Opportunistic virus DNA levels after pediatric stem cell transplantation: serostatus matching, anti-thymocyte globulin, and total body irradiation are additive risk factors

Risk factors for post-transplant Epstein-Barr virus events in pediatric recipients of hematopoietic stem cell transplants

BACKGROUND

Epstein-Barr virus (EBV) can cause severe disease following hematopoietic stem cell transplant (HSCT), including post-transplant lymphoproliferative disorder (PTLD). The objective was to analyze risk factors associated with post-transplant EBV outcomes among pediatric allogeneic HSCT recipients.

METHODS

We used data from 156 pediatric allogeneic HSCT recipients enrolled in the Canadian multicenter TREASuRE study. Cox and Prentice-Williams-Petersen models were used to analyze risk factors for post-transplant EBV events including occurrence and recurrence of EBV DNAemia, increase in EBV viral load (EBV-VL), and preemptive use of rituximab, an effective therapy against PTLD.

RESULTS

Females were at higher risk for increasing EBV-VL (adjusted hazard ratio (HR) = 2.83 [95% confidence intervals (CI): 1.33-6.03]) and rituximab use (HR = 3.08 [1.14-8.30]), but had the same EBV DNAemia occurrence (HR = 1.21 [0.74-1.99]) and recurrence risks (HR=1.05 [0.70-1.58]) compared to males. EBV DNAemia was associated with recipient pre-transplant EBV seropositivity (HR = 2.47 [1.17-5.21]) and with graft from an EBV-positive donor (HR = 3.53 [1.95-6.38]). Anti-thymocyte globulin (ATG) was strongly associated with all EBV outcomes, including the use of rituximab (HR = 5.33 [1.47-19.40]). Mycophenolate mofetil (MMF) significantly decreased the risk of all EBV events including the rituximab use (HR = 0.13 [0.03-0.63]).

CONCLUSION

This study in pediatric allogeneic HSCT patients reveals a reduced risk of all EBV outcomes with the use of MMF. Risk factors for EBV events such as EBV-VL occurrence and recurrence include EBV positivity in the donor and recipient, and use of ATG, whereas risk factors for the most severe forms of EBV outcome (EBV-VL and the use of rituximab) include female sex and ATG use.

Risk Factors for the Incidence of and the Mortality due to Post-Transplant Lymphoproliferative Disorder after Hematopoietic Cell Transplantation

Post-transplant lymphoproliferative disorder (PTLD) is a potentially serious complication that occurs following hematopoietic cell transplantation (HCT), in which B cells transformed by Epstein-Barr virus (EBV) proliferate uncontrollably. It is unknown whether risk factors for the incidence of PTLD are identical to those for mortality due to PTLD, a clinically more important outcome. We sought to determine the risk factors influencing the incidence of PTLD and those influencing mortality due to PTLD in a cohort of 1184 allogenic HCT recipients. All patients were predisposed to PTLD, because their graft-versus-host disease (GVHD) prophylaxis included antithymocyte globulin. The overall PTLD incidence was 9.0%, and mortality due to PTLD was 1.1%. In multivariate analysis, risk factors for PTLD incidence include donor+/recipient- (D+/R-) EBV serostatus (subhazard ratio [SHR], 3.3; P = .002), use of a donor other than an HLA-matched sibling donor (non-MSD) (SHR, 1.7; P = .029), receipt of total body irradiation (TBI; SHR, 3.3; P = .008), and the absence of GVHD (SHR, 3.3; P < .001). The sole risk factor for mortality due to PTLD among all patients was D+/R- serostatus (SHR, 5.8; P = .022). Risk factors for mortality due to PTLD among patients who developed PTLD were use of a bone marrow (BM) graft (compared with peripheral blood stem cells [PBSCs]; SHR, 22.8; P < .001) and extralymphatic involvement (SHR, 14.6; P < .001). Interestingly, whereas the absence of GVHD was a risk factor for PTLD incidence, there was a trend toward the presence of GVHD as a risk factor for PTLD mortality (SHR, 4.2; P = .093). Likewise, whereas use of a BM graft was a risk factor for PTLD mortality, there was a trend toward use of a PBSC graft as a risk factor for PTLD incidence (SHR, 0.44; P = .179). Some risk factors for the incidence of PTLD are identical to the risk factors for mortality due to PTLD (ie, D+/R- serostatus), whereas other risk factors are disparate. Specifically, TBI was identified as a risk factor for PTLD incidence but not for PTLD mortality; the absence of GVHD was a risk factor for PTLD incidence, whereas the presence of GVHD was possibly a risk factor for PTLD mortality; and receipt of a PBSC graft was possibly a risk factor for PTLD incidence, whereas receipt of a BM graft was a risk factor for PTLD mortality.

Factors Associated with Post-Transplant Active Epstein-Barr Virus Infection and Lymphoproliferative Disease in Hematopoietic Stem Cell Transplant Recipients: A Systematic Review and Meta-Analysis

This systematic review was undertaken to identify risk factors associated with post-transplant Epstein–Barr virus (EBV) active infection and post-transplant lymphoproliferative disease (PTLD) in pediatric and adult recipients of hematopoietic stem cell transplants (HSCT). A literature search was conducted in PubMed and EMBASE to identify studies published until 30 June 2020. Descriptive information was extracted for each individual study, and data were compiled for individual risk factors, including, when possible, relative risks with 95% confidence intervals and/or p-values. Meta-analyses were planned when possible. The methodological quality and potential for bias of included studies were also evaluated. Of the 3362 titles retrieved, 77 were included (62 for EBV infection and 22 for PTLD). The overall quality of the studies was strong. Several risk factors were explored in these studies, but few statistically significant associations were identified. The use of anti-thymocyte globulin (ATG) was identified as the most important risk factor positively associated with post-transplant active EBV infection and with PTLD. The pooled relative risks obtained using the random-effect model were 5.26 (95% CI: 2.92–9.45) and 4.17 (95% CI: 2.61–6.68) for the association between ATG and post-transplant EBV infection and PTLD, respectively. Other risk factors for EBV and PTLD were found in the included studies, such as graft-versus-host disease, type of conditioning regimen or type of donor, but results are conflicting. In conclusion, the results of this systematic review indicate that ATG increases the risk of EBV infection and PTLD, but the link with all other factors is either nonexistent or much less convincing.

Post-transplantation lymphoproliferative disorder after haematopoietic stem cell transplantation

Post-transplantation lymphoproliferative disorder (PTLD) is a severe complication of haematopoietic stem cell transplantation (HSCT), occurring in a setting of immune suppression and dysregulation. The disease is in most cases driven by the reactivation of the Epstein-Barr virus (EBV), which induces B cell proliferation through different pathomechanisms. Beyond EBV, many factors, variably dependent on HSCT-related immunosuppression, contribute to the disease development. PTLDs share several features with primary lymphomas, though clinical manifestations may be different, frequently depending on extranodal involvement. According to the WHO classification, histologic examination is required for diagnosis, allowing also to distinguish among PTLD subtypes. However, in cases of severe and abrupt presentation, a diagnosis based on a combination of imaging studies and EBV-load determination is accepted. Therapies include prophylactic and pre-emptive interventions, aimed at eradicating EBV proliferation before symptoms onset, and targeted treatments. Among them, rituximab has emerged as first-line option, possibly combined with a reduction of immunosuppression, while EBV-specific cytotoxic T lymphocytes are effective and safe alternatives. Though prognosis remains poor, survival has markedly improved following the adoption of the aforementioned treatments. The validation of innovative, combined approaches is the future challenge.

Transfusion-related Epstein-Barr virus (EBV) infection: A multicenter prospective cohort study among pediatric recipients of hematopoietic stem cell transplants (TREASuRE study)

BACKGROUND

Epstein-Barr virus (EBV) is carried in the blood of most adults, and transfusion-related infections have been reported. EBV is particularly deleterious in immunosuppressed transplant patients. The aim was to determine if EBV transmission occurred through leukodepleted blood product transfusion in pediatric recipients of hematopoietic stem cell transplants (HSCT).

STUDY DESIGN AND METHODS

This prospective Canadian multi-center cohort study includes 156 allogeneic HSCT pediatric recipients. The association between EBV and transfusion was analyzed using Cox regressions. EBV infection, defined by a PCR+ test in the blood of seronegative recipients of an EBV-negative graft, was monitored in order to correlate the recipient EBV strain with that of the blood donors. EBV genotypes were determined by PCR amplification followed by DNA sequencing at two loci (EBNA3b and LMP1).

RESULTS

No statistically significant associations were found between transfusions and EBV. One case of post-transplant EBV infection was identified among the 21 EBV-seronegative recipients receiving an EBV-negative graft. A total of 22 blood donors were retraced to determine whether the recipient's EBV strain matched that of a donor. One donor strain showed 100% sequence homology at the EBNA3b locus, but differed by one or two point mutations and by a 132-bp deletion at the LMP1 locus. The blood donor in question was alone among the 22 donors to show amplifiable virus in plasma. Blood from this donor readily produced an immortalized lymphoblastoid cell line in culture.

CONCLUSION

While considered a rare event, EBV transmission through transfusion may occur in the context of severe immunosuppression.

Outcomes of Human Adenovirus Infection and Disease in a Retrospective Cohort of Pediatric Hematopoietic Cell Transplant Recipients

BACKGROUND

Human adenoviruses (HAdVs) are associated with significant morbidity and death after hematopoietic cell transplantation (HCT). In this study, we sought to determine the incidence of HAdV infection among pediatric HCT recipients in the polymerase chain reaction (PCR) testing era, identify risk factors for viremia among patients undergoing HAdV surveillance, and assess the effectiveness of preemptive cidofovir.

METHODS

A single-center retrospective cohort of patients who underwent a transplant within a 10-year period was assembled. The incidence of and outcomes of patients with HAdV infection and disease were determined by PCR results and chart review. A Cox regression model was used for surveilled allogeneic HCT recipients to identify factors associated with viremia. We also used a discrete-time failure model with inverse probability treatment weights to assess the effectiveness of preemptive cidofovir for infection.

RESULTS

Among 572 HCT recipients, 76 (13.3%) had ≥1 sample that was HAdV PCR positive (3.5% of autologous HCT recipients and 19.7% of allogeneic HCT recipients). Among 191 allogeneic HCT recipients under surveillance, 58 (30.4%) had HAdV detected from any source, and 50 (26.2%) specifically had viremia. The mortality rate was higher in allogeneic HCT recipients with HAdV infection versus those without infection (25.9% vs 11.3%; P = .01). Factors associated with infection included an age of 6 to 12 years, an absolute lymphocyte count of <200 cells/μL, recent prednisone exposure, and recent bacteremia. Preemptive cidofovir was not associated with a reduced risk of infection progression (odds ratio, 0.96 [95% confidence interval, 0.30-3.05]).

CONCLUSIONS

HAdV infection is common and associated with an increased rate of death after allogeneic HCT. Using prediction models that incorporate factors associated with HAdV might help target surveillance. Preemptive cidofovir therapy was not protective in a subset of HAdV-positive patients. Larger observational or randomized investigations are necessary, because the utility of surveillance requires effective preemptive therapies.

Epstein-Barr virus infection is associated with a higher Child-Pugh score and may predict poor prognoses for patients with liver cirrhosis

BACKGROUND

Studies on Epstein-Barr virus (EBV) have focused mostly on neoplastic disease. Few studies have considered immunocompetent patients who are not severely immunocompromised. Liver cirrhosis is associated with various levels of immune dysfunction. In the current study, we determined EBV infection rates, the influence on liver function, and analyzed the risk factors for death in patients with liver cirrhosis.

METHODS

The medical records of patients diagnosed with liver cirrhosis between 1 January 2014 and 31 December 2016 were reviewed. Patients who were or were not infected with EBV were enrolled in this study. Liver functions were compared. The risk factors for 28-, 90-, and 180-day mortality rates were analyzed by univariate and multivariate logistic regression.

RESULTS

The medical records hospitalized patients diagnosed with liver cirrhosis were reviewed. Of these patients, 97 had assessed EBV deoxyribonucleic acid (DNA) and 36 (37.1%) patients were EBV DNA-positive. The age of the EBV-infected patients was older than patients not infected with EBV. EBV-infected patients had a lower level of albumin, and a lower albumin-to-globulin ratio (P = 0.019 and P = 0.013, respectively). EBV-infected patients had higher Child-Pugh scores (P = 0.033) and higher acute-on-chronic liver failure (ACLF) rate (P = 0.050). The Child-Pugh score and ACLF were the risk factors for the 28-, 90-, and 180-day mortality rates.

CONCLUSIONS

This study revealed that patients with liver cirrhosis had higher EBV infection rates, especially patients > 60 years of age, which likely reflected viral reactivation. And liver injury was aggravated in EBV-infected patients. Thus, EBV infection indirectly influenced the prognosis of EBV-infected patients by increasing the Child-Pugh score and ACLF rate.

The yield of monitoring adenovirus in pediatric hematopoietic stem cell transplant patients

Human adenovirus (HAdV) is recognized as a serious pathogen after allogeneic hematopoietic stem cell transplantation (HSCT), causing morbidity and mortality. Currently, there is no universal agreement regarding routine HAdV surveillance after HSCT. We assessed the impact of HAdV weekly monitoring by polymerase chain reaction (PCR) on HAdV viremia rates and the risk factors that influence survival. Three-hundred and fifty-six pediatric allogeneic HSCT were done between 2007 and 2015. Until July 2011, HAdV testing was performed based on clinical suspicion (cohort 1, n = 175) and from August 2011, weekly blood-HAdV monitoring was done (cohort 2, n = 181) until day +100. Twenty-three patients (4 [2.3%] from cohort 1 and 19 [10.5%] from cohort 2, p = .001) were found with HAdV viremia and seven of them died. Both cohorts had a similar incidence of HAdV-associated mortality (3/175; 1.7% in cohort 1 and 4/181; 2.2% in cohort 2). Respiratory failure was the cause of death in all patients. Clinical symptoms appeared prior to or within 5 days of HAdV detection in cohort 2. In summary, weekly monitoring was associated with higher detection of HAdV. The study could not assess survival benefit due to small numbers of HAdV-positive cases. In many instances, symptoms occurred with the development of positive HAdV blood PCR results and hence, symptomatology could have triggered the test. Future studies are needed to provide data that help establishing a uniform approach for regular monitoring of HAdV post-transplant.

Evaluation of the FilmArray™ Meningitis/Encephalitis panel with focus on bacteria and Cryptococcus spp

PURPOSE

Molecular methods provide fast and accurate detection of both bacteria and viruses in the cerebrospinal fluid (CSF) causing infection in the central nervous system (CNS). In the present study we evaluated the bacterial detection performance of the fully automated FilmArray™ Meningitis/Encephalitis (ME) panel (bioMérieux) by comparing it with culture and multiplexed in-house PCR.

METHODS

Three sample types were analysed; Contrived samples with known bacterial/fungal concentration (n = 29), clinical samples from patients with verified cause of CNS infection (n = 17) and external quality assessment (EQA) samples (n = 11). Another six samples were purposely prepared with multiple targets to evaluate multiplex capacity.

RESULTS

The FilmArray™ had a slightly higher limit of detection for Streptococcus pneumoniae, Neisseria meningitidis, Listeria monocytogenes and Streptococcus agalactiae compared to in-house PCR methods but performed equal or better when compared to culture. The FilmArray™ ME panel detected the expected pathogen in 17 of 17 clinical samples and yielded detection of three additional viruses of which one was confirmed with comparator techniques. All but one of the EQA samples were correctly detected.

CONCLUSIONS

The results of this study are promising and the FilmArray™ ME panel could add to the diagnostic algorithm in CNS-infections. However, the limit of detection for the important pathogens N. meningitidis and S. pneumoniae could be improved.

Human cytomegalovirus and Epstein-Barr virus infections, risk factors, and their influence on the liver function of patients with acute-on-chronic liver failure

Background

Studies on human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV) have focused primarily on the immunosuppressed population. Few studies have considered immunocompetent and not severely immunocompromised patients. We determined the infection rates of HCMV and EBV, their risk factors and their influence on liver function in patients with HBV-related acute-on-chronic liver failure (ACLF).

Methods

Patients infected with ACLF-based hepatitis B virus (HBV) from 1 December 2016 to 31 May 2018 were enrolled in our study and were divided into infected and uninfected groups. The risk factors for HCMV and EBV infection and their influence on liver function were analysed.

Results

A total of 100 hospitalized patients with ACLF due to HBV infection were enrolled in this study. Of these patients, 5% presented HCMV deoxyribonucleic acid (DNA) and 23.0% presented EBV DNA. An HBV DNA count of < 1000 IU/mL increased the occurrence of HCMV infection (P = 0.003). Age, especially older than 60 years, was a risk factor for EBV infection (P = 0.034, P = 0.033). HCMV-infected patients had lower alanine aminotransferase (ALT) levels; albumin levels and Child–Pugh scores in EBV-infected patients were higher than those in uninfected patients.

Conclusions

HCMV and EBV were detected in patients with ACLF caused by HBV infection. Lower replication of HBV (HBV DNA < 1000 IU/mL) may increase the probability of HCMV infection; age, especially older than 60 years of age, was a risk factor for EBV infection. HCMV infection may inhibit HBV proliferation and did not increase liver injury, while co-infection with EBV may influence liver function and may result in a poor prognosis.

Epstein-Barr virus post-transplant lymphoproliferative disease (PTLD) after hematopoietic stem cell transplantation

Epstein-Barr virus (EBV) viremia and post-transplant lymphoproliferative disease (PTLD) are severe complications after hematopoietic stem cell transplantation (HSCT). A series of risk factors have been found to predict EBV viremia and PTLD, including the T-cell depletion, reduced intensity conditioning, and alternative donor. The rituximab pre-emptive therapy could improve PTLD prognosis significantly, but the trigger of initiating rituximab pre-emptive therapy has not been well established. Additionally, EBV-specific cytotoxic T cell (CTL) is a promising approach to treat EBV-PTLD.

Human Herpesvirus-6B Reactivation Is a Risk Factor for Grades II to IV Acute Graft-versus-Host Disease after Hematopoietic Stem Cell Transplantation: A Systematic Review and Meta-Analysis

Graft-versus-host disease (GVHD) is an important cause of morbidity and mortality after allogeneic hematopoietic cell transplantation (HCT). Many studies have suggested that human herpesvirus-6B (HHV-6B) plays a role in acute GVHD (aGVHD) after HCT. Our objective was to systematically summarize and analyze evidence regarding HHV-6B reactivation and development of aGVHD. PubMed and EMBASE databases were searched using terms for HHV-6, HCT, and aGVHD, yielding 865 unique results. Case reports, reviews, articles focusing on inherited chromosomally integrated HHV-6, poster presentations, and articles not published in English were excluded. The remaining 467 articles were reviewed for the following requirements: a statistical analysis of HHV-6B reactivation and a GVHD was described, HHV-6B reactivation was defined by PCR, and blood (plasma, serum, or peripheral blood mononuclear cells) was used for HHV-6B PCR. Data were abstracted from publications that met these criteria (n = 33). Publications were assigned to 1 of 3 groups: (1) HHV-6B reactivation was analyzed as a time-dependent risk factor for subsequent aGVHD (n = 14), (2) aGVHD was analyzed as a time-dependent risk factor for subsequent HHV-6B reactivation (n = 1), and (3) analysis without temporal specification (n = 18). A statistically significant association (P < .05) between HHV-6B reactivation and aGVHD was observed in 10 of 14 studies (71%) in group 1, 0 of 1 study (0%) in Group 2, and 8 of 18 studies (44.4%) in Group 3. Of the 14 studies that analyzed HHV-6B as a risk factor for subsequent aGVHD, 11 performed a multivariate analysis and reported a hazard ratio, which reached statistical significance in 9 of these s tudies. Meta-analysis of these 11 studies demonstrated a statistically significant association between HHV-6B and subsequent grades II to IV aGVHD (hazard ratio, 2.65; 95% confidence interval, 1.89 to 3.72; P < .001).HHV-6B reactivation is associated with aGVHD, and when studies have a temporal component to their design, HHV-6B reactivation is associated with subsequent aGVHD. Further research is needed to investigate whether antiviral prophylaxis reduces incidence or severity of aGVHD.

Herpesvirus infections in hematopoietic stem cell transplant recipients seropositive for human cytomegalovirus before transplantation

BACKGROUND

Viral infections are a major cause of morbidity and mortality after hematopoietic stem cell transplantation (HSCT). The effect of herpesvirus infections in human cytomegalovirus (HCMV)-seropositive (IgG-positive/IgM-negative) HSCT recipients remains poorly understood. The risk factors associated with Epstein-Barr virus (EBV), HCMV, and human herpes virus type 6 (HHV-6) infections after HSCT, both alone and in combination, were investigated in this study.

METHODS

Peripheral blood specimens were collected from 44 HSCT recipients and examined for viral DNA using quantitative fluorescence PCR assays. Risk factors for EBV, HCMV, and HHV-6 infections were analyzed by binary logistic regression, and relationships between these viruses were analyzed using the Chi-square test.

RESULTS

EBV, HCMV, and HHV-6 were detected in 50%, 45.45%, and 25% of HCMV-seropositive (IgG-positive/IgM-negative) HSCT recipients, respectively. Male sex (p=0.007) and conditioning regimens including anti-thymocyte globulin (ATG) (p=0.034) were strongly associated with an increased risk of EBV infection. Graft-versus-host disease (GVHD) prophylaxis with corticosteroids was a risk factor for both EBV (p=0.013) and HCMV (p=0.040) infections, while EBV infection (p=0.029) was found to be an independent risk factor for HHV-6 infection. Pre-existing HHV-6 infection was associated with lower rates of HCMV infection (p=0.002); similarly, pre-existing HCMV infection was protective against HHV-6 infection (p=0.036).

CONCLUSIONS

HCMV-seropositive (IgG-positive/IgM-negative) HSCT recipients exhibited a high rate of herpesvirus infections, particularly EBV. ATG and male sex were strongly associated with an increased risk of EBV infection. GVHD prophylaxis with prednisone was found to affect both EBV and HCMV infections. Prior infection with EBV was shown to promote HHV-6 infection. Taken together, these data highlight the need for active monitoring of herpesvirus infections in patients undergoing HSCT.

Pre-Transplant Screening for Latent Adenovirus in Donors and Recipients

Human adenoviruses are frequent cause of slight self-limiting infections in immune competent subjects, while causing life-threatening and disseminated diseases in immunocompromised patients, particularly in the subjects affected by acquired immunodeficiency syndrome and in bone marrow and organ transplant recipients. Here, infections interest lungs, liver, encephalon, heart, kidney and gastro enteric tract. To date, human adenoviruses comprise 51 serotypes grouped into seven species, among which species C especially possesses the capability to persist in infected tissues. From numerous works, it emerges that in the recipient, because of loss of immune-competence, both primary infection, via the graft or from the environment, and reactivated endogenous viruses can be responsible for transplantation related adenovirus disease. The transplants management should include the evaluation of anti-adenovirus pre-transplant screening similar to that concerning cytomegalovirus. The serological screening on cytomegalovirus immunity is currently performed to prevent viral reactivation from grafts and recipient, the viral spread and dissemination to different organs and apparatus, and potentially lethal outcome.

Cytomegalovirus infection in seropositive unrelated cord blood recipients: a study of 349 Korean patients

To gain insight into the natural history of cytomegalovirus (CMV) infection following unrelated cord blood transplantation (UCBT) in seropositive patients, we analyzed the data of 349 seropositive patients who received UCBT in Korea between 2000 and 2011. CMV reactivation occurred in 49 % (171/349) of the CMV-seropositive transplant recipients at a median of 31 days post UCBT. One hundred sixty-four out of 171 patients (96 %) received preemptive therapy. The median duration of CMV reactivation was 29 days. In multivariate analysis, weight >22 kg, use of total body irradiation, use of pre-transplant antithymocyte globulin, graft-versus-host disease (GVHD) prophylaxis with mycophenolate mofetil, and presence of grade II-IV acute GVHD were independent predictors of CMV reactivation. CMV reactivation did not impact transplantation-related mortality (TRM), leukemia relapse, or survival. CMV disease was diagnosed in 62 patients (17.8 %) at a median 55 days after UCBT. Longer duration of CMV reactivation was the only risk factor for progression to CMV disease (p = 0.01). CMV disease resulted in higher TRM (56.0 vs. 31.4 %, p < 0.01) and lower survival (36.1 vs. 55.1 %, p = 0.02).

Features of Epstein-Barr virus reactivation after allogeneic hematopoietic cell transplantation in Korean children living in an area of high seroprevalence against Epstein-Barr virus

The present study was conducted to investigate Epstein-Barr virus (EBV) reactivation after hematopoietic cell transplantation (HCT) in Korean children living in an area of a high seroprevalence against EBV and to determine the impact of recipient age on EBV reactivation. Medical records of 248 children and adolescents who had received allogeneic HCT were retrospectively reviewed. The trends of EBV reactivation and post-transplant lymphoproliferative disorders (PTLDs) were evaluated and compared between younger (≤10 years old) and older (11-20 years old) groups. EBV reactivation occurred in 177 cases (71.4 %) and high-level EBV reactivation, defined as a virus DNA titer of 300,000 copies/mL or higher, occurred in 21 cases (8.5 %). PTLD was diagnosed in five cases (2.0 %), and one of these patients died. The EBV reactivation rate was not significantly different between the two age groups; however, high-level reactivation and PTLD were more significantly frequent in the older than in the younger group (P = 0.030 and P = 0.026, respectively). In conclusion, older children and adolescents are more likely to experience high-level EBV reactivation and PTLDs, and higher EBV DNA titers than those previously reported may be a predictor of PTLD in areas with a high seroprevalence against EBV.

Molecular diagnosis and management of viral infections in hematopoietic stem cell transplant recipients

Viral infections after allogeneic hematopoietic stem cell transplantation (HSCT) are important complications associated with high morbidity and mortality. In this setting, reactivations of persisting latent viral pathogens from donor and/or recipient cells play a central role whereas the sterile environment of transplant units renders new infections less likely. The viruses currently regarded as most relevant in the HSCT setting include particularly the herpes virus family--specifically cytomegalovirus (CMV), Epstein-Barr virus (EBV), and human herpesvirus 6 (HHV-6)--as well as human adenoviruses (AdVs) and the polyoma virus BK (BKV). Timely detection and monitoring of virus copy numbers are prerequisites for successful preemptive treatment approaches. Pre- and post-transplant surveillance by sensitive and quantitative molecular methods has therefore become an essential part of the diagnostic routine. In this review, we discuss diagnostic aspects and the clinical management of the most important viral infections in HSCT recipients, with a focus on pediatric patients.

Risk factors for molecular detection of adenovirus in pediatric hematopoietic stem cell transplantation recipients

Adenovirus (AdV) infections are a major cause of morbidity and mortality in patients undergoing hematopoietic stem cell transplantation (HSCT). To evaluate the use of molecular AdV testing in HSCT at our institution and identify risk factors for AdV viremia and disease, we performed a retrospective cohort study of all HSCT recipients who had undergone AdV polymerase chain reaction testing over a 2-year period. Two cohorts were identified: cohort 1, comprising patients testing positive for AdV (n = 7) and cohort 2, comprising patients testing negative (n = 36). Overall patient characteristics were not statistically significantly different between the 2 cohorts. A comparison of cohort 1 and cohort 2 identified the following medication exposures as risk factors influencing AdV status: preparatory regimens using fludarabine (relative risk [RR], 8.73; 95% confidence interval [CI], 1.18-64.27; P = .006), melphalan (RR, 3.47; 95% CI, 0.76-15.94: P = .08), and/or cyclophosphamide (RR, 0.18; 95% CI, 0.02-1.4; P = .05), and GVHD prophylaxis with methylprednisone (RR, 3.73; 95% CI, 1.01-13.9; P = .04). AdV-positive patients had higher grades of GVHD and higher rates of GVHD of the gastrointestinal tract (RR, 4; 95% CI, 1.18-13.5; P = .03) compared with AdV-negative patients. Four of the 7 AdV-positive patients had concomitant clinical manifestations of disease, including pneumonia, diarrhea, and/or disseminated disease. Clinical outcomes in symptomatic patients included resolution of disease in 2 patients and death in 2 patients. All 7 AdV-positive patients received antiviral therapy, including 1 patient with severe disseminated disease that resolved after administration of liposomal cidofovir. Our study at a large pediatric HSCT center provides important preliminary data for the development of a prospective trial destined to identify specific HCST patient subpopulations that might benefit most from molecular screening and early preemptive therapy.