Objective To explore expression and significance in serum levels of soluble receptor for advanced glycation end products (sRAGE) and interleukin-36 (IL-36) in patients with Hashimoto's thyroiditis (HT).

Methods A total of 180 individuals suspected of HT were enrolled as study subjects and divided into HT group (n=137) and non-HT group (n=43) based on final diagnostic outcomes. Within the HT group, patients were further divided into serum immunoglobulin G4 (IgG4)-related HT group (IgG4≥135 mg/dL) and non-IgG4-related HT group (IgG4 < 135 mg/dL) according to serum IgG4 levels. Serum levels of sRAGE and IL-36γ were measured in all subjects using enzyme-linked immunosorbent assay (ELISA). Receiver operating characteristic (ROC) curves were used to analyze the diagnostic value of serum sRAGE and IL-36γ levels forHT and its IgG4 phenotype.

Results Serum sRAGE levels were significantly lower in the HT group compared to the non-HT group, while serum IL-36γ levels were significantly higher (P < 0.001). Patients in the IgG4-related HT group had significantly lower serum sRAGE levels and higher serum IL-36γ levels compared to those in the non-IgG4-related HT group (P < 0.001). ROC curve analysis revealed that the combined diagnosis of serum sRAGE and IL-36γ for HT had an area under the curve (AUC) of 0.900 (95%CI, 0.846 to 0.939), demonstrating significantly higher diagnostic efficiency than either indicator (P < 0.05). For the IgG4 phenotype in HT patients, the combined AUC of serum sRAGE and IL-36γ was 0.897 (95%CI, 0.934 to 0.943), which also significantly higher than individual indicator (P < 0.05).

Conclusion Serum sRAGE levels are significantly decreased, while serum IL-36γ levels are significantly increased in HT patients. Combined detection of serum sRAGE and IL-36γ levels can effectively diagnose HT and assess the IgG4 phenotype.