Association between adenovirus viral load and mortality in pediatric allo-HCT recipients: the multinational AdVance study

Monitoring of adenoviremia in pediatric patients undergoing hematopoietic stem cell transplantation: Is it alone sufficient to predict adenoviral disease?

BACKGROUND

We aimed to evaluate our pediatric HSCT recipients routinely monitored for adenoviremia and to determine the adequacy of this monitoring in predicting adenoviral disease (AD).

METHODS

A retrospective cohort of patients who underwent allogeneic HSCT between January 2021 and August 2022, and routinely monitored for adenoviremia by real-time PCR was included in our survey. Demographic and clinical data of the patients were recorded. Incidence rates, risk factors, and mortality rates related to adenoviremia, and AD were analyzed.

RESULTS

Among 104 HSCTs performed in 94 patients adenovirus (AdV) was revealed in 27 (26%) episodes and adenoviremia in 18 (17.3%) HSCT episodes. AD without adenoviremia developed in nine episodes (8.6%). Disseminated disease was significantly more frequently detected in episodes with adenoviremia (p = .008). GVHD was independent risk factor for AdV detection (OR: 8.6, 95% CI: 2.03-33.7, p = .001). Viremia developed within a shorter time interval after HSCT in isolated episodes of adenoviremia compared to those with concomitant AD (p = .006). Initial and peak viral loads were significantly higher in adenoviremia with AD (p < .001). Mortality was higher in the AdV-detected episodes (p < .001) than in the AdV-undetected episodes. AdV-related mortality was found to be 22.2%. Adenoviremia increased the risk of mortality (OR: 1.2, 95% CI: 0.22-1.33, p = .01).

CONCLUSIONS

Adenoviremia monitoring is an important process in the detection of AD. Since some patients may develop AD without accompanying by adenoviremia, monitoring for AdV in blood samples should be supported with other monitoring methods in order to evaluate the probable involvement of different organs or systems.

Risk factors for severity in seasonal respiratory viral infections and how they guide management in hematopoietic cell transplant recipients

PURPOSE OF REVIEW

Seasonal respiratory virus infections (RVIs) often progress to severe diseases in hematopoietic cell transplant (HCT) recipients. This review summarizes the current evidence on risk factors for the severity of RVIs in this high-risk population and provides clinical management.

RECENT FINDINGS

The likelihood of the respiratory viral disease progression depends on the immune status of the host and the type of virus. Conventional host factors, such as the immunodeficiency scoring index and the severe immunodeficiency criteria, have been utilized to estimate the risk of progression to severe disease, including mortality. Recent reports have suggested nonconventional risk factors, such as hyperglycemia, hypoalbuminemia, prior use of antibiotics with broad anaerobic activity, posttransplant cyclophosphamide, and pulmonary impairment after RVIs. Identifying novel and modifiable risk factors is important with the advances of novel therapeutic and preventive interventions for RVIs.

SUMMARY

Validation of recently identified risk factors for severe RVIs in HCT recipients is required. The development of innovative interventions along with appropriate risk stratification is critical to improve outcomes in this vulnerable population.

Presence of human adenovirus 36 in visceral fat tissue, viral load, and analysis of its genetic variability

It has been proposed that infection by adipogenic viruses constitutes a "low risk" factor for obesity. Here, we report the presence of adenovirus 36 (Ad36) and its viral load copy number in fat tissue of participants with obesity and normal weight; phylogenetic analysis was performed to describe their relationship and genetic variability among viral haplotypes. Adipose tissue obtained from 105 adult patients with obesity (cases) and 26 normal-weight adult participants as controls were analyzed by quantitative polymerase chain reaction (qPCR) amplifying the partial Ad36 E1a gene. The amplicons were examined by melting curves and submitted to sequencing. Then, genetic diversity and phylogenetic inferences were performed. Ad36 was identified at rates of 82% and 46% in the case and control groups, respectively (p = 1.1 × 10-4 , odds ratio = 5.28); viral load copies were also significantly different between both groups, being 25% higher in the case group. Melting curve analysis showed clear amplification among positive samples. Phylogenetic inferences and genetic diversity analyses showed that the Ad36 E1a gene exhibits low genetic variability and differentiation with strong gene flow due to an expanding process. Our results suggest that the phenomenon of infectobesity by Ad36 might not be a low-risk factor, as has been previously argued by other authors.

Adenovirus Infection in Hematopoietic and Solid Organ Paediatric Transplant Recipients: Treatment, Outcomes, and Use of Cidofovir

BACKGROUND

human adenovirus (hAdV) infection constitutes an important cause of morbidity and mortality in transplant recipients, due to their immune status. Among drugs currently available, cidofovir (CDF) is the most prescribed.

METHODS

Retrospective study of hAdV infection in paediatric transplant recipients from a tertiary paediatric centre, describing characteristics, management, and outcomes, and focused on the role of CDF.

RESULTS

49 episodes of infection by hAdV were detected during a four-year period: 38 episodes in patients that received allogeneic hematopoietic stem cell transplantation (77.6%) and 11 in solid organ transplant recipients (22.4%). Twenty-five patients (52.1%) were symptomatic, presenting mainly fever and/or diarrhoea. CDF was prescribed in 24 patients (49%), with modest results. CDF use was associated with the presence of symptoms resulting in lower lymphocyte count, paediatric intensive care unit admission, and high viral load. Other therapeutic measures included administration of intravenous immunoglobulin, reducing immunosuppression, and T-lymphocyte infusion. Despite treatment, 22.9% of patients did not resolve the infection and there were three deaths related to hAdV infection. All-cause mortality was 16.7% (8 episodes) by 30 days, and 32.7% (16 episodes) by 90 days, of which, 3 episodes (3/16, 18.8%) were attributed to hAdV directly.

CONCLUSIONS

hAdV infection had high morbidity and mortality in our series. CDF use is controversial, and available therapeutic options are limited. Transplant patients with low lymphocyte count are at higher risk of persistent positive viremias, and short-term survival of these patients was influenced by the resolution of hAdV infection.

Engineering T cells to suppress acute GVHD and leukemia relapse after allogeneic hematopoietic stem cell transplantation

Acute graft-versus-host disease (aGVHD) limits the therapeutic benefit of allogeneic hematopoietic stem cell transplantation (allo-HSCT) and requires immunosuppressive prophylaxis that compromises antitumor and antipathogen immunity. OX40 is a costimulatory receptor upregulated on circulating T cells in aGVHD and plays a central role in driving the expansion of alloreactive T cells. Here, we show that OX40 is also upregulated on T cells infiltrating GVHD target organs in a rhesus macaque model, supporting the hypothesis that targeted ablation of OX40+ T cells will mitigate GVHD pathogenesis. We thus created an OX40-specific cytotoxic receptor that, when expressed on human T cells, enables selective elimination of OX40+ T cells. Because OX40 is primarily upregulated on CD4+ T cells upon activation, engineered OX40-specific T cells mediated potent cytotoxicity against activated CD4+ T cells and suppressed alloreactive T-cell expansion in a mixed lymphocyte reaction model. OX40 targeting did not inhibit antiviral activity of memory T cells specific to Epstein-Barr virus, cytomegalovirus, and adenoviral antigens. Systemic administration of OX40-targeting T cells fully protected mice from fatal xenogeneic GVHD mediated by human peripheral blood mononuclear cells. Furthermore, combining OX40 targeting with a leukemia-specific chimeric antigen receptor in a single T cell product provides simultaneous protection against leukemia and aGVHD in a mouse xenograft model of residual disease posttransplant. These results underscore the central role of OX40+ T cells in mediating aGVHD pathogenesis and support the feasibility of a bifunctional engineered T-cell product derived from the stem cell donor to suppress both disease relapse and aGVHD following allo-HSCT.

Clinical Correlation of Adenoviral Load in the Respiratory Tract Measured by Digital PCR in Immunocompromised Children

Immunocompromised patients can have life-threatening adenoviral infection. Viral load in blood and stool is commonly used to guide antiviral therapy. We developed and evaluated a digital polymerase chain reaction assay to quantify human adenovirus in the respiratory tract and showed that higher peak load correlates with disseminated infection, mechanical ventilation, and death.

Adenovirus Infection in Pediatric Hematopoietic Cell Transplantation: A Challenge Still Open for Survival

Human Adenovirus (HAdV) infection occurs in 14−16% of patients in the early months after pediatric hematopoietic cell transplantation (HCT) and this correlates with a higher risk of developing HAdV disease and overall 6-month mortality. The main risk factors for HAdV infection are T-cell depletion of the graft by ex vivo CD34+ selection or in vivo use of alemtuzumab or anti-thymocyte serum, the development of grade III-IV graft versus host disease (GVHD), the type of donor (unrelated donor, cord blood, haploidentical, or HLA mismatched parent), and severe lymphopenia (<0.2 × 109/L). The prevention of HAdV disease is based on early intervention with antivirals in the asymptomatic patient when the permitted viral load threshold in the blood (≥102−3 copies/mL) and/or in the stool (109 copies/g stool) is exceeded. Cidofovir, a monophosphate nucleotide analog of cytosine, is the primary drug for preemptive therapy, used at 5 mg/kg/week for 2 weeks followed by 3−5 mg/kg every 2 weeks. The alternative schedule is 1 mg/kg every other day (three times/week). Enhancing virus-specific T-cell immunity in the first months post-HCT by donor-derived or third-party-derived virus-specific T cells represents an innovative and promising way of intervention, applicable both in prevention and therapeutic settings.

Human Adenovirus Associated Hepatic Injury

Human adenovirus (HAdV) is a common virus, but the infections it causes are relatively uncommon. At the same time, the methods for the detection of HAdV are varied, among which viral culture is still the gold standard. HAdV infection is usually self-limited but can also cause clinically symptomatic in lots of organs and tissues, of which human adenovirus pneumonia is the most common. In contrast, human adenovirus hepatitis is rarely reported. However, HAdV hepatitis has a high fatality rate once it occurs, especially in immunocompromised patients. Although human adenovirus hepatitis has some pathological and imaging features, its clinical symptoms are not typical. Therefore, HAdV hepatitis is not easy to be found in the clinic. There are kinds of treatments to treat this disease, but few are absolutely effective. In view of the above reasons, HAdV hepatitis is a disease that is difficult to be found in time. We reviewed and summarized the previously reported cases, hoping to bring some relatively common characteristics to clinicians, so as to facilitate early detection, early diagnosis, and early treatment of patients.

Association between adenovirus infection and mortality outcome among pediatric patients after hematopoietic stem cell transplant

BACKGROUND

Adenovirus can cause severe diseases in post-hematopoietic stem cell transplant (HSCT) patients. Because these patients also have many other factors contributing to mortality, it remains controversial whether adenovirus infection itself contributes to increased mortality in these patients.

OBJECTIVE

To determine if adenovirus infection contributes to mortality in pediatric post-HSCT patients.

METHODS

This retrospective cohort study was performed in post HSCT patients, aged 0-18 years old, admitted at Ramathibodi Hospital from 2016 to 2020. Adenovirus infection was defined as the detection of adenovirus in blood or urine by polymerase chain reaction. Multivariate cox regression was used to identify factors associated with death.

RESULTS

The incidence of overall adenovirus infection (viremia or viruria) in this cohort was 20.8% (26 out of 125 enrolled patients). From the multivariate cox regression analysis, overall adenovirus infection was not significantly associated with death (hazard ratio [HR]: 2.41; 95% confidence interval [CI]: 0.96-6.06; p = .060). However, presence of viremia (HR: 3.90; 95% CI: 1.40-10.86; p = .009), having maximal serum viral load > 10 000 copies/ml (HR: 3.70; 95% CI: 1.20-11.38; p = .023), presence of end-organ diseases (HR: 3.44; 95% CI: 1.18-10.01; p = .023) were associated with mortality. Underlying diseases requiring long-term immunosuppressive drugs before HSCT, invasive fungal disease, invasive bacterial infection, cytomegalovirus infection, and longer engraftment time were also associated with mortality.

CONCLUSION

Overall adenovirus infection does not appear to play a significant role in mortality in pediatric post-HSCT patients. However, more invasive forms of adenovirus infection were associated with mortality in these patients.

TCRαβ/CD19 depleted HSCT from an HLA-haploidentical relative to treat children with different non-malignant disorders

Several non-malignant disorders (NMDs), either inherited or acquired, can be cured by allogeneic hematopoietic stem cell transplantation (HSCT). Between January 2012 and April 2020, 70 consecutive children affected by primary immunodeficiencies, inherited/acquired bone marrow failure syndromes, red blood cell disorders or metabolic diseases, lacking a fully-matched donor or requiring urgent transplantation, underwent TCRαβ/CD19-depleted haploidentical HSCT from an HLA-partially matched relative as part of a prospective study (#NCT01810120). Median age at transplant was 3.5 years (range 0.3-16.1); median time from diagnosis to transplant was 10.5 months (2.7 for SCID patients). Primary engraftment was obtained in 51 patients, while 19 and 2 patients experienced either primary or secondary graft failure (GF), the overall incidence of this complication being 30.4%. Most GFs were observed in children with disease at risk for this complication (e.g., aplastic anemia, thalassemia). All but 5 patients experiencing GF were successfully retransplanted. Six patients died of infectious complications (4 had active/recent infections at time of HSCT), the cumulative incidence of transplant-related mortality (TRM) being 8.5%. Cumulative incidence of grade I-II acute GvHD was 14.4% (no patient developed grade III-IV acute GVHD). Only one patient at risk developed mild chronic GvHD. With a median follow-up of 3.5 years, the 5-year probability of overall and disease-free survival was 91.4% and 86.8%, respectively. In conclusion, TCRαβ/CD19-depleted haploidentical HSCT from an HLA-partially matched relative is confirmed to be an effective treatment for children with NMDs. Prompt donor availability, low incidence of GvHD and TRM make this strategy an attractive option in NMDs patients.

Virus-specific T cells for adenovirus infection after stem cell transplantation are highly effective and class II HLA restricted

Infection with adenoviruses is a common and significant complication in pediatric patients after allogeneic hematopoietic stem cell transplantation. Treatment options with traditional antivirals are limited by poor efficacy and significant toxicities. T-cell reconstitution is critical for the management of adenoviral infections, but it generally takes place months after transplantation. Ex vivo-generated virus-specific T cells (VSTs) are an alternative approach for viral control and can be rapidly generated from either a stem cell donor or a healthy third-party donor. In the context of a single-center phase 1/2 clinical trial, we treated 30 patients with a total of 43 infusions of VSTs for adenoviremia and/or adenoviral disease. Seven patients received donor-derived VSTs, 21 patients received third-party VSTs, and 2 received VSTs from both donor sources. Clinical responses were observed in 81% of patients, with a complete response in 58%. Epitope prediction and potential epitope identification for common HLA molecules helped elucidate HLA restriction in a subset of patients receiving third-party products. Intracellular interferon-γ expression in T cells in response to single peptides and response to cell lines stably transfected with a single HLA molecule demonstrated HLA-restricted CD4+ T-cell response, and these results correlated with clinical outcomes. Taken together, these data suggest that VSTs are a highly safe and effective therapy for the management of adenoviral infection in immunocompromised hosts. The trials were registered at www.clinicaltrials.gov as #NCT02048332 and #NCT02532452.

Viral kinetics and outcomes of adenovirus viremia following allogeneic hematopoietic cell transplantation

BACKGROUND

Adenovirus (AdV) is a serious infection following hematopoietic cell transplantation (HCT). Little is known about AdV viral kinetics and optimal threshold for initiation of pre-emptive therapy.

METHODS

Single-center retrospective study of 16 consecutive adult HCT recipients with detectable AdV identified over a 5-year period.

RESULTS

Median time to AdV reactivation after HCT was 176 days (IQR 86-408). Nine patients received cidofovir, although 14/16 had no tissue-invasive disease. Among treated patients, median duration of viremia was shorter when initiating treatment at viral loads < 10,000 copies/ml (28 vs. 52 days). All-cause mortality in this cohort was 44%. All six patients (five of which were untreated) with peak viral loads < 10,000 copies/ml survived; whereas only 30% (3/10) of patients with peak viral loads greater than this threshold survived, despite most (n = 8; 80%) of them receiving cidofovir (P = .01). Three-month survival following diagnosis of AdV viremia was significantly lower with peak viremia > 10,000 copies/ml (100 vs. 17%; P = .005).

CONCLUSION

AdV is associated with high all-cause mortality, especially for viremia > 10,000 copies/ml. Delaying therapy until viremia reaches AdV levels ≥10,000 copies/ml was associated with more protracted infection and poor outcomes. Larger studies are needed.

Efficacy of Brincidofovir in Pediatric Stem Cell Transplant Recipients With Adenovirus Infections

BACKGROUND

Adenovirus (AdV) infections are of particular concern in pediatric hematopoietic stem cell transplantation (HSCT) recipients as therapeutic options are limited. Brincidofovir (BCV) is the lipid-conjugated pro-drug of cidofovir (CDV) with oral bioavailability and higher intracellular concentrations of the active drug.

METHODS

In this retrospective, single-center analysis, we included allogeneic pediatric HSCT recipients with refractory AdV infections because of contraindications or insufficient response to CDV. Common posttransplant viruses were monitored at least weekly by PCR in blood, stool, and urine.

RESULTS

Each of the 8 patients received 6 to 12 doses of BCV. BCV treatment was initiated between days +5 and +77. AdV DNAemia and intestinal AdV infection disappeared completely in 6/8 patients. Early AdV DNAemia before day +21 did not result in increased mortality. One patient with a systemic, acyclovir-resistant HSV-1 infection responded rapidly to BCV. Four patients did not survive. AdV infection-related death in 2 patients was accompanied by >1 × 109/mL AdV copy numbers in the blood. Two more patients died of graft-vs-host disease and acute respiratory distress syndrome, respectively, both not related to AdV.

CONCLUSIONS

AdV DNAemia and intestinal infection subsided completely in 75% of pediatric HSCT recipients treated with BCV. AdV DNAemia exceeding 1 × 109/mL and a poor lymphocyte recovery of <250/µL were associated with high mortality. Early AdV DNAemia before day +21, however, did not result in a worse outcome. Although access to BCV is currently suspended, further clinical trials are needed to clarify the role of BCV in HSCT recipients with AdV infections and its potential benefit in preventing AdV DNAemia in immunocompromised patients.

Between-group comparison of area under the curve in clinical trials with censored follow-up: Application to HIV therapeutic vaccines

In clinical trials, longitudinal data are commonly analyzed and compared between groups using a single summary statistic such as area under the outcome versus time curve (AUC). However, incomplete data, arising from censoring due to a limit of detection or missing data, can bias these analyses. In this article, we present a statistical test based on splines-based mixed-model accounting for both the censoring and missingness mechanisms in the AUC estimation. Inferential properties of the proposed method were evaluated and compared to ad hoc approaches and to a non-parametric method through a simulation study based on two-armed trial where trajectories and the proportion of missing data were varied. Simulation results highlight that our approach has significant advantages over the other methods. A real working example from two HIV therapeutic vaccine trials is presented to illustrate the applicability of our approach.

CMV viral load kinetics predict CMV end-organ disease and mortality after hematopoietic cell transplant (HCT)

BACKGROUND

We investigated the association between time-averaged area under the curve (AAUC) of CMV viral load (VL) by D100 and overall survival (OS) at one-year post-hematopoietic cell transplantation (HCT).

METHODS

A retrospective cohort study, including patients receiving HCT between 2010.6 and 2017.12 from Memorial Sloan Kettering Cancer Center. AAUC was calculated for patients with detected VL. Patients were categorized into "non-controllers" (Q4) and "controllers" (Q1-3) using the highest AAUC quartile as cutoff. Kaplan-Meier analyses and Cox models were used to estimate the association between AAUC and OS. Patients with non-detected CMV VL were categorized into "elite-controllers" (R+ or R-/D+) and "R-/D-".

RESULTS

The study (N=952) included 282 controllers, 93 non-controllers, 275 elite-controllers, and 302 R-/D-. OS was 80.1% and 58.1% for controllers and non-controllers, respectively. In multivariable models, non-controllers had worse OS versus controllers (adjusted hazard ratio [HR] 2.65, 95% CI 1.71-4.12). In landmark analyses, CMV controllers had similar OS as elite-controllers (HR 1.26, 95% CI 0.83-1.91) or R-/D- (HR 0.98, 95% CI 0.64-1.5).

CONCLUSION

CMV non-controllers had worse OS at one-year post-HCT. CMV controllers had similar OS as elite-controllers or R-/D-. Future studies are needed to validate our AAUC cutoff across different cohorts and CMV management strategies.

Adenovirus Viral Kinetics and Mortality in Ex Vivo T Cell-Depleted Hematopoietic Cell Transplant Recipients With Adenovirus Infection From a Single Center

BACKGROUND

We report on predictors of adenovirus (ADV) viremia and correlation of ADV viral kinetics with mortality in ex vivo T-cell depleted (TCD) hematopoietic cell transplant (HCT).

METHODS

T cell-depleted HCT recipients from January 1, 2012 through September 30, 2018 were prospectively monitored for ADV in the plasma through Day (D) +100 posttransplant or for 16 weeks after the onset of ADV viremia. Adenovirus viremia was defined as ≥2 consecutive viral loads (VLs) ≥1000 copies/mL through D +100. Time-averaged area under the curve (AAUC) or peak ADV VL through 16 weeks after onset of ADV viremia were explored as predictors of mortality in Cox models.

RESULTS

Of 586 patients (adult 81.7%), 51 (8.7%) developed ADV viremia by D +100. Age <18 years, recipient cytomegalovirus seropositivity, absolute lymphocyte count <300 cells/µL at D +30, and acute graft-versus-host disease were predictors of ADV viremia in multivariate models. Fifteen (29%) patients with ADV viremia died by D +180; 8 of 15 (53%) died from ADV. Peak ADV VL (hazard ratio [HR], 2.25; 95% confidence interval [CI], 1.52-3.33) and increasing AAUC (HR, 2.95; 95% CI, 1.83-4.75) correlated with mortality at D +180.

CONCLUSIONS

In TCD HCT, peak ADV VL and ADV AAUC correlated with mortality at D +180. Our data support the potential utility of ADV viral kinetics as endpoints in clinical trials of ADV therapies.

Clinical Characteristics of 204 Children With Human Adenovirus Type 7 Pneumonia Identified by Whole Genome Sequencing in Liuzhou, China

BACKGROUND

Clinical knowledge of human adenovirus type 7 (HAdV-7) pneumonia in children remains limited. Moreover, predictors for disease severity are largely unknown.

METHODS

This is a retrospective study of children hospitalized at Liuzhou Maternal and Child Health Hospital, China, with HAdV-7 pneumonia in 2018-2019. Demographics, clinical characteristics, laboratory results, and imaging data were collected. HAdV-7 was identified in plasma using whole genome sequencing, which yielded quantitative HAdV-7 sequence numbers.

RESULTS

There were 204 children; 145 (71%) were <2 years of age. There were 68 children with severe pneumonia (SP) and 136 with nonsevere pneumonia (NSP). Up to 43% in SP group with respiratory failure (SP-RF) were <12 months of age. Median duration of fever before hospitalization was shorter in NSP group than SP groups (P < 0.01). Fourteen (6.9%) underwent mechanical ventilation. There was a significant difference in mean plasma HAdV-7 sequence numbers among SP-RF, SP without respiratory failure (SP-NRF), and NSP groups (2485 ± 165, 2034 ± 124, and 286 ± 35, respectively) (P < 0.01). In a logistic regression analysis, we found that elevated plasma HAdV-7 sequence numbers significantly increased the risk of severe HAdV-7 pneumonia (OR 1.80, 95% confidence interval: 1.59-2.60, P < 0.01) after adjusting for age, fever duration, platelet counts, and serum lactate dehydrogenase levels.

CONCLUSIONS

Over two-thirds of children hospitalized with HAdV-7 pneumonia were <2 years of age. Approximately 40% of those with SP associated with respiratory failure were <12 months of age. Those with SP exhibited higher plasma HAdV-7 sequence numbers. Thus, plasma HAdV-7 sequence numbers have a potential in predicting severity of HAdV-7 pneumonia in children.

Harnessing T Cells to Control Infections After Allogeneic Hematopoietic Stem Cell Transplantation

Dramatic progress in the outcome of allogeneic hematopoietic stem cell transplantation (allo-HSCT) from alternative sources in pediatric patients has been registered over the past decade, providing a chance to cure children and adolescents in need of a transplant. Despite these advances, transplant-related mortality due to infectious complications remains a major problem, principally reflecting the inability of the depressed host immune system to limit infection replication and dissemination. In addition, development of multiple infections, a common occurrence after high-risk allo-HSCT, has important implications for overall survival. Prophylactic and preemptive pharmacotherapy is limited by toxicity and, to some extent, by lack of efficacy in breakthrough infections. T-cell reconstitution is a key requirement for effective infection control after HSCT. Consequently, T-cell immunotherapeutic strategies to boost pathogen-specific immunity may complement or represent an alternative to drug treatments. Pioneering proof of principle studies demonstrated that the administration of donor-derived T cells directed to human herpesviruses, on the basis of viral DNA monitoring, could effectively restore specific immunity and confer protection against viral infections. Since then, the field has evolved with implementation of techniques able to hasten production, allow for selection of specific cell subsets, and target multiple pathogens. This review provides a brief overview of current cellular therapeutic strategies to prevent or treat pathogen-related complications after HSCT, research carried out to increase efficacy and safety, including T-cell production for treatment of infections in patients with virus-naïve donors, results from clinical trials, and future developments to widen adoptive T-cell therapy access in the HSCT setting.

How We Treat Fever and Hypotension in Pediatric Hematopoietic Cell Transplant Patients

Pediatric allogeneic hematopoietic cell transplant (HCT) survival is limited by the development of post-transplant infections. In this overview, we discuss a clinical approach to the prompt recognition and treatment of fever and hypotension in pediatric HCT patients. Special attention is paid to individualized hemodynamic resuscitation, thorough diagnostic testing, novel anti-pathogen therapies, and the multimodal support required for recovery. We present three case vignettes that illustrate the complexities of post-HCT sepsis and highlight best practices that contribute to optimal transplant survival in children.

Recent Advances in Novel Antiviral Therapies against Human Adenovirus

Human adenovirus (HAdV) is a very common pathogen that typically causes minor disease in most patients. However, the virus can cause significant morbidity and mortality in certain populations, including young children, the elderly, and those with compromised immune systems. Currently, there are no approved therapeutics to treat HAdV infections, and the standard treatment relies on drugs approved to combat other viral infections. Such treatments often show inconsistent efficacy, and therefore, more effective antiviral therapies are necessary. In this review, we discuss recent developments in the search for new chemical and biological anti-HAdV therapeutics, including drugs that are currently undergoing preclinical/clinical testing, and small molecule screens for the identification of novel compounds that abrogate HAdV replication and disease.

Adenovirus persistence, reactivation, and clinical management

Adenoviral infections continue posing a major threat in severely immunocompromised patients including particularly allogeneic stem cell transplant recipients. Although exogenous infections occur in some instances, the majority of invasive events appear to arise from viral reactivation. In the pediatric setting, adenoviruses were demonstrated to persist in the gastrointestinal tract, and the intestinal epithelium serves as the main site of viral replication preceding invasive infection. Regular monitoring of serial stool samples for the presence and load of adenoviruses has therefore become a routine diagnostic tool for post-transplant patient surveillance, and can serve as a trigger for early initiation of treatment. In the adult setting, the source of infection or reactivation is less clear, and monitoring of peripheral blood specimens is the predominant approach for patient surveillance. Timely initiation of antiviral treatment is reportedly required for prevention or successful control of disseminated disease mediated by adenoviruses, and appropriate diagnostic monitoring is therefore of paramount importance. Currently available antiviral agents and immune therapeutic approaches have not been able to entirely overcome the life-threatening courses of invasive adenoviral infections in the immunocompromised clinical setting.