Successful foscarnet therapy for mucocutaneous infection with herpes simplex virus in a recipient after unrelated bone marrow transplantation

A 36-year-old Japanese man who received an unrelated bone marrow transplant (BMT) developed severe mucocutaneous infection with herpes simplex virus (HSV) type 1 during oral acyclovir prophylaxis. The lesions progressed despite treatment with intravenous acyclovir and vidarabine. The HSV isolates were sensitive to acyclovir, vidarabine and foscarnet in vitro, but peripheral CD3- or CD19-positive cells were barely detectable even 4 months after transplant. A 12-day course of treatment with foscarnet led to a rapid improvement. Foscarnet therapy should be considered for all severe HSV infections following BMT, regardless of whether or not the HSV isolates are sensitive to acyclovir.