Background and aim SARS-CoV-2 quick testing is relevant for the containment of new pandemic waves. Antigen testing in self-collected saliva might be useful. We compared salivary and naso-pharyngeal swab (NPS) SARS-CoV-2 antigen detection by a rapid chemiluminescent assay (CLEIA) and two different point-of-care (POC) immunochromatographic assays, with that of molecular testing. Methods 234 patients were prospectively enrolled. Paired self-collected saliva (Salivette) and NPS were obtained to perform rRT-PCR, chemiluminescent (Lumipulse G) and POC (NPS: Fujirebio and Abbott; saliva: Fujirebio) for SARS-CoV-2 antigen detection. Results The overall agreement between NPS and saliva rRT-PCR was 78.7%, reaching 91.7% at the first week from symptoms. SARS-CoV-2 CLEIA antigen was highly accurate in distinguishing positive and negative NPS (ROC-AUC=0.939, 95%CI:0.903-0.977), with 81.6% sensitivity and 93.8% specificity. This assay on saliva reached the optimal value within 7 days from symptoms onset (Sensitivity: 72%; Specificity: 97%). Saliva POC antigen was limited in sensitivity (13%), performing better in NPS (Sensitivity: 48% and 66%; Specificity: 100% and 99% for Espline and Abbott respectively), depending on viral loads. Conclusions Self-collected saliva is a valid alternative to NPS for SARS-CoV-2 detection by molecular, but also by CLEIA antigen testing, which is therefore potentially useful for large scale screening.

Tumor genetics and escape from immune surveillance concur in the poor prognosis of PDAC. In this study an experimental model was set up to verify whether SMAD4, deleted in about 55% PDAC and associated with poor prognosis, is involved in determining immunosuppression through Exosomes (Exo). Potential mechanisms and mediators underlying SMAD4-dependent immunosuppression were evaluated by studying intracellular calcium (Fluo-4), Exo-miRNAs (microarray) and Exo-proteins (SILAC). Two PDAC cell lines expressing (BxPC3-SMAD4+) or not-expressing (BxPC3) SMAD4 were used to prepare Exo-enriched conditioned media, employed in experiments with blood donors PBMCs. Exo expanded myeloid derived suppressor cells (gMDSC and mMDSC, flow cytometry) and altered intracellular calcium fluxes in an SMAD4 dependent manner. BxPC3-SMAD4+, but mainly BxPC3 Exo, increased calcium fluxes of PBMCs (p = 0.007) and this increased intracellular calcium trafficking characterized mMDSCs. The analysis of de-regulated Exo-miRNAs and transfection experiments revealed hsa-miR-494-3p and has-miR-1260a as potential mediators of SMAD4-associated de-regulated calcium fluxes. Eleven main biological processes were identified by the analysis of SMAD4-associated de-regulated Exo-proteins, including translation, cell adhesion, cell signaling and glycolysis. A reverse Warburg effect was observed by treating PBMCs with PDAC-derived Exo: BxPC3 Exo induced a higher glucose consumption and lactate production than BxPC3-SMAD4+ Exo. Conclusion: PDAC-derived Exo from cells with, but mainly from those without SMAD4 expression, create an immunosuppressive myeloid cell background by increasing calcium fluxes and glycolysis through the transfer of SMAD4-related differentially expressed miRNAs and proteins.

AbstractObjectivesThe direct identification of SARS-CoV-2 RNA in nasopharyngeal swabs is recommended for diagnosing the novel COVID-19 disease. Pre-analytical determinants, such as sampling procedures, time and temperature storage conditions, might impact on the end result. Our aim was to evaluate the effects of sampling procedures, time and temperature of the primary nasopharyngeal swabs storage on real-time reverse-transcription polymerase chain reaction (rRT-PCR) results.MethodsEach nasopharyngeal swab obtained from 10 hospitalized patients for COVID-19 was subdivided in 15 aliquots: five were kept at room temperature; five were refrigerated (+4 °C); five were immediately mixed with the extraction buffer and refrigerated at +4 °C. Every day and for 5 days, one aliquot per condition was analyzed (rRT-PCR) for SARS-CoV-2 gene E and RNaseP and threshold cycles (Ct) compared. To evaluate manual sampling, 70 nasopharyngeal swabs were sampled twice by two different operators and analyzed separately one from the other.ResultsA total of 6/10 swabs were SARS-CoV-2 positive. No significant time or storage-dependent variations were observed in SARS-CoV-2 Ct. Re-sampling of swabs with SARS-CoV-2 Ct lower than 33 resulted in highly reproducible results (CV=2.9%), while a high variability was observed when Ct values were higher than 33 (CV=10.3%).ConclusionsThis study demonstrates that time and temperature of nasopharyngeal swabs storage do not significantly impact on results reproducibility. However, swabs sampling is a critical step, and especially in case of low viral load, might be a potential source of diagnostic errors.

The high predictive accuracy of low and high warfarin requirements of our algorithm warrants its application in prospective studies for clinical validation.

BackgroundBlood and spleen expansion of immature myeloid cells (IMCs) might compromise the immune response to cancer. We studied in vivo circulating and splenic T lymphocyte and IMC subsets in patients with benign and malignant pancreatic diseases. We ascertained in vitro whether pancreatic adenocarcinoma (PDAC)-associated IMC subsets are induced by tumor-derived soluble factors and whether they are immunosuppressive focusing on the inhibitory co-stimulatory molecules PDL1 and CTLA4.Methodology and Principal Findings103 pancreatic and/or splenic surgical patients were enrolled including 52 PDAC, 10 borderline and 10 neuroendocrine tumors (NETs). Lymphocytes and IMCs were analysed by flow cytometry in blood, in spleen and in three PDAC cell conditioned (CM) or non conditioned PBMC. PDL1 and CTLA4 were studied in 30 splenic samples, in control and conditioned PBMC. IMCs were FACS sorted and co-coltured with allogenic T lymphocytes. In PDAC a reduction was found in circulating CD8+ lymphocytes (p = 0.004) and dendritic cells (p = 0.01), which were reduced in vitro by one PDAC CM (Capan1; p = 0.03). Blood myeloid derived suppressive cells (MDSCs) CD33+CD14−HLA-DR− were increased in PDAC (p = 0.022) and were induced in vitro by BxPC3 CM. Splenic dendritic cells had a higher PDL1 expression (p = 0.007), while CD33+CD14+HLA-DR− IMCs had a lower CTLA4 expression (p = 0.029) in PDAC patients. In vitro S100A8/A9 complex, one of the possible inflammatory mediators of immune suppression in PDAC, induced PDL1 (p = 0.018) and reduced CTLA4 expression (p = 0.028) among IMCs. IMCs not expressing CTLA4 were demonstrated to be immune suppressive.ConclusionIn PDAC circulating dendritic and cytotoxic T cells are reduced, while MDSCs are increased and this might favour tumoral growth and progression. The reduced CTLA4 expression found among splenic IMCs of PDAC patients was demonstrated to characterize an immune suppressive phenotype and to be consequent to the direct exposure of myeloid cells to pancreatic cancer derived products, S100A8/A9 complex in particular.