Factor VIII procoagulant activity, factor VIII related antigen and von Willebrand factor in newborn cord blood

ABO blood group and procoagulant factors: the hypercoagulation hypothesis ABO and Procoagulant Factors

BACKGROUND

The correlation between procoagulant levels-factor VIII (FVIII), von Willebrand factor (vWF), and fibrinogen-and risk of thrombosis has been well documented in adult populations. We hypothesize that interaction of passively transferred isoagglutinins in premature neonates with a compromised immune system may trigger an immune response that can target the immature gastrointestinal tract. The objective of this study is to evaluate if there are procoagulant level differences in preterm newborns stratified by ABO blood group.

METHODS

VWF, FVIII, and fibrinogen levels were analyzed in neonates ≤32 weeks and/or birthweight ≤1500 g over the first 6 weeks of life. Demographic, blood type, and transfusion data were collected.

RESULTS

Elevations in vWF and FVIII were found to be statistically significant in the third week of life in non-O neonates vs. type O neonates. FVIII was also found to be significantly elevated in week 1. Transfused neonates also showed elevations between weeks 0 and 3.

CONCLUSION

There appears to be a time-dependent variation in procoagulant factor levels in preterm newborns. Although the clinical significance remains unclear, prothrombotic factors vWF and FVIII are significantly higher in non-O blood-type preterm neonates in the third week of life.

Fetal and neonatal von Willebrand factor (vWF) is unusually large and similar to the vWF in patients with thrombotic thrombocytopenic purpura

We have investigated the distribution of vWF multimers in blood from the umbilical cord of infants delivered vaginally and by caesarean section, from heel-stick blood collected 1 d post-partum, and from fetuses undergoing evaluation for Rh compatibility. To examine vWF multimers, plasma was separated by electrophoresis on SDS-agarose gels, overlaid with 125I-anti-vWF, and analysed by densitometry of autoradiographs. Neonatal and fetal plasma contained unusually large von Willebrand factor multimers (ULvWFM), not present in normal adult plasma, in shed blood from adults, in maternal plasma at the time of birth, or in plasma from adults deficient in vitamin K-dependent coagulation proteins. We conclude that ULvWFM, similar in size to vWF present in the Weibel Paladie bodies of endothelial cells, the alpha granules of platelets, and the plasma of patients with TTP, is present in the fetal circulation, at birth, and shortly after delivery.

Newborn factor VIII complex: elevated activities in term infants and alterations in electrophoretic mobility related to illness and activated coagulation

The factor VIII coagulant activity (FVIII:C), factor VIII related antigen (FVIII:RAG), and factor VIII ristocetin cofactor activity (FVIII:RCF) was determined in the cord blood samples of 30 healthy term newborns. Sodium citrate anticoagulant, cold, and a proteolytic inhibitor were used in sample processing. All three factor VIII activities were elevated in infants compared to adults; additionally, FVIII:RAG was significantly higher in vaginally compared with caesarean section delivered infants. Crossed immunoelectrophoresis of the term infant plasma showed a consistently normal factor VIII mobility. An additional group of 22 sick premature and term infants had determinations of factor VIII antigen and crossed immunoelectrophoresis. The FVIII:RAG of sick infants was approximately twice that of the well term infants. Infants with severe lung disease, asphyxia, thrombosis and sepsis had normal electrophoretic mobility despite marked elevations in FVIII:RAG. Abnormal, symmetrical, more anodal migrations were seen only in a group of severely ill newborns with dissiminated intravascular coagulation (DIC) or signs of activated fibrinolysis. These results suggest that the elevated FVIII activities seen in well infants and most sick newborns are the result of increased release of a normal form of the FVIII molecule. Those elevations seen in sick newborns with DIC result from increased release and the production of an altered, faster moving FVIII molecule.