Tear Cytokine Signature in Vernal Keratoconjunctivitis: A Chemokine-Remodeling Axis Associated with Disease Severity

Vernal keratoconjunctivitis (VKC) is a chronic pediatric ocular allergy that can progress from seasonal to persistent inflammation with vision-threatening complications. Although Th2-associated mechanisms have been implicated, the immune correlates of disease severity are not well defined. Tear samples from VKC patients (moderate intermittent and moderate persistent) and healthy controls were collected using Schirmer's strips. Cytokine profiling was performed using the OLINK^® Target 48 Cytokine Panel. Differential expression, correlation with clinical features, and pathway enrichment analyses were performed. Compared to control, IL-15, CXCL11, CXCL9, MMP12, and CCL13 were significantly elevated in VKC, with higher levels in the persistent phenotype. These cytokines correlated with symptom duration, limbal involvement, and papillary hypertrophy. Pathway analysis revealed enrichment of IL-17, JAK-STAT, and chemokine signaling pathways. VKC severity is associated with distinct tear cytokine signatures, with the persistent phenotype showing enhanced chronic inflammatory signaling. These findings identify candidate tear-based markers of disease severity that require validation in larger, independent, and longitudinal cohorts.