- s / Biol Blood Marrow Transplant 20 (2014) S211eS256 S219 regimen, immunosuppressive regimen, stem cell source, time to engraftment, and underlying disease) predicted for HHV-6 reactivation. Comparing HSCTs with HHV-6 reactivation and those without, survival at 100 days (77% v. 73%, p1⁄40.706) and development of aGVHD (57% v. 32%, p1⁄40.062) were not significantly different. HHV-6 reactivation with > 1000 copies/mL trended towards increased development of aGVHD (63% v. 36%, p1⁄40.051). Notably, aGVHD developed significantly less often in Haplo-Cord HSCTs compared to HSCTs only using UCB (31% v. 61%, p1⁄40.022). Based on preliminary analysis, early HHV-6 reactivation after UCB HSCT occurs indiscriminately and does not influence survival or incidence of aGVHD at 100 days post-transplantation.