IL6 and congenital rubella syndrome: Temporal biomarker profiling identified day 7 post-infusion as a pivotal window for CRS escalation, marked by significantly elevated inflammatory markers in high-grade cases: CRP (42.85 vs. 19.1 mg/L, P < 0.001), ferritin (2868.7 vs. 1219.8 ng/mL, P < 0.001), and IL-6 (61.46 vs. 14.565 pg/mL, P = 0.013), alongside coagulation dysfunction evidenced by prolonged activated partial thromboplastin time (APTT) (43.6 vs. 39 s, P = 0.044).