Infections in Allogeneic Stem Cell Transplantation

Healthcare Resource Use and Costs of Allogeneic Hematopoietic Stem Cell Transplantation Complications: A Scoping Review

Allogeneic hematopoietic stem cell transplant (allo-HSCT) is an expensive and resource intensive procedure. This study aims to review the literature pertaining to healthcare resource utilization (HRU) and costs associated with allo-HSCT complications. The review followed the Joanna Briggs Institute methodology for scoping reviews. The PubMed, EMBASE, and Health Business Elite were searched in addition to the grey literature. Eligibility criteria included studies that reported HRU and/or costs associated with adult (≥18 years) allo-HSCT. Studies were categorized according to complications of allo-HSCT including graft-versus-host disease (acute and chronic GVHD) and infections (fungal, cytomegalovirus, virus-associated hemorrhagic cystitis, and acute respiratory tract infection). Commonly reported HRU and cost measures were extracted, including those associated with the direct management of allo-HSCT complications and intensive care unit (ICU) admissions. Reported costs were standardized to 2022 United States Dollars. Patients who experienced GVHD or infection post-transplant had an overall greater HRU including higher rates of hospitalization, hospital readmission, ICU admission, and longer length of stay compared to those patients who did not. Patients with severe or refractory GVHD and/or infection following allo-HSCT required greater healthcare intervention. This scoping review synthesizes the current literature on HRU and costs associated with post allo-HSCT complications. Patients who experienced post allo-HSCT complications had higher HRU and incurred higher costs overall, noting the variability across studies in their clinical context, reporting of HRU, and cost measures.

Efficacy and Safety of Letermovir for Cytomegalovirus Prophylaxis in Pediatric Hematopoietic Stem Cell Transplantation Recipients: A Systematic Review, Meta-Analysis, and Meta-Regression

OBJECTIVE

Letermovir (LTV) is a novel antiviral agent approved by the FDA in 2017 for CMV prophylaxis in adult CMV-seropositive allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients and approved for pediatric use in 2024. This study systematically evaluates the efficacy and safety of LTV prophylaxis for CMV infection in pediatric allo-HSCT recipients.

METHODS

We systematically searched PubMed, Scopus, Web of Science, Embase, and Cochrane Library up to December 2024 for studies that evaluated the use of LTV prophylaxis in pediatric allo-HSCT recipients. We conducted single-arm meta-analysis using Open Meta Analyst software and double-arm meta-analysis using R Studio. We pooled the dichotomous outcomes as event and total using the fixed-effects model.

RESULTS

Twelve articles were included in the analysis. The single-arm meta-analysis indicated that the prophylactic use of LTV against CMV among pediatrics was associated with a 10.9% (95% CI: 0.065, 0.153) infection rate without any disease occurrence. The percentage of patients who discontinued the drug due to adverse reactions was only 2.4% (95% CI: 0.003, 0.045), and all-cause mortality was 7.9% (95% CI: 0.032, 0.126). The double-arm meta-analysis results indicated that the incidence of CMV infection was significantly lower in the LTV group in comparison to the control group (RR: 0.29; 95% CI: 0.16, 0.56; p < 0.001).

CONCLUSION

LTV has demonstrated safety and efficacy in preventing CMV infection and disease among high-risk pediatric patients. Future large scale randomized trials are necessary to validate the findings.

Infectious complications and the utility of serum and cellular markers of infections in the setting of allogeneic hematopoietic stem cell transplantation

INTRODUCTION

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients are severely immunocompromised and susceptible to bacterial, viral, and fungal infections. Despite improved anti-microbial prophylaxis and preemptive strategies, bacterial bloodstream infections (BSIs) occur frequently in allo-HSCT recipients and are associated with increased morbidity and mortality. Cytomegalovirus (CMV) and Epstein Barr virus (EBV) are the most relevant viruses following allo-HSCT and remain major concerns. Fungal infections, including those caused by Candida and Aspergillus species, are persistent and feared complications.

AREAS COVERED

We aim to provide clinicians caring for allo-HSCT recipients with a comprehensive overview of the risk factors that predispose patients to common bacterial, fungal, and viral infections during the first years post-transplant. The focus is on the value of noninvasive diagnostic biomarkers and serological assays in enhancing the early detection and management of these infections.

EXPERT OPINION

Effective management of infectious complications following allo-HSCT relies on continuous immune recovery monitoring and the implementation of advanced diagnostic methods. Utilizing noninvasive diagnostic methods is crucial for early detection and different intervention strategies. The development and integration of reliable microbiological markers into clinical practice is essential for enhancing patient outcomes and mitigating infection-related risks. Emphasizing diagnostic innovation will be pivotal in advancing patient care post-allo-HSCT.

Seasonal Characterization of the Aerobiome in Hematopoietic Stem Cell Transplant Rooms: Potential Risk for Immunosuppressed Patients

Infections pose a risk for patients undergoing hematopoietic stem cell (HSC) transplants due to their immunosuppression, making them susceptible to opportunistic infections. Therefore, understanding the composition of the aerobiome in this area is vital. The aim of this study was to characterize the aerobiome in an HSC transplant area, evaluating the impact of infrastructure and health personnel operations on air contamination. The environmental parameters and aerobiome of the HSC transplant area at Hospital Juárez de México were quantified over one year. Finally, a double-entry Vester matrix was constructed to classify problems according to their degree of causality. The abundance and taxonomic diversity of the aerobiome were dependent on seasonality, environmental factors, and high-efficiency filtration. Gram-positive bacteria predominated, followed by fungi and Gram-negative bacteria. ANOVA revealed significant differences in the bacterial aerobiome but not in the fungal aerobiome among the transplant rooms. Clinically, fungi such as Aspergillus fumigatus, Alternaria spp., Cladosporium spp., and Penicillium spp. were identified. ESKAPE bacteria typing revealed clonal dispersion. Finally, the Vester matrix highlighted critical problems associated with contamination due to the absence of HEPA filtration and non-adherence in patient management practices. HEPA filtration and positive pressure are essential to improve the air quality and reduce the microbiological load. However, the control areas will depend on patient management and routine activities, such as entry protocols in controlled areas.

Review of advanced practice nurse role in infection throughout the hematopoietic stem cell transplant journey

BACKGROUND

Prolonged periods of immunosuppression during hematopoietic stem cell transplant (HSCT) can result in serious infectious complications and contribute to transplant-related morbidity and mortality. Adherence to standardized pre and postinfection screening guidelines, prescribed medications, and early identification of infectious symptoms through comprehensive patient and family education are crucial to minimizing infectious complications. Advanced practice nurses (APNs) are key members of the multidisciplinary care team in the HSCT specialty, maintaining a specialized skillset and scope of practice which includes a holistic based, preventative medicine and risk mitigation approach.

METHODS

This review sought to describe the role of the APN in HSCT care and to further examine existing APN led models of care which focus on infection prevention and education throughout the HSCT treatment journey.

RESULTS

No studies specifically examined the APN role in infectious diseases risk assessment, screening, and management throughout the HSCT journey were identified throughout our review, however, there was considerable evidence to demonstrate the benefits of APN led care in the oncology and solid organ transplantation specialty which led to improvements in continuity of care, overall patient outcomes, and multidisciplinary team collaboration. The key themes identified in our review, were the role of the APN in the delivery of comprehensive patient and family education, the role of the APN in supporting, mentoring, and educating junior medical and nursing teams, the collaboration between the APN and the multidisciplinary care team, and the role of the APN in prompt recognition, triage, and management of treatment related complications, such as infection.

How I approach: the transplant recipient with fever and pulmonary infiltrates

Recipients of hematopoietic stem cell transplants and solid organ transplants frequently develop pulmonary infiltrates from both infectious and non-infectious etiologies. Differentiation and further characterization of microbiologic etiologies-viral, bacterial, and fungal-can be exceedingly challenging. Pediatric patients face unique challenges as confirmatory evaluations with bronchoscopy or lung biopsy may be limited. A generalizable approach to diagnosing and managing these conditions has not been well established. This paper aims to summarize our initial clinical approach while discussing the relative evidence informing our practices. A pediatric patient with characteristic infiltrates who has undergone HSCT is presented to facilitate the discussion. Generalizable approaches to similar patients are highlighted as appropriate while highlighting considerations based on clinical course and key risk factors.

Drug monitoring during ciprofloxacin prophylaxis of allogeneic stem cell transplant patients: associations with bacterial infections through a monocentric observational prospective study

BACKGROUND

Bacterial infection ranks amongst the most common causes of morbidity and mortality in patients undergoing allogeneic haematopoietic stem cell transplantation (alloHSCT). Although ciprofloxacin (CIP) prophylaxis is recommended, information on serum levels and clinical course is lacking.

AIM

To investigate relationships between CIP level and failure of prophylaxis, particularly in terms of whether different pharmacokinetic (PK) indices [area under the concentration-time curve (AUC0-24h) vs single time samples] correlate differently with the outcome.

METHODS

This prospective observational monocentric study was conducted at a 1500-bed teaching hospital (March 2018-March 2019), including 63 adult patients with alloHSCT receiving CIP prophylaxis. Blood samples were drawn at three sampling times (1, 6 and 12 h post-administration), twice per week, and measured via high performance liquid chromatography. The onset of febrile episodes (FEBs) indicated suspected failure of CIP prophylaxis. Positive blood cultures [bloodstream infection (BSI)] indicated confirmed failure of prophylaxis.

FINDINGS

Seven of 63 patients died without significant differences in their average CIP levels compared with survivors, with patients experiencing FEBs (54/63) displaying a 13% [95% confidence interval (CI) 4-22%] lower probability of survival. In total, 225 sets of three values (triplets) were obtained from 58 primary CIP episodes. Triplets preceding BSI with Gram-negative bacteria (GNB-BSI) showed lower AUC0-24h on average, but similar single time sample indices. An AUC0-24h of ≤21.61 mgh/L resulted in four-fold higher odds of GNB-BSI (adjusted odds ratio 3.96, 95% CI 1.21-13.00). These results were independent of the administration route, patient demographics or sampling protocol deviations, indicating reduced CIP exposure upon GNB-BSI events.

CONCLUSION

Monitoring CIP levels, using multiple sampling times, may be useful to reduce alloHSCT-associated bacterial infections. Further analysis is needed to investigate causality.

Fluoroquinolone prophylaxis in patients with neutropenia at high risk of serious infections: Exploring pros and cons

BACKGROUND

The use of fluoroquinolones to prevent infections in neutropenic patients with cancer or undergoing hematopoietic stem cell transplantation (HSCT) is a controversial issue, with international guidelines providing conflicting recommendations. Although potential benefits are clear, concerns revolve around efficacy, potential harms, and antimicrobial resistance (AMR) implications.

DISCUSSION

Fluoroquinolone prophylaxis reduces neutropenic fever (NF) bloodstream infections and other serious bacterial infections, based on evidence from systematic reviews, randomized controlled trials, and observational studies in adults and children. Fluoroquinolone prophylaxis may also reduce infection-related morbidity and healthcare costs; however, evidence is conflicting. Adverse effects of fluoroquinolones are well recognized in the general population; however, studies in the cancer cohort where it is used for a defined period of neutropenia have not reflected this. The largest concern for routine use of fluoroquinolone prophylaxis remains AMR, as many, but not all, observational studies have found that fluoroquinolone prophylaxis might increase the risk of AMR, and some studies have suggested negative impacts on patient outcomes as a result.

CONCLUSIONS

The debate surrounding fluoroquinolone prophylaxis calls for individualized risk assessment based on patient characteristics and local AMR patterns, and prophylaxis should be restricted to patients at the highest risk of serious infection during the highest risk periods to ensure that the risk-benefit analysis is in favor of individual and community benefit. More research is needed to address important unanswered questions about fluoroquinolone prophylaxis in neutropenic patients with cancer or receiving HSCT.

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.

Human herpesvirus-6 in hematopoietic stem cell transplant recipients: a prospective cohort study in Egypt

BACKGROUND

Immunocompromised patients face reactivation of latent viruses that increase the risk of morbidity.

AIM

The study aimed to detect human herpes virus 6 (HHV-6) reactivation among allogeneic (allo) and autologous (auto) hematopoietic stem cell transplant (HSCT) recipients and to correlate potentially attributed clinical manifestations to HHV-6 DNA plasma level.

METHODS

A prospective study included all (forty) patients undergoing allo and auto-HSCT from Jan 2020 till June 2022. Plasma samples were collected for HHV-6 serology, and for HHV-6 quantitative PCR at post-transplantation weeks 2, 4, 6. Demographic and clinical data were recorded.

RESULTS

Out of 40 peripheral blood stem cell transplant (PBSCT) recipients, 34 (85%) were HHV-6 IgG positive pre-HSCT. Of which, fourteen patients (14/34, 41.2%) showed positive HHV-6 DNaemia. HHV-6 DNAemia (15/40, 37.5%) was significantly higher among allo (8/12, 66.7%) versus auto (7/28, 25%) HSCT recipients (p = 0.030). Patients with HHV-6 DNAemia developed fever, delayed engraftment and bone marrow suppression in 6/15, 40%, thrombocytopenia (5/15, 33.3%), rash and pneumonitis (2/15, 13.3%), acute GVHD (aGVHD) (1/15, 6.7%). HHV-6 DNAemia ranged from 101 to 102,000 copies/mL. Univariate analysis identified conditioning with busulfan-cyclophosphamide as a significant risk (p = 0.043), while receiving BEAM protocol was a protective factor (p = 0.045). In multivariate analysis, receiving BEAM protocol retained significance (p = 0.040).

CONCLUSION

Frequent HHV-6 reactivation was detected after HSCT, especially in allo-HSCT recipients with clinical manifestations which could not be otherwise explained. To our best knowledge this is the first study of HHV6 reactivation in HSCT recipients from Egypt. Raising awareness for HHV-6 reactivation manifestations and screening in HSCT recipients could be lifesaving.

Economic and clinical burden associated with respiratory viral infections after allogeneic hematopoietic cell transplant in the United States

Background

Methods

Results

Conclusion

Unusual oral presentation of acyclovir-resistant herpes simplex in an allogeneic haematopoietic stem cell transplant recipient

The early engraftment phase of allogeneic haematopoietic stem cell transplantation can be associated with a number of oromucosal infective complications. While the routine use of prophylactic acyclovir has reduced the incidence of herpes simplex virus (HSV) reactivation, there is an increasing prevalence of acyclovir resistance within this cohort of patients. The authors present a case of acyclovir-resistant HSV reactivation in a 26-year-old woman 7 days post T-deplete sibling allograft on a background of combined cyclophosphamide and total body irradiation myeloablative conditioning, successfully treated with foscarnet and cidofovir therapy and discuss the differential diagnoses for early/late engraftment oral disease.

Is it time to reconsider prophylactic antimicrobial use for hematopoietic stem cell transplantation? a narrative review of antimicrobials in stem cell transplantation

INTRODUCTION

Hematopoietic Stem Cell Transplantation (HSCT) is a life-saving procedure for multiple types of hematological cancer, autoimmune diseases, and genetic-linked metabolic diseases in humans. Recipients of HSCT transplant are at high risk of microbial infections that significantly correlate with the presence of graft-versus-host disease (GVHD) and the degree of immunosuppression. Infection in HSCT patients is a leading cause of life-threatening complications and mortality.

AREAS COVERED

This review covers issues pertinent to infection in the HSCT patient, including bacterial and viral infection; strategies to reduce GVHD; infection patterns; resistance and treatment options; adverse drug reactions to antimicrobials, problems of antimicrobial resistance; perturbation of the microbiome; the role of prebiotics, probiotics, and antimicrobial peptides. We highlight potential strategies to minimize the use of antimicrobials.

EXPERT OPINION

Measures to control infection and its transmission remain significant HSCT management policy and planning issues. Transplant centers need to consider carefully prophylactic use of antimicrobials for neutropenic patients. The judicious use of appropriate antimicrobials remains a crucial part of the treatment protocol. However, antimicrobials' adverse effects cause microbiome diversity and dysbiosis and have been shown to increase morbidity and mortality.

Hematopoietic stem cell transplantation for autoimmune diseases in the time of COVID-19: EBMT guidelines and recommendations

Coronavirus disease-19 (COVID-19), caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), represents one of the biggest challenges of 21st century, threatening public health around the globe. Increasing age and presence of co-morbidities are reported risk factors for severe disease and mortality, along with autoimmune diseases (ADs) and immunosuppressive treatments such as haematopoietic stem cell transplantation (HSCT), which are also associated with adverse outcomes. We review the impact of the pandemic on specific groups of patients with neurological, rheumatological, and gastroenterological indications, along with the challenges delivering HSCT in adult and pediatric populations. Moving forward, we developed consensus-based guidelines and recommendations for best practice and quality of patient care in order to support clinicians, scientists, and their multidisciplinary teams, as well as patients and their carers. These guidelines aim to support national and international organizations related to autoimmune diseases and local clinical teams delivering HSCT. Areas of unmet need and future research questions are also highlighted. The waves of the COVID-19 pandemic are predicted to be followed by an "endemic" phase and therefore an ongoing risk within a "new normality". These recommendations reflect currently available evidence, coupled with expert opinion, and will be revised according to necessary modifications in practice.