CHLOROQUINE MINIMIZES SAMPLING ARTIFACTS FOR RADIOIMMUNOLOGICAL DETERMINATION OF THROMBOXANE B-2 IN PLASMA

Chloroquine is known to inhibit platelet activation by various mechani sms including arachidonic acid liberation from membrane phospholipids. We therefore examined the influence of chloroquine in addition to the conventional EDTA/acetylsalicylic acid cocktail on thromboxane B-2-pl asma values. In 11 healthy volunteers the influence of venous occlusio n, needle diameter and EDTA (+ acetylsalicylic acid + chloroquine) was examined. In 27 healthy adults, 51 patients with clinically manifeste d coronary heart disease as well as in 31 patients with peripheral vas cular disease parallel samples drawn in the presence of chloroquine sh owed lower thromboxane B-2 in all these three groups of patients, espe cially in conditions associated with platelet activation and high thro mboxane B-2-values. These findings suggest that the routine addition o f 10 mM chloroquine to the conventional stabilization cocktail can str ongly be recommended.