Unrelated donor cord blood transplantation for non-malignant disorders in children and adolescents

The state of the art in the treatment of severe aplastic anemia: immunotherapy and hematopoietic cell transplantation in children and adults

Acquired aplastic anemia (AA) is an immune-mediated bone marrow (BM) failure where marrow disruption is driven by a cytotoxic T-cell-mediated autoimmune attack against hematopoietic stem cells. The key diagnostic challenge in children, but also in adults, is to exclude the possible underlying congenital condition and myelodysplasia. The choice of treatment options, either allogeneic hematopoietic cell transplantation (alloHCT) or immunosuppressive therapy (IST), depends on the patient's age, comorbidities, and access to a suitable donor and effective therapeutic agents. Since 2022, horse antithymocyte globulin (hATG) has been available again in Europe and is recommended for IST as a more effective option than rabbit ATG. Therefore, an update on immunosuppressive strategies is warranted. Despite an improved response to the new immunosuppression protocols with hATG and eltrombopag, some patients are not cured or remain at risk of aplasia relapse or clonal evolution and require postponed alloHCT. The transplantation field has evolved, becoming safer and more accessible. Upfront alloHCT from unrelated donors is becoming a tempting option. With the use of posttransplant cyclophosphamide, haploidentical HCT offers promising outcomes also in AA. In this paper, we present the state of the art in the management of severe AA for pediatric and adult patients based on the available guidelines and recently published studies.

Poor Outcome After Hematopoietic Stem Cell Transplantation Of Patients With Unclassified Inherited Bone Marrow Failure Syndromes

Classification of inherited bone marrow failure syndromes (IBMFSs) according to clinical and genetic diagnoses enables proper adjustment of treatment. Unfortunately, 30% of patients enrolled in the Canadian Inherited Marrow Failure Registry (CIMFR) with features suggesting hereditability could not be classified with a specific syndromic diagnosis. We analyzed the outcome of hematopoietic stem cell transplantation (HSCT) in unclassified IBMFSs (uIBMFSs) and the factors associated with outcome. Twenty-two patients with uIBMFSs and 70 patients with classified IBMFSs underwent HSCT. Five-year overall survival of uIBMFS patients after HSCT was inferior to that of patients with classified IBMFSs (56% vs 76.5%). The outcome of patients with uIBMFS who received cord blood was significantly lower than that of patients who received other stem cell sources (14.8% vs 90.9%). Engraftment failure was higher among patients with uIBMFS who received cord blood than those who received bone marrow. None of the following factors was significantly associated with poor survival: transfusion load, transplant indication, the intensity of conditioning regimen, human leukocyte antigen-identical sibling/alternative donor. We suggest that identifying the genetic diagnosis is essential to modulate the transplant procedure including conditioning agents and stem cell sources for better outcome and the standard CBT should be avoided in uIBMFS.

Repurposing the public cord blood bank inventory in Korea to enhance cord blood use

To enhance public cord blood (CB) use, we examined the current status of CB banking and tried to suggest revision of the banking standard. We retrospectively analyzed the use of stored public CB units between 2011 and 2016 using data from the CB information center in Korea. A total of 19,871 CB units were registered, and 363 units were selected for transplantation. The transplanted CB units contained significantly higher numbers of CD34+ cells than the average numbers in the stored CB units (5.5 × 10^6 vs. 3.2 × 10^6, p < 0.01). They also contained more total nucleated cells (TNCs) than the average of the stored CB units (13.7 × 10^8 vs. 10.7 × 10^8, p < 0.01). Only 49% of the stored CB units contained>10 × 10^8 TNCs, while 81% of the units transplanted contained >10 × 10^8 TNCs. The average length of cryopreservation of the transplanted CB units was 4.58 years and 95% of them had been stored for less than 10 years. During the study period, 18,763 CB units were requested for research, but only 5,888 were released. This discrepancy was mostly due to errors in regulatory and/or networking elements of the CB supply system. The data suggest that preserving CB units for less than 10 years and increasing the required minimum TNC count to 10 × 10^8 would produce an inventory containing units that were more useful for CBT. CB units that did not meet the requisite quality standards could be used for research, and systems for their fair distribution to researchers are needed.

Allogeneic Hematopoietic Cell Transplantation in Patients with Primary Immunodeficiencies in Korea: Eleven-Year Experience in a Single Center

PURPOSE

We aimed to report our single-center experience of allogeneic hematopoietic cell transplantation (HCT), which has been the only curative option for certain patients with lethal primary immunodeficiencies (PIDs).

METHODS

We summarized the results of HCT performed for patients with PIDs for 11 consecutive years from 2006 to 2016 at Samsung Medical Center, Seoul, Korea. Twenty-six patients with PIDs received HCT. Most had chronic granulomatous disease (42.3%), Wiskott Aldrich syndrome (15.4%), or severe combined immunodeficiency (11.5%).

RESULTS

Nine patients (34.6%) received HCT during the former half period and 17 patients (65.4%) during the latter half period. Donor types were categorized as: matched sibling donor (n = 5), unrelated donor (n = 17), and familial mismatched donor (FMMD) (n = 4). Unrelated HCT and FMMD transplantation were increasingly performed in the latter half period compared to the first (5 vs. 16, P = 0.034). Five patients experienced initial engraftment failure, but all of them were eventually engrafted after additional HCTs. The 3-year probability of overall survival was 72.0%. Seven patients (26.9%) died, and the causes of death were bacterial sepsis (n = 4), pneumonia (n = 1), chronic graft-versus-host disease (GVHD) (n = 1), and diffuse alveolar hemorrhage (n = 1). Two patients with bacterial sepsis and a patient with pneumonia also had chronic GVHD. Unrelated HCT and use of methotrexate were associated with poor outcome. Complete chimerism was attained in 85.0% at 1 year after HCT.

CONCLUSION

PID candidates have been increasingly identified for allogeneic HCT in Korea, and the majority of them could be cured by HCT. Establishment of a systematic registry of PID patients for HCT is needed.

Clinical outcomes of unrelated cord blood transplantation in children with malignant and non-malignant diseases: Multicenter experience in China

This multicenter retrospective study included 184 children with malignant and non-malignant diseases who underwent UCBT between January 1998 and August 2012. The malignant disease group included 101 children with ALL, AML, CML, JMML, and MDS, and the non-malignant disease group included 83 children with PID, β-thalassemia, IMD BMF, and HLH. The median duration to neutrophil and platelet engraftment was 16 and 35 days in the malignant disease group vs 15 and 38 days in the non-malignant disease group. The cumulative incidence of grade II-IV aGVHD and cGVHD was 25.6% and 13.5% in the malignant disease group vs 19.7% and 11.1% in the non-malignant disease group, respectively. The median duration and cumulative incidence of neutrophil and platelet engraftment, and the cumulative incidence of grade II-IV aGVHD and cGVHD were similar between the two groups. Of the 184 pediatric patients, 114 patients survived during a median follow-up period of 14 months (range 4-138). The 5-year OS and DFS were not statistically different between the two groups (56.3% and 46.1% in malignant disease group vs 68.5% and 52.8% in non-malignant disease group). The above results indicate that UCB is a viable source for HSCT for children with malignant or non-malignant diseases, especially in urgent cases.

Phenotype and Management of Infantile-onset Inflammatory Bowel Disease: Experience from a Tertiary Care Center in China

BACKGROUND

Infantile-onset inflammatory bowel disease (IBD) comprises rare and clinically severe disorders. We examined the phenotypes and genetic causes of patients with infantile-onset IBD from a tertiary medical center.

METHODS

We enrolled 38 patients with infantile-onset IBD and applied standardized treatment with medical, surgical, and supportive care. Targeted sequencing and whole-exome sequencing were performed. Clinical data were retrieved from medical records.

RESULTS

Median age of onset of disease was 12.5 (interquartile range: 7.0-30.0) days. All patients had diarrhea, whereas 18 (47.4%) patients reported hematochezia. Thirteen (34.2%) patients had oral ulcers, 15 (39.5%) patients had perianal abscess, and 9 (52.9%) female patients had rectovaginal fistula. Six (18.8%) patients had intestinal strictures and 4 (12.1%) patients had perforation. Twelve (31.6%) patients underwent surgical procedures. Median age of surgery was 272.5 days, and cumulative probability for surgery during first year was 32.1%. One-year mortality of patients was 25.9%. Sequencing showed 24 (63.2%) patients had causative IL10RA mutations, 1 patient had EPCAM mutation, 1 patient had TNFAIP3 mutation, and 1 patient had LRBA mutation, whereas causative mutations cannot be identified in the other 11 (28.9%) patients. Umbilical cord blood stem cell transplantation has been applied to 8 cases with IL10RA mutations, of whom 5 (71.4%) patients have achieved clinical remission.

CONCLUSIONS

Patients with infantile-onset IBD had severe phenotype and early onset. Medical, surgical interventions with supportive care are essential. High-throughput sequencing ensures appropriate treatment. Hematopoietic stem cell transplantation can be performed in selected patients with IL10RA mutations (see Video Abstract, Supplemental Digital Content 1, http://links.lww.com/IBD/B657).

Allogeneic hematopoietic stem cell transplantation in congenital disorders: A single-center experience

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the treatment of choice for a variety of congenital disorders. We report the experience of children affected by congenital diseases other than bone marrow failure syndromes who received allo-HSCT over a period of 25 years at G. Gaslini Paediatric Research Institute. HSCTs were performed in 57 children with congenital diseases (25 with congenital immunodeficiencies, 10 with severe combined immunodeficiencies, and 22 with metabolic diseases). Overall survival rate at 3 years in the whole group of patients was 76.9%, with a trend in favor of better outcome in children with metabolic diseases and in those who received cord blood cells (85.9%) vs bone marrow cells (72.4%).

Acquired aplastic anemia in Korean children: treatment guidelines from the Bone Marrow Failure Committee of the Korean Society of Pediatric Hematology Oncology

The treatment of choice for aplastic anemia (AA) in children has been HLA-matched family donor (MFD) hematopoietic stem cell transplantation (HSCT). For those lacking MFD, immunosuppressive therapy (IST) consisting of horse antithymocyte globulin (ATG) and cyclosporine has been successful. The choices of second and third line treatments are more complex and debatable, especially in the situation of unavailability of horse ATG. IST with rabbit ATG seems to be less effective. Recently, improved survival of non-MFD HSCTs has been documented. The outcome of matched or mismatched unrelated donor, umbilical cord blood, or haploidentical family donor transplantations will be discussed in AA children after IST failure. Experimental approaches of upfront HSCT using non-MFDs will be briefly touched. In this review, a treatment guideline for children with AA from the Korean Society of Pediatric Hematology Oncology will be presented along with a brief review of literature on current clinical practices in Korea.