Allogeneic hematopoietic stem cell transplantation from unrelated donors is associated with higher infection rates in children with acute lymphoblastic leukemia-A prospective international multicenter trial on behalf of the BFM-SG and the EBMT-PDWP

Epidemiology of bloodstream infections and the impact of antimicrobial resistance in pediatric hematopoietic cell transplant

Bloodstream infections (BSI) pose a substantial threat to the well-being and survival of patients undergoing hematopoietic stem cell transplantation (HSCT). Risk factors for these infections vary across the different post-HSCT phases. In the pre-engraftment period, patients are particularly susceptible to infection due to prolonged neutropenia, mucosal damage, and extensive use of central venous line (CVL). In the post-engraftment phase, the emergence of graft versus host diseases further compounds the risk. The epidemiology of these infections has undergone notable changes over the years due to multifactorial reasons, including the evolution of protocols that intensify immunosuppression. In this context, the emergence of multi-drug resistance (MDR) microorganisms can be a challenge due to the elevated risk of mortality in these vulnerable patients. Unfortunately, there is a lack of comprehensive data on this topic, particularly in pediatrics. This article aims to provide a summary of the epidemiology of BSI in the different post-transplant phases and the impact of MDR pathogens. Having knowledge about the local epidemiology of BSI can be instrumental in tailoring targeted therapies, leading to improved survival rates in HSCT recipients.

Assessment of the Prevalence of Infections in Pediatric Patients With Acute Lymphoblastic Leukemia

Infections cause notable treatment-related morbidity during pediatric acute lymphoblastic leukemia/lymphoma (ALL/LLy) therapy. Infections are the most critical cause of morbidity and mortality in children undergoing treatment for acute lymphoblastic leukemia (ALL). Children with ALL, who are frequently underweight, are at increased risk of community-acquired pathogens, nosocomial multidrug-resistant pathogens, and opportunistic microorganisms. A weakened immune system from ALL itself and chemotherapy's side effects further worsen the prognosis. PubMed and Google Scholar articles were curated in a Google document with shared access. Discussion and development of the paper were achieved over Zoom meetings. This narrative review aims to analyze and summarize various pathogens responsible for infections in children receiving treatment for ALL and their treatment regimen and prophylaxis. The incidence of viral infection is higher in ALL patients, followed by bacterial and fungal infections. Prevention via prophylaxis and timely initiation of treatment is essential for positive outcomes.

Impact of percutaneous endoscopic gastrostomy on pediatric bone marrow transplantation outcomes: Retrospectice single-center cohort study

BACKGROUND

Parenteral nutrition is commonly used to ensure nutrition support and prevent the harmful effects of malnutrition, which frequently occurs after allogeneic hematopoietic stem cell transplantation (aHSCT). Nevertheless, enteral nutrition supports the restoration of the gut barrier and microbiome as well as protects against infectious complications and acute graft-vs-host disease. Percutaneous endoscopic gastrostomy (PEG) may also be beneficial for gastric decompression and drug administration.

METHODS

We performed a retrospective cohort study to evaluate the impact of PEG on treatment outcomes in 75 children who underwent aHSCT with (n = 34) or without (n = 41) PEG from 2005 to 2016.

RESULTS

In 34 patients, PEG was used to ensure enteral nutrition support (n = 30), oral drug intake (n = 28), and abdominal decompression (n = 2). During the study period, we observed a beneficial association between PEG placement and transplant-related mortality as well as 5-year overall survival compared with the non-PEG group (12.9% vs 59.0%, P = 0.000; 85.3% vs 35.1%, P = 0.000, respectively). The beneficial impact of PEG was most prominent on 5-year overall survival in older children (12-17 years) with grafts from matched unrelated donors.

CONCLUSIONS

PEG placement had a positive association with transplant outcomes in pediatric patients undergoing aHSCT. To confirm these results, larger prospective studies are needed.

Relapsed acute lymphoblastic leukaemia after allogeneic stem cell transplantation: a therapeutic dilemma challenging the armamentarium of immunotherapies currently available (case reports)

While survival rates in paediatric acute lymphoblastic leukaemia (ALL) nowadays exceed 90%, systemic ALL relapse, especially after haemopoietic stem cell transplantation (HSCT), is associated with a poor outcome. As there is currently no standardized treatment for this situation, individualized treatment is often pursued. Exemplified by two clinical scenarios, the aim of this article is to highlight the challenge for treating physicians to find a customized treatment strategy integrating the role of conventional chemotherapy, immunotherapeutic approaches and second allogeneic HSCT. Case 1 describes a 2-year-old girl with an early isolated bone marrow relapse of an infant KMT2A-rearranged B-cell precursor ALL after allogeneic HSCT. After bridging chemotherapy and lymphodepleting chemotherapy, chimeric antigen receptor (CAR) T-cells (tisagenlecleucel) were administered for remission induction, followed by a second HSCT from the 9/10 human leukocyte antigen (HLA)-matched mother. Case 2 describes a 16-year-old girl with a late, isolated bone marrow relapse of B-cell precursor ALL after allogeneic HSCT who experienced severe treatment toxicities including stage IV renal insufficiency. After dose-reduced bridging chemotherapy, CAR T-cells (tisagenlecleucel) were administered for remission induction despite a CD19^- clone without prior lymphodepletion due to enhanced persisting toxicity. This was followed by a second allogeneic HSCT from the haploidentical mother. While patient 2 relapsed around Day + 180 after the second HSCT, patient 1 is still in complete remission >360 days after the second HSCT. Both cases demonstrate the challenges associated with systemic ALL relapse after first allogeneic HSCT, including chemotherapy-resistant disease and persisting organ damage inflicted by previous therapy. Immunotherapeutic approaches, such as CAR T-cells, can induce remission and enable a second allogeneic HSCT. However, optimal therapy for systemic ALL relapse after first HSCT remains to be defined.

Infectious complications after hematopoietic stem cell transplantation for primary immunodeficiency in children: A multicenter nationwide study

PURPOSE

The aim of this nationwide study was to evaluate the characteristics of bacterial infections (BI), invasive fungal disease (IFD), and viral infections (VI) in pediatric patients with PID after allogeneic hematopoietic stem cell transplantation (allo-HSCT).

PATIENTS AND METHODS

In total, 114 HSCT recipients were enrolled into the study. At least one infectious complication (IC) was diagnosed in 60 (52.6%) patients aged 0.1-17.7 years, that is, 59.5% with SCID and 49.4% with non-SCID.

RESULTS

Among 60 HSCT recipients diagnosed with at least one IC, 188 episodes of infectious complications (EIC) were recorded, that is, 46.8% of BI, 41.5% of VI, and 11.7% of proven/probable IFD. According to PID and HSCT donor type, the incidence of EIC was comparable (P = .679). The localization of infections differed significantly due to PID type (P = .002). After each HSCT donor type, the most common site of infection was GI. Overall, BI caused by Gram-positive strains (59.1%) were prevalent, especially Staphylococcaceae. The multidrug-resistant (MDR) pathogens were diagnosed in 52.3%, especially ESBL + Enterobacteriaceae. The profile of VI was comparable for SCID and non-SCID patients (P = .839). The incidence of IFD was comparable for each PID and HSCT donor type. Survival after infection was 91.5% and was comparable for PID and HSCT donor type.

CONCLUSIONS

The rate of patients diagnosed with IC among pediatric PID-HSCT recipients did not depend on PID type, but rather on HSCT donor type. The localization of IC depended on PID and HSCT donor type. Within bacterial infections, predominated Gram-positive strains and the MDR pathogens were responsible for more than half of EIC.

Allogeneic hematopoietic stem cell transplantation from unrelated donors is associated with higher infection rates in children with acute lymphoblastic leukemia-A prospective international multicenter trial on behalf of the BFM-SG and the EBMT-PDWP

Severe infections (SI) significantly impact on non‐relapse mortality after hematopoietic stem cell transplantation (HSCT). We assessed 432 children and adolescents with acute lymphoblastic leukemia (ALL) after total body irradiation based myeloablative HSCT within the multicenter ALL‐BFM‐SCT 2003 trial for SI grade 3 or higher according to common terminology criteria for adverse events. A total 172 patients experienced at least one SI. Transplantation from matched unrelated donors (MUD) was associated with any type of SI in the pre‐engraftment period (hazard ratio [HR]: 2.57; P < .001), and with any SI between day +30 and + 100 (HR: 2.91; P = .011). Bacterial (HR: 2.24; P = .041) and fungal infections (HR: 4.06; P = .057) occurred more often in the pre‐engraftment phase and viral infections more often before day +30 (HR: 2.66; P = .007) or between day +30 and + 100 (HR: 3.89; P = .002) after HSCT from MUD as compared to matched sibling donors. Chronic GvHD was an independent risk factor for any type of SI after day +100 (HR: 2.57; P < .002). We conclude that allogeneic HSCT from MUD in children and adolescents with pediatric ALL is associated with higher infection rates, which seems attributable to an intensified GvHD prophylaxis including serotherapy and methotrexate.