Effect of Interleukin-1 Blockade with Anakinra on Leukocyte Count in Patients with ST-Segment Elevation Acute Myocardial Infarction

Background: Leukocytosis is a common finding in patients with ST elevation myocardial infarction (STEMI) and portends a poor prognosis. Interleukin 1-b regulates leukopoiesis and pre-clinical studies suggest that anakinra (recombinant human interleukin-1 [IL-1] receptor antagonist) suppresses leukocytosis in myocardial infarction. However, the effect of IL-1 blockade with anakinra on leukocyte count in patients with STEMI is unknown. Methods: . We reviewed the white blood cell (WBC) and differential count of 99 patients enrolled in a clinical trial of anakinra (n=64) versus placebo (n=35) for 14 days after STEMI. A complete blood cell count with differential count were obtained at admission, and after 72 hours, 14 days and 3 months. Results: . After 72 hours from treatment, anakinra compared to placebo led to a statistically significant greater percent reduction in total WBC count (-35% [-48 to -24] vs -21% [-34 to -10], P =0.008), absolute neutrophil count (-48% [-60 to -22] vs -27% [-46 to -5], P =0.004) and to an increase in absolute eosinophil count (+50% [0 to +100] vs 0% [-50 to +62], P =0.022). These changes persisted while on treatment at 14 days and were no longer apparent at 3 months after treatment discontinuation. Conclusion: . We found that in patients with STEMI IL-1 blockade with anakinra accelerates resolution of leukocytosis and neutrophilia. This modulation may represent one of the mechanisms by which IL-1 blockade improves clinical outcomes.