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von Willebrand factor-collagen binding activity is increased in newborns and infants
K B Thomas1, A H Sutor, N Altinkaya
1Universitäts-Kinderklinik, Freiburg, Germany.
Insights
Newborns and infants show higher levels of von Willebrand factor (vWF) antigen and activity than adults. These elevated vWF levels normalize by 2-6 months, necessitating age-specific reference ranges for accurate diagnosis.
Area of Science:
- Pediatric Hematology
- Hemostasis and Thrombosis
- Clinical Biochemistry
Background:
- von Willebrand factor (vWF) is crucial for hemostasis.
- vWF levels and activity in neonates and infants are not well-established.
- Accurate interpretation of vWF parameters requires age-specific data.
Purpose of the Study:
- To quantify vWF antigen (vWF:Ag) and vWF-collagen binding activity (vWF:CBA) in newborns and infants.
- To compare pediatric vWF levels with adult reference ranges.
- To establish the developmental trajectory of vWF parameters in early life.
Main Methods:
- Plasma samples from 71 healthy newborns and infants (up to 6 months) and 36 adults were analyzed.
- Quantitative enzyme-linked immunosorbent assays (ELISAs) were used for parallel measurement of vWF:Ag and vWF:CBA.
- Data were stratified by age groups: 2-7 days, 2-4 weeks, and 2-6 months.
Main Results:
- Median vWF:Ag and vWF:CBA were elevated in newborns and infants compared to adults.
- Elevated vWF levels persisted for up to 4 weeks of life.
- Adult vWF levels were reached between 2 and 6 months of age.
Conclusions:
- Neonates and young infants exhibit significantly higher vWF:Ag and vWF:CBA.
- Age-specific reference ranges are essential for diagnosing von Willebrand disease in pediatric populations.
- Increased vWF interaction with collagen may contribute to efficient neonatal hemostasis.
Abstract:
von Willebrand factor (vWF) antigen (vWF:Ag) and vWF-collagen binding activity (vWF:CBA) were measured in plasma by parallel quantitative ELISAs in normal newborns and infants (n = 71). The medians for vWF:Ag (IU/ml) and vWF:CBA (U/ml), respectively, were 1.46 and 1.91 for 2-7 day-old (n = 43), 1.22 and 1.40 for 2-4 week-old (n = 14), 1.22 and 1.15 for 2-6-month-old (n = 14) infants and 0.98 and 1.08 (n = 36) in normal adults. Elevated levels of vWF:Ag, but particularly vWF:CBA were seen for up to 4 weeks of life reaching adult levels between 2 and 6 months of life. The elevated levels of the vWF parameters indicate that caution should be exercised when interpreting laboratory data and diagnosing von Willebrand disease in newborns and young infants and warrant the use of age-specific reference ranges. The efficient haemostasis observed during early neonatal life may in part be due to the increased ability of vWF to interact with collagen.