Neutrophil-driven and Interleukin-36γ associated ocular surface inflammation in chronic Stevens-Johnson syndrome

Abstract

Purpose : The mechanism of ocular surface damage in chronic Stevens-Johnson syndrome (SJS) is vaguely understood. This study aims to unravel the molecular mechanisms involved in the ocular surface complications of SJS.

Methods : Mass spectroscopy was performed to quantify the tear fluid proteins from chronic SJS patients (n=12) and age-gender matched controls (n=12). Significance test of the differentially expressed proteins was evaluated by student t-test. The candidate proteins were validated using Enzyme-Linked Immunosorbent Assay (ELISA; n=40) in tear samples and Immunohistochemistry (IHC; n=6) in eyelid margins respectively. The candidate proteins were compared between ocular severity gradings, duration of disease, age and gender.

Results : The total number of tear fluid proteins identified were 1692, of which 470 were significantly differentially regulated proteins in chronic SJS tears. The top ten significantly upregulated proteins were neutrophil secretions including neutrophil elastase (p<0.0001), defensin (p<0.0001) and matrix metalloproteinase 8 (p<0.0001). The presence of neutrophils was confirmed by the upregulation of Interleukin-8 (IL-8; p<0.001) in SJS tears and positive expression of myeloperoxidase and CD11b in the keratinized eyelid margins of SJS patients. Among 41 unique proteins, Interleukin-36γ (IL-36γ; p<0.01) was consistently expressed in 11 SJS patients and it was confirmed by ELISA and IHC. Interleukin-36γ expression was observed in the neutrophils present in the lid margin keratinized tissue of SJS patients. Majority of the significantly downregulated proteins were lacrimal gland secretions such as lacritin (p<0.0001) and opiorphin (p<0.002). Neutrophil elastase (p<0.02) was significantly elevated in patients with severe lid margin keratinization.

Conclusions : Our findings show that, ocular surface inflammation in chronic SJS was closely associated with neutrophils and IL-8 signaling molecule. Parallelly, neutrophils expressing IL-36γ was found to be associated with lid margin keratinization. Therefore IL-8 and IL-36γ can be potential therapeutic targets for ocular surface inflammation and lid margin keratinization in chronic ocular SJS.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.