Risk Factors and Outcome of HHV-6 Infections After Allogeneic Hematopoietic Cell Transplantation

Area of Science:

• Infectious Diseases
• Hematology
• Transplantation Immunology

Background:

• Human herpesvirus 6 (HHV-6) reactivation is common in allogeneic hematopoietic cell transplantation (HCT) recipients.
• Clinical outcomes and risk factors for HHV-6 infections post-HCT are not well-defined.

Purpose of the Study:

• To investigate the epidemiological features of clinically relevant HHV-6 infections within 180 days post-HCT.
• To assess the clinical outcomes and identify risk factors associated with HHV-6 infections in HCT recipients.

Main Methods:

• A single-center retrospective study involving 405 consecutive allogeneic HCT recipients.
• Cases with clinically relevant HHV-6 infection were matched with control patients for analysis.

Main Results:

• The cumulative incidence of clinically relevant HHV-6 infections was 3.7%.
• HHV-6 encephalitis was associated with a significantly higher hazard of nonrelapse mortality (HR, 3.821; P = .007).
• Risk factors for HHV-6 infection included female sex, steroid use, and sirolimus use; lymphopenia and acute graft-versus-host disease were common at diagnosis.

Conclusions:

• HHV-6 encephalitis is the most detrimental manifestation of HHV-6 infection post-HCT.
• Post-transplant factors related to immune suppression warrant further investigation in epidemiological studies of HHV-6.