Drug-resistant human cytomegalovirus infection in children after allogeneic stem cell transplantation may have different clinical outcomes

Three seropositive pediatric recipients of allogeneic stem cell transplanta tion out of a group of 42 patients receiving T-cell-depleted, unrelated tra nsplants and 37 patients receiving T-cell-depleted, haploidentical transpla nts were monitored longitudinally for human cytomegalovirus (HCMV) infectio n and the emergence of antiviral drug resistance. Early in the posttranspla nt course, all patients developed resistance to ganciclovir. One child addi tionally developed multidrug resistance to foscarnet and cidofovir, with mu tations in the viral phosphotransferase gene (UL97) and the DNA-polymerase gene (UL54) being found. These data show that resistant HCMV infection does not necessarily correlate with a severe clinical outcome. The early detect ion of genotypic resistance up to 129 days before the emergence of phenotyp ic resistance and the dissociation of resistance patterns among different b ody sites emphasize the importance of genotypic analyses of different DNA s pecimens for an efficient antiviral therapy. T-cell-depleted children havin g transplantation might be at an increased risk for the development of drug resistance. (C) 2000 by The American Society of Hematology.