Analysis of serum soluble CD40 ligand in patients with influenza virus-associated encephalopathy

Microfluidic Immuno-Serolomic Assay Reveals Systems Level Association with COVID-19 Pathology and Vaccine Protection

How to develop highly informative serology assays to evaluate the quality of immune protection against coronavirus disease-19 (COVID-19) has been a global pursuit over the past years. Here, a microfluidic high-plex immuno-serolomic assay is developed to simultaneously measure50 plasma or serum samples for50 soluble markers including 35proteins, 11 anti-spike/receptor binding domian (RBD) IgG antibodies spanningmajor variants, and controls. This assay demonstrates the quintuplicate test in a single run with high throughput, low sample volume, high reproducibilityand accuracy. It is applied to the measurement of 1012 blood samples including in-depth analysis of sera from 127 patients and 21 healthy donors over multiple time points, either with acute COVID infection or vaccination. The protein analysis reveals distinct immune mediator modules that exhibit a reduced degree of diversity in protein-protein cooperation in patients with hematologic malignancies or receiving B cell depletion therapy. Serological analysis identifies that COVID-infected patients with hematologic malignancies display impaired anti-RBD antibody response despite high level of anti-spike IgG, which can be associated with limited clonotype diversity and functional deficiency in B cells. These findings underscore the importance to individualize immunization strategies for these high-risk patients and provide an informative tool to monitor their responses at the systems level.

Microfluidic immuno-serology assay revealed a limited diversity of protection against COVID-19 in patients with altered immunity

The immune response to SARS-CoV-2 for patients with altered immunity such as hematologic malignancies and autoimmune disease may differ substantially from that in general population. These patients remain at high risk despite wide-spread adoption of vaccination. It is critical to examine the differences at the systems level between the general population and the patients with altered immunity in terms of immunologic and serological responses to COVID-19 infection and vaccination. Here, we developed a novel microfluidic chip for high-plex immuno-serological assay to simultaneously measure up to 50 plasma or serum samples for up to 50 soluble markers including 35 plasma proteins, 11 anti-spike/RBD IgG antibodies spanning all major variants, and controls. Our assay demonstrated the quintuplicate test in a single run with high throughput, low sample volume input, high reproducibility and high accuracy. It was applied to the measurement of 1,012 blood samples including in-depth analysis of sera from 127 patients and 21 healthy donors over multiple time points, either with acute COVID infection or vaccination. The protein association matrix analysis revealed distinct immune mediator protein modules that exhibited a reduced degree of diversity in protein-protein cooperation in patients with hematologic malignancies and patients with autoimmune disorders receiving B cell depletion therapy. Serological analysis identified that COVID infected patients with hematologic malignancies display impaired anti-RBD antibody response despite high level of anti-spike IgG, which could be associated with limited clonotype diversity and functional deficiency in B cells and was further confirmed by single-cell BCR and transcriptome sequencing. These findings underscore the importance to individualize immunization strategy for these high-risk patients and provide an informative tool to monitor their responses at the systems level.

Platelet-Released Factors: Their Role in Viral Disease and Applications for Extracellular Vesicle (EV) Therapy

Platelets, which are small anuclear cell fragments, play important roles in thrombosis and hemostasis, but also actively release factors that can both suppress and induce viral infections. Platelet-released factors include sCD40L, microvesicles (MVs), and alpha granules that have the capacity to exert either pro-inflammatory or anti-inflammatory effects depending on the virus. These factors are prime targets for use in extracellular vesicle (EV)-based therapy due to their ability to reduce viral infections and exert anti-inflammatory effects. While there are some studies regarding platelet microvesicle-based (PMV-based) therapy, there is still much to learn about PMVs before such therapy can be used. This review provides the background necessary to understand the roles of platelet-released factors, how these factors might be useful in PMV-based therapy, and a critical discussion of current knowledge of platelets and their role in viral diseases.

Identification of immune correlates of fatal outcomes in critically ill COVID-19 patients

Prior studies have demonstrated that immunologic dysfunction underpins severe illness in COVID-19 patients, but have lacked an in-depth analysis of the immunologic drivers of death in the most critically ill patients. We performed immunophenotyping of viral antigen-specific and unconventional T cell responses, neutralizing antibodies, and serum proteins in critically ill patients with SARS-CoV-2 infection, using influenza infection, SARS-CoV-2-convalescent health care workers, and healthy adults as controls. We identify mucosal-associated invariant T (MAIT) cell activation as an independent and significant predictor of death in COVID-19 (HR = 5.92, 95% CI = 2.49-14.1). MAIT cell activation correlates with several other mortality-associated immunologic measures including broad activation of CD8+ T cells and non-Vδ2 γδT cells, and elevated levels of cytokines and chemokines, including GM-CSF, CXCL10, CCL2, and IL-6. MAIT cell activation is also a predictor of disease severity in influenza (ECMO/death HR = 4.43, 95% CI = 1.08-18.2). Single-cell RNA-sequencing reveals a shift from focused IFNα-driven signals in COVID-19 ICU patients who survive to broad pro-inflammatory responses in fatal COVID-19 -a feature not observed in severe influenza. We conclude that fatal COVID-19 infection is driven by uncoordinated inflammatory responses that drive a hierarchy of T cell activation, elements of which can serve as prognostic indicators and potential targets for immune intervention.

Serum soluble CD40 ligand levels after acute intracerebral hemorrhage

BACKGROUND

Soluble CD40 ligand (sCD40L) is associated with inflammation. This study aimed to assess the prognostic value of sCD40L for clinical outcomes of acute intracerebral hemorrhage (ICH) patients.

MATERIALS AND METHODS

The serum sCD40L levels of 110 patients and 110 age- and gender-matched healthy controls were measured using sandwich immunoassays. The relationships between serum sCD40L levels and 1-week mortality, 6-month mortality, 6-month overall survival, 6-month unfavorable outcome (modified Rankin Scale score >2), and ICH severity including hematoma volume and National Institutes of Health Stroke Scale (NIHSS) score were assessed using multivariate analysis.

RESULTS

Compared with healthy controls, ICH patients had higher serum sCD40L levels. Serum sCD40L levels were correlated positively with hematoma volumes and NIHSS scores using a multivariate linear regression. Multivariate analysis results indicated that sCD40L was identified an independent predictor of 1-week mortality, 6-month mortality, 6-month unfavorable outcome and 6-month overall survival. sCD40L also showed high predictive performances for 1-week mortality, 6-month mortality and 6-month unfavorable outcome based on receiver operating characteristic curve.

CONCLUSIONS

Elevated serum sCD40L levels are independently associated with ICH severity and clinical outcomes. And sCD40L has potential to be a good prognostic biomarker of ICH.

The prognostic value of plasma soluble CD40 ligand levels following aneurysmal subarachnoid hemorrhage

BACKGROUND

Increased circulating soluble CD40 ligand (sCD40L) levels have been reported to be associated with severity and mortality of severe traumatic brain injury. The current study tested the hypothesis that elevated plasma sCD40L levels are predictive of clinical outcomes of aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

Plasma sCD40L concentrations of 120 aSAH patients and 120 healthy volunteers were measured using enzyme-linked immunosorbent assay. An unfavorable outcome was defined as Glasgow Outcome Scale score of 1-3.

RESULTS

Plasma sCD40L levels were significantly elevated in aSAH patients compared with healthy controls; plasma sCD40L levels were highly associated with clinical severity reflected by World Federation of Neurological Surgeons (WFNS) score and Fisher score; sCD40L emerged as an independent predictor of 6-month mortality and unfavorable outcome and 6-month overall survival; although a combined logistic-regression model did not demonstrate the additive benefit of sCD40L to WFNS score and Fisher score, sCD40L possessed similar predictive value to WFNS score and Fisher score based on receiver operating characteristic curves.

CONCLUSIONS

Higher plasma sCD40L levels on presentation are associated with clinical severity and have potential to be a good prognostic biomarker of aSAH.

In vivo platelet activation in critically ill patients with primary 2009 influenza A(H1N1)

BACKGROUND

Changes in platelet reactivity during 2009 influenza A(H1N1) (A[H1N1]) have not been characterized.

METHODS

We prospectively examined platelet activation and cytokine responses in patients with A(H1N1) (n = 20), matched patients with bacterial pneumonia (n = 15), and nonhospitalized, healthy control subjects (n = 10).

RESULTS

Platelet-monocyte aggregation was higher in patients with A(H1N1) (21.4% ± 4.7%) compared with patients with pneumonia (10.9% ± 3.7%) and control subjects (8.1% ± 4.5%, P < .05). Similarly, PAC-1 (antibody that binds to the active conformation of integrin α(IIb)β(3)) binding to platelets is increased in patients with A(H1N1) (9.5% ± 4.7%) compared with patients with pneumonia (1.0% ± 0.7%) and healthy subjects (0.61% ± 0.15%, P < .10). PAC-1 binding was twofold higher in patients with A(H1N1) with shock vs those without shock. IL-6 levels were elevated in patients with A(H1N1), indicating systemic inflammation consistent with activation of circulating platelets.

CONCLUSIONS

These findings, derived from a small but documented cohort of patients, demonstrate that platelet activation responses during A(H1N1) are enhanced-exceeding responses in patients with bacterial pneumonia-and provide new evidence that platelets may contribute to inflammatory responses during A(H1N1).

Acute encephalopathy and encephalitis caused by influenza virus infection

PURPOSE OF REVIEW

Influenza-associated acute encephalopathy/encephalitis (IAE) is an uncommon but serious complication with high mortality and neurological sequelae. This review discusses recent progress in IAE research for a better understanding of the disease features, populations, outcomes, diagnosis, and pathogenesis.

RECENT FINDINGS

In recent years, many IAE cases were reported from many countries, including Japan, Canada, Australia, Austria, The Netherlands, United States, Sweden, and other countries and regions. During the novel influenza A/H1N1 pandemic, many IAE cases with A/H1N1 infection in children were reported, particularly in those hospitalized with influenza infection. Pathogenesis of IAE is not fully understood but may involve viral invasion of the CNS, proinflammatory cytokines, metabolic disorders, or genetic susceptibility. An autosomal dominant viral acute necrotizing encephalopathy (ANE) was recently found to have missense mutations in the gene Ran-binding 2 (RANBP2). Another recurrent ANE case following influenza A infection was also reported in a genetically predisposed family with an RANBP2 mutation.

SUMMARY

Although IAE is uncommon, compared with the high incidence of influenza infection, it is severe. However, this complication is not duly recognized by health practitioners. Recent advances highlight the threat of this complication, which will help us to have a better understanding of IAE.

Influenza virus associated encephalopathy

Perspective on the paper by Hosoya et al (see page 469)