Systemic response of peripheral blood leukocytes and their phagocytic activity during acute myocardial infarction.

OBJECTIVES

To determine changes in leukocyte counts and phagocytic activity of peripheral blood mononuclear (MN) and polymorphonuclear (PMN) cells as potential cellular markers of systemic immunological events in acute myocardial infarction (AMI).

PATIENTS AND METHODS

Thirty patients with a first AMI and 30 healthy volunteers were examined. Immunological analyses were performed at admission and repeated at one and seven days after the acute event. MN and PMN cells were obtained from heparinized whole blood after centrifugation and separation on a density gradient, and incubated with a fixed number of heat-inactivated and labelled yeast particles. Total leukocyte counts, leukocyte populations and some parameters of phagocytic activity were determined: percentage phagocytosis, phagocytic index, absolute phagocytic index, count of phagocytes in a fixed volume of peripheral blood (CP) and phagocytic capacity.

RESULTS

Patients with AMI had increased total leukocyte counts accompanied by increased PMN counts, while there were no significant differences in total MN count and MN populations. Except for the phagocytic index, all phagocytic parameters of MN and PMN cells were increased in patients with AMI at admission and on the first day of disease. On the seventh day after AMI only the CP of MN cells had increased significantly in patients with AMI, while percentage phagocytosis, CP and capacity of phagocytosis of PMN cells increased during the acute phase of AMI.

CONCLUSIONS

These data suggest that AMI was followed with a strongly systemic inflammatory response to myocardial damage. Furthermore, activated MN and PMN cells may be a significant source of free radicals that may be involved in lipid peroxidation and produce tissue damage in the early postinfarction period.