Publications by authors named "Sandra Duvnjak"

Article Synopsis
  • Genetic defects in perforin delivery have been implicated in hemophagocytic lymphohistiocytosis, leading researchers to investigate its role in severe COVID-19 infections.
  • A study of 54 SARS-CoV-2-infected patients revealed significantly lower levels of perforin-expressing NK cells compared to healthy controls, but this decrease was not associated with disease severity or predictive of mortality.
  • Findings suggest that the low frequency of perforin-positive NK cells in COVID-19 patients may be due to consumption rather than a primary defect in perforin expression, as levels returned to normal one year post-infection.
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Background: As about 10% of patients with COVID-19 present sequelae, it is important to better understand the physiopathology of so-called long COVID.

Method: To this aim, we recruited 29 patients hospitalized for SARS-CoV-2 infection and, by Luminex, quantified 19 soluble factors in their plasma and in the supernatant of their peripheral blood mononuclear cells, including inflammatory and anti-inflammatory cytokines and chemokines, Th1/Th2/Th17 cytokines, and endothelium activation markers. We also measured their T4, T8 and NK differentiation, activation, exhaustion and senescence, T cell apoptosis, and monocyte subpopulations by flow cytometry.

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Since the initial spread of severe acute respiratory syndrome coronavirus 2 infection, several viral variants have emerged and represent a major challenge for immune control, particularly in the context of vaccination. We evaluated the quantity, quality, and persistence of immunoglobulin G (IgG) and IgA in individuals who received two or three doses of messenger RNA (mRNA) vaccines, compared with previously infected vaccinated individuals. We show that three doses of mRNA vaccine were required to match the humoral responses of preinfected vaccinees.

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Article Synopsis
  • T cell cytotoxicity is crucial for fighting antiviral infections like SARS-CoV-2, especially in determining the severity of acute disease and the development of long COVID.
  • A study measured the levels of perforin in T cells from hospitalized COVID-19 patients and found that perforin-positive T cells were more prevalent compared to healthy controls, but this did not relate to disease severity or mortality.
  • Interestingly, high levels of perforin-positive T8 cells during the acute phase could predict long COVID symptoms one year later, suggesting that enhancing T cell activity early on might reduce the chances of prolonged health issues post-infection.
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In addition to an inflammatory reaction, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)-infected patients present lymphopenia, which we recently reported as being related to abnormal programmed cell death. As an efficient humoral response requires CD4 T-cell help, we hypothesized that the propensity of CD4 T cells to die may impact the quantity and quality of the humoral response in acutely infected individuals. In addition to specific immunoglobulins (Ig)A, IgM, and IgG against SARS-CoV-2 nucleocapsid (N), membrane (M), and spike (S1) proteins, we assessed the quality of IgG response by measuring the avidity index.

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Background: Lymphopenia is predictive of survival in patients with coronavirus disease 2019 (COVID-19).

Objective: The aim of this study was to understand the cause of the lymphocyte count drop in severe forms of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.

Methods: Monocytic production of reactive oxygen species (ROSs) and T-cell apoptosis were measured by flow cytometry, DNA damage in PBMCs was measured by immunofluorescence, and angiotensin II (AngII) was measured by ELISA in patients infected with SARS-CoV-2 at admission to an intensive care unit (ICU) (n = 29) or not admitted to an ICU (n = 29) and in age- and sex-matched healthy controls.

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Severe SARS-CoV-2 infections are characterized by lymphopenia, but the mechanisms involved are still elusive. Based on our knowledge of HIV pathophysiology, we hypothesized that SARS-CoV-2 infection-mediated lymphopenia could also be related to T cell apoptosis. By comparing intensive care unit (ICU) and non-ICU COVID-19 patients with age-matched healthy donors, we found a strong positive correlation between plasma levels of soluble FasL (sFasL) and T cell surface expression of Fas/CD95 with the propensity of T cells to die and CD4 T cell counts.

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We compared lesion-based sensitivity of dual-time-point FDG-PET/CT, bone scintigraphy (BS), and low-dose CT (LDCT) for detection of various types of bone metastases in patients with metastatic breast cancer. Prospectively, we included 18 patients with recurrent breast cancer who underwent dual-time-point FDG-PET/CT with LDCT and BS within a median time interval of three days. A total of 488 bone lesions were detected on any of the modalities and were categorized by the LDCT into osteolytic, osteosclerotic, mixed morphologic, and CT-negative lesions.

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Generalized arterial calcification of infancy is a very rare genetic disorder characterized by arterial calcifications. The symptoms are apparent within the first few weeks of life and the disease shows high mortality rates. This case report describes the clinical presentation, the radiological findings and the treatments challenges.

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Purpose: To prospectively investigate the diagnostic accuracy of [(18)F]fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) with dual-time-point imaging, contrast-enhanced CT (ceCT), and bone scintigraphy (BS) in patients with suspected breast cancer recurrence.

Patients And Methods: One hundred women with suspected recurrence of breast cancer underwent 1-hour and 3-hour FDG-PET/CT, ceCT, and BS within approximately 10 days. The study was powered to estimate the precision of the individual imaging tests.

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