Early postnatal changes of immunoglobulin levels in very low birth weight (less than or equal to 1500 g) preterm infants

Immunoglobulin levels were measured in 16 very low birth weight preterm infants (birth weight: 1091 +/- 221 g, gestational age: 28.8 +/- 1.6 wks, mean +/- SD) at birth and at postnatal ages of 2, 4, 6 and 8 weeks. IgM level increased significantly by the age of 2 weeks (0.26 +/- 0.25 g/l vs 0.76 +/- 0.45 g/l, p less than 0.05), then remained unchanged throughout the study period. IgA level did not change significantly. IgG level decreased significantly by the age of 6 weeks (6.04 +/- 3.8 g/l vs 4.4 +/- 1.4 g/l, p less than 0.05), but after that no further decrease could be detected. The extent of the decrease in IgG level, however, proved to be smaller than expected on the basis of the reference data for term infants. The possibility is suggested that the packed red cell transfusions given to the patients may have resulted in the higher immunoglobulin levels.