IL4 and food allergy: Receiver operated characteristic (ROC) analysis revealed that among patients with S. aureus skin colonization, an IL-4 concentration of >10.6 pg/mL had a specificity of 84.6% (95% CI: 57.8%–97.3%) and sensitivity of 68.2% (47.3%–83.6%) for food allergy (Figure 1C).