Gut bacteria-derived serotonin promotes immune tolerance in early life.

The gut microbiota promotes immune system development in early life, but the interactions between the gut metabolome and immune cells in the neonatal gut remain largely undefined. Here, we demonstrate that the neonatal gut is uniquely enriched with neurotransmitters, including serotonin, and that specific gut bacteria directly produce serotonin while down-regulating monoamine oxidase A to limit serotonin breakdown. We found that serotonin directly signals to T cells to increase intracellular indole-3-acetaldehdye and inhibit mTOR activation, thereby promoting the differentiation of regulatory T cells, both ex vivo and in vivo in the neonatal intestine.

SARS CoV-2 detected in neonatal stool remote from maternal COVID-19 during pregnancy.

Background: In utero transmission of SARS coronavirus 2 (SARS-CoV-2) has not been fully investigated. We investigated whether newborns of mothers with COVID-19 during pregnancy might harbor SARS-CoV-2 in the gastrointestinal tract.

Methods: This cohort study investigated stool from 14 newborns born at 25-41 weeks admitted at delivery to our urban academic hospital whose mothers had COVID-19 during pregnancy.

Blood group A mothers are more likely to develop anemia during antenatal intravenous immunoglobulin treatment of fetal and neonatal alloimmune thrombocytopenia.

Background: Incompatibility between parental platelet (PLT) antigens may lead to sensitization of mother and development of fetal and neonatal alloimmune thrombocytopenia (FNAIT) resulting in fetal thrombocytopenia. Intravenous immunoglobulin (IVIG) with or without prednisone is the most effective, evidence-based antenatal treatment for subsequent FNAIT-affected pregnancies. IVIG infusion causes hemolysis in other settings, the degree depending upon patient blood groups (BGs).

Omission of fetal sampling in treatment of subsequent pregnancies in fetal-neonatal alloimmune thrombocytopenia.

Background: Fetal-neonatal alloimmune thrombocytopenia affects approximately 1 of 1000 live births, most of which are not severely thrombocytopenic. Despite effective treatment with intravenous gammaglobulin and/or prednisone, antenatal management of a subsequent affected pregnancy is complicated by the risks associated with fetal blood sampling. Furthermore, there are no biomarker(s) of high risk other than the occurrence of intracranial hemorrhage in a previous sibling.