Preterm infants with low immunoglobulin G levels have increased risk of neonatal sepsis but do not benefit from prophylactic immunoglobulin G

Objective: In a prospective, randomized, placebo-controlled, multicenter st udy, we evaluated the prevention of neonatal infections with intravenous im munoglobulin G (IVIgG) prophylaxis For preterm infants (gestational age <33 weeks) with umbilical cord blood IgG levels <less than or equal to>4 g/L. Study design: Intravenous Ige or placebo (albumin), 1 g/kg body weight, was given on days 0, 3, 7, 14, and 21 to 81 infants with umbilical cord blood IgG levels 14 g/L: (1) IVIgG group, n = 40, mean (SD) gestational age 27.5 (2.2) weeks and birth weight 1.06 (0.39) kg; (2) placebo group, n = 41, mea n (SD) gestational age 27.7 (2.5) weeks and birth weight 1.13 (0.38) kg. In fants with umbilical cord blood IgG levels 24 g/L (n = 238) served as a sep arate comparison group. Neonatal infections according to European Society o f Pediatric Infectious Disease criteria were monitored until 28 days of lif e. Results: Infants with IgG levels less than or equal to4 g/L at birth who re ceived IVIgG had no significant reduction in infectious episodes or mortali ty rate when compared with those given placebo. However, infants with a ser um concentration of IgG >4 g/L at birth had significantly fewer infectious episodes (culture-proven sepsis) than infants with low serum concentrations of IgG (14 g/L) when compared at the same gestational ages (26 to 29 weeks , P < .003). Conclusions: Prophylactic immunotherapy with IVIgG did not improve the immu ne competence in preterm infants with low serum IgG concentrations at birth . We speculate that a spontaneously high serum IgG concentration at birth r eflects placenta function and is an indicator of a more mature immune syste m capable of protecting the preterm infant against severe neonatal infectio ns.