Late HHV-6B reactivation an independent risk factor for mortality in pediatric HCT

Late HHV-6B reactivation after 60 days was an independent risk factor for mortality in Japanese pediatric hematopoietic cell transplant recipients. Older patients (>10 years old) and those with hematologic malignancy were  10x more likely to develop late reactivation.

Japanese investigators led by Tetsushi Yoshikawa monitored 89 transplant recipients for HHV-6B infection weekly for at least 60 days after transplant, and used multivariable logistic regression analysis to estimate odds ratios. Unrelated donor transplantation and sex-mismatched donor transplantation increased also increased the risk of late infection by 6 and 5 fold, respectively.

Among the 12 patients with late HHV-6B infection, 9 or 75% had a high copy number detected continuously post-transplant. Only two patients were treated with antiviral therapy during late stage HHV-6B infection.

The authors point out that HHV-6 has been associated with increased mortality (Zerr 2005) and non-relapse mortality (Zerr 2012, Aoki 2015) but most studies have focused on early reactivation. They suggestion more studies are needed to clarify the potentially pathogenic role of HHV-6B infection beyond 60 days post-transplant.

Read the full study: Miura 2018