Regulatory T Cells in Post-Thrombotic Vessel Repair

Abstract

Blood clots form as part of the physiological host response to localised infections and tissue injury, but they cause major disabilities in the context of vascular thrombosis, heart attacks and ischemic stroke. Studies on the role of individual immune cell populations have shown that innate immune cells exclusively trigger thrombus formation while adaptive cells participate in the subsequent inflammation and regulate thrombus resolution. CD4+ Foxp3+ regulatory T (Treg) cells play a pivotal role in the control of autoimmunity and pathological immune responses and also promote non-immunological processes such as tissue homeostasis and tissue repair. In this work, a specialised population of resident "thrombus-busting" Treg was identified for the first time. These specialist cells develop in venous thrombus, are activated by cytokines from monocytes and regulate thrombus resolution by imposing phenotypic and functional changes in the myeloid compartment. Understanding the Treg population in venous thrombi may provide novel therapeutic strategies that can improve recovery in thrombosis patients and facilitate the restoration of organ function in chronic thrombo-inflammatory diseases.