CD15⁺ as a marker of ocular surface dysregulation in type 2 diabetes mellitus: association with tear mucin and squamous metaplasia

Abstract

Purpose: To evaluate the potential of CD15⁺ expression in bulbar conjunc- tival epithelial cells as a marker of ocular surface dysregulation in patients with type 2 diabetes mellitus, and to investigate its association with tear mucin levels and the degree of squamous metaplasia. Methods: The study involved 37 patients (37 eyes) with ocular surface changes and type 2 diabetes mellitus, who comprised the main group. Based on the cytological changes in the bulbar conjunctiva and accord- ing to Nelson’s classification, patients were divided into two main groups: Group 1–29 patients (29 eyes) with changes in the bulbar conjunctiva cor- responding to grades II and III of squamous metaplasia according to Nel- son’s classification; Group 2–8 patients (8 eyes) with bulbar conjunctival changes corresponding to grades 0–I according to Nelson’s classification. The control group consisted of 15 patients (15 eyes) who were healthy in- dividuals. The average age of patients in both the main and control groups was 62.07 ± 5.94 years and 63.93 ± 7.00 years, respectively. All participants underwent a full ophthalmologic exam, including conjunctival impression cytology (graded using Nelson’s scale). CD15⁺ expression was assessed by immunohistochemistry, and tear mucin levels were measured biochemi- cally. Results: The level of mucin was significantly lower in study group I–0.95 ± 0.18 g/l compared to study group I I–1.28 ± 0.09 g/l and con- trols–1.59 ± 0.08 g/l (p < 0.0001). Further intragroup comparative anal- ysis between patients with Nelson’s grades II and III has revealed signif- icant differences in both relative expression of C D 15+ and mucin level (p < 0.0001). A strong negative correlation was found between CD15⁺ ex- pression and mucin levels in study group I (rs = –0.87; p < 0.0001). Across all T2 DM patients (37 eyes), the correlation remained strong (rs = –0.9). Nelson’s grades also negatively correlated with mucin levels (rs = –0.87; p < 0.0001). In group I, mucin levels strongly correlated with abnormal Nelson’s grades (rs = –0.83; p < 0.0001). These associations were not evi- dent in group II or the control group. Conclusion: CD15⁺ expression in the conjunctival epithelium demon- strates a strong inverse correlation with tear mucin levels and is associ- ated with the severity of squamous metaplasia in patients with type 2 di- abetes mellitus. These findings suggest that CD15⁺ may serve as a useful marker of ocular surface inflammation and homeostatic imbalance in dia- betic eye disease. Angaben zu potentiellen Interessenkonflikten: Tetiana Zhmud Consulting: No Employee: No Financial support: No Patent: No Financial participation: No Related individuals employed: No Other: No Industrial sponsoring: No