Alpha-1 antitrypsin elevation in healthy neonates.

alpha 1-Antitrypsin concentrations and phenotypes were determined in plasma of 257 healthy newborns. Samples were taken during the first 3 days after birth (time 1) and approximately after 30 days (time 2). We found the alpha1-antitrypsin levels immediately after birth elevated in the three Pi phenotypes M, M1M2, and MS as compared to the concentrations in cord blood and those at the age of 30 days. The concentrations in cord blood were within the normal range for adults. The concentrations (in mg/ml) at times 1 and 2 (+/- S.D.) for the different phenotypes were M: 2.94 +/- 0.58, 1.99 +/- 0.35; M1M2: 2.81 +/- 0.48, 2.01 +/- 0.37; MS: 2.45 +/- 0.5, 1.55 +/- 0.33. These differences were highly significant (p less than 0.001). Samples with the PiMZ phenotype had the characteristically reduced levels and did not show a significant difference in concentration between the two samples: 1.54 +/- 0.25 mg/ml (time 1) and 1.42 +/- 0.34 (time 2). We conclude that the alpha 1-antitrypsin level in plasma of normal infants rises in response to stimuli in the immediate neonatal period, or that perhaps the rise is due to the process of delivery itself. Heterozygotes for Piz can apparently not respond, or respond only minimally, to the same factor(s).