title: Inflammation and the nervous system: the connection in the cornea in patients with infectious keratitis.
abstract: OBJECTIVE
  To study the density and morphologic characteristics of epithelial dendritic cells, as correlated to subbasal corneal nerve alterations in acute infectious keratitis (IK) by in vivo confocal microscopy (IVCM).
  
  
  METHODS
  IVCM of the central cornea was performed prospectively in 53 eyes with acute bacterial (n = 23), fungal (n = 13), and Acanthamoeba (n = 17) keratitis, and in 20 normal eyes, by using laser in vivo confocal microscopy. Density and morphology of dendritic-shaped cells (DCs) of the central cornea, corneal nerve density, nerve numbers, branching, and tortuosity were assessed and correlated. It should be noted that due to the "in vivo" nature of the study, the exact identity of these DCs cannot be specified, as they could be monocytes or tissue macrophages, but most likely dendritic cells.
  
  
  RESULTS
  IVCM revealed the presence of central corneal DCs in all patients and controls. The mean DC density was significantly higher in patients with bacterial (441.1 ± 320.5 cells/mm(2); P < 0.0001), fungal (608.9 ± 812.5 cells/mm(2); P < 0.0001), and Acanthamoeba keratitis (1000.2 ± 1090.3 cells/mm(2); P < 0.0001) compared with controls (49.3 ± 39.6 cells/mm(2)). DCs had an increased size and dendrites in patients with IK. Corneal nerves were significantly reduced in eyes with IK compared with controls across all subgroups, including nerve density (674.2 ± 976.1 vs. 3913.9 ± 507.4 μm/frame), total nerve numbers (2.7 ± 3.9 vs. 20.2 ± 3.3), main trunks (1.5 ± 2.2 vs. 6.9 ± 1.1), and branching (1.2 ± 2.0 vs. 13.5 ± 3.1; P < 0.0001). A strong association between the diminishment of corneal nerves and the increase of DC density was observed (r = -0.44; P < 0.0005).
  
  
  CONCLUSIONS
  IVCM reveals an increased density and morphologic changes of central epithelial DCs in infectious keratitis. There is a strong and significant correlation between the increase in DC numbers and the decreased subbasal corneal nerves, suggesting a potential interaction between the immune and nervous system in the cornea.
authors: Ocular Surface Imaging Center, Massachusetts Eye & Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts 02114, USA.
authors: Andrea
authors: A
authors: Cruzat
authors: Deborah
authors: D
authors: Witkin
authors: Neda
authors: N
authors: Baniasadi
authors: Lixin
authors: L
authors: Zheng
authors: Joseph B
authors: JB
authors: Ciolino
authors: Ula V
authors: UV
authors: Jurkunas
authors: James
authors: J
authors: Chodosh
authors: Deborah
authors: D
authors: Pavan-Langston
authors: Reza
authors: R
authors: Dana
authors: Pedram
authors: P
authors: Hamrah
mesh_terms: D000208:Acute Disease; D000328:Adult; D002452:Cell Count; D003315:Cornea / Q000294:innervation*; D003320:Corneal Ulcer / Q000382:microbiology* / Q000469:parasitology*; D003430:Cross-Sectional Studies; D003713:Dendritic Cells / Q000473:pathology*; D015817:Eye Infections / Q000382:microbiology* / Q000469:parasitology*; D005260:Female; D006801:Humans; D007107:Immune System / Q000502:physiology; D008297:Male; D018613:Microscopy, Confocal; D008875:Middle Aged; D009420:Nervous System; D009882:Ophthalmic Nerve / Q000276:immunology / Q000473:pathology*; D011446:Prospective Studies; D016037:Single-Blind Method