The appearance of L‐selectinlow polymorphonuclear leukocytes in the circulating pool of peripheral blood during myocardial infarction correlates with neutrophilia and with the size of the infarct

Background: It is assumed that not only leukocytosis, but also the activation of white blood cells (WBC) may play a role in the pathogenesis and prognosis of patients with myocardial infarction (MI). Activation of WBC includes upregulation of CD11b∖CD18 and downregulation of CD62L (L‐selectin) antigens. Hypothesis: The activation of WBC is associated with the appearance of a larger MI. Methods: CD11b∖CD18 and CD62L were measured on the surface of WBC on Day 1 and Day 3 from the onset of MI. The size of the infarct was estimated by calculating the area under the curve of the creatine kinase enzyme, which was measured every 6 h. Results: A negative correlation was noted between the absolute polymorphonuclear count and the availability of the CD62L on these cells during Day 1 (r = ‐0.46, p = 0.003) and Day 3 (r = ‐0.35, p = 0.05). There was a positive correlation between the size of MI and the WBC count (r = 0.46, p = 0.004) and a negative correlation with CD62L on polymorphonuclears (r = ‐0.35, p = 0.03). During Day 3, the CD11b∖CD18 on the polymorphonuclears increased despite a decrement in the absolute number of these cells. Conclusion: The neutrophilia during the early phases of acute MI correspond to the appearance of the L‐selectinlow population of polymorphonuclear leukocytes. There is a correlation between the appearance of this population and the size of the infarct.