Objective:To investigate the expression and significance of serum soluble T cell immunoglobulin-domain and mucin-domain protein-3 (sTIM-3) and galectin-9 (Gal-9) in patients with early acute pancreatitis (AP), so as to provide theoretical and clinical evidence for the early prediction and diagnosis of AP.Methods:From 15 September 2020 to 23 July 2021, a total of 94 AP patients with a time from onset to admission ≤48 h who were admitted to Changzhou No.2 People′s Hospital, Nanjing Medical University were selected, including 42 cases of mild acute pancreatitis (MAP), 35 cases of moderately severe acute pancreatitis (MSAP) and 17 cases of severe acute pancreatitis (SAP). The basic clinical features of AP patients were collected. Acute physiology and chronic health evaluation Ⅱ(APACHE Ⅱ), modified computed tomography severity index (MCTSI) and bedside index for severity in acute pancreatitis (BISAP) scores were evaluated in all AP patients. The levels of serum interleukin (IL)-6, IL-10, Gal-9 and sTIM-3 were detected with enzyme linked immunosorbent assay. Kruskal-Wallis test and Mann-Whitney U test were used for statistical analysis. Spearman rank correlation test and Pearson correlation analysis were used to analyze the correlation of sTIM-3, Gal-9 with inflammatory indicators and AP related scoring systems. Receiver operating characteristic curve (ROC) was performed for efficiency analysis of the combination of sTIM-3 and Gal-9 in predicting the severity of AP patients. Results:Serum sTIM-3, Gal-9 and IL-6 levels of SAP patients were higher than those of MAP patients (2 085.00 ng/L (1 628.00 ng/L, 2 673.00 ng/L) vs. 746.10 ng/L (514.50 ng/L, 1 303.00 ng/L); 466.60 ng/L (375.90 ng/L, 629.30 ng/L) vs. 108.10 ng/L (90.29 ng/L, 138.90 ng/L); (323.60±62.93) ng/L vs. (42.90±28.82) ng/L), while IL-10 level was lower than that of MAP patients ((760.30±200.40) ng/L vs. (1 206.00±566.30) ng/L), and the differences were statistically significant ( Z=45.00 and <0.01, t=23.62 and 3.15; all P<0.01). The APACHE Ⅱ and BISAP scores of SAP patients were higher than those of MAP and MSAP patients (12.00(6.00, 16.50) vs. 3.00(2.00, 5.00) and 6.00(3.00, 8.00); 3.00(3.00, 4.00) vs.1.00(1.00, 1.00) and 2.00(2.00, 3.00)), and the MCTSI score was higher than that of MAP patients (4.00(3.00, 6.00) vs. 2.00(0.00, 2.00)), and the differences were statistically significant ( Z=644.50, 704.00, 474.50, 492.50 and 664.00, all P<0.001). Serum sTIM-3 and Gal-9 were positively correlated with the pro-inflammatory factor IL-6 ( r=0.552 and 0.297, P<0.001 and =0.004). Serum sTIM-3 was negatively correlated with the anti-inflammatory factor IL-10 ( r=-0.397, P<0.001). There was no correlation between Gal-9 and the anti-inflammatory factor IL-10 ( P>0.05). Serum sTIM-3 and Gal-9 were positively correlated with APACHE Ⅱ, MCTSI and BISAP scores ( r=0.210, 0.271 and 0.363, P=0.042, =0.008 and <0.001; r=0.390, 0.448 and 0.440, all P<0.001). The areas under ROC curves (95% confidence interval) of serum sTIM-3 and Gal-9 detected alone and in combination was 0.805 (0.716 to 0.895), 0.814 (0.725 to 0.903) and 0.856 (0.773 to 0.939), respectively, and the sensitivity was 69.2%, 67.3%, 75.0%, respectively, and the specificity was 83.3%, 97.6%, 97.6%, respectively. Conclusions:The serum levels of sTIM-3 and Gal-9 increased in patients with early AP and are correlated with the severity of AP. The combined detection of sTIM-3 and Gal-9 has high sensitivity in predicting early AP, and the two indicators may be the reliable predictors of early AP.