Study finds nearly 10% of cord blood transplant patients develop HHV-6 encephalitis

Meta-analysis Finds nearly 10% of all Umbilical Cord Blood Transplant Patients (UCBT) Develop HHV-6 Encephalitis; Calls for Routine HHV-6 Surveillance in All Cases of UCBT

A group of international investigators have collaborated on a meta-analysis to determine the significance of HHV-6 encephalitis in cord blood transplant patients, which has been published in Bone Marrow Transplantation. Reviewing the published literature on HHV-6 and stem cell transplantation (SCT), the group found that patients receiving umbilical cord blood as the stem cell source (UCBT) experienced elevated prevalences of both HHV-6 reactivation (72%) and HHV-6 encephalitis (8%) when compared to patients receiving traditional (non-UCB) hematopoietic stem cell transplantation (HSCT) (37% and 0.5%, respectively). This finding is consistent with results from a large cohort study published earlier this year by Harvard, which reported that HHV-6 encephalitis might also be associated with a fatality rate of up to 50% among UCBT patients (Hill 2012).

At this time, many transplant centers still do not routinely test for HHV-6 reactivation in their patients, believing it to be a minority risk factor. However, the authors of this study—which was lead by investigators from the Dan L. Duncan Cancer Center/Baylor College of Medicine, NIH/NIAID, Karolinska Institute, and the HHV-6 Foundation—echo the recent call by several groups to implement routine HHV-6 surveillance in all cases of cord blood transplantation moving forward (Zerr 2012, Hill 2012, Chevallier 2010), and suggest that a treatment trial is warranted to begin establishing effective preventative therapies which seek to limit the devastating effects of HHV-6 in this patient population.

For more information, view the abstract and visit the following HHV-6 Foundation webpages:

HHV-6 & Transplant Complications

HHV-6 Encephalitis