Tear proteomic atlas of local host-response states in herpes simplex keratitis

Herpes simplex keratitis (HSK) is a leading cause of infectious corneal blindness, yet local host-response programs underlying active disease, recurrence, and stromal involvement remain incompletely understood. This study aimed to establish a deep tear proteomic atlas of HSK and characterize phenotype-associated local host-response states.

Data-independent acquisition mass spectrometry was used to profile tear proteins from HSK-affected eyes (n = 20), contralateral unaffected eyes (n = 12), and healthy control eyes (n = 25). Differential abundance testing, co-expression network analysis, functional enrichment, and exploratory analyses of recurrence status and clinical phenotypes were performed. Bootstrap LASSO prioritized candidate tear host-response signatures, and cross-omic concordance was examined using an independent RNA-seq dataset.

We quantified 4656 proteins, with 480 upregulated and 267 downregulated in HSK-affected eyes versus controls. HSK-affected eyes showed immune-metabolic remodeling, with activated humoral immunity/coagulation pathways and suppressed glycoprotein metabolism and mitochondrial energy homeostasis. Co-expression networks identified HSK-associated modules enriched in immune activation and oxidative stress, alongside negatively associated modules linked to structural maintenance. Recurrent HSK showed distinct proteomic programs involving epidermal development and actin cytoskeleton regulation. Stromal HSK showed enrichment of extracellular matrix organization and wound healing programs, whereas epithelial/mixed subtypes were enriched for translational and post-transcriptional regulatory processes. KRT12 and SNRPD3 were prioritized as tissue-concordant candidate tear host-response signatures showing consistent upregulation in an independent corneal-tissue RNA-seq dataset.

This comprehensive tear proteomic atlas provides a molecular resource for investigating local host-response heterogeneity in HSK and prioritizes candidate tear markers for future prospective and independent validation.