Antigen density of P-selectin (CD 62P) on the platelets of healthy term newborns.

Measurements have been made of the antigen density of P-selectin (CD 62P) on the surface of platelets of healthy term newborns in relation to sex and in different umbilical vessels. The effect of thrombin or ADP on the density of CD 62P has been determined. The study was performed in 18 healthy term newborns, 10 girls and eight boys. Dako QIFIKIT was applied to calculate the number of these antigens. No differences were observed in the number of antigens of CD 62P on newborn platelets between the umbilical vein and artery in both sexes. On the other hand, boys demonstrated 31,245 antigens/plt, girls 26,397/plt (P = 0.045). A statistically significant increase in the expression of CD 62P was also observed following activation of thrombin in both sexes and in the umbilical vein and artery. ADP as a weaker agonist demonstrated less changes. A high number of the CD 62P antigens on the platelets of newborns may be interpreted as an effect of increased thrombinogenesis during birth. It can be suggested that this process is more pronounced in boys than girls.