetent individuals, calling for further studies for early diagnosis and management.

Potential Anionic Substances Binding to Platelet Factor 4 in Vaccine-Induced Thrombotic Thrombocytopenia of ChAdOx1-S Vaccine for SARS-CoV-2

Recent reports of rare ChAdOx1-S vaccine-related venous thrombosis led to the suspension of its usage in several countries. Vaccine-induced thrombotic thrombocytopenia (VITT) is characterized by thrombocytopenia and thrombosis in association with anti-platelet factor 4 (PF4) antibodies. Herein, we propose five potential anionic substances of the ChAdOx1-S vaccine that can combine with PF4 and trigger VITT, including (1) the proteins on the surface of adenovirus, e.g., negative charged glycoprotein, (2) the adjuvant components of the vaccine, e.g., Tween 80, (3) the DNA of adenovirus, (4) the S protein antigen expressed by the vaccine, and (5) the negatively charged impurity proteins expressed by the vaccine, e.g., adenovirus skeleton proteins. After analysis of each case, we consider the most possible trigger to be the negatively charged impurity proteins expressed by the vaccine. Then, we display the possible extravascular route and intravascular route of the formation of PF4 autoantibodies triggered by the negatively charged impurity proteins, which is accordant with the clinical situation. Accordingly, the susceptible individuals of VITT after ChAdOx1-S vaccination may be people who express negatively charged impurity proteins and reach a certain high titer.

VACCINE-INDUCED MASSIVE PULMONARY EMBOLISM AND THROMBOCYTOPENIA FOLLOWING A SINGLE DOSE OF JANSSEN AD26.COV2.S VACCINATION

Vaccine-induced immune thrombotic thrombocytopenia (VITT) has emerged as a rare side effect of adenoviral vector-based vaccines against Coronavirus disease 2019 (COVID-19), and it is most frequently reported after Vaxzevria (AstraZeneca) vaccine. We described a case of severe thrombocytopenia associated with massive pulmonary embolism and portal vein thrombosis, occurring 13 days after the administration of the single dose adeno viral vector-based vaccine Ad26.COV2.S (Janssen vaccines, Leiden, Netherlands). Based on an early clinical suspect, the patient quickly received treatment with corticosteroids and intravenous immunoglobulins, followed by a rapid increase in platelet count that allowed full dose anticoagulation to be timely administered. Treatment with intravenous immunoglobulins, however, could mask the ability of anti-PF4-heparin antibodies to bind and activate platelets in the presence of heparin, leading to false negative results at the immunoassay functional test. Therefore, if VITT is suspected, blood samples for diagnostic confirmation should be collected prior to any treatment to improve diagnostic performance.

Safety of COVID-19 vaccination in patients with previous cerebral venous sinus thrombosis

Introduction

Cerebral venous sinus thrombosis (CVST) after coronavirus (COVID-19) vaccination has been reported. There are no data about thrombosis risk in prior CVST patients. The objective of the study was to describe short-term serious adverse events to COVID-19 vaccines in patients with history of CVST.

Material and methods

We present an observational prospective study of patients with known CVST who received COVID-19 vaccination. Serious event rates within 30 days after second dose vaccination (except one dose for Janssen) were evaluated, including recurrences, hospital admission and death.

Results

The 62 vaccinated patients received: BNT162b2 (Pfizer-BioNTech) in 43 patients (69.4%), mRNA-1273 (Moderna) in 7 patients (11.3%), AZD1222 (ChAdOx1) in 7 patients (11.3%) and Ad26.COV2.S (Janssen) in 5 patients (8.1%). There were no thrombotic recurrences within 30 days of vaccination (95% confidence interval, 0.0–5.8). There was one death (1.6%), not attributable to the vaccine.

Conclusions

COVID-19 vaccines are safe for previous CVST patients.

Philadelphia-Negative Chronic Myeloproliferative Neoplasms during the COVID-19 Pandemic: Challenges and Future Scenarios

An outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) started in December 2019 in China and then become pandemic in February 2020. Several publications investigated the possible increased rate of COVID-19 infection in hematological malignancies. Based on the published data, strategies for the management of chronic Philadelphia-negative chronic myeloproliferative neoplasms (MPNs) are provided. The risk of severe COVID-19 seems high in MPN, particularly in patients with essential thrombocythemia, but not negligible in myelofibrosis. MPN patients are at high risk of both thrombotic and hemorrhagic complications and this must be accounted in the case of COVID-19 deciding on a case-by-case basis. There are currently no data to suggest that hydroxyurea or interferon may influence the risk or severity of COVID-19 infection. Conversely, while the immunosuppressive activity of ruxolitinib might pose increased risk of infection, its abrupt discontinuation during COVID-19 syndrome is associated with worse outcome. All MPN patients should receive vaccine against COVID-19; reassuring data are available on efficacy of mRNA vaccines in MPNs.