Standardized whole blood stimulation improves immunomonitoring of induced immune responses in multi-center study

Functional immune responses are increasingly important for clinical studies, providing in depth biomarker information to assess immunotherapy or vaccination. Incorporating functional immune assays into routine clinical practice has remained limited due to challenges in standardizing sample preparation. We recently described the use of a whole blood syringe-based system, TruCulture®, which permits point-of-care standardized immune stimulation. Here, we report on a multi-center clinical study in seven FOCIS Centers of Excellence to directly compare TruCulture to conventional PBMC methods. Whole blood and PBMCs from healthy donors were exposed to LPS, anti-CD3 anti-CD28 antibodies, or media alone. 55 protein analytes were analyzed centrally by Luminex multi-analyte profiling in a CLIA-certified laboratory. TruCulture responses showed greater reproducibility and improved the statistical power for monitoring differential immune response activation. The use of TruCulture addresses a major unmet need through a robust and flexible method for immunomonitoring that can be reproducibly applied in multi-center clinical studies.

ONE SENTENCE SUMMARY

A multi-center study revealed greater reproducibility from whole blood stimulation systems as compared to PBMC stimulation for studying induced immune responses.

Liposome-based immunotherapy against autoimmune diseases: therapeutic effect on multiple sclerosis

AIM

Based on the ability of apoptosis to induce immunological tolerance, liposomes were generated mimicking apoptotic cells, and they arrest autoimmunity in Type 1 diabetes. Our aim was to validate the immunotherapy in other autoimmune disease: multiple sclerosis.

MATERIALS & METHODS

Phosphatidylserine-rich liposomes were loaded with disease-specific autoantigen. Therapeutic capability of liposomes was assessed in vitro and in vivo.

RESULTS

Liposomes induced a tolerogenic phenotype in dendritic cells, and arrested autoimmunity, thus decreasing the incidence, delaying the onset and reducing the severity of experimental disease, correlating with an increase in a probably regulatory CD25⁺ FoxP3^- CD4⁺ T-cell subset.

CONCLUSION

This is the first work that confirms phosphatidylserine-liposomes as a powerful tool to arrest multiple sclerosis, demonstrating its relevance for clinical application.

Ways Forward for Tolerance-Inducing Cellular Therapies- an AFACTT Perspective

Clinical studies with cellular therapies using tolerance-inducing cells, such as tolerogenic antigen-presenting cells (tolAPC) and regulatory T cells (Treg) for the prevention of transplant rejection and the treatment of autoimmune diseases have been expanding the last decade. In this perspective, we will summarize the current perspectives of the clinical application of both tolAPC and Treg, and will address future directions and the importance of immunomonitoring in clinical studies that will result in progress in the field.

Regenerating gene Iα is a biomarker for diagnosis and monitoring of celiac disease: a preliminary study

The regenerating gene (REG) is a multigene family in humans that plays a role in tissue regeneration. The REG Iα protein is expressed in the pancreas and the gastrointestinal tract and is involved in the pathophysiology of gastritis, pancreatitis, cancer, inflammatory bowel disease, and type 1 diabetes (T1D). Celiac disease (CD) is an autoimmune disease caused by the ingestion of gluten in genetically susceptible individuals. Our aim was to determine whether the serum REG Iα concentration reflects the destructive/regenerative process in the small bowel in CD. REG Iα was determined by enzyme-linked immunosorbent assay (ELISA) in 40 patients with active CD, and in 19 of them, REG Iα was assessed after following a gluten free diet. As controls, 35 healthy subjects were included in the study. Autoantibodies to transglutaminase, gliadin, and endomisium were measured also. We found a significant increase in REG Iα in the sera of CD patients when compared with controls. REG Iα levels decreased after a gluten-free diet together with a significant reduction in antitransglutaminase antibodies. T1D and pernicious anemia patients displayed normal serum REG Iα concentrations. This preliminary study suggests that REG Iα protein levels can be used as a biomarker for the diagnosis and monitoring of CD.

Seroprevalence of SARS-CoV-2 IgG specific antibodies among healthcare workers in the Northern Metropolitan Area of Barcelona, Spain, after the first pandemic wave

Background

The rapid spread of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) around the world has caused a global pandemic, infecting millions of individuals, with an unprecedented impact in health care systems worldwide. Healthcare workers are one of the risk groups that need to be well protected, due to their strategic role in patient management, presently and in prevention of healthcare needs for future outbreaks. Here, we present the results of the first SARS-CoV-2 seroprevalence study in the Northern Metropolitan Area of Barcelona, Spain.

Methods

IgG SARS-CoV-2 antibodies were analyzed in serum samples from 7563 healthcare workers of the Northern Metropolitan Area of Barcelona. Samples were collected after the first pandemic wave (from May 4th to May 22nd, 2020) and were analyzed by automated chemiluminescence assays. All samples were tested for IgG anti-S1/S2. Participant samples with negative or equivocal results but with analytical signals above the limit of detection and/or previously confirmed COVID-19 diagnosis were also tested for IgG anti-Nucleocapsid.

Results

A total of 779 of 7563 (10.3%) healthcare workers were positive for anti-SARS-CoV-2 IgG (specific for either S1/S2 or N antigens). No significant differences were observed between those working at primary care or at the reference hospital. Interestingly, among 341 participants with a confirmed COVID-19 diagnosis, 36 (10.55%) tested negative for SARS-CoV-2 IgG (both S1/S2 and recombinant N antigen).

Conclusion

Seroprevalence of anti-SARS-CoV-2 IgG in the healthcare workers of the North Metropolitan Area of Barcelona was higher than in the general population in the same geographical area. Safety measures have to be stressed in order to protect these essential workers from future pandemic waves.

Elevated Neopterin Levels Predict Fatal Outcome in SARS-CoV-2-Infected Patients

Highlights

Innate immune activation during Covid-19 infection is associated with pernicious clinical outcome.

Background

Coronavirus disease 2019 (Covid-19) is a worldwide threat that has already caused more than 3 000 000 deaths. It is characterized by different patterns of disease evolution depending on host factors among which old-age and pre-existing comorbidities play a detrimental role. Previous coronavirus epidemics, notably SARS-CoV, were associated with increased serum neopterin levels, which can be interpreted as a sign of acute innate immunity in response to viral infection. Here we hypothesize that neopterin may serve as a biomarker of SARS-CoV-2 viral infection and Covid-19 disease severity.

Methods

We measured neopterin blood levels by ELISA. Seric concentration was quantified from 256 healthy donors and 374 Covid-19 patients at hospital admission. Enrolled Covid-19 patients were all symptomatic and displayed a large spectrum of comorbidities. Patients were followed until disease resolution or death.

Results

Severe and critically ill SARS-CoV-2 infected patients were characterized by a profound exacerbation of immune activation characterized by elevated neopterin blood levels. Systemic neopterin levels above 19nM stratified healthy individuals from Covid-19 patients with 87% specificity and 100% sensitivity. Moreover, systemic neopterin levels above 53nM differentiated non-survivors from survivors with 64% specificity and 100% sensitivity.

Conclusion

We propose that neopterin concentration measured at arrival to hospital is a hallmark of severe Covid-19 and identifies a high-risk population of pernicious clinical outcome with a need for special medical care.

Cell-based Tolerogenic Therapy, Experience from Animal Models of Multiple Sclerosis, Type 1 Diabetes and Rheumatoid Arthritis

Cell-based tolerogenic therapy is a promising approach for the treatment of autoimmune diseases and transplant rejection. Regulatory T cells and tolerogenic dendritic cells have been particularly explored in the treatment of various autoimmune disorders in experimental models of disease. Although some of these cells have already been tested in a limited number of clinical trials, there is still a need for preclinical research on tolerogenic cells in animal models of autoimmunity. This review will focus on the relevance of data obtained from studies in experimental animal models for the use of tolerogenic cell-based therapy in humans. Also, perspectives for further improvement of tolerogenic cell preparation towards enhanced suppressive activity and stability of the cells will be discussed.

Comparison of dendritic cells obtained from autoimmunty-prone and resistant rats

Dendritic cells (DC) are responsible for the initiation and shaping of the adaptive immune response and are in the focus of autoimmunity research. We were interested in comparison of DC obtained from autoimmunity-prone Dark Agouti (DA) rats and autoimmunity-resistant Albino Oxford (AO) rats. DC were generated from bone marrow precursors and matured (mDC) by lipopolysaccharide. Tolerogenic DC (tolDC) obtained by vitamin D3 treatment were studied in parallel. Profile of cytokine production was different in AO and DA mDC and tolDC. Expression of MHC class II molecules and CD86 were higher in DA DC, while vitamin D3 reduced their expression in dendritic cells of both strains. Allogeneic proliferation of CD4⁺ T cells was reduced by AO tolDC, but not with DA tolDC in comparison to respective mDC. Finally, expression of various genes identified as differentially expressed in human mDC and tolDC was also analyzed in AO and DA DC. Again, AO and DA DC differed in the expression of the analyzed genes. To conclude, AO and DA DC differ in production of cytokines, expression of antigen presentation-related molecules and in regulation of CD4⁺ T proliferation. The difference is valuable for understanding the divergence of the strains in their susceptibility to autoimmunity.

Detection of Autoantibodies in Bronchoalveolar Lavage in Patients with Diffuse Interstitial Lung Disease

INTRODUCTION

Serum autoantibodies support the diagnosis of interstitial lung disease (ILD) related to systemic autoimmune diseases (SAD-ILD). Nevertheless, their presence in the bronchoalveolar lavage (BAL) has not been explored.

OBJECTIVES

To demonstrate the presence of autoantibodies in the BAL of ILD patients at onset of clinical evaluation, its relation with serum autoantibodies and to analyze clinical features of patients with autoantibodies in BAL.

METHODS

Autoantibodies against extractable nuclear antigens (ENAs) were analyzed by immunoblot in the BAL of 155 patient with suspected diagnosis of ILD and 10 controls.

RESULTS

Seven ENAs were detected in the BAL of 19 patients (Anti-Ro52, Anti-Ro60, CENP-B, Anti-La, Jo-1, Sm/RNP and Anti-SL70). The most frequent ENA was anti-Ro52 (13 patients; 68,4% of positives ones). Seven patients presented more than one ENAs. Fourteen were diagnosed of SAD-ILD, 3 of interstitial pneumonia with autoimmune features, one of non-specific idiopathic pneumonia and other of silicosis. In 10 cases (52%) IgA autoantibodies were also detected. The autoantibodies observed in BAL were also detected in the serum of 17 patients (90%). There were no significant clinical differences with the patients with SAD-ILD or interstitial pneumonia with autoimmune features with patients with negative BAL.

CONCLUSION

The study of ENAs in BAL is feasible and can be a useful tool in the ILD initial algorithm, specifically sustaining the suspected diagnosis of SAD-ILD.

CD27 induction on thymocytes

CD27 mAb recognize a disulfide-linked homodimer of 55 kDa present in the majority of T cells and in a minor subpopulation of thymocytes. Although an increase of CD27 expression has been described in activated T cells, this Ag is poorly expressed in long term growing T cells. It has been also reported that CD27- becomes CD27+ upon activation. In the aim to better know the relationship between CD27 expression and the activation and maturation processes, the induction of this Ag in thymocytes was analyzed. The results obtained in this work show that: 1) CD27 is expressed only in thymocytes with high CD3 Ag density. 2) Its expression can be induced in low density CD3 CD4+ CD8+ cells by Con A and in low CD3 Ag density by PMA+ionomycin. 3) PMA alone or in combination with rIL-2 induces CD25 and CD71 expression but not CD27. 4) Unlike CD27, the Ag CD45RA, CD26, and CD76, which are present only in a minor thymocyte subpopulation, are not induced in double positive thymocytes. Because it has been reported that cyclosporin A interferes with thymocytes maturation and blocks the transition from double to single positive cells, its effect was measured on CD27 induction. Cyclosporin A did not inhibit CD25 expression induced by both Con A and PMA+ionomycin, but under these conditions it inhibited the induction of CD27. In this paper we discuss whether CD27 could be implicated in T cell maturation.

CD27 induction on thymocytes

CD27 mAb recognize a disulfide-linked homodimer of 55 kDa present in the majority of T cells and in a minor subpopulation of thymocytes. Although an increase of CD27 expression has been described in activated T cells, this Ag is poorly expressed in long term growing T cells. It has been also reported that CD27- becomes CD27+ upon activation. In the aim to better know the relationship between CD27 expression and the activation and maturation processes, the induction of this Ag in thymocytes was analyzed. The results obtained in this work show that: 1) CD27 is expressed only in thymocytes with high CD3 Ag density. 2) Its expression can be induced in low density CD3 CD4+ CD8+ cells by Con A and in low CD3 Ag density by PMA+ionomycin. 3) PMA alone or in combination with rIL-2 induces CD25 and CD71 expression but not CD27. 4) Unlike CD27, the Ag CD45RA, CD26, and CD76, which are present only in a minor thymocyte subpopulation, are not induced in double positive thymocytes. Because it has been reported that cyclosporin A interferes with thymocytes maturation and blocks the transition from double to single positive cells, its effect was measured on CD27 induction. Cyclosporin A did not inhibit CD25 expression induced by both Con A and PMA+ionomycin, but under these conditions it inhibited the induction of CD27. In this paper we discuss whether CD27 could be implicated in T cell maturation.

Follow up of the Humoral Response in Healthcare Workers after the Administration of Two Dose of the Anti SARS-CoV-2 Vaccines-Effectiveness in Delta Variant Breakthrough Infections

The implementation of vaccination among healthcare workers (HCWs) allowed the management of the pandemic in a manner that differed from that in the first waves. It has been demonstrated that the mRNA vaccines elicit good humoral responses but that there are still breakthrough infections. In summer 2021, a fifth wave emerged, despite the good coverage of HCWs in Spain. We aimed to study the SARS-CoV-2 IgG antibody levels as a marker to predict the possibility of Delta variant infections after vaccination after a seroepidemiological campaign. Of the 5000 participants, a total of 4902 (98.04%) showed a positive result in the serological anti-S test and only 98 (1.96%) were negative. Among the 4368 fully vaccinated participants, only in five cases was the serology negative. Of the total number of participants that received antibody results during the study, 162 were PCR positive in the subsequent two months. Among these, 151 were fully vaccinated (two doses). Significant differences between antibody BAU/mL levels were found between PCR positive and non-PCR positive participants (p < 0.01). The median of BAU/mL was higher in those vaccinated patients with no infection (1260 BAU/mL; 465−2080) versus infected patients (661 BAU/mL; 361−2080). These data support the idea that vaccines play an important role in the control of the pandemic, especially among HCWs at the time of the Delta variant circulation. More studies with other variants of concern must be performed in order to establish a correlation between the levels of IgG and the new infections.

Peripheral blood T-cell modulation by omalizumab in chronic urticaria patients

Background

Chronic spontaneous urticaria (CSU) is a highly prevalent and difficult to manage cutaneous disease characterized by the presence of recurrent urticaria, angioedema, or both, for a period of 6 weeks or longer. One of the biological treatments used for patients with CSU with an autoimmune background and bad control of the disease is omalizumab, an anti-IgE monoclonal antibody. The understanding of the mechanism of action of this biological drug in CSU along with the identification of potential biomarkers of clinical response can be helpful in the personalized management of the disease.

Objective

The purpose of this study was to analyze the effect of omalizumab on peripheral blood lymphocyte subpopulations in patients with CSU in order to identify potential biomarkers of treatment response.

Methods

We analyzed 71 patients with CSU [33 under omalizumab and 38 under non-immunomodulatory drugs (treated with antihistamines; NID)] and 50 healthy controls. An exhaustive immunophenotyping of whole blood T-cell subpopulations, including naïve, central memory, effector memory, effector cells, Th1, Th2, and Th17 was performed by multiparametric flow cytometry. Moreover, in CSU patients, we analyzed markers of inflammation (ESR, DD, CRP), atopy (prick test, IgE quantification), and autoimmunity (anti-thyroid antibodies and indirect basophil activation test).To evaluate the clinical activity, the Urticaria Activity Score 7 (UAS 7) test was used.

Results

In patients with CSU under treatment with omalizumab, there was a significant decrease in the percentage of naïve and an increase in the percentage of central memory CD4 T cells as well as a decrease in the percentage of naïve and increase in the percentage of effector CD8 T-cell subsets. Moreover, patients under treatment with omalizumab had higher percentages of Th1 and Th2 cells than patients under treatment with NID.

Conclusion

The immune monitoring of T-cell subpopulations in patients with CSU starting omalizumab, may be a useful strategy to analyze treatment response in the clinical practice.