CXCL12 and CXCL13 Cytokine Serum Levels Are Associated with the Magnitude and the Quality of SARS-CoV-2 Humoral Responses

Amino Acids Frequency and Interaction Trends: Comprehensive Analysis of Experimentally Validated Viral Antigen-Antibody Complexes

Antibodies have specific binding capabilities and therapeutic potential for treating various diseases, including viral infections. The amino acid composition of the hypervariable complementarity determining regions (CDR) loops and the framework regions (FR) are the determining factors for the affinity and therapeutic efficacy of the antibodies. In this study selected and curated, 77 viral antigen-human antibody complexes from Protein data bank from the Thera-SAbdab database were analyzed. The results revealed diversity indices within specific CDR regions, amino acid frequencies, paratope-epitope interactions, bond formations, and bond types among the analyzed viral Ag-Ab complexes. The finding revealed that Ser, Gly, Tyr, Thr, and Phe are prominently present in the antibody CDRs. Analysis of CDR profiles indicated an average amino acid diversity of 60-80% in heavy chain CDRs and 45-60% in light chain CDRs. Aromatic residues, particularly Tyr, Phe, and Trp showed significant involvement in the paratope-epitope interactions in the heavy chain, while Tyr, Ser, and Thr were key contributors in the light chain. Furthermore, the study examined the occurrence of amino acids in both light and heavy chains of viral Ag- human Ab complexes, analyzing the presence of amino acids as single residues, dipeptides and tripeptides. The analysis is crucial for enhancing the antibody engineering processes including, design, optimization, affinity enhancement, and overall antibody development.

Tocilizumab provides dual benefits in treating immune checkpoint inhibitor-associated arthritis and preventing relapse during ICI rechallenge: the TAPIR study

BACKGROUND

The aim of this retrospective study was to evaluate the dual efficacy of tocilizumab (TCZ) in the treatment of immune checkpoint inhibitor (ICI)-associated arthritis (ICI-AR) and the prevention of relapses after rechallenge.

PATIENTS AND METHODS

We identified 26 patients with ICI-AR. The primary objectives were to evaluate TCZ efficacy in ICI-AR treatment and as secondary prophylaxis during ICI rechallenge in 11 of them. Patients received prednisone (CS) at 0.3 mg/kg tapered at 0.05 mg/kg weekly for six weeks. TCZ was administered at a dose of 8 mg/kg every 2 weeks. In the subgroup receiving secondary prophylaxis (rechallenge n = 11), TCZ was reintroduced with the same regimen concurrently with ICI rechallenge, and without the addition of CS. A control group of patients (rechallenge n = 5) was rechallenged without TCZ. Secondary endpoints included post-rechallenge evaluation of ICI duration, reintroduction of CS >0.1 mg/kg/day, ICI-AR flares, and disease control rate.

RESULTS

The median age of the patients was 70 years. The median follow-up from ICI initiation was 864 days. Among the 20 patients treated with TCZ for ICI-AR, all (100%) achieved an ACR70 response rate, defined as greater than 70% improvement, at 10 weeks. Some 81% of these patients achieved steroid-free remission after 24 weeks on TCZ. The median follow-up period was 552 days in rechallenged patients. The results demonstrated a reduction in ICI-AR relapses upon ICI rechallenge in patients receiving TCZ prophylaxis compared with patients who did not receive prophylaxis (17% versus 40%). The requirement for CS was completely abolished with prophylaxis (0% versus 20%), and the mean duration of ICI treatment was notably extended from 113 to 206 days. The 12-month post-rechallenge outcomes showed a disease control rate of 77%. During TCZ prophylaxis, CXCL9 remained elevated, showing no decline from their concentrations at the onset of ICI-AR.

CONCLUSIONS

In addition to treating ICI-AR, TCZ demonstrated efficacy as a secondary prophylactic agent, preventing the recurrence of symptoms and lengthening ICI treatment duration after ICI rechallenge.

Tocilizumab and immune signatures for targeted management of cytokine release syndrome in immune checkpoint therapy

BACKGROUND

This study aimed to identify specific biomarkers in oncology patients experiencing immune-related cytokine release syndrome (irCRS)-like symptoms during immune checkpoint inhibitor (ICI) therapy, including severe cases like hemophagocytic lymphohistiocytosis (irHLH), and to distinguish these from sepsis. A secondary objective was to retrospectively analyze the efficacy of tocilizumab (TCZ) in treating corticosteroid (CS)-refractory high-grade irCRS.

PATIENTS AND METHODS

A cohort of 35 patients presenting with irCRS-like symptoms was studied, including 9 with irHLH-like manifestations and 8 with sepsis. Immune profiling was carried out using 48 mass cytometry markers, along with an analysis of 45 serum biomarkers, including 27 cytokines and 18 additional markers from the HScore. Twelve patients with high-grade irCRS refractory to CS were treated with TCZ.

RESULTS

Twenty-four biomarkers significantly distinguished between irHLH and grade 3 irCRS (P = 0.0027-0.0455). Hepatocyte growth factor (HGF) and ferritin had superior predictive values compared with the traditional HScore, both with a positive predictive value (PPV) and negative predictive value (NPV) of 100%. CXCL9 differentiated irHLH from grade 3 irCRS and predicted the need for TCZ treatment intensification (PPV = 90%, NPV = 100%). Additional biomarkers, including leukocyte count, neutrophils, ferritin, interleukin (IL)-6, IL-7, epidermal growth factor, fibrinogen, and granulocyte-macrophage colony-stimulating factor (GM-CSF), discriminated sepsis from high-grade irCRS (PPV = 75%-80%, NPV = 100%). Elevated frequencies of CXCR5+ or CCR4+ CD8 memory cells, CD38+ intermediate monocytes, and CD62L+ neutrophils were observed in high-grade irCRS compared with sepsis. All 12 patients with high-grade irCRS refractory to CS treated with TCZ experienced complete resolution.

CONCLUSIONS

This study highlights the importance of specific immunologic biomarkers in determining irCRS severity, predicting outcomes, and distinguishing between irHLH, irCRS, and sepsis. It also demonstrates the efficacy of TCZ in managing high-grade irCRS, underscoring the need for personalized therapeutic strategies based on these biomarkers.

Addressing Post-Acute COVID-19 Syndrome in Cancer Patients, from Visceral Obesity and Myosteatosis to Systemic Inflammation: Implications in Cardio-Onco-Metabolism

Cardiovascular disease and cancer are the two leading causes of morbidity and mortality in the world. The emerging field of cardio-oncology described several shared risk factors that predispose patients to both cardiovascular disease and cancer. Post-acute COVID-19 syndrome is a chronic condition that occurs in many patients who have experienced a SARS-CoV-2 infection, mainly based on chronic fatigue, sedentary lifestyle, cramps, breathing difficulties, and reduced lung performance. Post-acute COVID-19 exposes patients to increased visceral adiposity, insulin resistance, myosteatosis, and white adipose tissue content (surrounded by M1 macrophages and characterized by a Th1/Th17 phenotype), which increases the risk of cardiovascular mortality and cancer recurrence. In this review, the main metabolic affections of post-acute COVID-19 syndrome in cancer patients at low and high risk of cardiomyopathies will be summarized. Furthermore, several non-pharmacological strategies aimed at reducing atherosclerotic and cardiac risk will be provided, especially through anti-inflammatory nutrition with a low insulin and glycemic index, appropriate physical activity, and immune-modulating bioactivities able to reduce visceral obesity and myosteatosis, improving insulin-related signaling and myocardial metabolism.

Assessing the Potential of an Enzymatically Liberated Salmon Oil to Support Immune Health Recovery from Acute SARS-CoV-2 Infection via Change in the Expression of Cytokine, Chemokine and Interferon-Related Genes

Cytokines, chemokines, and interferons are released in response to viral infection with the ultimate aim of viral clearance. However, in SARS-CoV-2 infection, there is an imbalanced immune response, with raised cytokine levels but only a limited interferon response with inefficient viral clearance. Furthermore, the inflammatory response can be exaggerated, which risks both acute and chronic sequelae. Several observational studies have suggested a reduced risk of progression to severe COVID-19 in subjects with a higher omega-3 index. However, randomized studies of omega-3 supplementation have failed to replicate this benefit. Omega-3 fats provide important anti-inflammatory effects; however, fatty fish contains many other fatty acids that provide health benefits distinct from omega-3. Therefore, the immune health benefit of whole salmon oil (SO) was assessed in adults with mild to moderate COVID-19. Eleven subjects were randomized to best supportive care (BSC) with or without a full spectrum, enzymatically liberated SO, dosed at 4g daily, for twenty-eight days. Nasal swabs were taken to measure the change in gene expression of markers of immune response and showed that the SO provided both broad inflammation-resolving effects and improved interferon response. The results also suggest improved lung barrier function and enhanced immune memory, although the clinical relevance needs to be assessed in longer-duration studies. In conclusion, the salmon oil was well tolerated and provided broad inflammation-resolving effects, indicating a potential to enhance immune health.

Primary prophylaxis with mTOR inhibitor enhances T cell effector function and prevents heart transplant rejection during talimogene laherparepvec therapy of squamous cell carcinoma

The application of mammalian target of rapamycin inhibition (mTORi) as primary prophylactic therapy to optimize T cell effector function while preserving allograft tolerance remains challenging. Here, we present a comprehensive two-step therapeutic approach in a male patient with metastatic cutaneous squamous cell carcinoma and heart transplantation followed with concomitant longitudinal analysis of systemic immunologic changes. In the first step, calcineurin inhibitor/ mycophenolic acid is replaced by the mTORi everolimus to achieve an improved effector T cell status with increased cytotoxic activity (perforin, granzyme), enhanced proliferation (Ki67) and upregulated activation markers (CD38, CD69). In the second step, talimogene laherparepvec (T-VEC) injection further enhances effector function by switching CD4 and CD8 cells from central memory to effector memory profiles, enhancing Th1 responses, and boosting cytotoxic and proliferative activities. In addition, cytokine release (IL-6, IL-18, sCD25, CCL-2, CCL-4) is enhanced and the frequency of circulating regulatory T cells is increased. Notably, no histologic signs of allograft rejection are observed in consecutive end-myocardial biopsies. These findings provide valuable insights into the dynamics of T cell activation and differentiation and suggest that timely initiation of mTORi-based primary prophylaxis may provide a dual benefit of revitalizing T cell function while maintaining allograft tolerance.

Cytokine profiles of mild-to-moderate SARS-CoV-2 infected and recovered pre-vaccinated individuals residing in Indonesia

Background

Accumulating evidence suggests the involvement of cytokine-mediated inflammation, in clinical severity and death related to SARS-CoV-2 infection, especially among pre-vaccinated individuals. An increased risk of death was also described among SARS-CoV-2 recovered individuals, which might be correlated with prolonged inflammatory responses. Despite being among the countries with the highest cumulative deaths due to COVID-19, evidence regarding cytokine profiles among SARS-CoV-2 infected and recovered pre-vaccinated individuals in Indonesia is scarce. Thus, this study aimed to describe the cytokines profiles of pre-vaccinated individuals residing in Indonesia, with mild-to-moderate SARS-CoV-2 infection and those who recovered.

Methods

Sixty-one sera from 24 hospitalized patients with mild-to-moderate SARS-CoV-2 infection, 24 individuals recovered from asymptomatic-to-moderate SARS-CoV-2 infection, and 13 healthy controls unexposed to SARS-CoV-2 were used in this study. Quantification of serum cytokine levels, including IL-6, IL-8, IP-10, TNF-α, CCL-2, CCL-3, CCL-4, and CXCL-13, was performed using a Luminex multi-analyte-profiling (xMAP)-based assay.

Results

The levels of IL-8 along with CCL-2 and CCL-4, were significantly higher (p ≤ 0.01) in hospitalized patients with mild-to-moderate SARS-CoV-2 infection and recovered individuals compared to healthy controls. However, no significant difference was observed in these cytokine levels between infected and recovered individuals. On the other hand, there were no significant differences in several other cytokine levels, including IL-6, IL-10, TNF-α, CCL-3, and CXCL-13, among all groups.

Conclusion

IL-8, CCL-2, and CCL-4 were significantly elevated in pre-vaccinated Indonesian individuals with mild-to-moderate SARS-CoV-2 infection and those who recovered. The cytokine profiles described in this study might indicate inflammatory responses not only among SARS-CoV-2 infected, but also recovered individuals.

A Broad-Spectrum Multi-Antigen mRNA/LNP-Based Pan-Coronavirus Vaccine Induced Potent Cross-Protective Immunity Against Infection and Disease Caused by Highly Pathogenic and Heavily Spike-Mutated SARS-CoV-2 Variants of Concern in the Syrian Hamster Model

The first-generation Spike-alone-based COVID-19 vaccines have successfully contributed to reducing the risk of hospitalization, serious illness, and death caused by SARS-CoV-2 infections. However, waning immunity induced by these vaccines failed to prevent immune escape by many variants of concern (VOCs) that emerged from 2020 to 2024, resulting in a prolonged COVID-19 pandemic. We hypothesize that a next-generation Coronavirus (CoV) vaccine incorporating highly conserved non-Spike SARS-CoV-2 antigens would confer stronger and broader cross-protective immunity against multiple VOCs. In the present study, we identified ten non-Spike antigens that are highly conserved in 8.7 million SARS-CoV-2 strains, twenty-one VOCs, SARS-CoV, MERS-CoV, Common Cold CoVs, and animal CoVs. Seven of the 10 antigens were preferentially recognized by CD8+ and CD4+ T-cells from unvaccinated asymptomatic COVID-19 patients, irrespective of VOC infection. Three out of the seven conserved non-Spike T cell antigens belong to the early expressed Replication and Transcription Complex (RTC) region, when administered to the golden Syrian hamsters, in combination with Spike, as nucleoside-modified mRNA encapsulated in lipid nanoparticles (LNP) (i.e., combined mRNA/LNP-based pan-CoV vaccine): (i) Induced high frequencies of lung-resident antigen-specific CXCR5+CD4+ T follicular helper (TFH) cells, GzmB+CD4+ and GzmB+CD8+ cytotoxic T cells (TCYT), and CD69+IFN-γ+TNFα+CD4+ and CD69+IFN-γ+TNFα+CD8+ effector T cells (TEFF); and (ii) Reduced viral load and COVID-19-like symptoms caused by various VOCs, including the highly pathogenic B.1.617.2 Delta variant and the highly transmittable heavily Spike-mutated XBB1.5 Omicron sub-variant. The combined mRNA/LNP-based pan-CoV vaccine could be rapidly adapted for clinical use to confer broader cross-protective immunity against emerging highly mutated and pathogenic VOCs.

Proteolytic inactivation of CXCL12 in the lungs and circulation of COVID-19 patients

The human chemokine stromal cell-derived factor-1 (SDF-1) or CXCL12 is involved in several homeostatic processes and pathologies through interaction with its cognate G protein-coupled receptor CXCR4. Recent research has shown that CXCL12 is present in the lungs and circulation of patients with coronavirus disease 2019 (COVID-19). However, the question whether the detected CXCL12 is bioactive was not addressed. Indeed, the activity of CXCL12 is regulated by NH2- and COOH-terminal post-translational proteolysis, which significantly impairs its biological activity. The aim of the present study was to characterize proteolytic processing of CXCL12 in broncho-alveolar lavage (BAL) fluid and blood plasma samples from critically ill COVID-19 patients. Therefore, we optimized immunosorbent tandem mass spectrometry proteoform analysis (ISTAMPA) for detection of CXCL12 proteoforms. In patient samples, this approach uncovered that CXCL12 is rapidly processed by site-specific NH2- and COOH-terminal proteolysis and ultimately degraded. This proteolytic inactivation occurred more rapidly in COVID-19 plasma than in COVID-19 BAL fluids, whereas BAL fluid samples from stable lung transplantation patients and the non-affected lung of lung cancer patients (control groups) hardly induced any processing of CXCL12. In COVID-19 BAL fluids with high proteolytic activity, processing occurred exclusively NH2-terminally and was predominantly mediated by neutrophil elastase. In low proteolytic activity BAL fluid and plasma samples, NH2- and COOH-terminal proteolysis by CD26 and carboxypeptidases were observed. Finally, protease inhibitors already approved for clinical use such as sitagliptin and sivelestat prevented CXCL12 processing and may therefore be of pharmacological interest to prolong CXCL12 half-life and biological activity in vivo.