Abstract
Purpose: :
To study the density and morphological characteristics of epithelial dendritic cells (DC) as correlated to subbasal corneal nerve alterations in acute infectious keratitis (IK) by laser in vivo confocal microscopy (IVCM).
Methods: :
IVCM of the central cornea was performed in 37 eyes with acute bacterial (n=11), Acanthamoeba (n=15), fungal (n=6), and adenoviral keratitis (n=5), and in 20 normal eyes, by using the Heidelberg Retina Tomograph 3 with the Rostock Cornea Module (HRT3/RCM). Central corneal DC density, DC morphology, corneal nerve density, nerve numbers, branching and tortuosity were assessed and correlated. A new DC classification for the cornea was developed based on morphological changes.
Results: :
The mean epithelial DC density was significantly higher in patients with bacterial keratitis (585±660 cells/mm2; p=0.0004), Acanthamoeba (1106±1207 cells/mm2; p<0.0001), adenoviral (2261±1766 cells/mm2; p<0.0001) as compared to controls (42.2±34.7 cells/mm2), except for fungal keratitis (820±1368 cells/mm2; p=0.1). Corneal subbasal nerve plexus was significantly diminished in eyes with IK as compared to controls across all sub-groups, including nerve density (308 vs. 2792 µm/µm2), total nerve number (1.6 vs. 14.9), main trunks (1.1 vs. 5.2), and branching (0.5 vs. 5.8) (p<0.0001). Decreased nerve density was associated with an increase in DC (r = -0.4, p<0.0001). DC morphology changed over time, but was not associated with the etiology of the keratitis.
Conclusions: :
IVCM revealed an increased density and morphological changes of central epithelial DC in infectious keratitis. The increase in DC density is strongly associated with the diminishment of the subbasal corneal nerves, suggesting a direct interaction between the immune and nervous system in the cornea.
Keywords: imaging/image analysis: clinical • keratitis • microscopy: confocal/tunneling