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Background Immune dysregulation in individuals with Down syndrome (DS) leads to an increased risk for hospitalization and death due to coronavirus disease 2019 (COVID-19) and may impair the generation of protective immunity after vaccine administration. Methods The cellular and humoral responses of 55 individuals with DS who received a complete SARS-CoV-2 vaccination regime at 1 to 3 (visit [V 1]) and 6 (V2) months were characterized. Results SARS-CoV-2–reactive CD4+ and CD8+ T lymphocytes with a predominant Th1 phenotype were observed at V1 and increased at V2. Likewise, an increase in SARS-CoV-2–specific circulating Tfh (cTfh) cells and CD8+ CXCR5+ PD-1hi lymphocytes was already observed at V1 after vaccine administration. Specific immunoglobulin G (IgG) antibodies against SARS-CoV-2 S protein were detected in 96% and 98% of subjects at V1 and V2, respectively, although IgG titers decreased significantly between both time points. Conclusions Our findings show that DS individuals develop an effective immune response to usual regimes of SARS-CoV-2 vaccination.

Antibody detection is essential to establish exposure, infection, and immunity to SARS-CoV-2, as well as to perform epidemiological studies. The worldwide urge for new diagnostic tools to control the pandemic has led to a quick incorporation in clinical practice of the recently developed serological assays. However, as only few comparative studies have been published, there is a lack of data about the diagnostic accuracy of currently available assays. We evaluated the diagnostic accuracy to detect Ig G, Ig M+A, and/or IgA anti SARS-CoV-2 of 10 different assays: lateral flow card immunoassays, 4 enzyme-linked immunosorbent assay (ELISA), and 3 chemiluminescent particle immunoassays (CMIA). Using reverse transcriptase polymerase chain reaction (RT-PCR) for COVID-19 as gold standard, sensitivity, specificity, PPV, and NPV were determined. Each assay was tested in 2 groups, namely, positive control, formed by 50 sera from 50 patients with SARS-CoV-2 pneumonia with positive RT-PCR; and negative control, formed by 50 sera from 50 patients with respiratory infection non-COVID-19. Sensitivity range of the 10 assays evaluated for patients with positive COVID-19 RT-PCR was 40-77% (65-81% considering IgG plus IgM). Specificity ranged 83-100%. VPP and VPN were respectively 81-100% and 61.6-81%. Among the lateral flow immunoassays, the highest sensitivity and specificity results were found in Wondfo® SARS-CoV-2 Antibody Test. ELISA IgG and IgA from EUROIMMUN® were the most sensitive ELISA. However, poor results were obtained for isolated detection of IgG. We found similar sensitivity for IgG with SARS-CoV-2 for Architect by Abbott® and ELISA by Vircell®. Results obtained varied widely among the assays evaluated. Due to a better specificity, overall diagnostic accuracy of the assays evaluated was higher in case of positive result. On the other side, lack of antibody detection should be taken with care because of the low sensitivity described. Highest diagnostic accuracy was obtained with ELISA and CMIAs, but they last much longer.

Immune dysregulation in individuals with Down syndrome (DS) leads to an increased risk for hospitalization and death due to COVID-19 and may impair the generation of protective immunity after vaccine administration.The cellular and humoral responses of 55 DS patients who received a complete SARS-CoV-2 vaccination regime at one to three (V1) and six (V2) months were characterized.SARS-CoV-2-reactive CD4 + and CD8+ T lymphocytes with a predominant Th1 phenotype were observed at V1 and increased at V2. Likewise, an increase of SARS-CoV-2-specific circulating Tfh (cTfh) cells and CD8+ CXCR5+ PD-1hi lymphocytes were already observed at V1 after vaccine administration. Specific IgG antibodies against SARS-CoV-2 S protein were detected in 96% and 98% of subjects at V1 and V2, respectively, though IgG titers decreased significantly between both timepoints.Our findings show that DS individuals develop an effective immune response to usual regimes of SARS-CoV-2 vaccination.

Background COVID-19 patients can develop a cytokine release syndrome that eventually leads to acute respiratory distress syndrome (ARDS) requiring invasive mechanical ventilation (IMV). Since interleukin-6 (IL-6) is a relevant cytokine in ARDS, the blockade of its receptor with Tocilizumab (TCZ) could reduce mortality and/or morbidity in severe COVID-19. Objective To determine whether baseline IL-6 serum levels can predict the need for IMV and the response to TCZ. Methods Retrospective observational study performed in hospitalized patients diagnosed of COVID-19. Clinical information and laboratory findings, including IL-6 levels, were collected approximately 3 and 9 days after admission to be matched with pre- and post-administration of TCZ. Multivariable logistic and linear regressions, and survival analysis were performed depending on outcomes: need for IMV, evolution of arterial oxygen tension/fraction of inspired oxygen ratio (PaO2/FiO2) or mortality. Results One hundred and forty-six patients were studied, predominantly male (66%); median age was 63 years. Forty-four patients (30%) required IMV, and 58 patients (40%) received treatment with TCZ. IL-6 levels>30 pg/ml was the best predictor for IMV (OR:7.1; p30 pg/ml predicts IMV requirement in patients with COVID-19 and contributes to establish an adequate indication for TCZ administration., Baseline IL-6 serum levels>30 pg/ml identify severe COVID-19 patients and should be used to guide the intervention with IL-6R inhibitors, aiming to improve their use in an uncertain and evolving therapeutic scenario.

Presence of SARS-CoV-2 RNA in serum (viremia) of COVID-19 patients has been related to poor prognosis and death. The aim of this study was to evaluate both the ability to detect viremia in COVID-19 patients of two commercial reverse real-time-PCR (rRT-PCR) tests, Cobas® and TaqPath™, comparing them with a gold standard method, and their implementation in microbiology laboratories. This retrospective cohort study included 303 adult patients (203 diagnosed with COVID-19 and 100 non-COVID-19 patients) admitted to a tertiary hospital, with at least one serum sample collected within the first 48 hours from admission. A total of 365 serum samples were included: 100 from non-COVID-19 patients (pre-pandemic and pandemic control groups) and 265 from COVID-19 patients. Serum samples were considered positive when at least one target was detected. All patients in control groups showed negative viremia. Cobas® and TaqPath™ tests showed specificity and Positive Predictive Value over 96%. Nevertheless, sensitivity (53.72 and 73.63, respectively) and Negative Predictive Value (64.78 and 75) were lower. Viremia difference between ICU and non-ICU patients was significant (p ≤ 0.001) for both techniques. Consequently, SARS-CoV-2 viremia detection by both rRT-PCR tests should be considered a good tool to stratify COVID-19 patients and could be implemented in microbiology laboratories.

Resumen Introduccion Las variaciones del gen C originan las mutaciones precore y las core, que influyen en la produccion de AgHBe. El fallo en los tratamientos antivirales se debe a la presencia de las variaciones en el gen P, que originan las mutaciones de la polimerasa viral. Metodo Hemos realizado estudio genotipico del VHB mediante secuenciacion del gen P, y del gen C en pacientes con hepatitis cronica por virus B durante un periodo de cinco anos. Resultados El 75 % presentaron alguna mutacion en la region precore, core o en ambas. El 37 % mostro mutaciones de resistencia al tratamiento antiviral. Los genotipos mas frecuentes fueron el A y el D. Conclusiones La presencia de mutaciones core/precore en pacientes con hepatitis cronica hace obligado un control mas estrecho de estos enfermos. La deteccion de resistencias debe hacerse lo mas rapido posible antes de que se produzca un aumento de la carga viral.

Variations of C gene give rise to precore and basal core mutations, which influence HBeAg expression The antiviral treatment failure is due to the presence of variations in the gene P, which cause mutations in the viral polymerase.We performed genotyping of HBV P gene by sequencing, and gene C in patients with chronic hepatitis B over a period of five years.A total of 75% of the patients had some mutation in precore or in basal core promoter regions, and 37% demonstrated resistance mutations to antiviral treatment. The most frequent genotypes were A and D.The presence of mutations in core/precore regions in patients with chronic hepatitis has led to tighter control of these patients. Detecting for resistance should be done as quickly as possible before there is an increase in viral load.