CXCL8 and thymoma: As determined by Youden’s index, the optimal cutoff point of the proportion of IL-8+ naïve CD4+ T cells for the diagnosis of thymoma was 2.66% (95% CI for cutoff point: 2.225–3.945%), with 94.1% specificity and 92.8% sensitivity (Fig. 3c); the optimal cutoff point of the proportion of IL-8+ naïve CD8+ T cells for the diagnosis of thymoma was 3.35% (95% CI for cutoff point: 1.775–5%), with 94% specificity and 88.2% sensitivity (Fig. 3d).