The Influence of Cyclosporin Immunosuppression on the Efficacy of Famciclovir or Valaciclovir Chemotherapy Studied in a Murine Herpes Simplex Virus Type 1 Infection Model

Abstract

Mice with or without immunosuppression by cyclosporin (Cy) were inoculated with herpes simplex virus type 1 in the ear pinna. Without immunosuppression, 20% of the mice died; clinical signs resolved in survivors and infectious virus was cleared by 7 to 10 days post-inoculation (p.i.). With Cy, mortality was 50%, clinical signs increased and infectious virus persisted. Mice were treated with either valaciclovir (VACV) or famciclovir (FCV) from days 1–5 or 5–10 p.i. and both compounds moderated the disease, but only FCV led to rapid restoration of body weight and complete protection from mortality. Resolution of clinical signs was more marked with immunosuppression. On cessation of VACV therapy, infectious virus recurred on individual days. Without immunosuppression, recurrence was detected in neural tissues only, but with Cy, infectious virus also recurred in skin. No recurrences of infectious virus were observed in any FCV-treated mice.