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Editor,—According to polymerase chain reaction (PCR) studies1 up to 20% of organ culture donor corneas may contain herpes simplex virus (HSV) DNA. Only five HSV donor cornea infections, however, have been reported worldwide1-3 (J Garweg, M Böhnke, personal communication). In only one of the five cases published so far the infection was transmitted to the recipient.1 The other four corneas showed severe endothelial damage and were discarded before transplantation.1 2 It is likely therefore that the whole virus must be present at the time of donor retrieval to result in subsequent transmission of disease to the recipient.4 We here report another donor cornea with HSV infection in organ culture.
The donor was a 74 year old woman with a history of severe ischaemic heart disease. After cardiac surgery she required ventilation for 3 weeks and finally died as a result of septicaemia. Screening serological tests performed 5 days before the donor's death revealed evidence of previous exposure to herpes simplex virus, varicella zoster virus, and cytomegalovirus infection without acute exacerbation. No conjunctival injection or corneal opacity was observed macroscopically. Both corneas were excised 2 hours post mortem and placed in organ culture 11 hours later. Slit lamp evaluation of the corneoscleral discs revealed epithelial dendritiform changes of the left cornea whereas the right cornea was clear (Fig 1). Endothelial cell count was estimated at 2500/mm2 by phase contrast microscopy in both corneas. Seven days later total necrosis of the endothelium and the keratocytes was observed in the left cornea in contrast with only minor endothelial alterations of the right cornea. Routine bacteriological and mycological cultures at that time were negative, and the storage media were clear and normally coloured. A sample of each storage medium was cultured for virus and examined by PCR and the left cornea was fixed for microscopic examination. HSV-1 was detected by both methods in the medium of the left cornea but not of the right cornea. Histopathological examination confirmed unilateral total necrosis of the endothelium and the keratocytes. Immunohistochemical examination also gave an HSV-1 positive result. The right cornea was discarded 8 days later because of an insufficient endothelial cell count (below 2000).
This report illustrates for the first time in an organ culture cornea the course of an HSV-1 dendritic keratitis in the absence of immunological influence leading to complete necrosis of the endothelium and keratocytes. HSV-1 infection of the donor cornea was present already at the time of donor cornea excision supporting our hypothesis that horizontal transmission of HSV can only occur if active virus, and not only HSV-DNA fragments, is placed in organ culture. In addition to previously published reports we observed the typical clinical appearance of a dendritic corneal lesion in vitro. This provides compelling further evidence for HSV-1 infection of donor cornea as a cause for subsequent endothelial cell loss in organ culture.