Newborn platelet dysfunction: a storage pool and release defect.

Per cent aggregation, release and content of adenine nucleotides, and specific radioactivity were evaluated in citrated platelet-rich plasma (PRP) prepared from paired samples of maternal and cord blood. Platelets of newborn infants aggregated normally in response to highdose ADP (20 muM), strong collagen suspensions, and thrombin; however, when compared with PRP from the mothers or from normal adults, per cent aggregation in response to lower concentrations of ADP (2 muM), weak collagen, and part particularly epinephrine was markedly reduced. Nucleotide release after stimulation of the newborns' PRP with the latter two inducers was also impaired. ATP and ADP content of the newborns' platelets was also significantly less than that of their mothers or of normal adults, but specific activity was normal. The data suggest that the impairment of ADP release in the platelets of newborn infants is due to decreased sensitivity to external stimuli. Since metabolic ATP is necessary for the platelet release reaction, it is postulated that the platelet dysfunction results from a lack of metabolic ATP.