INCREASED PLASMIN GENERATION AND ACTIVITY IN HIV-INFECTED PATIENTS - IN-VIVO RATHER THAN IN-VITRO ACTIVATION OF THE FIBRINOLYTIC SYSTEM

Since changes in the fibrinolytic system have been previously reported in patients infected by the immunodeficiency virus (HIV), the present study was undertaken to evaluate plasminogen activation as well as pl asmin activity in HIV-infected patients. For that purpose, we studied two groups of 20 HIV-infected patients each, classified upon the absol ute number of CD4+ lymphocytes: patients with CD4+ below 200 x 10(6)/L (n = 20) were classified as having AIDS, according to the classificat ion of the Centers for Disease Control (CDC, Atlanta). The control gro up consisted of 20 age- and sex-matched healthy HIV-negative individua ls. Plasmin-plasmin inhibitor complexes (PPI complexes), fibrin and fi brinogen degradation products (FbDP, FgDP) were evaluated using commer cially available ELISA. All blood samples were collected into evacuate d tubes containing 0.129 M tri-Na citrate. In addition, PPI complex we re assayed in specimen collected in two other anticoagulant mixtures. The plasma levels of PPI complex, FbDP, and FgDP were found significan tly higher in both groups of HIV-infected patients than in controls. H owever, despite a trend to higher levels, the plasma levels of markers were not significantly different in AIDS and non AIDS patients. The c omposition of the anticoagulant mixture did not significantly influenc e the plasma levels of PPI complex. So, the citrated evacuated tubes w ere found to be convenient for the measurement of PPI complexes in cli nical materials. These results suggest that plasmin is overgenerated i n HIV-infected patients and only neutralized in part by alpha(2)-antip lasmin. The presence of unopposed plasmin was suggested by the signifi cant increased levels of fibrin and fibrinogen degradation products. I n conclusion, the highly significant correlation demonstrated between PPI complex: and FbDP support the hypothesis of an activation of both the fibrinolytic and the coagulation systems in HIV-infected patients.