Background and Objectives

Extracorporeal circuits made of artificial substances may induce blood cells and humoral activation. Negatively charged surfaces may activate Factor XII and the prekallikrein-kinin cascade, resulting in bradykinin (BK) produc-tion. BK has been considered to be involved in severe hypotensive reactions occurring during therapeutic apheresis in patients taking angiotensin-converting enzyme (ACE) inhibitors or in those receiving platelet transfusion. In this study we investigated BK production during donor plasmapheresis procedures. Patients and Methods Eighteen volunteer donors entered the study protocol. Nine of them were taking ACE inhibitors. Their blood pressure (BP) was monitored both pre-and post-apheresis, and BK determination was carried out using a competitive enzyme immunoassay (EIA), in plasma samples collected both during and at completion of the procedure. In addition, a limited number of thawed plasma units were checked for BK. Results No side-effects were observed during the procedures. However, donors taking ACE inhibitors showed a higher variation of their systolic BP compared to those who were not taking ACE inhibitors, while diastolic BP percentage variations did not differ significantly between the two groups. The BK concentration was considerably highe