Viral reactivations following hematopoietic stem cell transplantation are thought to result from the breakdown of both cell‐mediated and humoral immunity. As a result, many viruses could be reactivated individually or simultaneously. Using a multiplex polymerase chain reaction (PCR), we prospectively examined many kinds of viral DNAs at a time in 105 patients who underwent allogeneic hematopoietic stem cell transplantation. In total, 591 whole blood samples were collected weekly from pre‐ to 42 days post‐transplantation and the following 13 viruses were tested; herpes simplex virus 1 (HSV‐1), HSV‐2, varicella‐zoster virus (VZV), Epstein–Barr virus (EBV), cytomegalovirus (CMV), human herpes virus 6 (HHV‐6), HHV‐7, HHV‐8, adenovirus, BK virus (BKV), JC virus (JCV), parvovirus B19, and hepatitis B virus (HBV). Several viral DNAs were detected in 12 patients before hematopoietic stem cell transplantation. The detection rate gradually increased after transplantation and peaked at 21 days. The most frequently detected virus was HHV‐6 (n = 63; 60.0%), followed by EBV (n = 11; 10.5%), CMV (n = 11; 10.5%), and HHV‐7 (n = 9; 8.6%). Adenovirus and HBV were each detected in one patient (1.0%). Detection of HHV‐6 DNA was significantly more common among patients undergoing cord blood transplantation or with steroid treatment. EBV DNA tended to be more common in patients treated with anti‐thymocyte globulin. Multiplex PCR was useful for detecting many viral reactivations after hematopoietic stem cell transplantation, simultaneously. Cord blood transplantation, steroid treatment, or anti‐thymocyte globulin use was confirmed to be risk factors after transplantation. J. Med. Virol. 87:1427–1435, 2015. © 2015 Wiley Periodicals, Inc.

Long-term venous access is essential when treating malignant diseases. We reviewed our experience with peripherally inserted central venous catheters (PICC) in children suffering from various malignancies with regard to catheter life, reasons for removal, and complications. Ninety-three PICCs were inserted in 78 children. Median catheter life was 162 days (range 6-575 days) with a total of 16,266 catheter days. Seventy-five PICCs (80.6%) had been placed until the elective removal or patients' death, whereas 18 PICCs (19.4%) were removed due to PICC-related complications; a rate of 1.11 per 1,000 catheter days. Complications requiring removal of PICCs included infection (n = 12), occlusion (n = 3), dislodgement (n = 2), and phlebitis (n = 1) with rates of 0.74, 0.18, 0.12 and 0.06 per 1,000 catheter days, respectively. We conclude that PICC provides reliable long-term intravenous access in children suffering from malignancies.

Several studies have indicated that viral reactivations following allogeneic hematopoietic stem cell transplantation (allo-HSCT) are frequent, but viral reactivations after autologous HSCT (auto-HSCT) have not been investigated in detail. We performed multiplex polymerase chain reaction (PCR) assay to examine multiple viral reactivations simultaneously in 24 patients undergoing auto-HSCT between September 2010 and December 2012. Weekly whole blood samples were collected from pre- to 42 days post-HSCT, and tested for the following 13 viruses; herpes simplex virus 1 (HSV-1), HSV-2, varicella-zoster virus (VZV), Epstein-Barr virus (EBV), cytomegalovirus (CMV), human herpesvirus 6 (HHV-6), HHV-7, HHV-8, adeno virus (ADV), BK virus (BKV), JC virus (JCV), parvovirus B19 (B19V), and hepatitis B virus (HBV).  Fifteen (63%) patients had at least one type of viral reactivation. HHV6 (n = 10; 41.7%) was most frequently detected followed by EBV (n = 7; 29.2%). HHV-6 peaked on day 21 after HSCT and promptly declined. In addition, HBV, CMV, HHV7, and B19V were each detected in one patient. HHV6 reactivation was detected in almost half the auto-HSCT patients, which was similar to the incidence in allo-HSCT patients. The incidence of EBV was unexpectedly high. Viral infections in patients undergoing auto-HSCT were higher than previously reported in other studies. Although there were no particular complications of viral infection, we should pay attention to possible viral reactivations in auto-HSCT patients. J. Med. Virol. 89:358-362, 2017. © 2016 Wiley Periodicals, Inc.

Thymic involvement with Langerhans cell histiocytosis (LCH) typically occurs in children as part of multi-system (M-S) LCH. Patients who develop skin-only LCH during infancy may either follow a self-healing course with spontaneous regression or may progress to M-S involvement. We describe a male infant who developed isolated thymic LCH after spontaneous complete regression of isolated cutaneous lesions. His erythrocyte sedimentation rate and C-reactive protein increased temporarily during the skin-only stage of LCH, and increased again considerably during the thymic relapse. Even for patients with skin-only LCH, these laboratory data might indicate possible relapse or late progression of the disease.

Viral reactivation following hematopoietic stem cell transplantation (HSCT) can cause various complications especially viral encephalitis. In this prospective study, we investigated the correlation of post-HSCT viral reactivation in blood with CNS dysfunction. We employed a multiplex PCR that detects 13 kinds of viruses as a first-line screening test and real-time PCR for subsequent quantitative evaluation. Five hundred ninety-one whole blood samples were collected from 105 patients from before until 42 days after HSCT. Seven patients developed CNS dysfunction such as altered consciousness. In six of the seven, the multiplex PCR test detected HHV-6 DNA in at least one sample. In contrast, DNA from other viruses, such as CMV, EBV, HHV-7, adenovirus, and HBV was never detected in any of the seven patients throughout the study period. Quantitative measurement of whole blood HHV-6 DNA levels demonstrated four of the six HHV-6 DNA loads were elevated at successive time points during the CNS dysfunction. In addition, the virus DNA peaks were temporally associated with the development of CNS dysfunction. CSF was tested in two of the four patients and high HHV-6 DNA levels comparable to those in whole blood were confirmed in both. These four patients were, thus, suspected to have developed HHV-6 encephalitis, a rate of 3.8% in the study population. Our results suggest that early diagnosis of probable HHV-6 encephalitis can be improved by confirming high HHV-6 DNA load in blood.