[Maturation of proteins C and S in childhood].

The antigenic concentrations of protein C, total protein S (TPS), free protein S (FPS) percentage of protein S that corresponds to the free form (PFPS), C4BP and factor II throughout childhood (values in cord blood, at 48 hours, at 15 days, 1-6 months, 6 months-2 years, 2-7 years and 7-14 years) have been studied. The maturation of these factors is variable, reaching average values similar to those of adults at between 1 to 6 months for protein C and TPS; at 15 days for factor II; and at between 6 months and 2 years for C4BP, whose development occurs latest. Vitamin K increases the values of protein C, factor II and FPS at 48 hours after birth, but does not modify the figures for TPS or C4BP. The thrombotic index is below 0.6 for protein C at 15 days, but at this age the figure for protein S is above 1.0.