Serum concentrations of 10 acute-phase proteins in healthy term and preterm infants from birth to age 6 months.

Aiming to define the evolution pattern of 10 acute-phase proteins in early infancy, we measured nephelometrically the serum concentrations of albumin, prealbumin, retinol-binding protein, transferrin, ceruloplasmin, hemopexin, haptoglobin, alpha 1-acid glycoprotein, alpha 2-macroglobulin, and alpha 1-antitrypsin in 395 term and preterm infants (gestational ages 26-41 weeks). Measurements were performed within 24 h after birth and then at the end of 1 (n = 171), 3 (n = 155), and 6 (n = 90) months afterwards. Data obtained from 250 healthy adults were used as adult reference values. All proteins increased progressively with postnatal age, except for alpha 1-antitrypsin, which remained stable from birth to the 6th month. Concentrations of almost all measured proteins were significantly lower in preterm than in term infants in the first 3 months. Compared with adult values, alpha 2-macroglobulin and alpha 1-antitrypsin were higher in infants throughout the 6 months. The other proteins were significantly lower at birth than adult values but after 6 months, only albumin, prealbumin, retinol-binding protein, and alpha 1-acid glycoprotein still remained lower in infants. Thus both gestational and postnatal age should be considered when interpreting concentrations of these proteins in early infancy.