Single-center serological surveillance of SARS-CoV-2 in pregnant patients presenting to labor and delivery.

OBJECTIVE: To measure maternal/fetal SARS-CoV-2 antibody levels. METHODS: A prospective observational study of eligible parturients admitted to the hospital for infant delivery was conducted between April and September 2020. SARS-CoV-2 antibody levels were measured in maternal and umbilical cord specimens using an in-house ELISA based on the receptor-binding domain (RBD) of the spike protein. Among SARS-CoV-2 seropositive patients, spike RBD antibody isotypes (IgG, IgM, and IgA) and ACE2 inhibiting antibodies were measured. RESULTS: In total, 402 mothers were enrolled and spike RBD antibodies in 388 pregnancies were measured (336 maternal and 52 cord specimens). Of them, 19 were positive (15 maternal, 4 cord) resulting in a seroprevalence estimate of 4.8% (95% confidence interval 2.9-7.4). Of the 15 positive maternal specimens, all had cord blood tested. Of the 15 paired specimens, 14 (93.3%) were concordant. Four of the 15 pairs were from symptomatic mothers, and all four showed high spike-ACE2 blocking antibody levels, compared to only 3 of 11 (27.3%) from asymptomatic mothers. CONCLUSION: A variable antibody response to SARS-CoV-2 in pregnancy among asymptomatic infections compared to symptomatic infections was found, the significance of which is unknown. Although transfer of transplacental neutralizing antibodies occurred, additional research is needed to determine how long maternal antibodies can protect the infant against SARS-CoV-2 infection.

Discovery of biomarkers that reflect the intake of sodium selenate by nutritional proteomics.

Selenium offers important health benefits, including the prevention of some types of cancer. The traditional selenium indexes, such as selenium concentration, do not account for the metabolic status of this element regarding its chemoprotective effect. Then, the knowledge of a group of proteins that respond to selenium supplementation could be useful in the assessment of the metabolic status of selenium. The effect of dietary supplementation of rats with sodium-selenate on the blood plasma proteome is investigated. A group composed of six rats is fed a basic diet supplemented with sodium-selenate at 1.9 microg of Selenium per g of food, and a control group is fed a diet that covers the minimum selenium requirements, each for ten weeks. A proteomic approach is used to both quantify the changes in the abundance of some plasmatic proteins and to identify them. Fibrinogen, apolipoproteins, haptoglobin, and transthyretin changed significantly their abundance due to selenium administration. Those proteins are indirectly related to selenium metabolism. Then, the change in the proteomic profile due to selenium supplementation could probably be considered as a new index to assess the metabolic status of selenium. This index might help in the prevention of some diseases by nutritional diagnosis and, consequently, the adequate dietary recommendation.