Serial IgG and IgM serum levels after infusion of different Ig-preparations (IgG or IgM-enriched) in preterm infants.

Intravenous administration of Immunoglobulin (IVIG) has been used for prevention or treatment of neonatal sepsis. However, therapeutic efficacy of IVIG is dependent on pharmacokinetic factors. There have been no comparative studies in neonates between licensed IgG and IgM enriched preparations. The aim of this study was to investigate serial IgG and IgM serum levels during the neonatal period in two groups of non-septic, preterm infants treated prophylactically with IVIG. Twenty-two very low birth weight (VLBW) patients (1001-1500g) (gestational age 31.8 +/- 2.0 weeks and 1265 +/- 245g birth weight) and 12 extremely low birth weight (ELBW) patients (< 1000g) (gestational age 28.6 +/- 2.5 weeks and 910-85g birth weight) received at random three standard doses of Sandoglobulin (SG) (0.5 g/kg/day) or IgM enriched Pentaglobin (PG) (5 ml/kg/day). IgG and IgM concentrations were assayed by rate nephelometry before treatment and at day 3, 5, 7, 14 and 28 of life. At any time IgG levels were higher in the SG-VLBW group (p < 0.01), no difference being observed in the ELBW group (p > 0.5). IgM levels were higher at day 3 and 5 in the PG-VLBW group and until day 7 in the ELBW group (p < 0.01). This study indicates a wide range of IgG and IgM kinetics in the healthy premature and suggests frequent monitoring of immunoglobulin serum levels during efficacy studies.