t-PA, PAI, and protein C before and after vascular occlusion of the upper limb in patients with Raynaud's phenomenon

Abstract

Tissue plasminogen activator (t-PA) and its inhibitor (PAI) were assessed in venous blood drawn before and after venous occlusion (bvo, avo) for 33 patients with Raynaud's phenomenon (RP), 14 with primary RP (PRP), 9 with suspected secondary RP (SSRP), and 10 with definite collagen disease and secondary RP (SRP). There were significant differences in PAI values avo between PRP (and controls), SSRP, and SRP. PAI activity decreased significantly avo only in controls and in PRP, and there was significant t-PA antigen elevation avo in the same groups. In addition, since PAI is neutralized by activated protein C (PC), both PC antigen and PC activity were assessed avo and bvo. PC Ag remained unchanged in all groups, with PC activity significantly lower than controls in SRP and SSRP. Finally the authors looked for interference of anticardiolipin antibodies (ACA) and lupus-like anticoagulant (LAC) with the PC system in collagen disease-associated RP. Specific IgG ACA were found in only 1 patient with SRP. In conclusion, there is an endothelial derangement, involving t-PA release and PAI, in SSRP and SRP patients. The reduced PC activity in these latter groups appears to be due to increased PAI influence rather than to ACA/LAC.