Cord blood versus haploidentical stem cell transplantation for hematological malignancies

Spleen-targeted delivery systems and strategies for spleen-related diseases

The spleen, body's largest secondary lymphoid organ, is also a vital hematopoietic and immunological organ. It is regarded as one of the most significant organs in humans. As more researchers recognize the functions of the spleen, clinical methods for treating splenic diseases and spleen-targeted drug delivery systems to improve the efficacy of spleen-related therapies have gradually developed. Many modification strategies (size, charge, ligand, protein corona) and hitchhiking strategies (erythrocytes, neutrophils) of nanoparticles (NPs) have shown a significant increase in spleen targeting efficiency. However, most of the targeted drug therapy strategies for the spleen are to enhance or inhibit the immune function of the spleen to achieve therapeutic effects, and there are few studies on spleen-related diseases. In this review, we not only provide a detailed summary of the design rules for spleen-targeted drug delivery systems in recent years, but also introduce common spleen diseases (splenic tumors, splenic injuries, and splenomegaly) with the hopes of generating more ideas for future spleen research.

Haploidentical versus Double-Cord Blood Stem Cells as a Second Transplantation for Relapsed Acute Myeloid Leukemia

There are limited data on second stem cell transplantation (SCT2) outcomes with alternative donors for relapsed AML after the first stem cell transplantation (SCT1). We analyzed the outcomes of 52 adult AML patients who received SCT2 from haploidentical donors (HIT, N = 32) and double-cord blood (dCBT, N = 20) between 2008 and 2021. The HIT group received T-cell-replete peripheral blood stem cells after reduced-toxicity conditioning with anti-thymocyte globulin (ATG), while the dCBT group received myeloablative conditioning. For a median follow-up of 64.9 months, the HIT group, compared to the dCBT group, had earlier engraftment, superior 2-year overall survival (OS), disease-free survival (DFS), and non-relapse mortality (NRM) with similar relapse. Multivariate analysis demonstrated that HIT was significantly associated with better OS, DFS, and lower NRM than dCBT. Both longer remission duration after SCT1 and complete remission at SCT2 were significantly associated with a lower relapse rate. In addition, bone marrow WT1 measurable residual disease (MRD) positivity was significantly associated with inferior OS and higher relapse. This study suggests that T-cell-replete HIT with ATG-based GVHD prophylaxis may be preferred over dCBT as SCT2 for relapsed AML and that WT1-MRD negativity may be warranted for better SCT2 outcomes.

Allele and Haplotype Frequencies of HLA-A, -B, -C, and -DRB1 Genes in 3,750 Cord Blood Units From a Kinh Vietnamese Population

The frequencies and diversities of human leukocyte antigen (HLA) alleles and haplotypes are representative of ethnicities. Matching HLA alleles is essential for many clinical applications, including blood transfusion, stem cell transplantation, and tissue/organ transplantation. To date, the information about the frequencies and distributions of HLA alleles and haplotypes among the Kinh Vietnamese population is limited because of the small sample size. In this study, more than 3,750 cord blood units from individuals belonging to the Kinh Vietnamese population were genotyped using PCR sequence-specific oligonucleotide (PCR-SSO) for HLA testing. The results of the study demonstrated that the most frequently occurring HLA-A, -B, -C, and -DRB1 alleles were A*11:01 (25%), A*24:02 (12.3%), A*02:01 (11.2); A*03:03 (8.95%), A*02:03 (7.81%), A*29:01 (7.03%); B*15:02 (15.1%), B*46:01 (10.7%), B*58:01 (7.65%), B*38:02 (7.29%); C*08:01 (17.2), C*07:02 (16.2%), C*01:02 (15.2), C*03:02 (8.3%), C*15:05 (6.13); DRB1*12:02 (31.0%), DRB1*09:01 (10.47%), DRB1*15:02 (7.54%); DRB1*07:01 (6.68%), DRB1*10:01 (6.63%), respectively, with the highest allele diversity level observed in locus B (93 alleles). The most frequent haplotypes of two-locus combinations of HLA-A–B, HLA-A–C, HLA-A–DRB1, HLA-B–C, HLA-B–DRB1, and HLA-C–DRB1 haplotypes were A*11:01–B*15:02 (7.63%), A*11:01–C*08:01 (7.98%), A*11:01–DRB1*12:02 (10.56%), B*15:02–C*08:01 (14.0%), B*15:02–DRB1*12:02 (10.47%), and C*08:01–DRB1*12:02 (11.38%), respectively. In addition, the most frequent haplotypes of three- and four-locus sets of HLA-A–B–C, HLA-A–B–DRB1, HLA-A–C–DRB1, HLA-B–C–DRB1, and HLA-A–B–C–DRB1 were A*11:01–B*15:02–C*08:01 (7.57%), A*11:01–B*15:02–DRB1*12:02 (5.39%), A*11:01–C*08:01–DRB1*12:02 (5.54%), B*15:02–C*08:01–DRB1*12:02 (10.21%), and A*11:01–B*15:02–C*08:01–DRB1*12:02 (5.45%), respectively. This study provides critical information on the frequencies and distributions of HLA alleles and haplotypes in the Kinh Vietnamese population, accounting for more than 85% of Vietnamese citizens. It paves the way to establish an umbilical cord blood bank for cord blood transplantation programs in Vietnam.

Comparison of clinical outcomes between unrelated single umbilical cord blood and "ex-vivo" T-cell depleted haploidentical transplantation in children with hematological malignancies

BACKGROUND

Over the last two decades, umbilical cord blood (UCB) and haploidentical transplantation (HaploHSCT) have emerged as alternative sources of hematopoietic stem cell for allogeneic transplantation. There are few retrospective studies and no prospective studies comparing both types of alternative transplantation in pediatric patients.

RESULTS

We analyzed the data of 134 children with hematological malignancies who received a hematopoietic stem cell transplantation from a single umbilical cord blood (UCB) (n = 42) or an "ex-vivo" T-cell depleted transplant from a haploidentical-related donor (HaploHSCT) (n = 92) between 1996 and 2014. Hematological recovery was faster after HaploHSCT than the UCB transplant group (median times to neutrophil and platelet recovery: 13 vs. 16 days, 10 vs. 57 days, respectively) (P < 0.001). The HaploHSCT group had a significantly early immune reconstitution based on NK and CD8 + T cells compared with the UCB group. However, after the first year post-transplantation, HaploHSCT had a lower number of CD4 + T and B lymphocytes compared with the UCB transplant recipients. The cumulative incidence of TRM was 29±8% in the HaploHSCT group versus 40±5% in the UCB group. Relapse incidence was 21±7% in the HaploHSCT group and 19±8% in the UCB group. Probability of DFS was 58±8% in the HaploHSCT group versus 40±9% in the UCB group (P = 0.051).

CONCLUSIONS

TCD haploidentical transplant is associated with advantages in terms of engraftment and early immune reconstitution kinetics. TCD haploidentical transplant was associated with lower incidence of infectious and non-infectious complications, especially in the early phases of the transplant compared with UCB transplant recipients. However, there are no advantages in transplant outcomes compared with UCB transplant.

Haploidentical Hematopoietic Cell Transplantation Using Posttransplant Cyclophosphamide for Sézary Syndrome

Patients with advanced-stage mycosis fungoides (MF) and Sézary syndrome (SS) have a poor prognosis. Allogeneic hematopoietic cell transplantation (HCT) is a potentially curative treatment option; however, since most patients with MF/SS are elderly, they often have difficulty in finding HLA-matched donors. In recent years, HCT from HLA-haploidentical donors (haplo-HCT) using posttransplant cyclophosphamide (PTCy) as graft-versus-host disease prophylaxis has been conducted for patients without HLA-matched donors. Infectious complications, particularly cutaneous bacterial infections, are common among patients with MF/SS. The lower incidence of severe infectious complications after haplo-HCT than after an unrelated cord blood transplantation could lead to lower transplant-related mortality. Here, we report on a patient with SS who was treated successfully with haplo-HCT with PTCy. The patient has remained in complete remission for more than 24 months.

[Haploidentical hematopoietic stem cell transplant: How to choose the best donor? Guidelines from the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC)]

Haploidentical hematopoietic stem cell transplantation has been growing steadily since 2012. The SFGM-TC has twice published guidelines concerning T-cell repleted haploidentical grafts with high dose cyclophosphamide post-transplantation. The 2013 workshop recommended using the non-myeloablative Baltimore protocol with bone marrow and developed prospective protocols to evaluate these transplantations. The 2015 workshop reported improved results of reduced conditioning regimens in Hodgkin's lymphoma and intensive conditioning in myeloid hemopathies, and a similar outcome with 10/10 HLA matched donor with the same disease-risk score thus raising the question of the qualifier "alternative" for haploidentical transplants. The current work concerns the criteria for selecting the donor. The main criterion remains the absence of anti-HLA antibodies directed against the donor present in the recipient sera (DSA - Donor Specific Antibodies). In case of DSA and in the absence of an alternative donor, desensitization protocols exist. The other criteria are impossible to prioritize: age, sex, CMV, and blood type. The degree of relatedness and the number of HLA incompatibilities do not seem to be a criterion of choice. The 'ideal' donor would be a young man, CMV-matched, without major ABO incompatibility with a marrow transplant. There is insufficient data for the KIR-ligand and NIMA/NIPA mismatch. Peripheral stem cell grafts appear to yield more acute GVHD than bone marrow grafts after intensive conditioning, but with comparable survival rates. Based on the literature review, the comparison of haploidentical with unrelated donors encourages inclusion in existing national protocols randomizing these different donors.

Foxp3 expression in induced T regulatory cells derived from human umbilical cord blood vs. adult peripheral blood

Foxp3 is essential for T regulatory cell (Treg) function. Broad complex-Tramtrack-Bric-a-brac domain (BTB) and Cap'n'collar (CNC) homology 1, transcription factor 2 (BACH2) stabilizes Treg immune homeostasis in murine studies. However, little is known regarding what role, if any, BACH2 may have in Foxp3 regulation in human-induced Treg (iTreg). We examined Foxp3 expression and regulation comparing iTreg differentiated from umbilical cord blood (UCB) vs. adult blood (AB) naive CD4⁺ T-cells. Foxp3 expression was higher in UCB vs. AB-derived iTreg, and was sustained during 21-day expansion in vitro. The number of Foxp3⁺ iTreg generated from UCB vs. AB naive CD4⁺ T-cells was higher in iTreg differentiation conditions. In addition, UCB iTreg were more potent in suppressing T-cell proliferation compared to AB iTreg. Naive UCB CD4⁺ T-cells highly expressed BACH2 protein compared to AB. Putative transcriptional BACH2 binding sites were identified at the Foxp3 promoter, using BACH2 consensus sequence. Cross-linking chromatin immunoprecipitation (ChIP) showed that BACH2 binds to the Foxp3 proximal promoter in UCB iTreg, but not AB iTreg. BACH2 was transcriptionally active, as shRNA-mediated BACH2 knockdown resulted in reduction of Foxp3 gene transcription in UCB CD4⁺ T-cells. In summary, BACH2 serves to stabilize robust Foxp3 expression in UCB CD4⁺ T-cell-derived iTreg.

Graft predominance after double umbilical cord blood transplantation: a review

Several parameters are involved in graft predominance after double umbilical cord blood transplantation (dUCBT), of which T-cell alloreactivity between the grafts is now considered to be the major denominator. We recently showed that alloreactive CD4+ T-cells originating from the predominant CBU recognize HLA-class II allele mismatches and can readily be detected in the majority of patients. In addition, it was shown that HLA-class II allele-specific CD4+ T-cells were able to recognize primary leukemic cells when the mismatched HLA-class II allele was shared between the rejected CBU and the patient. These results further underscored the role of alloreactive T-cells, notably class II specific CD4+ T-cells, in graft-versus-graft reactions and in graft-versus-leukemia after dUCBT.

Advances in umbilical cord blood cell therapy: the present and the future

INTRODUCTION

Umbilical cord blood (UCB), previously seen as medical waste, is increasingly recognized as a valuable source of cells for therapeutic use. The best-known application is in hematopoietic stem cell transplantation (HSCT), where UCB has become an increasingly important graft source in the 28 years since the first umbilical cord blood transplantation (UCBT) was performed. Recently, UCB has been increasingly investigated as a putative source for adoptive cell therapy. Areas covered: This review covers the advances in umbilical cord blood transplantation (UCBT) to overcome the limitation regarding cellular dose, immunological naivety and additional cell doses such as DLI. It also provides an overview regarding the progress in adoptive cellular therapy using UCB. Expert opinion: UCB has been established as an important source of stem cells for HSCT. Successful strategies to overcome the limitations of UCBT, such as the limited cell numbers and naivety of the cells, are being developed, including novel methods to perform in vitro expansion of progenitor cells, and to improve their homing to the bone marrow. Promising early clinical trials of adoptive therapies with UCB cells, including non-immunological cells, are currently performed for viral infections, malignant diseases and in regenerative medicine.

CD4+ T-cell alloreactivity toward mismatched HLA class II alleles early after double umbilical cord blood transplantation

Although double umbilical cord blood transplantation (dUCBT) in adult patients may be associated with less graft failure compared with single UCBT, hematopoietic recovery generally originates from a single cord blood unit (CBU). CBU predominance is still incompletely understood. We recently showed that blood CD4⁺ T-cell numbers rapidly increase after dUCBT, and early CD4⁺ T-cell chimerism predicts for graft predominance. Given the frequent HLA class II allele mismatches between CBUs in dUCBT, we hypothesized that alloreactive HLA class II-specific CD4⁺ T cells from the "winning" CBU may contribute to rejection of the "loser" CBU. We evaluated whether CD4⁺ T cells originating from the predominant (PD)-CBU would recognize HLA class II allele mismatches, expressed by the nonengrafting (NE)-CBU. Alloreactive effector CD4⁺ T cells toward 1 or more mismatched HLA class II alleles of the NE-CBU were detected in 11 of 11 patients, with reactivity toward 29 of 33 (88%) tested mismatches, and the strongest reactivity toward DR and DQ alleles early after dUCBT. Mismatched HLA class II allele-specific CD4⁺ T cells recognized primary leukemic cells when the mismatched HLA class II allele was shared between NE-CBU and patient. Our results suggest that cytotoxicity exerted by CD4⁺ T cells from the PD-CBU drives the rapid rejection of the NE-CBU, whose alloreactive effect might also contribute to graft-versus-leukemia.