Lid margin stem cell in trachoma

Purpose : Abnormal stem cells at the lid margin contribute to chronic conjunctivitis. The major objective of this study was to evaluate the stem cells and the immunohistological changes in the mucocutaneous junction in patients with inactive trachoma. Design : This is a case controlled histological study. Participants and control : The participants are five patients with chronic conjunctivitis but no active trachoma with or without lid margin keratinization and the controls are four cases scheduled for chalazion excision. Method : Lid margin specimen from five patients and four controls were fixed and stained with PAS, anticytokeratin, Involucrin and Ki67. The cytokeratins included CK68 for keratinization and CK8, 18, 19 and CK13 for nonkeratinization. Main Outcome Measures : The number of Ki67 positive cells at the mucocutaneous junction and the pattern of staining of keratinization and nonkeratinization cytokeratins. Results : Goblet cells were decreased in severely affected cases. Keratinization marker CK68 and involucrin were positive at the conjunctiva and simple epithelium marker CK 8, 18, 19 was negative in severe conjunctival disease. Ki67 revealed aggregates of proliferating suprabasal cells at the mucocutaneous junction (56 cell/HPF in controls versus 25 cells/HPF in affected patients). Conclusion : In patients with inactive trachoma, alteration of the stem cells at the lid margin mucocutaneous junction may lead to squamous metaplasia with abnormal cytokeratins expression and chronic conjunctivitis.