Brief report Development of drug-resistant herpes simplex virus infection after haploidentical hematopoietic progenitor cell transplantation

An unusually high incidence of acyclovir-and foscarnet-resistant herpes simplex virus (HSV) infection was noted after lym-phocyte-depleted blood hematopoietic progenitor cell (HPC) transplantation from HLA-haploidentical family donors. Four-teen adults with hematologic malignan-cies underwent blood HPC transplanta-tion from haploidentical family donors. Pheresis products were stringently de-pleted of T and B cells by immunomag-netic adsorption, and patients received no immunosuppression after transplanta-tion. HSV reactivation occurred in all 7 evaluable HSV-1 – or HSV-2–seropositive patients, at a median of 40 days after transplantation. Susceptibility testing of clinically resistant viral isolates demon-strated acyclovir resistance in all 5 cases tested. Second-line therapy produced only partial responses, and in vitro evidence of foscarnet resistance developed rapidly in all 3 patients treated with foscarnet. Healing of lesions coincided with T-cell recovery. The prolonged immunodefi-ciency associated with stringent lympho-cyte depletion of the graft appears to strongly predispose to emergence of drug-resistant HSV. Furthermore, immune reconstitution is necessary for eradication of infection. (Blood. 2002;99:1085-1088) © 2002 by The American Society of Hematolog