Human herpesvirus‐6B infection in pediatric allogenic hematopoietic stem cell transplant patients: Risk factors and encephalitis

• Published in: Transplant infectious disease Vol. 22; no. 1; pp. e13203 - n/a
• Main Authors: Miura, Hiroki, Kawamura, Yoshiki, Hattori, Fumihiko, Tanaka, Makito, Kudo, Kazuko, Ihira, Masaru, Yatsuya, Hiroshi, Takahashi, Yoshiyuki, Kojima, Seiji, Sakaguchi, Hirotoshi, Yoshida, Nao, Hama, Asahito, Yoshikawa, Tetsushi
• Format: Journal Article
• Language: English
• Published: Denmark Wiley Subscription Services, Inc 01-02-2020
• Subjects: Central nervous system; Confidence intervals; Encephalitis; Encephalopathy; Hazard identification; Health risk assessment; Hematology; Hematopoietic stem cells; Herpes viruses; HHV‐6; HSCT; Infections; Malignancy; Medical records; Patients; Pediatrics; Risk analysis; risk factor; Risk factors; Sex; Solid tumors; Statistical models; Stem cell transplantation; Stem cells; Transplantation; Transplants & implants; Tumors; Viruses; encephalitis; HSCT; risk factor; HHV-6
• ISSN: 1398-2273; 1399-3062
• DOI: 10.1111/tid.13203

Background
Human herpesvirus‐6B (HHV‐6B) infection after allogenic hematopoietic stem cell transplantation (allo‐HSCT) is known to be associated with post‐transplant limbic encephalitis in adults. Meanwhile, the association between HHV‐6B infection and central nervous system complications remains unclear in pediatric allo‐HSCT patients.
Methods
In this study, HHV‐6B infection was monitored for more than 50 days after HSCT using virus isolation and real‐time PCR. Clinical information such as patient background and encephalitis status was collected retrospectively from medical records. Risk factors for HHV‐6B infection were determined by the Cox proportional hazards model, and the clinical features of HHV‐6B encephalitis in pediatric allo‐HSCT patients were elucidated.
Results
Human herpesvirus‐6B infection was observed in 74 (33.8%) of 219 patients at 3‐47 days (median 18, interquartile range 13‐20). Risk factors identified in multivariable analysis were hematological malignancy (hazards ratio [HR], 5.0; 95% confidence interval [CI], 2.3/12.5; P < .0001), solid tumor (HR, 4.8; CI, 1.5/16.3; P = .0104), unrelated donor (HR, 2.1; CI, 1.0/4.6; P = .0378), and sex‐mismatched donor (HR 1.8; CI, 1.1/3.0; P = .0257). HHV‐6B encephalitis occurred in only one of the 219 patients (0.46%); this patient demonstrated the typical clinical course of posterior reversible encephalopathy syndrome.
Conclusion
Hematological malignancy, solid tumor, unrelated donor, and sex‐mismatched donor were significant risk factors for HHV‐6B infection after pediatric allo‐HSCT. In pediatric allo‐HSCT patients, the incidence of HHV‐6B encephalitis was low and the clinical features differed from those in adult patients.