The expression of vWF receptor on newborn platelets.

Background: Platelets contain a complex known as GPIb-IX-V. The receptor for vWF is located in GPIbalpha. The number of functional receptors decreases during thrombin activation of platelets. This study was performed to evaluate the percentage of platelets displaying the GPIbalpha -IX complex on their surface.

Material/methods: We studied 51 healthy term newborns (21 females and 30 males). Blood was collected from the umbilical artery and vein immediately after severance of the umbilical cord, using a Diatube TM CTAD Vacutainer System. The GPIbalpha-IX complex was tested with CD42b-PE antibody, using a EPICS XL flow cytometer.

Results: Practically no differences were observed in the percentage of platelets demonstrating CD42b in venous blood (18.59%) and arterial blood (19.37%). The percentage of platelets bearing the CD42b molecule is higher in male newborns (20.58%) than female (17.38%). Healthy control adults demonstrated an increased percentage of CD42b on platelets (30.4%) in comparison to newborns (18.98%).

Conclusions: The sex of neonates affects the tested complex: higher values were noted in males. The particular umbilical vessel (vein or artery) has no effect on the percentage of platelets bearing CD42b.