Prevalence and Clinical Consequences of Herpes Simplex Virus Type 1 DNA in Human Cornea Tissues

Background. We determined the prevalence and clinical consequences of herpes simplex virus (HSV) type 1 (HSV-1), HSV type 2 (HSV-2), and varicella-zoster virus (VZV) in cornea tissues obtained after penetrating keratoplasty (PKP) was performed. Methods. The excised corneas of 83 patients with a history of herpetic keratitis (HK; hereafter referred to as "patients with HK") and 367 patients without a history of HK (hereafter referred to "patients without HK") were analyzed by real-time polymerase chain reaction (PCR) and virus culture for the presence of HSV-1, HSV-2, and VZV. In addition, 273 post-PKP donor corneoscleral rims were analyzed. The medical records of the transplant patients were reviewed to determine the risk factors influencing intracorneal viral load and graft survival. Results. HSV-1 was the most prevalent herpesvirus. Both the prevalence of HSV-1 and the HSV-1 DNA load were higher in the corneas of patients with HK than in those of patients without HK. The HSV-1 DNA load in the corneas of patients with HK correlated with age, the recurrence-free interval, cornea neovascularization, steroid treatment before PKP, and disease severity. Herpesvirus DNA was detected in 2 of 273 corneoscleral rims. Graft survival was inversely correlated with the corneal HSV-1 DNA load in patients with HK. Conclusions. The data presented in this study argue for the implementation of real-time HSV-1 PCR to analyze the excised corneas of patients with HK, to improve post-PKP diagnosis and therapy. Screening of donor corneal tissues for herpesviruses is redundant to prevent newly acquired post-PKP HK.