Cytomegalovirus (CMV) DNA load predicts relapsing CMV infection after solid organ transplantation

Cytomegalovirus (CMV) DNA load was analyzed as a marker for relapse of CMV infection in 24 solid organ transplant patients with CMV infection or disease who received a fixed 14-day course of intravenous ganciclovir. Viral load was measured in blood samples obtained before and at the completion of treatment. Eight (33%) of 24 patients developed relapsing CMV infection. Median pretreatment viral loads were higher in the relapsing group (80,150 copies/10⁶ leukocytes) than in the nonrelapsing group (5500 copies/10⁶ leukocytes; P = .007). The relapsing group also had persistent detectable viral DNA (median, 5810 copies/10⁶ leukocytes) after treatment, whereas it was undetectable in the nonrelapsing group (P < .0001). Primary CMV infection (seronegative recipients of seropositive organs, D+R-) was an independent marker for CMV relapse (P = .03), and these patients had higher pre- and posttreatment viral loads than did non-D+/R- patients (P< .0001 and P = .0014, respectively). CMV DNA load is a useful marker for individualizing antiviral treatment of CMV infection in solid organ transplant recipients.