Acyclovir-resistant herpes simplex virus type 1 infection after HLA-haploidentical stem cell transplantation

Abstract

A 14-year-old girl with FLT3-ITD-positive acute myeloid leukemia underwent HLA-haploidentical stem cell transplantation (SCT) from her father using a myeloablative conditioning regimen. Despite acyclovir (ACV) prophylaxis, the patient developed severe gingivostomatitis on day 56 after SCT, and herpes simplex virus type (HSV)-1 was detected in the oral mucosal membrane and blood. Increasing the dose of ACV did not improve her symptoms. A genetic drug resistance test revealed a mutation in the viral thymidine kinase gene. Furthermore, an antiviral susceptibility test confirmed the ACV resistance of HSV-1. Subsequent switching of antiviral therapy from ACV to foscarnet led to a prompt improvement. The incidence of ACV-resistant HSV infection will likely increase owing to the prevalence of HLA-mismatched SCT. Therefore, it is desirable to develop an examination system for drug-resistance-associated tests to insure the adaptation of antiviral drugs effective against ACV-resistant HSV-1.