Abstract: Objective To explore the expression and clinical significance of serum OX40 and OX40 ligand (OX40L) in the elderly patients with acute cerebral infarction. Methods A total of 146 elderly patients with acute cerebral infarction (observation group) and 50 healthy elderly (control group) in our hospital from January 2018 to December 2019 were selected, and the serum levels of OX40 and OX40L were detected. The National Institutes of Health Stroke Scale (NIHSS) was used to evaluate the neurological impairment, and the patients with acute cerebral infarction were divided into mild impairment group (n=32), moderate impairment group (n=72) and severe impairment group (n=42) according to the NIHSS scores. Three months after discharge, the modified Rankin Scale (mRS) was used to evaluate the prognosis of the elderly patients with cerebral infarction, and the patients were divided into good prognosis group (n=97) and poor prognosis group (n=49). Pearson test and Logistic regression were used for correlation analysis. Receiver operating characteristic (ROC) curve was drawn to analyze the prognostic value of serum OX40 and OX40L. Results The levels of serum OX40 and OX40L in mild impairment group, moderate impairment group and severe impairment group were higher than those in the control group (P<0.05); The levels of OX40 and OX40L increased with the increasing severity of the disease(P<0.05). NIHSS scores were positively correlated with the levels of OX40 and OX40L (r were 0.578 and 0.701 respectively, P＜0.05). The levels of serum OX40 and OX40L in the poor prognosis group were higher than those in the good prognosis group (P<0.05). Multivariate Logistic regression analysis showed that OX40 and OX40L were the independent risk factors for the prognosis of the elderly patients with acute cerebral infarction (P<0.05).ROC curve showed that the AUC of OX40 and OX40L for predicting the prognosis of patients was 0.793 and 0.854, respectively. The combined detection of the two indexes could increase the AUC to 0.914. Conclusions OX40 and OX40L are related to the severity of neurological deficit in the elderly patients with acute cerebral infarction, and can be used to predict the early clinical prognosis.

Key words: OX40, OX40 ligand, acute cerebral infarction, neurological deficit, prognosis