Abstract
We herein report the cytokine expression at different stages for three patients who developed cardiac complications after immune checkpoint inhibitor (ICI) therapy. Case 1 with biopsy-proven myocarditis showed increased levels of interleukin (IL)-8, monocyte chemotactic and activating factor, and granulocyte macrophage colony-stimulating factor (GM-CSF) when he developed Takotsubo cardiomyopathy. Case 2 with subclinical myocarditis showed predominant activation of IL-8 during the progressive clinical course. Case 3 with cytokine-releasing syndrome showed substantial activations of IL-6, IL-8, GM-CSF, and interferon-γ. Our data suggest the development of unique cytokine activation in individual patients with cardiac complications after ICI therapy.