Platelet caspase-1 and Bruton tyrosine kinase activation in patients with COVID-19 is associated with disease severity and reversed in vitro by ibrutinib

The Relationship between the Clinical Course of SARS-CoV-2 Infections and Expression of Bruton's Tyrosine Kinase

INTRODUCTION

Bruton's Tyrosine Kinase (BTK), an important element for the production of several inflammatory cytokines, may play a role in the pathogenesis of COVID-19. This study aimed to assess BTK gene expression levels in COVID-19 cases based on disease severity and outcome.

METHODS

In this study, 33 hospitalized patients with COVID-19 were recruited and divided into two groups based on the severity of the disease: "mild to moderate" and "severe to critical". A blood sample was taken from each patient, peripheral blood mononuclear cells (PBMCs) were extracted, and BTK gene expression was measured. The level of BTK gene expression was compared based on the demographic data, laboratory results, and the severity and outcome of the disease.

RESULTS

Among the 33 patients, 22 (66.7%) were male, with nearly half having at least one underlying condition. The severity groups comprised 12 patients in the "mild to moderate" category and 21 in the "severe to critical" category, with eight (24.2%) experiencing fatal outcomes. Age, weight, and BMI showed no significant associations with BTK expression. BTK expression was notably lower in "severe to critical" and ICU-admitted cases, as well as in individuals with low O2 saturation. However, no significant difference in BTK expression was observed between cured and deceased patients (p = 0.117).

CONCLUSION

BTK gene expression in PBMCs exhibited an inverse correlation with COVID- 19 severity. However, no difference was found between BTK expression and disease outcome.

The Ways of the Virus: Interactions of Platelets and Red Blood Cells with SARS-CoV-2, and Their Potential Pathophysiological Significance in COVID-19

The hematological effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are important in COVID-19 pathophysiology. However, the interactions of SARS-CoV-2 with platelets and red blood cells are still poorly understood. There are conflicting data regarding the mechanisms and significance of these interactions. The aim of this review is to put together available data and discuss hypotheses, the known and suspected effects of the virus on these blood cells, their pathophysiological and diagnostic significance, and the potential role of platelets and red blood cells in the virus's transport, propagation, and clearance by the immune system. We pay particular attention to the mutual activation of platelets, the immune system, the endothelium, and blood coagulation and how this changes with the evolution of SARS-CoV-2. There is now convincing evidence that platelets, along with platelet and erythroid precursors (but not mature erythrocytes), are frequently infected by SARS-CoV-2 and functionally changed. The mechanisms of infection of these cells and their role are not yet entirely clear. Still, the changes in platelets and red blood cells in COVID-19 are significantly associated with disease severity and are likely to have prognostic and pathophysiological significance in the development of thrombotic and pulmonary complications.

Differential Gene Expression of SARS-CoV-2 Positive Bronchoalveolar Lavages: A Case Series

BACKGROUND

Transcriptomic data on bronchoalveolar lavage (BAL) from COVID-19 patients are currently scarce.

OBJECTIVES

This case series seeks to characterize the intra-alveolar immunopathology of COVID-19.

METHOD

BALs were performed on 14 patients (5 COVID-19, of which 3 mild and 2 largely asymptomatic, 9 controls). Controls included asthma (n = 1), unremarkable BALs (n = 3), infections with respiratory syncytial virus (n = 1), influenza B (n = 1), and infections with other coronaviruses (n = 3). SARS-CoV-2 RNA load was measured by quantitative nucleic acid testing, while the detection of other pathogens was performed by immunofluorescence or multiplex NAT.

RESULTS

Gene expression profiling showed 71 significantly downregulated and 5 upregulated transcripts in SARS-CoV-2-positive lavages versus controls. Downregulated transcripts included genes involved in macrophage development, polarization, and crosstalk (LGALS3, MARCO, ERG2, BTK, RAC1, CD83), and genes involved in chemokine signaling and immunometabolism (NUPR1, CEBPB, CEBPA, PECAM1, CCL18, PPARG, ALOX5, ALOX5AP). Upregulated transcripts featured genes involved in NK-T cell signaling (GZMA, GZMH, GNLY, PRF1, CD3G). Patients with mild COVID-19 showed a significant upregulation of genes involved in blood mononuclear cell/leukocyte function (G0S2, ANXA6, FCGR2B, ADORA3), coagulation (von Willebrand factor [VWF]), interferon response (IFRD1, IL12RB2), and a zinc metalloprotease elevated in asthma (CPA3) compared to asymptomatic cases. In-silico comparison of the 5 COVID-19 BAL cases to a published cohort of lethal COVID-19 showed a significant upregulation of "antigen processing and presentation" and "lysosome" pathways in lethal cases.

CONCLUSIONS

These data underscore the heterogeneity of immune response in COVID-19. Further studies with a larger dataset are required to gain a better understanding of the hallmarks of SARS-CoV-2 immunological response.