Summary
A new phenomenon is described: Whole blood clots lyse faster in the plasma of the
same donor than in another donor’s plasma. We have confirmed this finding in 68 healthy
volunteers by a standardized, pairwise analysis and have found a mean difference in
clot weights of 8.8 ± 0.99% (SEM, p<0.0001) after 6 h of urokinase-induced (200 U/ml)
clot lysis. Nu difference was found in a group of 7 pairs of identical twins. Further
analysis revealed that increasing concentrations of platelets in the plasma reduced
the difference significantly but did not abolish it. A 1:1 mixture of autologous with
homologous plasma reduced the autologous advantage by almost 50%, thus making an inhibitor
unlikely. The absence of cellular components in clots of platelet- poor plasma resulted
in the loss of the advantage after 2 h of lysis, but not in the early phase. We conclude
that there is a clear advantage of autologous over homologous clot lysis. Potential
mechanisms are discussed and include an increased affinity of enzymes for their substrates
in a given individual.
