Change in Eosinophil Count in Patients with Heart Failure Treated with Anakinra

Interleukin-1 blockade with anakinra leads to a transient increase in eosinophil blood count (eosinophils) in patients with acute myocardial infarction. We aimed to investigate the effect of anakinra on changes in eosinophils in patients with heart failure (HF) and their correlation with cardiorespiratory fitness (CRF).

We measured eosinophils in 64 patients with HF (50% females), 55 (51-63) years of age, before and after treatment, and, in a subset of 41 patients, also after treatment cessation. We also evaluated CRF, measuring peak oxygen consumption (VO₂) with a treadmill test.

Treatment with anakinra significantly and transiently increased eosinophils, from 0.2 [0.1-0.3] to 0.3 [0.1-0.4] × 10³ cells/µL (p < 0.001) and from 0.3 [0.2-0.5] to 0.2 [0.1-0.3] × 10³ cells/µL, with suspension (p < 0.001). Changes in eosinophils correlated with the changes in peak VO₂ (Spearman's Rho = +0.228, p = 0.020). Eosinophils were higher in patients with injection site reactions (ISR) (n = 8, 13%; 0.5 [0.4-0.6] vs. 0.2 [0.1-0.4] × 10³ cells/µL, p = 0.023), who also showed a greater increase in peak VO₂ (3.0 [0.9-4.3] vs. 0.3 [-0.6-1.8] mLO₂·kg^-1·min^-1, p = 0.015).

Patients with HF treated with anakinra experience a transient increase in eosinophils, which is associated with ISR and a greater improvement in peak VO₂.