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Published on: May 27, 2011
Human herpesvirus 7 in pediatric hematopoietic stem cell transplantation
Muhammad Khanani1, Ali Al-Ahmari, Raymond Tellier
1Division of Hematology/Oncology/Bone Marrow Transplantation, The Hospital for Sick Children, University of Toronto, Canada.
Insights
Human herpesvirus 7 (HHV-7) is uncommon after pediatric hematopoietic stem cell transplantation (HSCT). HHV-7 infection was linked to severe graft-versus-host disease (GVHD) and sepsis in these young patients.
Area of Science:
- Pediatric Hematology
- Infectious Diseases
- Transplantation Immunology
Background:
- The role of human herpesvirus 7 (HHV-7) in pediatric hematopoietic stem cell transplantation (HSCT) remains largely uncharacterized.
- Understanding HHV-7's impact is crucial for improving outcomes in young HSCT recipients.
Purpose of the Study:
- To investigate the clinical significance of HHV-7 detection in children undergoing autologous and allogeneic HSCT.
- To correlate HHV-7 positivity with clinical outcomes, including GVHD, infections, and survival.
Main Methods:
- Retrospective analysis of pediatric HSCT recipients with positive HHV-7 PCR or immunohistochemistry from various specimens.
- Collection of clinical data on symptoms, engraftment, infectious complications, GVHD, and survival.
Main Results:
- Nine out of 265 pediatric HSCT recipients (3.4%) tested positive for HHV-7, all after allogeneic HSCT.
- Patients positive for HHV-7 were frequently diagnosed with acute leukemia and received matched unrelated donor transplants.
- These patients experienced severe acute graft-versus-host disease (GVHD) and multiple infectious episodes, with four deaths attributed to GVHD and sepsis.
Conclusions:
- HHV-7 detection is infrequent following pediatric HSCT but is associated with significant morbidity.
- The findings suggest HHV-7 may indicate a state of profound immunosuppression, increasing the risk of severe GVHD and secondary infections.
Background:
Little is known about the significance of human herpesvirus 7 (HHV-7) in pediatric hematopoietic stem cell transplantation (HSCT).
Objective:
To evaluate children post autologous and allogeneic HSCT, with a positive PCR or immunohistochemistry for HHV-7 either from blood, cerebrospinal fluid (CSF) or any other pathology specimen. Clinical data for these patients were collected examining symptoms and signs, engraftment, acute infectious complications, graft versus host disease (GVHD) where applicable, and survival.
Results:
Between June 1999 and June 2003, 265 HSCT were performed in The Hospital for Sick Children, Toronto, allogeneic (n = 163) and autologous (n = 102). Nine children were positive for HHV-7 at a median of 21 days (range 16-27 days) post-HSCT. All had allogeneic transplantation. The most common underlying diagnosis was acute leukemia and 7 had matched unrelated donor (MUD) transplantation. Eight of the nine patients had grade II-IV acute GVHD and all of them had multiple infectious episodes with fungal, bacterial and other viral pathogens. Although not fully attributed to HHV-7, the clinical syndrome varied from fever, vomiting and diarrhea to septic shock. Four patients died due to GVHD and sepsis.
Conclusion:
HHV-7 was uncommon post-HSCT. It was associated with severe GVHD and sepsis secondary to severe immunosuppression.
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