The biological variation of serum 1,25-dihydroxyvitamin D and parathyroid hormone, and plasma fibroblast growth factor 23 in healthy individuals.

BACKGROUND AND AIMS: Measuring 1,25-dihydroxyvitamin D (1,25(OH)2D), parathyroid hormone 1-84 (PTH 1-84) and intact FGF23 (iFGF23) is crucial for diagnosing a variety of diseases affecting bone and mineral homeostasis. Biological variability (BV) data are important for defining analytical quality specifications (APS), the usefulness of reference intervals, and the significance of variations in serial measurements in the same subject. The aim of this study was to pioneer the provision of BV estimates for 1,25(OH)2D and to improve existing BV estimates for iFGF23 and PTH 1-84. MATERIALS AND METHODS: Serum and plasma-EDTA samples of sixteen healthy subjects have been collected for seven weeks and measured in duplicate by chemiluminescent immunoassay on the DiaSorin Liaison platform. After variance verification, within-subject (CVI) and between-subject (CVG) BV estimates were assessed by either standard ANOVA, or CV-ANOVA. The APSs were calculated according to the EFLM-BV-model. RESULTS: We found the following CVI estimates with 95% confidence intervals:1,25(OH)2D, 22.2% (18.9-26.4); iFGF23, 16.1% (13.5-19.5); and PTH 1-84, 17.9% (14.8-21.8). The CVG were: 1,25(OH)2D, 21.2% (14.2-35.1); iFGF23, 21.1% (14.5-35.8); and PTH 1-84, 31.1% (22.1-50.8). CONCLUSIONS: We report for the first time BV estimates for 1,25(OH)2D and enhance existing data about iFGF23-BV and PTH 1-84-BV through cutting-edge immunometric methods.

The spike-specific TCRß repertoire shows distinct features in unvaccinated or vaccinated patients with SARS-CoV-2 infection.

BACKGROUND: The evolving variants of SARS-CoV-2 may escape immunity from prior infections or vaccinations. It's vital to understand how immunity adapts to these changes. Both infection and mRNA vaccination induce T cells that target the Spike protein. These T cells can recognize multiple variants, such as Delta and Omicron, even if neutralizing antibodies are weakened. However, the degree of recognition can vary among people, affecting vaccine efficacy. Previous studies demonstrated the capability of T-cell receptor (TCR) repertoire analysis to identify conserved and immunodominant peptides with cross-reactive potential among variant of concerns. However, there is a need to extend the analysis of the TCR repertoire to different clinical scenarios. The aim of this study was to examine the Spike-specific TCR repertoire profiles in natural infections and those with combined natural and vaccine immunity. METHODS: A T-cell enrichment approach and bioinformatic tools were used to investigate the Spike-specific TCRß repertoire in peripheral blood mononuclear cells of previously vaccinated (n = 8) or unvaccinated (n = 6) COVID-19 patients. RESULTS: Diversity and clonality of the TCRß repertoire showed no significant differences between vaccinated and unvaccinated groups. When comparing the TCRß data to public databases, 692 unique TCRß sequences linked to S epitopes were found in the vaccinated group and 670 in the unvaccinated group. TCRß clonotypes related to spike regions S135-177, S264-276, S319-350, and S448-472 appear notably more prevalent in the vaccinated group. In contrast, the S673-699 epitope, believed to have super antigenic properties, is observed more frequently in the unvaccinated group. In-silico analyses suggest that mutations in epitopes, relative to the main SARS-CoV-2 variants of concern, don't hinder their cross-reactive recognition by associated TCRß clonotypes. CONCLUSIONS: Our findings reveal distinct TCRß signatures in vaccinated and unvaccinated individuals with COVID-19. These differences might be associated with disease severity and could influence clinical outcomes. TRIAL REGISTRATION: FESR/FSE 2014-2020 DDRC n. 585, Action 10.5.12, noCOVID19@UMG.

Bariatric surgery and dimethyl fumarate-induced lymphopenia in patients with multiple sclerosis.

INTRODUCTION: Lymphopenia is a known side effect of dimethyl fumarate (DMF), a disease-modifying therapy (DMT) for patients with multiple sclerosis (pwMS). A body mass index ≥ 30 kg/m2 has been identified as a protective factor; however, no data are available on lymphopenia in pwMS undergoing to weight loss due to bariatric surgery. METHODS: We described two pwMS with history of bariatric surgery who started DMF as DMT. RESULTS: The two pwMS experienced persistent lymphopenia during DMF-treatment, which was resolved after its discontinuation. CONCLUSIONS: Several mechanisms might modify DMF pharmacokinetic profiles after bariatric surgery and its bioavailability. Absolute lymphocyte count should be monitored in pwMS treated with DMF and history of bariatric surgery and weight loss.

Spike-specific T-cell responses in patients with COVID-19 successfully treated with neutralizing monoclonal antibodies against SARS-CoV-2.

OBJECTIVES: Neutralizing monoclonal antibodies (moAbs) improves clinical outcomes in patients with COVID-19 when administered during the initial days of infection. The action of moAbs may impair the generation or maintenance of effective immune memory, similar to that demonstrated in other viral diseases. We aimed to evaluate short-term memory T-cell responses in patients effectively treated with bamlanivimab/etesevimab, casirivimab/imdevimab, or sotrovimab (SOT). METHODS: Spike (S)-specific T-cell responses were analyzed in 23 patients with COVID-19 (vaccinated or unvaccinated) before and after a median of 50 (range: 28-93) days from moAb treatment, compared with 11 vaccinated healthy controls. T-cell responses were measured by interferon-γ-enzyme-linked immunospot and flow cytometric activation-induced marker assay. RESULTS: No statistically significant difference in S-specific T-cell responses was observed between patients treated with moAb and vaccinated healthy controls. Bamlanivimab/etesevimab and casirivimab/imdevimab groups showed significant increases in cellular responses in paired baseline/postrecovery series, as well as vaccinated patients receiving SOT. In contrast, unvaccinated patients prescribed SOT presented no statistically significant increases in T-cell-responses, suggesting diverse impacts of different moAbs on the evolution of S-specific T-cell responses in vaccinated and unvaccinated patients. CONCLUSION: The moAbs did not hinder short-term memory S-specific T-cell responses in the overall group of patients; however, differences among moAbs must be further investigated both in vaccinated and unvaccinated individuals.