Association of Conjunctival Cell HLA-DR Expression with the Severity of Signs and Symptoms of Dry Eye Disease at Baseline in the NORTHERN LIGHTS Phase 2 Trial

Purpose: To assess the association of HLA-DR on ocular surface conjunctival cells with the severity of signs and symptoms of dry eye disease (DED) in patients enrolled in the NORTHERN LIGHTS phase 2 trial. Methods: Patients with moderate to severe DED were recruited from 10 different countries in Europe. Symptoms of DED were assessed using the visual analog scale (VAS) global discomfort score, and signs via corneal fluorescein staining (CFS), lissamine green staining, Schirmer's test, and tear osmolarity. HLA-DR expression was evaluated via flow cytometry from impression cytology of conjunctival cells using the EyePrim (TM) device sampled from 205 DED patients. Results: HLA-DR expression was detected in a mean of 3.4% of cells at baseline. HLA-DR expression was significantly associated with corneal staining severity at baseline (p < 0.01). HLA-DR expression was not significantly associated with DED symptoms (VAS global discomfort score), nor lissamine green staining, Schirmer's test, tear osmolarity, or Sjogren's syndrome. Conclusion: HLA-DR was present in a wide range of percentages among DED patients indicating the heterogeneous nature of DED. HLA-DR was significantly associated with corneal fluorescein staining suggesting a correlation of the biomarker with ocular surface damage.