Detection of neutrophils and possible involvement of interleukin-8 in diffuse lamellar keratitis after laser in situ keratomileusis

PURPOSE: To investigate the cell populations in diffuse lamellar keratitis (DLK) infiltration after laser in situ keratomileusis and the possible mechanism underlying the infiltration. SETTING: Department of Ophthalmology, Tokyo Dental College, Chiba, Japan. METHODS: To develop DLK in rabbit eyes, 25 microL of lipopolysaccharide (LPS) solution at a concentration of 50 microg/mL was applied to the stromal bed beneath corneal flaps. For control rabbits, phosphate-buffered saline was applied. Postoperative examination by slitlamp microscopy was performed for 3 days after surgery. Rabbit eyes were excised and examined for histopathology with hematoxylin and eosin staining. Immunohistochemical analysis for interleukin (IL)-8 was performed. RESULTS: Diffuse lamellar keratitis-like inflammation composed mainly of neutrophils was reproduced by LPS instillation in rabbit eyes. In eyes with severe inflammation, IL-8 immunoreactivity was found in the stromal keratocytes and infiltrating neutrophils. CONCLUSIONS: The major cell type in the DLK infiltration induced by LPS instillation in rabbit eyes was the neutrophil. Interleukin-8, a prototype of CXC chemokine produced by keratocytes and neutrophils, may contribute to the development of DLK.