Susceptibility to acyclovir of herpes simplex virus: emergence of resistance in patients with lymphoid and myeloid neoplasia.

We have examined the susceptibility to acyclovir (ACV) of herpes simplex virus isolated from immunocompetent and immunocompromised patients. Susceptibility to ACV was determined in a dye-uptake assay with vero cells grown in 96-well microtitre plates. Resistant strains were found in two out of 35 (5.7%) patients and partially resistant strains in four out of 35 (11.4%) patients immunodeficient as a result of treatment for lymphoid or myeloid malignancy. Strains resistant to ACV were not found in organ transplant recipients or in immunocompetent patients.