Project description:The oral mucosa is the first site of SARS-CoV-2 entry and replication, and it plays a central role in the early defense against infection. Thus, SARS-CoV-2 viral load, miRNAs, cytokines, and neutralizing activity (NA) were assessed in saliva and plasma from mild (MD) and severe (SD) COVID-19 patients. Here we show that of the 84 miRNAs analysed, 8 are differently express in plasma and saliva of SD. In particular: 1) miRNAs let-7a-5p, let-7b-5p, let-7c-5p are significantly downregulated; and 2) miR-23a and b, miR-29c, as well as three immunomodulatory miRNAs (miR-34a-5p, miR-181d-5p, miR-146) are significantly upregulated. The production of pro-inflammatory cytokines (IL-1β, IL-2, IL-6, IL-8, IL-9 and TNFα) and chemokines (CCL2 and RANTES) increase in both saliva and plasma of SD and MD. Notably, disease severity correlates with NA and immune activation. Monitoring these parameters could help to predict disease outcome and identify new markers of disease progression.
Project description:The oral mucosa is the first site of SARS-CoV-2 entry and replication, and it plays a central role in the early defense against infection. Thus, SARS-CoV-2 viral load, miRNAs, cytokines, and neutralizing activity (NA) were assessed in saliva and plasma from mild (MD) and severe (SD) COVID-19 patients. Here we show that of the 84 miRNAs analysed, 8 are differently express in plasma and saliva of SD. In particular: 1) miRNAs let-7a-5p, let-7b-5p, let-7c-5p are significantly downregulated; and 2) miR-23a and b, miR-29c, as well as three immunomodulatory miRNAs (miR-34a-5p, miR-181d-5p, miR-146) are significantly upregulated. The production of pro-inflammatory cytokines (IL-1β, IL-2, IL-6, IL-8, IL-9 and TNFα) and chemokines (CCL2 and RANTES) increase in both saliva and plasma of SD and MD. Notably, disease severity correlates with NA and immune activation. Monitoring these parameters could help to predict disease outcome and identify new markers of disease progression.
Project description:BackgroundThe current diagnostic standard for coronavirus disease 2019 (COVID-19) is reverse transcriptase-polymerase chain reaction (RT-PCR) testing with nasopharyngeal (NP) swabs. The invasiveness and need for trained personnel make the NP technique unsuited for repeated community-based mass screening. We developed a technique to collect saliva in a simple and easy way with the sponges that are usually used for tamponade of epistaxis. This study was carried out to validate the clinical performance of oral sponge (OS) sampling for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing.MethodsOver a period of 22 weeks, we collected prospectively 409 paired NP and OS samples from consecutive subjects presenting to a public community-based free screening centre. Subjects were referred by their attending physician because of recent COVID-19 symptoms (n = 147) or by the contact tracing staff of the French public health insurance because they were considered as close contacts of a laboratory-confirmed COVID-19 case (n = 262).ResultsIn symptomatic subjects, RT-PCR SARS-CoV-2 testing with OS showed a 96.5% (95% CI: 89.6-94.8) concordance with NP testing, and a 93.2% (95% CI: 89.1-97.3) sensitivity when using the IdyllaTM platform and a sensitivity of 76.3% (95% CI: 69.4-83.2) on the Synlab Barla laboratory platform. In close contacts the NP-OS concordance (93.8%, 95% CI: 90.9-96.7) and OS sensitivity (71.9%, 95% CI: 66.5-77.3) were slightly lower.ConclusionThese results strongly suggest that OS testing is a straightforward, low-cost and high-throughput sampling method that can be used for frequent RT-PCR testing of COVID-19 patients and mass screening of populations.
Project description:Saliva, a biofluid enriched in biological omic constituents, has emerged as a promising source for exosomal biomarkers due to its easy accessibility. Despite the understanding of the coronavirus disease-19 (COVID-19), the role of Salivary Extracellular Vesicles (sEVs) in COVID-19 remains poorly understood. Exploring the proteomic cargo of sEVs could prove valuable for diagnostic and prognostic purposes in assessing COVID-19. The proteomic cargo of sEVs from COVID-19 (+) subjects and their healthy close contacts (HCC) was explored. Nine COVID-19 positive (+) patients and eleven in-house close contact patients identified by real-time quantitative polymerase chain reaction (RT-qPCR) of nasopharyngeal swabs were included. In-house close contacts were defined as individuals with a negative RT-qPCR result sharing a residence with a confirmed COVID-19 case. sEVs were isolated by ultracentrifugation from unstimulated saliva samples, and subsequently characterized through nanoparticle tracking, transmission electron microscopy, and western-blot analyses. The proteomic cargo of sEVs was processed by LC-MS/MS. sEVs were morphologically compatible with EVs, with the presence of Syntenin-1 and CD81 EVs markers. The sEVs proteome showed 1,417 proteins: 1,288 in COVID-19 (+) cases and 1,382 in HCC. 35 proteins were found exclusively and 89 were more abundant in sEVs from COVID-19 (+) subjects. “Coronavirus disease response”, “complement and coagulation cascades”, and “PMN extracellular trap formation” were the most enriched KEGG pathways in COVID-19 (+) cases. The most represented biological processes were “Hemoglobin and haptoglobin binding” and “oxygen carrier activity”, and the best-denoted molecular functions were “regulated exocytosis and secretion” and “leucocyte and PMN mediated immunity”. We suggest that sEVs proteomic cargo in COVID-19 is related to immune response processes, oxygen transport, and antioxidant mechanisms. In contrast, in HCC, sEVs signature profiles are mainly associated with epithelial homeostasis.
Project description:The pandemic of COVID-19 is continuously spreading, becoming a worldwide emergency. Early and fast identification of subjects with a current or past infection must be achieved to slow down the epidemiological widening. Here we report a Raman-based approach for the analysis of saliva, able to significantly discriminate the signal of patients with a current infection by COVID-19 from healthy subjects and/or subjects with a past infection. Our results demonstrated the differences in saliva biochemical composition of the three experimental groups, with modifications grouped in specific attributable spectral regions. The Raman-based classification model was able to discriminate the signal collected from COVID-19 patients with accuracy, precision, sensitivity and specificity of more than 95%. In order to translate this discrimination from the signal-level to the patient-level, we developed a Deep Learning model obtaining accuracy in the range 89-92%. These findings have implications for the creation of a potential Raman-based diagnostic tool, using saliva as minimal invasive and highly informative biofluid, demonstrating the efficacy of the classification model.
Project description:The SARS-CoV-2 Delta (B.1.617.2) variant is capable of infecting vaccinated persons. An open question remains as to whether deficiencies in specific vaccine-elicited immune responses result in susceptibility to vaccine breakthrough infection. We investigated 55 vaccine breakthrough infection cases (mostly Delta) in Singapore, comparing them against 86 vaccinated close contacts who did not contract infection. Vaccine breakthrough cases showed lower memory B cell frequencies against SARS-CoV-2 receptor binding domain (RBD). Compared to plasma antibodies, antibodies secreted by memory B cells retained a higher fraction of neutralizing properties against the Delta variant. Inflammatory cytokines including IL-1β and TNF were lower in vaccine breakthrough infections than primary infection of similar disease severity, underscoring the usefulness of vaccination in preventing inflammation. This report highlights the importance of memory B cells against vaccine breakthrough, and suggests that lower memory B cell levels may be a correlate of risk for Delta vaccine breakthrough infection.