Withaferin-A alleviates acute graft versus host disease without compromising graft versus leukemia effect

•Withaferin-A (WA) administration to mice mitigates aGvHD morbidity and improves survival.•WA also showed superiority over standard regimen in terms of lowering the aGvHD sign and improving the survival of mice.•WA do not interfere with graft versus leukemia effect.•Mechanistically, WA inhibits T-cell proliferation, cytokine storm and regulates immune cell phenotypes of hPBMCs probably via inhibition of JAK2-STAT3 signaling.