Summary
Blood clotting activation and fibrin deposition are common findings in lymphoma patients.
We evaluated the capacity of peripheral blood mononuclear cells to produce procoagulant
activity (PCA) and plasminogen activator inhibitor (PAI) in 12 children with newly
diagnosed lymphoma (8 non-Hodgkin’s, 4 Hodgkin’s) and in 12 matched healthy donors.
In the same subjects we also measured plasma antigen levels of tissue-type PA (t-PA),
urokinase-type PA (u-PA), PAI-1, PAI-2, and D-dimer. PCA generated by mononuclear
cells after incubation for 20 h at 37° C was significantly higher in patients than
in controls (p = 0.027). In all samples it was identified as tissue factor by functional
criteria (dependence on factor VII). Moreover, culture medium obtained from patients’
mononuclear cells after incubation for 20 h at 37° C contained significantly higher
amounts of PAI activity and PAI-2 antigen than control samples (p <0.001). Plasma
PAI-1 and t-PA antigens were significantly augmented in patients (p <0.005), the mean
increase of PAI-I being about 5 times higher than that of t-PA. Plasma levels of D-dimer
wete markedly increased in the patients’ group (p <0.001), whereas u-PA and PAI-2
antigens did not differ from controls. It is suggested that monocytes from lymphoma
patients are endowed with functional abnormalities leading to the simultaneous expression
of tissue factor and antifibrinolytic activity. These abnormalities, coupled with
a reduced plasma fibrinolytic potential, could play an important pathogenetic role
in blood clotting activation and fibrin deposition associated with lymphoma.
