Directed immune globulin for the prevention or treatment of neonatal group B streptococcal infections: a review.

Intravenous immune globulin (IVIG) is now used in many nurseries to prevent or treat neonatal infections. The most common cause of early-onset neonatal sepsis is the group B streptococcus (GBS). Commercially available IVIG preparations have variable levels of specific antibody directed against GBS. Therefore, to ensure high levels of anti-GBS antibody, we developed a polyvalent IVIG directed against GBS (GBS-IVIG) by immunizing plasma donors. This GBS-IVIG was superior to standard IVIG both in vitro using opsonic studies and in vivo using a lethal suckling rat model of GBS sepsis. GBS-IVIG also protected neonatal rhesus monkeys in a GBS sepsis model. Safety and pharmacokinetic studies have been completed in 20 neonates with suspected sepsis. Fifteen infants were randomized to receive 500, 250, or 100 mg/kg of GBS-IVIG and were compared with 5 infants given 500 mg/kg of standard IVIG. No adverse effects of standard IVIG or GBS-IVIG were observed. While total serum IgG and IgG subclasses reflected the dose administered, the specific GBS antibody reflected both the dose and IVIG preparation utilized. At 500 mg/kg, the GBS-specific antibody rises more than fourfold above baseline in all babies that were observed for greater than 42 days postinfusion, while standard IVIG provided a fourfold rise in less than 20% of babies for less than 1 day. These studies suggest that GBS-IVIG can effectively and reliably elevate GBS-specific antibody levels in neonates. Clinical trials are needed to evaluate the efficacy of GBS-IVIG in preventing or treating neonatal GBS infections.