Persistent CMV infection after allogeneic hematopoietic stem cell transplantation in a CMV-seronegative donor-to-positive recipient constellation: Development of multidrug resistance in the absence of anti-viral cellular immunity.

We describe a case of persistent cytomegalovirus (CMV) infection after allogeneic hematopoietic stem cell transplantation (allo-HSCT) with discordant and high-risk (D-/R+) constellation of CMV serostatus. Despite the use of different and innovative antiviral strategies, viral replication could not be suppressed successfully promoting a protracted CMV colitis associated with severe gastrointestinal graft-versus-host disease (GI GVHD). We illustrate that the development of multidrug viral resistance, the failure to mount a CMV-specific cellular immune response, as confirmed by QuantiFERON(®)-CMV (Qiagen) assay, and the refractory GVHD requiring prolonged immunosuppression were the main factors contributing to persistent viral replication and the fulminant unfavorable course.