Abstract:Objective To explore the correlations of neutrophil-to-lymphocyte ratio（NLR），T helper 17（Th17）cell to regulatory T cell（Treg）ratio with disease severity of acute pancreatitis（AP），and analyze their predictive value for prognosis. Methods A total of 152 AP patients admitted to NORINCO General Hospital between March 2021 and March 2025 were enrolled. On the one hand，patients were classified into 3 groups，including mild acute pancreatitis（MAP，n=51），moderately severe acute pancreatitis（MSAP，n=56），and severe acute pancreatitis（SAP，n=45）according to the severity of the disease. On the other hand，patients were divided into poor prognosis and good prognosis groups based on clinical outcomes during hospitalization（followed up for 1 month or death）. The whole blood NLR and peripheral blood Th17/Treg levels were measured and compared among different severity groups or between different prognosis groups，respectively. Receiver operating characteristic（ROC）curves were plotted to analyze the prognosis predictive value of each index for AP. Kaplan-Meier method was used to draw survival curves for prognostic evaluation.Results Whole blood NLR and peripheral Th17/Treg levels progressively increased in MAP，MSAP，and SAP groups，with statistically significant differences（P＜0.05）. Among 152 patients，42 had poor prognosis and 110 had good prognosis. The poor prognosis group showed significantly higher NLR（11.07±3.98 vs 8.71±2.71，t=3.542，P＜0.05）and Th17/Treg（3.34 ± 0.52 vs 2.95 ± 0.54，t=2.528，P＜0.05）levels than those in the good prognosis group. ROC analysis demonstrated that the area under the curve（AUC）of combined NLR and Th17/Treg for predicting the prognosis of patients with AP was 0.835（95%CI：0.766-0.890），which was higher than that of NLR alone（AUC=0.638，95%CI：0.556-0.714）and Th17/Treg alone（AUC=0.662，95%CI：0.581-0.736）. Kaplan-Meier survival analysis revealed that patients with elevated NLR or Th17/Treg levels exhibited markedly poor prognoses（P＜0.05）. Conclusion The levels of NLR and Th17/Treg in AP patients increased with the aggravation of disease severity. The combined application of NLR and Th17/Treg demonstrates substantial clinical value in predicting prognosis，providing guidance for clinical management of AP.