Abstract: Objective To investigate the predictive value of serum intercellular adhesion molecule-1 (ICAM-1), lipase (LPS), and soluble programmed death ligand 1 (sPD-L1) for infectious pancreatic necrosis (IPN) secondary to severe acute pancreatitis (SAP) in the elderly. Methods Forty-five elderly patients with SAP admitted to our hospital from January 2019 to July 2021 were selected and divided into observation group (17 cases) and control group (28 cases) according to whether they presented with secondary IPN within 4 weeks of hospitalization. The clinical data, serum levels of ICAM-1, LPS, and sPD-L1 of the two groups were compared, and the correlation between each peripheral blood index and Ranson score, Acute Physiological and Chronic Health Evaluation Ⅱ (APACHEⅡ) score was analyzed, and the relationship between serum ICAM-1, LPS, and sPD-L1 and secondary IPN of SAP was analyzed. The value of each peripheral blood index to predict IPN secondary to SAP was evaluated. Results In the observation group, Ranson score, APACHEⅡscore, serum levels of ICAM-1, LPS, and sPD-L1 were higher than those in the control group (P<0.05); Pearson correlation analysis showed that the serum levels of ICAM-1, LPS, and sPD-L1 were positively correlated with Ranson score and APACHEⅡ score(P<0.05); Logistic regression analysis showed that serum ICAM-1, LPS, and sPD-L1 were independently correlated with IPN secondary to SAP(P<0.05); Receiver operator characteristic curve analysis showed that the area under the curve(AUC) of serum ICAM-1, LPS, and sPD-L1 to predict IPN secondary to SAP was 0.800, 0.712, and 0.687, respectively. And the AUC of combination of serum ICAM-1, LPS, and sPD-L1 to predict IPN secondary to SAP was 0.876(95% CI: 0.764-0.988), with sensitivity of 76.47% and specificity of 89.29%, which was significantly higher than that of the three index alone. Conclusions Serum levels of ICAM-1, LPS, and sPD-L1 are significantly correlated with the severity of SAP, and the combined detection of the three indexes can be a potential way to predict secondary IPN.

Key words: severe acute pancreatitis, infectious pancreatic necrosis, intercellular adhesion molecule-1, lipase, soluble programmed death ligand 1