In vivo immunofluorescence to diagnose herpes simplex virus keratitis in mice

Background/aims-Herpes simplex virus keratitis (HSK) is the most common cause of corneal blindness in the Western world. Delay in the treatment of HSK can lead to a more significant corneal scar and topical steroid treatment in unsuspected active HSK can lead to corneal melting. Current culture techniques for herpes simplex virus (HSV) take several days and commercially available HSV laboratory based diagnostic techniques such as Herpchek vary in sensitivity. This study was conducted to assess the viability of a new, quicker, and simpler method to diagnose HSK. Methods-Direct immunofluorescence was used in vivo in a masked study to diagnose HSK in mice using a standard slit lamp with cobalt blue illumination. Murine monoclonal fluorescently labelled antibody was applied to the cornea for 10 or 20 minutes and then washed off with phosphate buffered solution. Mice with HSK were stained with either fluorescently labelled monoclonal against HSV or fluorescently monoclonal antibody against cytomegalovirus. Mice with corneal abrasions of nonviral origin were given fluorescently labelled monoclonal antibody against HSV. Results-Fluorescence was seen only in the mice with HSK given fluorescently labelled monoclonal antibody against HSV. This observation was confirmed upon microscopic immunofluorescent imaging of the corneal epithelial sheets. Conclusion-In vivo immunofluorescence may be useful in the clinical diagnosis of HSK.