CD4T cells aggravate hemorrhagic brain injury.

Abstract

Leukocyte infiltration accelerates brain injury following intracerebral hemorrhage (ICH). Yet, the involvement of T lymphocytes in this process has not been fully elucidated. Here, we report that CD4T cells accumulate in the perihematomal regions in the brains of patients with ICH and ICH mouse models. T cells activation in the ICH brain is concurrent with the course of perihematomal edema (PHE) development, and depletion of CD4T cells reduced PHE volumes and improved neurological deficits in ICH mice. Single-cell transcriptomic analysis revealed that brain-infiltrating T cells exhibited enhanced proinflammatory and proapoptotic signatures. Consequently, CD4T cells disrupt the blood-brain barrier integrity and promote PHE progression through interleukin-17 release; furthermore, the TRAIL-expressing CD4T cells engage DR5 to trigger endothelial death. Recognition of T cell contribution to ICH-induced neural injury is instrumental for designing immunomodulatory therapies for this dreadful disease.