Hemostasis in Glanzmann's thrombasthenia (GT): GT platelets interfere with the aggregation of normal platelets.
The transfusion requirements for a 6-year-old Glanzmann's thrombasthenia (GT) patient undergoing tonsillectomy and adenoidectomy were studied. Transfusion of pheresed platelets from a single normal donor increased the platelet count by 63 x 10(9)/L but did not correct the bleeding time. Since the ratio of normal:GT platelets in vivo was approximately 1:5, it was possible that GT platelets interfered with the function of normal platelets. To test this hypothesis, mixtures of platelet-rich plasma (PRP) from a normal donor and the patient were studied to determine a ratio of normal:GT platelets that would yield acceptable in vitro aggregation. Normal:GT ratios of 1:4 and 3:2 resulted in 25% and 59% aggregation, respectively. Mixtures of normal and nonfunctional ethylene glycol tetra-acetic acid-treated platelets gave similar results. Aggregates from mixtures of normal and patient platelets were also examined morphologically by light microscopy and were proportional in size to the normal:GT platelet ratio. Transfusion of platelets from the pheresis of four donors increased the patient's platelet count by greater than 300 x 10(9)/L (normal:GT ratio 1:1), produced 53% aggregation, and resulted in satisfactory postoperative hemostasis. The platelet transfusion requirement for this GT patient was much greater than would have been expected in the absence of aggregation-defective platelets.
Jennings
L K
LK
Department of Medicine, University of Tennessee, Memphis.
Wang
W C
WC
Jackson
C W
CW
Fox
C F
CF
Bell
A
A
D000911:Antibodies, Monoclonal; D001760:Bleeding Time; D002648:Child; D005434:Flow Cytometry; D006487:Hemostasis / Q000502:physiology*; D006801:Humans; D008297:Male; D010974:Platelet Aggregation / Q000502:physiology*; D013915:Thrombasthenia / Q000097:blood*
D000911:Antibodies, Monoclonal