The appearance of L-selectin(low) 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 with 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-selectin(low) population of polymorphonuclear leukocytes. There is a correlation between the appearance of this population and the size of the infarct.

Combined leukocyte and erythrocyte aggregation in patients with acute myocardial infarction

OBJECTIVES

To determine whether the increased aggregability of both white and red blood cells previously reported in acute myocardial infarction (aMI) correlates with each other.

DESIGN

Cross-sectional study comparing two groups of patients and a group of healthy controls.

SETTING

A tertiary university affiliated hospital (Intensive Cardiac Care Unit and Department of General Internal Medicine).

PATIENTS

Consecutive patients with aMI, patients with chest pain and no infarction, and healthy controls.

MEASUREMENTS AND RESULTS

We adapted a simple slide test and image analysis to reveal the state of both leukocyte and erythrocyte adhesiveness/aggregation in the peripheral blood of patients with aMI. A significant (P=0.0001) increment in the aggregation of both cellular populations was noted in 48 patients with aMI as opposed to the 141 patients with ischemic heart disease and no infarction and in 45 matched controls. In addition, a significant correlation was noted between the various variables of the leukocyte and erythrocyte adhesiveness/aggregation tests.

CONCLUSIONS

The significant correlation between the aggregability of white and red blood cells in patients with aMI is suggestive of there being a commonly shared adhesive protein(s). The prompt identification of patients with increased aggregation might have clinical and therapeutic implications.