Evaluation of Langerhans Cell Density and Distribution in the Corneal Epithelium of Healthy Volunteers and Contact Lens Wearers With in vivo Confocal Microscopy

Abstract

Abstract: : Objective: dendritic cells are highly potent antigen–presenting cells of bone–marrow origin that can stimulate both primary and secondary T– and B–cell responses. The aim of our in vivo study was (i) to prove the presence of Langerhans cells (LCs) as in center as in a periphery of the cornea and (ii) to examine and compare the density and distribution of LCs in the corneal epithelium of healthy volunteers and contact lens wearers. Method: 225 eyes of 129 healthy volunteers (age: 16–81 years) without history of ocular inflammation or surgery and 99 eyes of 59 contact lens wearers (age: 13–76 years) were examined in vivo with the combination of the Heidelberg Retina Tomograph II and in–house developed Rostock Cornea Module. The confocal microscopy was made after the slit lamp investigation. The identification of the LCs was performed immunohistochemically on enucleated eyes. Results: Rostock Cornea Module allows to determine LCs as bright corpuscular particles with DC morphology and a diameter of up to 15µm. Moreover, LCs presented as either large cells bearing long processes or smaller cells lacking cell dendrites, most supposedly indicating mature and immature phenotype, respectively. LCs were located at the depth of 35–55µm, i.e. the level of intermediate cells, basal cells and subepithelial nervous plexus. In healthy volunteers, in vivo confocal microscopy revealed 70 eyes with LCs including 55 eyes presenting with both central and peripheral LC location. LC densities averaged 30±3 cells/mm² (range 0–64 cells/mm²) in the central part and 89±6 cells/mm² (range 0–240 cells/mm²) in the periphery of the cornea. The group of contact lens wearers comprised 59 eyes with LCs including 24 eyes with both central and peripheral LC location. In contact lens wearers, density of LCs varied from 60±16 cells/mm² (range 0–600 cells/mm²) in the central to 159±18 cells/mm² (range 0–700 cells/mm²) in the peripheral part of the cornea. LC densities significantly differed between healthy volunteers and contact lens wearers both in the central (p=0.03) and the peripheral cornea (p=0.001). Conclusions: In vivo confocal microscopy makes possible in vivo assessment of density and distribution of LCs in the corneal epithelium, providing insight into human eye immunology.

Keywords: cornea: epithelium • inflammation • microscopy: confocal/tunneling