BACKGROUND: Allogeneic hematopoietic cell transplantation (HCT) remains the only curative treatment for most patients with hematological malignancies. A well-matched donor (related or unrelated) remains as the preferred donor for patients undergoing allogeneic HCT; however, a large number of patients rely on alternative donor choices of mismatched related (haploidentical) or unrelated donors to access HCT. In this retrospective study, we described outcomes of patients who underwent mismatched donor (related or unrelated) HCT with radiation-based MAC regimen in combination with FLU, and PTCy as higher intensity GVHD prophylaxis. We analyzed outcomes based on donor type.
METHODS: We retrospectively assessed HCT outcomes in 155 patients who underwent mismatched donor HCT [related/haploidentical vs unrelated (MMUD)] with fractionated-total body irradiation (FTBI) plus fludarabine and post-transplant cyclophosphamide (PTCy) as graft-versus-host disease (GVHD) prophylaxis at City of Hope from 2015 to 2021. Diagnoses included ALL (46.5%), AML (36.1%) and MDS (6.5%). The median age at HCT was 38 years and 126 (81.3%) patients were from ethnic minorities. HCT-CI was ≥3 in 36.1% and 29% had a disease-risk-index (DRI) of high/very high. Donor type was haplo (67.1%) or MMUD (32.9%).
RESULTS: At 2-years post-HCT, disease-free survival (DFS) and overall survival (OS) for all subjects were 75.4% and 80.6%, respectively. Donor type did not impact OS [HR=0.72, (95% CI: 0.35,1.49), p=0.37] and DFS [HR=0.78, (95% CI: 0.41,1.48), p=0.44] but younger donors resulted in less grade III-IV acute GVHD (aGVHD, [HR=6.60, (95% CI: 1.80,24.19), p=0.004] and less moderate or severe chronic GVHD [HR=3.53, (95% CI: 1.70,7.34), p<0.001] with a trend toward better survival (p=0.099). MMUD led to significantly faster neutrophil (median 15 vs 16 days, p=0.014) and platelet recovery (median 18 vs 24 days, p=0.029); however, there was no difference in GVHD outcomes between these groups. Non-relapse mortality [HR=0.86, (95% CI: 0.34,2.20), p=0.76] and relapse risk [HR=0.78, 95%CI: (0.33,1.85), p=0.57] were comparable between the two groups. Patient age <40-years and low-intermediate DRI showed a DFS benefit (p=0.004 and 0.029, respectively). High or very High DRI was the only predictor of increased relapse [HR=2.89, 95%CI: (1.32, 6.34), p=0.008].
CONCLUSIONS: In conclusion, FLU/FTBI with PTCy was well-tolerated in mismatched donor HCT, regardless of relationship with patient, provided promising results, and improved access to HCT for patients without a matched donor especially patients from ethnic minorities and mixed race.

We present the case of a patient who underwent human leukocyte antigen-haploidentical transplantation for T-cell acute lymphoblastic leukemia. Seven weeks after transplantation, the patient developed intestinal transplant-associated microangiopathy (iTAM). Although the iTAM was resolved temporarily, it recurred. Video capsule enteroscopy revealed multiple erosions and shallow ulcers in the jejunum and ileum. To the best of our knowledge, this is the first report to present images of possible small intestinal lesions in iTAM. The small intestinal mucosal images presented herein may potentially aid in the management of similar patients.

Microbiome dysbiosis has emerged as a critical factor influencing the outcomes of hematopoietic stem cell transplantation (HSCT). This comprehensive review delves into the intricate relationship between microbiome composition and HSCT outcomes, highlighting the mechanisms through which dysbiosis impacts engraftment, graft-versus-host disease (GVHD), infection rates, and overall survival. The gut microbiome plays a pivotal role in modulating immune responses and maintaining intestinal homeostasis, both of which are crucial for the success of HSCT. This review aims to elucidate the underlying pathways and potential therapeutic strategies to mitigate adverse outcomes associated with microbiome imbalances in HSCT patients. Integrating microbiome modulation strategies such as probiotics, prebiotics, fecal microbiota transplantation (FMT), and antibiotic stewardship into clinical practice can significantly improve patient outcomes and quality of life post-transplantation.

Lipopolysaccharide (LPS)-responsive beige ankyrin (LRBA) gene mutations were first reported as the cause of immunodeficiency syndromes and autoimmunity in 2012. The majority of LRBA patients have multiple organ system involvement and a complex clinical phenotype. Herein we present a comprehensive account on the disease progression and transplantation procedure in a patient with LRBA deficiency who exhibited progressive autoimmune disease symptoms along with recurrent pulmonary infections since the age of 6 years old. Despite receiving abatacept therapy and immunoglobulin replacement treatments to manage the symptoms, but the symptoms still progressed. Therefore, nine years after disease onset, patients were treated with allogeneic haematopoietic stem cell transplantation (allo-HSCT). The patient experienced acute and chronic graft-versus-host disease (GVHD) and recurrent infections after transplantation. During one and a half years of follow-up, we found that allogeneic haematopoietic stem cell transplantation can relieve the symptoms of autoimmune disease in patients with LRBA deficiency, and marked clinical improvement and recovery of immune function were observed following stem cell transplantation.

Allogeneic hematopoietic cell transplantation (alloHCT) provides a potential curative treatment for haematological malignancies. The therapeutic Graft-versus-Leukaemia (GvL) effect is induced by donor T cells attacking patient hematopoietic (malignant) cells. However, if healthy non-hematopoietic tissues are targeted, Graft-versus-Disease (GvHD) may develop. After HLA-matched alloHCT, GvL and GvHD are induced by donor T cells recognizing polymorphic peptides presented by HLA on patient cells, so-called minor histocompatibility antigens (MiHAs). The balance between GvL and GvHD depends on the tissue distribution of MiHAs and T-cell frequencies targeting these MiHAs. T cells against broadly expressed MiHAs induce GvL and GvHD, whereas those targeting MiHAs with hematopoietic-restricted expression induce GvL without GvHD. Recently, the MiHA repertoire identified in natural immune responses after alloHCT was expanded to 159 total HLA-I-restricted MiHAs, including 14 hematopoietic-restricted MiHAs. This review explores their potential relevance to predict, monitor, and manipulate GvL and GvHD for improving clinical outcome after HLA-matched alloHCT.

Chronic graft-versus-host disease (GvHD) is the leading cause of late death in allogenic hematopoietic stem cell transplantation recipients, of which the kidney is a potential target. In this article, we report an extremely rare case of chronic GvHD, characterized by immune complex-mediated diffuse proliferative glomerulonephritis and various autoantibodies detected in the serum; it is the first case of lupus-like chronic GvHD reported to date. The patient responded well to intensive immunosuppressive therapy and reached complete remission. Mycophenolate mofetil was more effective than tacrolimus in this case, suggesting that treatment of kidney diseases associated with chronic GvHD should be based on pathogenesis and pathological patterns.

A new strategy combining anti-thymocyte globulin with post-transplant cyclophosphamide (ATG/PTCy) for graft-versus-host disease (GVHD) prevention was developed. This study aims to perform a systematic review and meta-analysis of studies comparing ATG/PTCy with ATG or PTCy in patients with hematological malignancies undergoing haploidentical hematopoietic stem cell transplantation. Meta-analysis was conducted with Review Manager version 5.4, pooled risk ratios (RRs) and hazard ratios (HRs) were calculated for dichotomous data and time-to-event data respectively. Fixed-effects model was used if there is no significant heterogeneity. Literature search and study selection identified 14 eligible studies, including both randomized controlled trial and retrospective comparative studies. Different dosage adjustment strategies were applied, the total dose is 2.5-10 mg/kg for ATG and 29-100 mg/kg for PTCy. Meta-analysis results suggest that ATG/PTCy is associated with significantly lower risk of grade II-IV acute GVHD compared with ATG (RR 0.52; 95% CI: 0.41-0.65; P < 0.00001) and PTCy (RR 0.53; 95% CI: 0.34-0.83; P = 0.005) without increasing risk of disease relapse. In addition, ATG/PTCy is associated with significantly better overall survival and GVHD-free/relapse-free survival than ATG and PTCy. Future researches are required to further establish the benefits of ATG/PTCy and determine the optimal dosage adjustment strategies.
BACKGROUND: Haploidentical stem cell transplantation (haplo-HSCT) is associated with higher incidences of graft-versus-host disease (GVHD). A new strategy combining anti-thymocyte globulin with post-transplant cyclophosphamide (ATG/PTCy) for GVHD prevention has been developed, but its benefits and risks remain unclear.
OBJECTIVE: This study aims to performs a systematic review and meta-analysis of studies comparing ATG/PTCy with ATG or PTCy in patients with hematological malignancies undergoing haplo-HSCT.
METHODS: Literature search was performed in databases including Ovid Medline, Embase, Cochrane Library and China Biology Medicine (CBM). Two investigators independently screened eligible studies and extracted data. Meta-analysis was conducted with Review Manager version 5.4, pooled hazard ratios (HRs) for time-to-event outcomes were obtained using generic inverse-variance method, and pooled risk ratios (RRs) for dichotomous data were obtained using Mantel-Haenszel method. Fixed-effects model was adopted if there is no significant heterogeneity. The primary outcome is incidence of acute GVHD.
RESULTS: Literature search and study selection identified 14 eligible studies, including both 1 randomized controlled trial and 13 retrospective comparative studies. Different dosage adjustment strategies were applied, the total dose is 2.5-10 mg/kg for ATG and 29-100 mg/kg for PTCy. Meta-analysis results suggest that ATG/PTCy is associated with significantly lower risk of grade II-IV acute GVHD compared with ATG (RR 0.52; 95% CI: 0.41-0.65; P < 0.00001) and PTCy (RR 0.53; 95% CI: 0.34-0.83; P = 0.005) without increasing risk of disease relapse. In addition, ATG/PTCy is associated with significantly lower risk of grade III-IV acute GVHD (RR 0.33; 95% CI: 0.23-0.49; P < 0.00001) and chronic GVHD (RR 0.65; 95% CI: 0.51-0.81; P = 0.0002) in comparison with ATG. Further analyses suggest that ATG/PTCy is associated with significantly better overall survival and GVHD-free/relapse-free survival than ATG and PTCy, but the risks of CMV (RR 1.42; 95% CI: 1.03-1.95; P = 0.03) and EBV (RR 3.17; 95% CI: 1.61-6.23; P = 0.0008) reactivation are higher when compared with PTCy.
CONCLUSIONS: Our results suggest that combination of ATG with PTCy for GVHD prevention in haplo-HSCT is associated with improved efficacy but higher risk of infection. Future researches are required to further establish the benefits and risks of ATG/PTCy and determine the optimal dosage adjustment strategies.

This study assessed the effect of serum magnesium levels and their role in the outcome of allogeneic hematopoietic cell transplantation (allo-HSCT) in acute leukemia. Fifty-four patients with acute leukemia who underwent allo-HSCT were divided into two groups according to their serum magnesium levels before transplantation. The results showed that serum magnesium level is an independent factor influencing the prognosis of patients undergoing allo-HSCT. Low magnesium levels were associated with inferior overall survival and event-free survival compared with the associations of high magnesium levels (HR = 0.149; (95% CI: 0.029-0.755 for overall survival; HR = 0.369; 95% CI: 0.144-0.949, p = 0.039 for event-free survival). The competing risk model showed that the cumulative incidence of acute graft-versus-host disease was significantly low in the high magnesium group (p = 0.028). In general, there is a correlation between high magnesium levels and superior outcomes, including less and milder acute graft-versus-host disease, which does not affect cyclosporine-A levels. These findings provide valuable information for identifying the risk of poor prognosis in patients preparing for transplantation.

BACKGROUND: Interleukin-17 (IL-17) is elevated in human inflammatory and autoimmune diseases. The polymorphism in the promoter region of the IL-17 A gene is associated with susceptibility to several inflammatory diseases, including acute graft-versus-host disease (GVHD) following allogeneic hematopoietic cell transplantation from adult donors. However, the impacts of IL-17 A polymorphism on cord blood transplantation (CBT) outcomes remain unclear.
OBJECTIVE: The objective of this study was to assess the impact of IL-17 A polymorphism rs2275913 on GVHD, survival, relapse, non-relapse mortality (NRM), and hematopoietic recovery after CBT.
METHODS: We conducted a retrospective analysis of data from adult patients who underwent single-unit CBT at our institution from January 2005 to March 2023 for whose recipient or donor DNA samples were available. IL-17 A genotyping was performed using real-time polymerase chain reaction with the TaqMan® SNP genotyping assay for rs2275913.
RESULTS: A total of 158 recipients and 136 donors were evaluated in this study. Multivariate analysis showed that rs2275913 GA or AA recipients were associated with increased risk of grades II to IV acute GVHD compared to GG recipients (hazard ratio [HR], 1.46; 95% confidence interval [CI], 1.00-2.13; P = 0.047). Serum IL-17 A levels at eight weeks were significantly higher in rs2275913 GA or AA recipients compared to GG. The rs2275913 polymorphism did not affect survival, relapse, NRM, or hematopoietic recovery after single-unit CBT.
CONCLUSIONS: Our data showed recipient IL-17 A polymorphism rs2275913 was associated with the risk of grade II to IV acute GVHD in adults undergoing single-unit CBT. However, the rs2275913 polymorphism in recipients and donors did not affect survival or relapse. Thus, the polymorphism of IL-17 A rs2275913 in recipients might predict the risk of acute GVHD after single-unit CBT.

BACKGROUND: Acute graft-versus-host disease (aGVHD), which is mainly mediated by allogeneic T cells, is a decisive factor in the success of allogeneic hematopoietic stem cell transplantation (allo-HCT). Prophylaxis for aGVHD in clinical patients is unsatisfactory, and there is still a huge unmet need for novel approaches. Icariin (ICA) shows potent anti-inflammatory activity and suppresses T cell-mediated immune responses. Thus, ICA is a potential drug for the prevention of aGVHD. However, there is no data assessing the impact of ICA on aGVHD after allo-HCT.
OBJECTIVE: This study aimed to investigate the protective effect of ICA against aGVHD and its mechanisms. Moreover, the impact of ICA on the graft-versus-leukemia (GVL) effect and engraftment of donor hematopoietic and immune cells were assessed.
METHODS: Different murine models of allo-HCT were developed to study the influence of the ICA on GVHD and GVL effect. Flow cytometry was used to analyze the growth of leukemia cells, alterations in different immune cells, and apoptosis. Cell proliferation was determined using a CCK-8 assay. RNA sequencing and quantitative proteomic analysis were performed to elucidate the underlying mechanisms, which were further verified by polymerase chain reaction or functional experiments.
RESULTS: Different concentrations of ICA exhibited opposite effects: low-concentration ICA promoted, while high concentrations suppressed the proliferation and function of T cells. A high dose of ICA administration during days +3 to +5 post-allo-HCT can alleviate murine aGVHD but does not affect the course of chronic GVHD (cGVHD), the GVL effect against both acute myeloid and lymphoblastic leukemia, or the recovery of donor hematological and immune cells. ICA extensively represses the expansion, function, and infiltration of donor alloreactive T cells, while preserving regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSC). Quantitative proteomic analysis showed that downregulation of integrin-linked kinase (ILK) and lymphocyte cytosolic protein 2 (LCP2) expression was possibly associated with ICA-mediated aGVHD protective effects. Furthermore, an inhibitor of ILK, which can alleviate murine aGVHD administered early after allo-HCT.
CONCLUSIONS: These findings suggest that the bioactivities of ICA are associated with its concentration and that ICA can effectively mitigate aGVHD without losing GVL activity or engraftment of donor hematopoietic and immune cells. Thus, ICA may be a promising drug for preventing aGVHD in clinical settings.