IL9 and appendicitis: Concentrations of IL-9 and IL-13 were significantly higher in the children with complicated appendicitis [1.8 (IQR 1.1-3.2) pg/mL and 24.6 (IQR 12.9–58.5) pg/mL] compared to the children with uncomplicated appendicitis [1.4 (IQR 0.8–2.1) pg/mL and 14.6 (IQR 10.2–24.3) pg/mL, p = 0.047 and 0.002, respectively].