IGHG2 and Behcet disease: Using an XGBoost‐based model, key features including TNC, F11, ITIH4.2, FN11, ITIH4, F5, IGHG2, VWF, VTN, APMAP, IGHG1, LRG1, DBI, IGKV1‐27, and SERPINA3 were identified as critical biomarkers for BD severity stratification (Figure 4C).