Anti-K1 (Kell) Antibody Expressed in Maternal Breastmilk: A Case Report of a Neonate with Multiple Intrauterine Transfusions and Postnatal Exposure to Kell Antibody in Maternal Breastmilk.

Hemolytic disease of the fetus and newborn is a common consideration in newborn medicine, especially among the jaundiced. Maternal breastmilk provides numerous benefits to the infant, including nutrition and immunologic factors. Here, we present an infant who received three intrauterine transfusions for anemia secondary to anti-K1 (Kell), anti-C, and anti-e antibodies and whose maternal breastmilk tested positive for anti-Kell antibodies. The infant required another transfusion at 4 weeks of life for anemia. We review the pathophysiology of anti-Kell antibodies, the immunology of breast milk, and the intersection of these two topics.

Dexamethasone induces apoptosis of progenitor cells in the subventricular zone and dentate gyrus of developing rat brain.

The use of dexamethasone in premature infants to prevent and/or treat bronchopulmonary dysplasia adversely affects neurocognitive development and is associated with cerebral palsy. The underlying mechanisms of these effects are multifactorial and likely include apoptosis. The objective of this study was to confirm whether dexamethasone causes apoptosis in different regions of the developing rat brain. On postnatal day 2, pups in each litter were randomly divided into the dexamethasone-treated (n = 91) or vehicle-treated (n = 92) groups. Rat pups in the dexamethasone group received tapering doses of dexamethasone on postnatal days 3-6 (0.5, 0.25, 0.125, and 0.06 mg/kg/day, respectively). Dexamethasone treatment significantly decreased the gain of body and brain weight and increased brain caspase-3 activity, DNA fragments, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling, and cleaved caspse-3-positive cells at 24 hr after treatment. Dexamethasone increased cleaved caspse-3-positive cells in the cortex, thalamus, hippocampus, cerebellum, dentate gyrus, and subventricular zone. Double-immunofluorescence studies show that progenitor cells in the subventricular zone and dentate gyrus preferentially undergo apoptosis following dexamethasone exposure. These results indicate that dexamethasone-induced apoptosis in immature cells in developing brain is one of the mechanisms of its neurodegenerative effects in newborn rats.