INTERLEUKIN-8 IS NOT INVOLVED IN THE INCREASED CHEMOTACTIC ACTIVITY OF PERIPHERAL-BLOOD PLASMA DURING ACUTE MYOCARDIAL-INFARCTION

Polymorphonuclear neutrophils (PMN) are known to participate in the de velopment of tissue injury during myocardial infarction due to both fr ee oxygen radicals release, as well as to their involvement in the ''n o-reflow'' phenomenon. We have previously shown that pheripheral blood plasma (obtained from patients with acute myocardial infarction) has chemotactic activity for PMN and is able to induce PMN adherence as we ll as superoxide anion production. To investigate whether interleukin- 8 (IL-8/NAP-1), a potent chemotactic factor for PMN, is involved in pl asma-mediated PMN stimulation, we measured plasma levels of IL-8 in fi ve patients with transmural myocardial infarction with highly sensitiv e enzyme-linked immunosorbent assay (ELISA) using specific antibodies. Blood samples were taken immediately after patients' admission, withi n 15 and 30 min of treatment with intravenous nitrates, as well as aft er 1, 2, 3, and 7 days. All samples expressed IL-8 activity within the detection limit (0.4 ng/ml) as observed at the basal state. Thus, IL- 8 may not be considered as responsible for the chemotactic acitivity i n peripheral blood in patients with myocardial infarction.