Outcomes of Haploidentical Stem Cell Transplant Recipients With HHV-6B Reactivation

Area of Science:

• Hematology
• Virology
• Immunology

Background:

• Human herpesvirus 6B (HHV-6B) reactivation is common after allogeneic stem cell transplant (alloHCT).
• Haploidentical alloHCT (haplo-alloHCT) may pose a higher risk for HHV-6B reactivation, with limited existing evidence.
• Further investigation into HHV-6B reactivation in haplo-alloHCT is warranted.

Purpose of the Study:

• To evaluate clinical outcomes in patients with HHV-6B reactivation following haploidentical alloHCT.
• To compare outcomes between patients receiving targeted antiviral therapy versus clinical observation.

Main Methods:

• A single-center retrospective study of 188 adult patients undergoing haploidentical alloHCT.
• Comparison of outcomes between patients with HHV-6B reactivation who received antiviral therapy and those who were clinically observed.

Main Results:

• Of 58 patients with HHV-6B reactivation, 21 received antiviral therapy (foscarnet or ganciclovir).
• Treated patients had higher viral loads (DNAemia) but similar time to viral clearance, engraftment, and graft-versus-host disease (GVHD) rates compared to observed patients.
• Central nervous system symptoms were associated with worse survival, irrespective of treatment group.

Conclusions:

• No significant difference in clinical outcomes was observed between treated and observed groups for HHV-6B reactivation post-haploidentical alloHCT.
• Prospective studies are essential to better characterize risks and outcomes of HHV-6B reactivation and its therapy in the context of increasing haplo-alloHCT use.