Patient cytomegalovirus seropositivity with or without reactivation is themost important prognostic factor for survival and treatment-related mortality in stem cell transplantation from unrelated donors using pretransplant in vivo T-cell depletion with anti-thymocyte globulin

We evaluated the cytomegalovirus (CMV) sero-status as a risk factor fbr sur vival and treatment-related mortality (TRM) in 125 patients allografted fro m an unrelated donor between 1994 and 1999. All patients received pretransp lant in vivo T-cell depletion using rabbit anti-thymocyte globulin (ATG). O nly one patient had primary graft failure and severe grade III/IV graft-ver sus-host disease occurred in 14% of the patients. The overall survival (OS) at 3 years was 70% for CMV-negative patients (n = 76) and 29% in the serop ositive cohort (n = 49) (P > 0.001). In multivariate analyses, CMV seroposi tivity remained an independent negative prognostic factor for OS (RR: 2.1; CI: 1.2-3.8; P = 0.014), apart from age > 20 years (RR: 2.74; CI: 1.2-3.8; P = 0.004) and late leucocyte engraftment (RR: 2.4; CI: 1.2-4.9; p = 0.015) . The TRM for all patients was 27%. Despite monitoring for CMV antigenaemia and preemptive therapy with ganciclovir when reactivation occurred, seropo sitive patients had a three times higher risk of fatal treatment-related co mplications than seronegative patients. In multi-variate analyses, CMI sero positivity remained the strongest independent negative factor for TRM (RR: 5.3; CI: 1.9-14.6; P = 0.002), followed by age > 20 years (RR: 4.8; CI: 1.3 -18.1; P = 0.02) and delayed leucocyte engraftment (RR: 3.6; CI: 1.2-11; P = 0.02). The TRM was identical in seropositive patients with (n = 27) or wi thout (n = 22) CMV reactivation (44% versus 50%). We conclude that CMV sero positivity, despite preemptive ganciclovir therapy and even without reactiv ation is a major negative prognostic factor for survival as well as for TRM in unrelated stem cell transplantation using pretransplant in vivo T-cell depletion with ATG.