Performance Assessment of the LIAISON® SARS-CoV-2 Antigen Assay On Nasopharyngeal Swabs.

The SARS-CoV-2 pandemic is ongoing worldwide, causing prolonged pressure on molecular diagnostics. Viral antigen (Ag) assays have several advantages, ranging from lower cost to shorter turnaround time to detection. Given the rare occurrence of low-load viremia, antigen assays for SARSCoV-2 have focused on nasopharyngeal swab and saliva as biological matrices, but their effectiveness must be validated. We assayed here the performances of the novel quantitative Liaison® SARSCoV-2 Ag assay on 119 nasopharyngeal swabs and obtained results were compared with Hologic Panther and Abbott m2000 RT-qPCR. The Ag assay demonstrated a good correlation with viral load, shorter turnaround time, and favorable economics. The best performance was obtained in the acute phase of disease.

Symptomatic SARS-CoV-2 infections after full schedule BNT162b2 vaccination in seropositive healthcare workers: a case series from a single institution.

We report 11 cases of SARS-CoV-2 infection in healthcare workers (HCW) naïve for COVID-19 and seropositive after the second dose of the BNT162b2 mRNA vaccine. Based on voluntary-based surveillance, they tested positive for different strains of SARS-CoV-2, as Spike gene sequencing showed. Five of them reported mild symptoms. Given the risk for SARS-CoV-2 introduction from asymptomatic vaccinees, this case series suggests the need to continue nasopharyngeal screening programmes.

Introduction of SARS-CoV-2 variant of concern 20h/501Y.V2 (B.1.351) from Malawi to Italy.

We report here an imported case of SARS-CoV-2 variant of concern B.1.1.351 (also known as 20H/501Y.V2 or "South African variant" or VOC 202012/02) in a 66-years old symptomatic male who returned from Malawi to Italy.

Imported SARS-CoV-2 Variant P.1 in Traveler Returning from Brazil to Italy.

We report an imported case of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant P.1 detected in an asymptomatic traveler who arrived in Italy on an indirect flight from Brazil. This case shows the risk for introduction of SARS-CoV-2 variants from indirect flights and the need for continued SARS-CoV-2 surveillance.

Comparison of the LIAISON®XL and ARCHITECT IgG, IgM, and IgG avidity assays for the diagnosis of Toxoplasma, cytomegalovirus, and rubella virus infections.

This study compared the performance of the LIAISON®XL system of immunoglobulin (Ig) G and IgM immunoassays for the diagnosis of Toxoplasma gondii, cytomegalovirus (CMV), and rubella virus infections with that of the ARCHITECT system. Patient serum samples, previously screened and clinically diagnosed with T. gondii, CMV or rubella, were used to compare LIAISON®XL and ARCHITECT IgG and IgM immunoassays. LIAISON®XL Toxo and CMV IgG avidity assays were also compared with equivalent ARCHITECT assays and reference methods. Overall agreement between the LIAISON®XL and ARCHITECT assays was 99% and 92% for the Toxo IgG and IgM assays, respectively, 98% and 96% for the CMV IgG and IgM assays, respectively, and 93% and 98% for the rubella virus IgG and IgM assays, respectively. LIAISON®XL IgG Toxo and CMV avidity assays showed high concordance with the VIDAS® Toxo IgG avidity assay and an in-house CMV avidity assay (reference methods), and faster IgG avidity maturation in a larger number of samples collected months after the primary infection compared with equivalent ARCHITECT assays. LIAISON®XL assays for detection of anti-T. gondii, CMV and rubella virus IgG and IgM are at least equal to the competitor assays on the ARCHITECT platform.

Store-operated Ca2+ entry does not control proliferation in primary cultures of human metastatic renal cellular carcinoma.

Store-operated Ca(2+) entry (SOCE) is activated following depletion of the inositol-1,4,5-trisphosphate (InsP3)-sensitive Ca(2+) pool to regulate proliferation in immortalized cell lines established from either primary or metastatic lesions. The molecular nature of SOCE may involve both Stim1, which senses Ca(2+) levels within the endoplasmic reticulum (ER) Ca(2+) reservoir, and a number of a Ca(2+)-permeable channels on the plasma membrane, including Orai1, Orai3, and members of the canonical transient receptor (TRPC1-7) family of ion channels. The present study was undertaken to assess whether SOCE is expressed and controls proliferation in primary cultures isolated from secondary lesions of heavily pretreated metastatic renal cell carcinoma (mRCC) patients. SOCE was induced following pharmacological depletion of the ER Ca(2+) store, but not by InsP3-dependent Ca(2+) release. Metastatic RCC cells express Stim1-2, Orai1-3, and TRPC1-7 transcripts and proteins. In these cells, SOCE was insensitive to BTP-2, 10 µM Gd(3+) and Pyr6, while it was inhibited by 100 µM Gd(3+), 2-APB, and carboxyamidotriazole (CAI). Neither Gd(3+) nor 2-APB or CAI impaired mRCC cell proliferation. Consistently, no detectable Ca(2+) signal was elicited by growth factor stimulation. Therefore, a functional SOCE is expressed but does not control proliferation of mRCC cells isolated from patients resistant to multikinase inhibitors.