Newborn Factor VIII Complex: Elevated Activities in Term Infants and Alterations in Electrophoretic Mobility Related to Illness and Activated Coagulatio

Abstract

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.

Coagulation Parameters in Maternal and Cord Blood at Delivery

“…This disagrees with an earlier study in which factor VIII:C levels in cord blood were found to be unrelated to those in maternal blood at parturition. 8 Conversely, and in confirmation of other reports, 7,10 we found the levels of ristocetin cofactor higher in neonates than in the nonpregnant adults. This parallels the recent finding in fetal but not adult plasma of unusually large von Willebrand factor multimers.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] The data, which represent the reference values for Saudi neonates, are compared in Table 2 with similar data from other ethnic populations.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] Although this subject has interested many researchers in the last two decades, the numerous data available for healthy newborn infants are inconsistent and difficult to obtain and interpret. This is due to such factors as variable methods of blood collection and assay procedures, variable gestational age, birth weight and vitamin K status, wide ranges of clotting factor proteins, and small number of observations, which make it difficult to define true normal values or to draw valid comparisons between these data.…”

On the Versatility of Von Willebrand Factor

“…The intricate linkage between VWF and FVIII is perhaps best illustrated by the nomenclature that was previously used to distinguish between the coagulation- and platelet-related activities of the complex: FVIII coagulant activity (FVIII:C), FVIII related antigen (FVIII:RAg) and FVIII ristocetin cofactor activity (FVIII:RCF) 42. In fact, some still use the term FVIII:RAg instead of VWF to describe staining of endothelial cells in the immunohistochemical analysis of healthy and pathological tissues (see e.g.…”

Von Willebrand Disease: Range of the Disease, and Management

“…(3) Diagnosis for neonates is challenging because the stress of vaginal delivery increases VWF levels [28,29]. (4) Plasma levels of FVIII and VWF increase twofold to fivefold during physiologic stress, for example fainting and exercise [30].…”