Introduction: This study aimed to investigate the correlation between serum interleukin (IL)-17A levels and responsiveness to intravenous immunoglobulin (IVIG) therapy in Kawasaki disease (KD) patients. Methods: A retrospective analysis on data from 192 KD patients admitted to the Anqing Municipal Hospital between January 2021 and January 2024 was conducted. Patients were categorized into IVIG-nonresponsive and IVIG-sensitive groups as per the treatment outcomes. Outcome measures included serum IL-17A levels, left coronary artery (LCA) Z scores, and relevant laboratory parameters. Logistic regression analysis was performed to identify predictive factors for IVIG responsiveness, and diagnostic performance was assessed using receiver operating characteristic (ROC) curves and calculation of the area under the curve (AUC). Results: A total of 40 IVIG-nonresponsive cases and 152 IVIG-sensitive cases were included. Prior to intervention, IVIG-nonresponsive patients had significantly higher serum IL-17A levels compared to IVIG-sensitive patients, with a statistically significant difference. After intervention, serum IL-17A levels significantly decreased in IVIG-sensitive patients while remaining elevated in IVIG-nonresponsive patients. IVIG-nonresponsive patients exhibited significantly higher levels of C-reactive protein (CRP), white blood cell count (WBC), NE, and ALT compared to IVIG-sensitive patients, whereas no significant differences in LCA Z scores between the two groups existed. Multivariable logistic regression analysis identified pre-IL-17A, CRP, WBC, and ALT as independent predictors of IVIG-nonresponsiveness in KD. When pre-IL-17A was ≥39.96 pg/mL, the specificity and sensitivity for predicting IVIG-nonresponsive KD were 63.9% and 71.9%, respectively, with an AUC of 0.637. The combined diagnosis of IL-17A, CRP, WBC, and ALT yielded an AUC of 0.780. Conclusion: Serum IL-17A levels were remarkably elevated in IVIG-nonresponsive KD patients both before and after intervention. A serum IL-17A level (≥39.96 pg/mL) demonstrated good predictive profile for IVIG-nonresponsive KD, and combining IL-17A with CRP, WBC, and ALT improved diagnostic performance.
