Could Coronavirus Disease 2019 (COVID-19) Render Natural Immunity to Re-infections? A Spotlight on the Therapeutic Pipeline

Alterations in Gut Microbiota Composition in Patients with COVID-19: A Pilot Study of Whole Hypervariable 16S rRNA Gene Sequencing

It is crucial to consider the importance of the microbiome and the gut-lung axis in the context of SARS-CoV-2 infection. This pilot study examined the fecal microbial composition of patients with COVID-19 following a 3-month recovery. Using for the first time metagenomic analysis based on all hypervariable regions (V1-V9) of the 16S rRNA gene, we have identified 561 microbial species; however, 17 were specific only for the COVID-19 group (n = 8). The patients' cohorts revealed significantly greater alpha diversity of the gut microbiota compared to healthy controls (n = 14). This finding has been demonstrated by operational taxonomic units (OTUs) richness (p < 0.001) and Chao1 index (p < 0.01). The abundance of the phylum Verrucomicrobia was 30 times higher in COVID-19 patients compared to healthy subjects. Accordingly, this disproportion was also noted at other taxonomic levels: in the class Verrucomicrobiae, the family Verrucomicrobiaceae, and the genus Akkermansia. Elevated pathobionts such as Escherichia coli, Bilophila wadsworthia, and Parabacteroides distasonis were found in COVID-19 patients. Considering the gut microbiota's ability to disturb the immune response, our findings suggest the importance of the enteric microbiota in the course of SARS-CoV-2 infection. This pilot study shows that the composition of the microbial community may not be fully restored in individuals with SARS-CoV-2 following a 3-month recovery.

Evidence of exhausted lymphocytes after the third anti-SARS-CoV-2 vaccine dose in cancer patients

Introduction

Evidence is scant regarding the long-term humoral and cellular responses Q7 triggered by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccines in cancer patients after repeated booster doses. The possibility of T-cell exhaustion following these booster doses in this population has not yet been fully studied and remains uncertain.

Methods

In this single-center prospective observational study, we explored the specific humoral and cellular response to S1 antigen in 36 patients with solid malignancies at baseline, and after the second and third doses of the mRNA-1273 vaccine.

Results

A dual behavior was observed: 24 (66.7%) patients showed partial specific IFN-γ response after the second dose that was further enhanced after the third dose; and 11 (30.5%) already showed an optimal response after the second dose and experienced a marked fall-off of specific IFN-γ production after the third (4 patients negativization), which might suggest T cell exhaustion due to repetitive priming to the same antigen. One (2.8%) patient had persistently negative responses after all three doses. Seroconversion occurred in all patients after the second dose. We then studied circulating exhausted CD8+ T-cells in 4 patients from each of the two response patterns, those with increase and those with decrease in cellular response after the third booster. The patients with decreased cellular response after the booster had a higher expression of PD1⁺CD8⁺ and CD57⁺PD1⁺CD8⁺ exhausted T cells compared with those with an increased cellular response both in vivo and in vitro. The proportion of PD1⁺CD8⁺ and CD57⁺PD1⁺CD8⁺ exhausted T cells inversely correlated with IFN-γ production.

Discussion

Our preliminary data show that the two-dose SARS-CoV-2 vaccine regimen was beneficial in all cancer patients of our study. An additional booster seems to be beneficial in suboptimal vaccine seroconverters, in contrast to maximal responders that might develop exhaustion. Our data should be interpreted with caution given the small sample size and highlight the urgent need to validate our results in other independent and larger cohorts. Altogether, our data support the relevance of immunological functional studies to personalize preventive and treatment decisions in cancer patients.

Gut microbiome and anti-viral immunity in COVID-19

SARS-CoV-2 mainly affects the respiratory system, but the gastrointestinal tract is also a target. Prolonged gut disorders, in COVID-19 patients, were correlated with decreased richness and diversity of the gut microbiota, immune deregulation and delayed viral clearance. Although there are no definitive conclusions, ample evidence would suggest that the gut microbiome composition and function play a role in COVID-19 progression. Microbiome modulation strategies for population stratification and management of COVID-19 infection are under investigation, representing an area of interest in the ongoing pandemic. In this review, we present the existing data related to the interaction between gut microbes and the host's immune response to SARS-CoV-2 and discuss the implications for current disease management and readiness to face future pandemics.

SARS-CoV-2 Variants, Vaccines, and Host Immunity

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a new beta coronavirus that emerged at the end of 2019 in the Hubei province of China. SARS-CoV-2 causes coronavirus disease 2019 (COVID-19) and was declared a pandemic by the World Health Organization (WHO) on 11 March 2020. Herd or community immunity has been proposed as a strategy to protect the vulnerable, and can be established through immunity from past infection or vaccination. Whether SARS-CoV-2 infection results in the development of a reservoir of resilient memory cells is under investigation. Vaccines have been developed at an unprecedented rate and 7 408 870 760 vaccine doses have been administered worldwide. Recently emerged SARS-CoV-2 variants are more transmissible with a reduced sensitivity to immune mechanisms. This is due to the presence of amino acid substitutions in the spike protein, which confer a selective advantage. The emergence of variants therefore poses a risk for vaccine effectiveness and long-term immunity, and it is crucial therefore to determine the effectiveness of vaccines against currently circulating variants. Here we review both SARS-CoV-2-induced host immune activation and vaccine-induced immune responses, highlighting the responses of immune memory cells that are key indicators of host immunity. We further discuss how variants emerge and the currently circulating variants of concern (VOC), with particular focus on implications for vaccine effectiveness. Finally, we describe new antibody treatments and future vaccine approaches that will be important as we navigate through the COVID-19 pandemic.

State of the CAR-T: Risk of Infections with Chimeric Antigen Receptor T-Cell Therapy and Determinants of SARS-CoV-2 Vaccine Responses

Chimeric antigen receptor T cell (CAR-T) therapy has shown unprecedented response rates in patients with relapsed/refractory (R/R) hematologic malignancies. Although CAR-T therapy gives hope to heavily pretreated patients, the rapid commercialization and cumulative immunosuppression of this therapy predispose patients to infections for a prolonged period. CAR-T therapy poses distinctive short- and long-term toxicities and infection risks among patients who receive CAR T-cells after multiple prior treatments, often including hematopoietic cell transplantation. The acute toxicities include cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome. The long-term B cell depletion, hypogammaglobulinemia, and cytopenia further predispose patients to severe infections and abrogate the remission success achieved by the living drug. These on-target-off-tumor toxicities deplete B-cells across the entire lineage and further diminish immune responses to vaccines. Early observational data suggest that patients with hematologic malignancies may not mount adequate humoral and cellular responses to SARS-CoV-2 vaccines. In this review, we summarize the immune compromising factors indigenous to CAR-T recipients. We discuss the immunogenic potential of different SARS-CoV-2 vaccines for CAR-T recipients based on the differences in vaccine manufacturing platforms. Given the lack of data related to the safety and efficacy of SARS-CoV-2 vaccines in this distinctively immunosuppressed cohort, we summarize the infection risks associated with Food and Drug Administration-approved CAR-T constructs and the potential determinants of vaccine responses. The review further highlights the potential need for booster vaccine dosing and the promise for heterologous prime-boosting and other novel vaccine strategies in CAR-T recipients. © 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

Is COVID-19 impacting cancer screening in Pakistan? An observational study of cancer screening test requests during the pandemic

Background

The purpose of this study is to assess how the COVID-19 pandemic affected cancer screening at a large tertiary care setting in the city of Karachi, the third largest city in the world, and to identify if there has been any decrease in cancer screening during the ongoing pandemic.

Methods

A retrospective observational study was conducted at the clinical chemistry laboratory at the Department of Pathology & Laboratory Medicine, Aga Khan University Hospital (AKUH), Karachi Pakistan. Data for test volumes was extracted from the Integrated Laboratory Management System (ILMS) for the following tumor markers: CA19 Carbohydrate Antigen 19-9 (CA 19-9), Calcitonin, Prostate Specific Antigen (PSA), from 2017 to 2020. Data from January 1st, 2017 till December 31st, 2019 was recorded and compared with the test volume data from January 1st, 2020 till December 31st, 2020. Number of tests performed in the prior 3 years were compared with tests performed in 2020, specifically looking at changes during the lockdown period in 2020 (1st March – 9 th April) and compared with the same period in preceding years.

Results

During the four-year period, a total of 6,530 tests were performed for CA19-9, 893 for Calcitonin, and 54,769 for PSA. Year 2019 recorded the highest volume for all 3 tests with test volumes increasing continuously from 2017 to 2019. Number of tests performed decreased throughout the year 2020 for Calcitonin and PSA, whereas volume of tests for CA19-9 only reduced during the lockdown period while increased in the non-lockdown period as compared to previous years. Highest percent decline during the 2020 lockdown period was seen for Calcitonin (-62.5%), followed by PSA (-51.8%) and CA19-9 (-19%).

Conclusion

In conclusion, the amount of CA19-9, Calcitonin, and PSA tests performed in Karachi, Pakistan has drastically reduced due to the lockdown that was mandated due to the COVID-19 outbreak. It is crucial that despite an imposed lockdown, regular cancer screening must continue.

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Lockdowns and general fear of visiting hospitals during COVID-19 impacted cancer screening in Pakistan.

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A comparison of lab test requisitions from January 2017–December 2019 and January–December 2020 was undertaken.

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CA19-9, Calcitonin, and PSA screening tests reported a major decline.

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Highest percent decline during the 2020 lockdown period was seen for Calcitonin (−62.5%).

Role of Gut Microbiome in COVID-19: An Insight Into Pathogenesis and Therapeutic Potential

Coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), resulted in an unprecedented global crisis. Although primarily a respiratory illness, dysregulated immune responses may lead to multi-organ dysfunction. Prior data showed that the resident microbial communities of gastrointestinal and respiratory tracts act as modulators of local and systemic inflammatory activity (the gut-lung axis). Evolving evidence now signals an alteration in the gut microbiome, brought upon either by cytokines from the infected respiratory tract or from direct infection of the gut, or both. Dysbiosis leads to a "leaky gut". The intestinal permeability then allows access to bacterial products and toxins into the circulatory system and further exacerbates the systemic inflammatory response. In this review, we discuss the available data related to the role of the gut microbiome in the development and progression of COVID-19. We provide mechanistic insights into early data with a focus on immunological crosstalk and the microbiome's potential as a biomarker and therapeutic target.

Remdesivir in Coronavirus Disease 2019 (COVID-19) treatment: a review of evidence

COVID-19 is an infectious disease caused by a novel β-coronavirus, belonging to the same subgenus as the Severe Acute Respiratory Syndrome (SARS) virus. Remdesivir, an investigational broad-spectrum antiviral agent has previously demonstrated in vitro activity against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), and in vivo efficacy against other related coronaviruses in animal models. Its safety profile has been tested in a compassionate use setting for patients with COVID-19. The current therapeutic studies demonstrate clinical effectiveness of remdesivir in COVID-19 patients by shortening time to clinical recovery, and hospital stay. In this review, we critically analyze the current evidence of remdesivir against COVID-19 and dissect the aspects over its safety and efficacy. Based on existing data, remdesivir can be regarded as a potential therapeutic agent against COVID-19. Further large-scale, randomized placebo-controlled clinical trials are, however, awaited to validate these findings.

Transient disappearance of CD19+/CD5+ B-lymphocyte clone in peripheral blood in a patient with CLL during SARS-CoV-2-related mild disease

Although lymphopenia is currently considered a good predictor for the prognosis of COVID-19, it must be critically evaluated in patients with CLL, where other clinical markers should be considered to define the prognosis and treatment.

Overlap of immunotherapy-related pneumonitis and COVID-19 pneumonia: diagnostic and vaccine considerations

The clinically indistinguishable overlap between pneumonitis caused due to immune checkpoint inhibition (ICI) and pneumonia associated with COVID-19 has posed considerable challenges for patients with cancer and oncologists alike. The cancer community continues to face the challenges that lay at the complex immunological intersection of immune-based cancer therapy and immune dysregulation that results from COVID-19. Is there compounded immune dysregulation that could lead to poor outcomes? Could ICIs, in fact, ameliorate SARS-CoV-2-driven T-cell exhaustion?A little more is known about the kinetics of the viral replication in immunocompromised patients now as compared with earlier during the pandemic. Working knowledge of the diagnostic and therapeutic nuances of SARS-CoV-2 infection in patients with active cancers, issues related to viability and replication potential of the virus, unclear role of corticosteroids among those with diminished or dysfunctional effector T-cell repertoire, and the type of immunotherapy with differential risk of pneumonitis will inform decision making related to immunotherapy choices and decision for ICI continuation in the era of COVID-19.

Case Report: Severe COVID-19 Pneumonia in a Patient With Relapsed/Refractory Hodgkin's Lymphoma

First identified in China in December 2019, coronavirus disease 2019 (COVID-19) has rapidly evolved into a global pandemic. The presence of haematological malignancies are expected to increase the risk of adverse outcomes from this viral infection due to the immunosuppression brought about by the underlying cancer and the effects of therapy. We present a 55-year-old woman diagnosed with relapsed/refractory Hodgkin’s lymphoma (HL) who had been heavily pretreated with multiagent chemotherapy, autologous hematopoietic stem cell transplantation (autoHCT), allogeneic hematopoietic stem cell transplantation (alloHCT) and was complicated with EBV associated posttransplant lymphoproliferative disease (PTLD) and chronic graft-versus-host-disease (GVHD). The patient was recently treated with brentuximab and donor lymphocyte infusion (DLI) for relapse after alloHCT. She suffered from severe COVID-19 pneumonia and eventually succumbed to acute respiratory distress syndrome (ARDS) and multiorgan failure. Of note, this is the first reported case of COVID-19 in a HL patient who was being treated with brentuximab for relapse after alloHCT.

Autologous hematopoietic transplantation following COVID-19 infection

Autologous hematopoietic cell transplantation following induction therapy is standard of care for most patients with newly diagnosed multiple myeloma (N Engl J Med 2017, 376; 1311). Though active COVID-19 infection is typically a contraindication to aggressive therapy, little is known about the safety of autologous transplantation after resolution of acute symptoms and undetectable pathogen by nasopharyngeal PCR.

Synchronous presentation of COVID-19 pneumonia and pulmonary embolism

The patients with COVID-19 pneumonia who suffer from worsening of the clinical respiratory symptoms, after the beginning of the treatment, should be evaluated for pulmonary embolism using CT angiography if there are no contraindications.

First report of COVID-19 reinfection in a patient with beta thalassemia major

To optimize care for patients with hemoglobinopathies, frequent screening for COVID-19 is prudent as viral kinetics in asplenic patients are unknown and differentiating prolonged viral shedding versus reinfection remains a challenge.

Case Report: B Lymphocyte Disorders Under COVID-19 Inflammatory Pressure

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infects humans through the angiotensin converting enzyme-2 (ACE-2) receptor expressed on many cells, including lymphocytes. In Covid-19 patients IL-6 is overexpressed, and hyperactivated plasmacytoid lymphocytes are detected in peripheral blood film. We hypothesize that, due to the unpredictable interaction between the new virus and the B cell lineage of infected patients, a cascade of out of control events can ensue, capable of determining unexpected pathologic disorders involving such lineage. Here we report two cases of autoimmune hemolytic anemia (AIHA) and two cases of B-cell hematological malignancies developed or reactivated during acute SARS-CoV-2 infection. The temporal relationship of the events may suggest a potential causal relationship between SARS-CoV-2 infection and the hematopoietic disorders. We suggest that special attention should be paid to COVID-19 patients with underlining B cell lineage disorders.

Bronchoalveolar lavage-based COVID-19 testing in patients with cancer

Objective/Background

A few case reports in the setting of coronavirus disease 2019 (COVID-19) and multiplex polymerase chain reaction (PCR)-based assays for common respiratory pathogens have shown a higher yield of bronchoalveolar lavage (BAL) samples than upper airway specimens in immunocompromised patients.

Methods

A retrospective study was conducted reviewing patients diagnosed with COVID-19 at the Medical College of Wisconsin (Milwaukee, WI, USA) between March 13, 2020 and June 11, 2020. All patients tested positive for SARS-CoV-2 via real-time reverse transcriptase PCR (RT-PCR), through a nasopharyngeal or a bronchoscopy specimen.

Results

During the study period, 53 bronchoscopy procedures were performed at the institution, of which five patients tested positive for COVID-19. Of the five patients, three underwent BAL testing based on high clinical suspicion for COVID-19 after the nasopharyngeal (NP) swab(s) was negative. All three patients had underlying cancers and had lymphopenia for a considerable duration prior to being diagnosed with COVID-19. Two patients had better outcomes that could be attributed to earlier BAL specimen testing resulting in timely medical intervention.

Conclusion

This study underscores the need for early lower respiratory tract sampling, whenever possible, in patients with cancer and prolonged lymphopenia. High clinical suspicion ought to supersede false-negative NP reverse transcriptase–PCR as early bronchoscopic evaluation in cancer patients, who are either receiving active treatment or are immunosuppressed, can allow timely institution of efficacious treatment, enrollment into clinical trials, as well as effective infection control. In the apt clinical setting in patients with cancer, presumptive treatment may also be considered to minimize exposure to healthcare providers and proceduralists.