INCREASED MONONUCLEAR CELL TISSUE FACTOR AND TYPE-2 PLASMINOGEN-ACTIVATOR INHIBITOR AND REDUCED PLASMA FIBRINOLYTIC CAPACITY IN CHILDREN WITH LYMPHOMA

Blood clotting activation and fibrin deposition are common findings in lymphoma patients. We evaluated the capacity of peripheral blood mono nuclear cells to produce procoagulant activity (PCA) and plasminogen a ctivator inhibitor (PAI) in 12 children with newly diagnosed lymphoma (8 non-Hodgkin's, 4 Hodgkin's) and in 12 matched healthy donors. In th e 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 ge nerated by mononuclear cells after incubation for 20 h at 37 degrees 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 W). Moreover, culture medium obtained from pati ents' mononuclear cells after incubation for 20 h at 37 degrees C cont ained significantly higher amounts of PAI activity and PAI-2 antigen t han control samples (p<0.001). Plasma PAI-1 and fPA antigens were sign ificantly augmented in patients (p <0.005), the mean increase of PAI-1 being about 5 times higher than that of t-PA. Plasma levels of D-dime r were markedly increased in the patients' group (p<0.001), whereas u- PA and PAI-2 antigens did not differ from controls. It is suggested th at monocytes from lymphoma patients are endowed with functional abnorm alities leading to the simultaneous expression of tissue factor and an tifibrinolytic activity. These abnormalities, coupled with a reduced p lasma fibrinolytic potential, could play an important pathogenetic rol e in blood clotting activation and fibrin deposition associated with l ymphoma.