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Biphasic reduction and concanavalin A binding properties of serum alpha-fetoprotein in preterm and term infants
P Lahdenne1, P Kuusela, M A Siimes
1Children's Hospital, University of Helsinki, Finland.
Insights
Serum alpha-fetoprotein (AFP) levels are significantly higher in preterm infants and decrease differently based on gestational age. AFP maturation and its ConA nonreactive subfraction correlate with infant development and neonatal tumor recurrence.
Area of Science:
- Biochemistry
- Neonatology
- Pediatric Endocrinology
Background:
- Serum alpha-fetoprotein (AFP) is a key biomarker in neonatal care.
- Understanding AFP's postnatal decline and glycosylation patterns is crucial for interpreting its levels in infants.
- Gestational age significantly influences AFP levels and maturation in newborns.
Purpose of the Study:
- To establish reference values for postnatal serum AFP and its ConA binding subfractions in preterm and term infants.
- To investigate the developmental trajectory of AFP and its carbohydrate moiety postnatally.
- To correlate AFP patterns with gestational age and neonatal sacrococcygeal teratoma recurrence.
Main Methods:
- Measurement of serum alpha-fetoprotein (AFP) concentrations.
- Fractionation of AFP using concanavalin A (ConA) to analyze binding subfractions.
- Longitudinal monitoring of AFP levels and ConA subfractions in preterm and term infants.
- Correlation analysis with gestational age and clinical outcomes (teratoma recurrence).
Main Results:
- Preterm infants exhibit 10-fold higher cord serum AFP than term infants.
- Postnatal AFP reduction is biphasic, with a slower decline in preterm infants, reaching adult levels by 9-12 months.
- The ConA nonreactive AFP subfraction increases postnatally, reaching 85-95% by 6 months, with a faster rise in term infants.
- Increased serum AFP and decreased ConA nonreactive subfraction indicate malignant recurrence of neonatal teratomas.
Conclusions:
- Postnatal AFP synthesis maturation is dependent on gestational age.
- AFP glycosylation patterns (ConA subfractions) provide insights into neonatal development.
- Changes in AFP and its subfractions are valuable indicators for monitoring neonatal health and detecting teratoma recurrence.
Abstract:
Reference values for postnatal serum alpha-fetoprotein (AFP) and concanavalin A (ConA) binding subfractions of AFP in preterm and term infants are presented. Preterm infants had 10-fold higher serum concentrations of AFP than did term infants at birth. The reduction of serum values of AFP was biphasic in both groups and differed significantly between the two groups. The first declining phase continued for approximately 4 months in preterm and for 2 months in term infants, and was related to the degree of prematurity. The AFP values reached adult levels by 12 months in preterm and by 9 months in term infants. The developmental pattern of the carbohydrate moiety of AFP was determined by ConA fractioning. The proportion of the ConA nonreactive subfraction of AFP in preterm and term infants at birth was 6% and 13%, respectively; it increased more rapidly in term than in preterm infants but reached 85% to 95% by the age of 6 months in both infant groups. Our results indicate that the postnatal maturation of AFP synthesis is dependent on gestational age. Malignant recurrences of neonatal sacrococcygeal teratomas were associated with an increase in serum concentration of AFP and a decrease in the proportion of the ConA nonreactive subfraction of AFP.