Multiplex polymerase chain reaction for six herpesviruses after hematopoietic stem cell transplantation

Pediatric Infectious Diseases Related to Transplantation: Insights From Japan

Infectious diseases after transplantation account for significant morbidity and mortality in children undergoing transplantation; the importance of pediatric transplant infectious disease (TID) specialists has therefore been recognized. Although tremendous advancement continues in transplantation medicine, pediatric-specific data and evidence are limited. In Japan, the majority of TIDs had not been managed by infectious disease specialists because pediatric infectious diseases have not been recognized as a solo subspecialty until recently in Japan. However, in the last decade, there was a new movement for pediatric TID in Japan; some pediatric infectious disease specialists trained outside Japan have been playing an important role in managing pediatric TID in a few academic and pediatric institutions. In this review article, we introduce the current status of infectious complications related to pediatric hematopoietic cell and solid organ transplantation, highlighting currently available local evidence, common practice and issues in the field of pediatric TID in Japan.

Presence of Parvovirus B19 but Not Herpesvirus Genome in Acute Skin Rash after Allogeneic Stem Cell Transplantation Correlates with Outcome

INTRODUCTION

Skin rash is a first symptom of acute graft-versus-host disease (GvHD) after allogeneic stem cell transplantation (ASCT) but can also be caused by viruses. The relevance of virus DNA analyses in skin rash for diagnosis and clinical outcome is unknown.

OBJECTIVES

To record the frequencies of detection of herpes and parvovirus B19 (ParvoB19) DNA in skin rash within 100 days after ASCT and to analyze their relevance for diagnosis, clinical course, and non-relapse mortality (NRM).

METHODS

We retrospectively identified 55 patients with virus DNA analysis for CMV, EBV, HHV6, HHV8, HSV, VZV, or ParvoB19. We assessed the rate of virus DNA detection and studied associations with histological diagnosis, virus DNA from concomitantly analyzed blood, clinical presentation, exanthema treatment, and NRM.

RESULTS

CMV, EBV, HHV6, HHV8, HSV, VZV and ParvoB19 DNA were detected in 12.5, 11.8, 10, 0, 0, 2.9, and 26.7% of exanthemas. Histopathological diagnosis was not associated with virus polymerase chain reaction (PCR) results. Detection of CMV, EBV, or HHV6 DNA but not ParvoB19 in skin and blood was associated with PCR results (p = 0.016; p < 0.001; p = 0.067; p = n.a.). Detection of CMV, EBV, HHV6, or ParvoB19 DNA in the skin was not significantly associated with patient, ASCT, or GvHD characteristics. Detection of ParvoB19 but not herpes virus DNA was associated with less immunosuppressive treatment (p = 0.015) and lower NRM (p = 0.041). In multivariate analyses, detection of ParvoB19 was associated with a lower NRM.

CONCLUSIONS

Detection of ParvoB19 DNA in exanthema after ASCT might be associated with lower NRM.

Risk factors for herpes simplex virus-1/2 viremia and clinical outcomes following unmanipulated haploidentical haematopoietic stem cell transplantation

BACKGROUND

Herpes simplex virus (HSV)-1/2 can still be reactivated after allogeneic haematopoietic stem cell transplantation (allo-HSCT) even when the prophylactic acyclovir is used. However, the risk factors for HSV-1/2 viremia and the clinical outcomes following unmanipulated haploidentical HSCT remain unknown.

OBJECTIVES AND STUDY DESIGN

Nineteen patients with HSV-1/2 viremia and fifty-seven patients without HSV-1/2 viremia which were selected using the case-pair method after undergoing haploidentical HSCT were enrolled. We analysed the risk factors for HSV-1/2 viremia and compared the clinical outcomes between the two groups.

RESULTS

The risk factors for HSV-1/2 viremia included HLA disparity ≥2 loci (p=0.049) and cytomegalovirus (CMV) reactivation (p=0.028). The incidences of platelet engraftment, oral mucositis and severe haemorrhagic cystitis (HC) in patients with and without HSV-1/2 viremia were 77% and 94% (p=0.003), 78% and 13% (p=0.000), and 25% and 6% (p=0.04), respectively. Moreover, the median time to platelet engraftment in patients with and without HSV-1/2 viremia was +25days (range, +11-+80) and +17days (range, +8-+67) (p=0.004), respectively. According to the multivariate analyses, HSV-1/2 viremia was associated with delayed platelet engraftment (p=0.038), a higher incidence of oral mucositis (p=0.000) and severe HC (p=0.038). However, HSV-1/2 viremia was not associated with non-relapse mortality (34.0% vs. 31.5%, p=0.26), leukaemia-free survival (60.9% vs. 57.9%, p=0.46) and overall survival (61.2% vs. 60.7%, p=0.37).

CONCLUSIONS

Based on our study results, we recommend that HSV-1/2 PCR should be performed upon clinical suspicion of HSV-1/2 infection.

Feasibility of HLA-haploidentical hematopoietic stem cell transplantation with post-transplantation cyclophosphamide for advanced pediatric malignancies

BACKGROUND

Patients with advanced malignancies in non-complete remission (CR) have a dismal prognosis after HLA-matched hematopoietic stem cell transplantation (HSCT). T-cell-replete HLA-haploidentical HSCT has remarkable anti-leukemia/tumor effects on these patients, but also a high risk of severe/extensive graft-versus-host disease (GHVD). Post-transplantation cyclophosphamide (PTCY) is regarded as a GVHD-specific immunosuppressant in adults, but its feasibility is unknown in children.

METHODS

We performed a prospective feasibility study of PTCY at 50 mg/kg on day 3 for children with advanced leukemias or malignant solid tumors: refractory to chemotherapy or relapsed after conventional allogeneic HSCT. Conditioning consisted of fludarabine (180 mg/m2) and melphalan (140-210 mg/m2).

RESULTS

Long-term engraftments were achieved in 11 patients (73.3%) after bone marrow transplantation (BMT, n = 13) or peripheral blood (PB) stem cell transplantation (n = 2). The incidence of severe acute GHVD was 25.0% and that of extensive chronic GVHD 0.0% after evaluable BMT. CR was achieved in 6/15 and partial response in 4/15 as the best response. Finally, 11/15 experienced disease progression/relapse, 2/15 suffered treatment-related mortality without evidence of disease, and 2/15 are alive in continuous CR.

CONCLUSIONS

PTCY is feasible in children; however, for a better outcome in such patients with advanced malignancies, some modifications are anticipated.

Umbilical cord blood as an alternative source of reduced-intensity hematopoietic stem cell transplantation for chronic Epstein-Barr virus-associated T or natural killer cell lymphoproliferative diseases

Chronic Epstein-Barr virus-associated T/natural killer cell lymphoproliferative diseases represented by chronic active Epstein-Barr virus infection are lethal but are curable with several courses of chemotherapy and allogeneic hematopoietic stem cell transplantation (HSCT). Recently, we reported that reduced-intensity conditioning (RIC) provided better outcomes than myeloablative conditioning because RIC was less toxic. However, it was unclear whether cord blood transplantation (CBT) works in the context of RIC. We retrospectively analyzed 17 patients who underwent RIC followed by bone marrow transplantation (RIC-BMT) and 15 patients who underwent RIC followed by CBT (RIC-CBT). The representative regimen was fludarabine and melphalan based. The overall survival rates with RIC-BMT and RIC-CBT were 92.9% ± 6.9% and 93.3% ± 6.4%, respectively (P = .87). One patient died of lung graft-versus-host disease after RIC-BMT, and 1 patient died of multiple viral infections after RIC-CBT. Although cytotoxic chemotherapy was also immunosuppressive and might contribute to better donor cell engraftment after RIC-HSCT, the rate of engraftment failure after RIC-CBT was still higher than that after RIC-BMT (not significant); however, patients who had experienced graft failure were successfully rescued with a second HSCT. Unrelated cord blood can be an alternative source for RIC-HSCT if a patient has no family donor.

Herpesvirus-associated central nervous system diseases after allogeneic hematopoietic stem cell transplantation

Herpesvirus infections of the central nervous system (CNS) are associated with encephalitis/myelitis and lymphoproliferative diseases in immunocompromised individuals. As of now, data of herpesvirus-associated CNS diseases in transplant recipients is limited. Hence, in this prospective study, we investigated the incidence of herpesvirus-associated CNS diseases and explored the diagnosis of these diseases in 281 allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients. Herpesvirus-DNA and cerebrospinal fluid (CSF) cells were sampled from 58 recipients with herpesvirus-associated diseases or with unexplainable CNS manifestations. Results showed that 23 patients were diagnosed as herpesvirus-associated CNS diseases, including 15 Epstein-Barr virus (EBV)-associated diseases (4 encephalitis and 11 lymphoproliferative diseases), 5 herpes simplex virus type 1 encephalitis, 2 cytomegalovirus encephalitis/myelitis and 1 varicella zoster virus encephalitis. The median time of diseases onset was 65 (range 22-542) days post-transplantation. The 3-year cumulative incidence of herpesvirus-associated encephalitis/myelitis and post-transplant lymphoproliferative disorder (PTLD) was 6.3% ±1.9% and 4.1% ±1.2%, respectively. Of the evaluable cases, CSF cells mainly consisted of CD19⁺CD20⁺ B cells (7/11) and had clonal rearrangement of immunoglobulin genes (3/11) in patients with CNS-PTLD. On the contrary, in patients with encephalitis/myelitis, CSF cells were comprised of different cell populations and none of the gene rearrangement was detected. Herpesvirus-associated CNS diseases are common in the early stages of allo-HSCT, wherein EBV is the most frequent causative virus. The immunophenotypic and clonal analysis of CSF cells might be helpful in the differential diagnosis between encephalitis and lymphoproliferative diseases.