Corneal herpes simplex virus type 1 superinfection in patients with recrudescent herpetic keratitis.

Herpetic keratitis is a common sequel of a corneal infection with herpes simplex virus (HSV)-1. Recrudescent herpetic keratitis (RHK) may result in irreversible damage to the cornea. Recurrences may be caused by reactivation of endogenous HSV-1 or reinfection with exogenous HSV-1. The objective of this study was to determine the incidence and risk factors involved of HSV-1 superinfection in patients with RHK. From 30 patients with RHK, sequential corneal HSV-1 isolates were genotyped by PCR amplification of the hypervariable regions located within the HSV-1 genes US1, US10/11, and US12. The clinical data from the patients obtained retrospectively were: ophthalmologic history, clinical picture during recurrences, number and time points of penetrating keratoplasty (PKP), and steroid or acyclovir treatment. Whereas the sequential corneal HSV-1 isolates of 19 (63%) of 30 patients had the same genotype (designated as group 1), the sequential isolates of 11 patients (37%) were genetically different (designated as group 2). Among the clinical data analyzed, only the time point of PKP was significantly different between the patient groups. Although no patients in group 1 had undergone transplantation between samplings, 4 of 11 patients in group 2 underwent PKP during the inter-recurrence period in the same eye from which the corneal HSV-1 isolates were obtained. The data demonstrate that RHK is frequently associated with corneal reinfection with a different HSV-1 strain and suggest that PKP is a risk factor for corneal HSV-1 superinfection.