Background: Unusually large von Willebrand factor (VWF) multimers have been observed in patients with thrombotic microangiopathies (TMA), and absence of the VWF cleaving protease ADAMTS-13 activity is considered to be involved in the etiology of TMA. Increased amounts of large multimers of VWF have also been identified in neonates. Objective: We assessed ADAMTS-13 activity in healthy neonates, children and adults to establish baseline levels. Patients and methods: Cord blood was collected from 38 full-term newborns; venous samples were taken from 15 neonates on day 2-3 of life. Seventeen children, 24 healthy adults and seven patients with TMA were studied as well. ADAMTS-13 activity was quantified by the binding of the subjects' plasma VWF to collagen before and after enzyme activation. The multimer distribution of VWF was also determined. Results: Neonates and children had percentage ADAMTS-13 activity similar to adults. However, two groups were apparent in the cord blood samples: while 28/38 newborns had percentage activity within the normal range of healthy adults (102 ± 3.0%), 10 had significantly lower percentage activity (53 ± 1.1%; P <0.0001) that normalized by day 2-3. The VWF multimer distribution was the same in all cord blood samples and was not different compared with children and adults. High-molecular-weight VWF multimers were significantly increased in the 2-3-day-old neonates and in TMA patients. Conclusions: Although ADAMTS-13 activity was similar in neonates compared with adults, 26% of neonates had mildly reduced activity. Further studies are needed to investigate the complex interaction of VWF production and secretion with its size control by ADAMTS-13 in different age groups. © 2003 International Society on Thrombosis and Haemostasis.
CITATION STYLE
Schmugge, M., Dunn, M. S., Amankwah, K. S., Blanchette, V. S., Freedman, J., & Rand, M. L. (2004). The activity of the von Willebrand factor cleaving protease ADAMTS-13 in newborn infants. Journal of Thrombosis and Haemostasis, 2(2), 228–233. https://doi.org/10.1046/j.1538-7933.2003.00575.x
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