Cerebral artery atherosclerosis is the main reason leading to cerebral infarction. CD40/CD40L overexpression will stimulate the immune and inflammatory responses,leading to local inflammatory cell infiltration within the atherosclerotic plaque, triggering plaque rupture, and thus causing cerebral infarction. Studies have suggested that that CD40L is associated with the severity of cerebral infarction, Therefore, clinical detection of CD40L can be used as an indicator for identifying the severity of cerebral infarction to guide clinical treatment.