Comparison of group B streptococcal hyperimmune globulin and standard intravenously administered immune globulin in neonates.

Standard intravenously administered immune globulin (IVIG) contains varying amounts of group B streptococcus (GBS) antibody. A GBS hyperimmune IVIG was produced by immunizing plasma donors. The GBS type-specific opsonic activity was > or = 90% in the hyperimmune IVIG at a 1280 dilution-1 versus at a 10 dilution-1 in standard IVIG. Suckling rat survival after GBS type-specific infection was 100% when the rats were treated with hyperimmune IVIG versus < or = 20% with standard IVIG. To evaluate the effect of this product on GBS antibody levels and clinical toxic effects, we randomly administered either GBS hyperimmune IVIG, 500, 250, or 100 mg/kg, or standard IVIG, 500 mg/kg, to 20 neonates with suspected sepsis. No adverse effects were observed. Total and subclass serum IgG levels reflected only the dose; serum GBS type-specific IgG and opsonic activity reflected both the product and dose of IVIG administered. Standard IVIG did not significantly increase serum GBS type-specific IgG, whereas hyperimmune IVIG, 500 mg/kg, produced a fourfold rise for > 6 weeks; more variable increases were observed after 250 and 100 mg/kg doses were given. Serum GBS type-specific opsonic activity correlated with serum GBS type-specific IgG levels (R2 = 0.74; p < 0.0001). Further studies of this or similar products will be necessary to determine whether GBS type-specific antibody improves the outcome of GBS-infected neonates.