Haploidentical transplantation compared with matched sibling and unrelated donor transplantation for adults with standard-risk acute lymphoblastic leukaemia in first complete remission

PASS-ALL study of paediatric-inspired versus adult chemotherapy regimens on survival of high-risk Philadelphia-negative B-cell acute lymphoblastic leukaemia with allogeneic haematopoietic stem cell transplantation

This PASS-ALL study was designed to explore the effect of paediatric-inspired versus adult chemotherapy regimens on survival of adolescents and young adults (AYA) with high-risk Philadelphia chromosome-negative B-cell acute lymphoblastic leukaemia (HR PH-ve B-cell ALL) eligible for allogeneic haematopoietic stem cell transplantation (allo-HSCT). The PASS-ALL study is a multicentre, observational cohort study, and 143 patients with HR B-cell PH-ve ALL were enrolled from five centres-77 patients allocated in the paediatric-inspired cohort and 66 in the adult cohort with comparable baseline characteristics. Of the 143 patients, 128 cases underwent allo-HSCT. Three-year leukaemia-free survival (LFS) in the paediatric-inspired cohort was 72.2% (95% CI 60.8%-83.6%) compared with 44.6% (95% CI 31.9%-57.3%; p = 0.001). Furthermore, time-to-positive minimal residual disease (TTP-MRD) post-HSCT was marked different, 3-year cumulative incidence of relapse was 25.9% (95% CI 15.8%-37.2%) in paediatric cohort and 45.4% (95% CI 40.0%-57.9%) in adult cohort (p = 0.026). Finally, the 3-year OS rate was 75.3% (95% CI 64.9%-85.7%) for the paediatric-inspired cohort and 64.1% (95% CI 51.8%-76.4%) for the adult cohort (p = 0.074). On a multivariate analysis, paediatric-inspired regimen is a predictive factor for LFS (HR = 2.540, 95% CI 1.327-4.862, p = 0.005). Collectively, our data suggest that paediatric-inspired chemotherapy pre-HSCT results in deeper and durable MRD response reduces relapse post-HSCT and improves survival in HR B-cell PH-ve ALL patients with allo-HSCT.

Outcomes of allogeneic or autologous stem cell transplantation followed by maintenance chemotherapy in adult patient with B-ALL in CR1 with no detectable minimal residual disease

Autologous haematopoietic stem cell transplantation (auto-HSCT) as a treatment for B-cell acute lymphoblastic leukaemia (B-ALL) has been rigorously debated in recent years. We retrospectively analysed the outcomes of 355 adult patients with B-ALL in first complete remission who had received auto-HSCT or allogeneic HSCT (allo-HSCT) in our centre. The treatment efficacy was evaluated from a model stratified on the risk classification and minimal residue disease (MRD) status after three chemotherapy cycles. Auto-HSCT demonstrated comparable 3-year overall survival (OS) (72.7% vs. 68.5%, p = 0.441) and leukaemia-free survival rates (62.8% vs. 56.1%, p = 0.383) compared to allo-HSCT for patients with negative MRD, while the advantage of lower non-relapse mortality (1.5% vs. 25.1%, p < 0.001) was offset by a higher cumulative incidence of relapse (CIR) rates (35.7% vs. 18.9%, p = 0.018), especially in high-risk patients. For patients at high risk and with positive MRD, there was a lower trend of 3-year OS (50.0% vs. 66.0%, p = 0.078) and significantly higher CIR rates (71.4% vs. 39.1%, p = 0.018) in auto-HSCT. However, no significant interaction was observed in the tests. In conclusion, auto-HSCT appears to be an attractive treatment for patients with negative MRD after three chemotherapy cycles. For MRD-positive patients, allo-HSCT may be a more effective treatment.

Comparison of efficacies of haploidentical transplantation and matched sibling donor transplantation in treating T-cell lymphoblastic lymphoma

OBJECTIVE

To investigate the differences in efficacy and safety between haploidentical donor hematopoietic stem cell transplantation (HID-HSCT) and matched sibling donor HSCT (MSD-HSCT) in patients with T-cell lymphoblastic lymphoma (T-LBL).

METHODS

In this retrospective analysis, we enrolled 38 patients who had undergone allogeneic HSCT at our institution between 2013 and 2021. The study participants included 28 patients who underwent HID-HSCT and 10 patients who underwent MSD-HSCT. We compared the patient characteristics and treatment effectiveness and safety between the two groups and evaluated potential prognostic variables for patients with T-LBL.

RESULTS

The median follow-up durations in the HID-HSCT and MSD-HSCT groups were 23.5 (range: 4-111) and 28.5 (range: 13-56) months, respectively. All patients showed full-donor chimerism after hematopoietic stem cell transplantation (HSCT). Except for two patients in the HID-HSCT cohort who developed poor graft function, all patients showed neutrophil and platelet engraftments after HSCT. The cumulative incidences of grades III-IV acute graft-versus-host disease were 37.5% and 28.57% in the HID-HSCT and MSD-HSCT groups, respectively (p = 0.84). The cumulative incidences of limited (34.13% vs. 28.57%, p = 0.82) and extensive (31.22% vs. 37.50%, p = 0.53) chronic graft-versus-host disease did not differ between the two cohorts. In the HID-HSCT and MSD-HSCT cohorts, the estimated 2-year overall survival rates were 70.3% (95% confidence interval [CI]: 54.9%-90.0%) and 56.2% (95% CI: 31.6%-100%), respectively (p = 1.00), and the estimated 2-year progression-free survival (PFS) rates were 48.5% (95% CI: 32.8%-71.6%) and 48.0% (95% CI: 24.6%-93.8%), respectively (p = 0.94). Furthermore, the Cox proportional-hazards model showed that a positive positron emission tomography/computed tomography (PET/CT) status before HSCT in patients who had completed chemotherapy was an independent risk factor for PFS in the multivariate analysis (p = 0.0367).

CONCLUSION

This study showed that HID-HSCT had comparable effectiveness and safety to MSD-HSCT in treating T-LBL. HID-HSCT could serve as an alternate treatment option for T-LBL in patients without an eligible identical donor. Achievement of the PET/CT-negative status before HSCT may contribute to better survival.

Busulfan Plus Cyclophosphamide Versus Total Body Irradiation Plus Cyclophosphamide for Adults Acute B Lymphoblastic Leukemia: An Open-Label, Multicenter, Phase III Trial

PURPOSE

It remains controversial whether busulfan-based versus total body irradiation (TBI)-based regimens have comparable outcomes in patients with acute lymphoblastic leukemia (ALL) undergoing allogeneic hematopoietic stem-cell transplantation (allo-HSCT). We investigated the efficacy and toxicity of busulfan plus cyclophosphamide (BuCy) and TBI plus cyclophosphamide (TBI-Cy) conditioning in allo-HSCT for adult standard-risk B-cell-ALL in first complete remission (CR1).

PATIENTS AND METHODS

We performed an open-label, randomized phase III trial at 13 hospitals in China. Eligible patients (age 14-65 years) had standard-risk ALL in CR1. Patients were randomly assigned (1:1) to BuCy (0.8 mg/kg four times per day on days -7 to -4 and cyclophosphamide 60 mg/kg once daily on days -3 to -2) or TBI-Cy (4.5 Gy TBI on days -5 to -4 and cyclophosphamide 60 mg/kg once daily on days -3 to -2). The primary end point was 2-year overall survival. Analysis was per protocol. This trial is registered with ClinicalTrials.gov (identifier: NCT02670252) and is complete.

RESULTS

Between January 2016 and February 2020, 275 patients were assigned to receive BuCy (273 assessed) and 275 to TBI-Cy (272 assessed). The 2-year overall survival was 76.6% (95% CI, 71.7 to 81.8) and 79.4% (74.7 to 84.4; P = .457; difference 2.9%; 95% CI, -4.1 to 9.8; P = .022), indicating noninferiority of BuCy. The 2-year relapse was 20.2% (95% CI, 15.6 to 25.1) and 18.4% (14.0 to 23.2; P = .616), and the nonrelapse mortality was 11.0% (95% CI, 7.6 to 15.0) and 11.0% (7.7 to 15.1; P = .988) in the BuCy and TBI-Cy groups, respectively. There were no differences in regimen-related toxicity, graft-versus-host disease, or late effects between the two groups.

CONCLUSION

The BuCy regimen has noninferior efficiency and safety as TBI-Cy (4.5 Gy × 2) for patients with adult standard-risk B cell-ALL in CR1 undergoing HLA-matched allo-HSCT.

Haplo-Peripheral Blood Stem Cell Plus Cord Blood Grafts for Hematologic Malignancies Might Lead to Lower Relapse Compared with Haplo-Peripheral Blood Stem Cell Plus Bone Marrow Grafts

To compare the outcomes between peripheral blood stem cell (PBSC)+cord blood and PBSC+bone marrow (BM) grafts in the setting of haploidentical donor (HID) transplantation, 110 patients were enrolled in this retrospective study, including 54 recipients of haplo-PBSC+cord transplants and 56 recipients of haplo-PBSC+BM transplants. Chimerism analyses revealed that by day 30 post-transplantation, 94.3% of surviving patients in the haplo-PBSC+cord group had achieved full haploidentical chimerism and 5.7% had <10% cord chimerism, whereas 100% of surviving patients in the haplo-PBSC+BM group had achieved full donor chimerism. The cumulative incidence of platelet engraftment at 30 days was 92.6% in the haplo-PBSC+cord group versus 89.3% in the haplo-PBSC+BM group (P =.024), that of grade II-IV acute graft-versus-host disease (GVHD) at 100 days was 31.5% versus 48.2% (P =.060), and 1-year relapse was 13.0% versus 25.0% (P =.027), nonrelapse mortality was 9.3% versus 12.5% (P =.76), disease-free survival (DFS) was 77.7% versus 62.5% (P =.028), and overall survival (OS) was 81.4% versus 69.6% (P =.046). Multivariate analysis identified haplo-PBSC+cord transplantation as a protective factor for relapse (hazard ratio [HR], .31; P =.007), DFS (HR, .40; P =.007), and OS (HR, .44; P =.016). Overall, haplo-PBSC+cord transplantation led to faster platelet engraftment, lower relapse, and superior DFS and OS compared with haplo-PBSC+BM transplantation and thus might be a better transplant mode in the setting of HID transplantation.

Haploidentical donor stem cell transplantation had a lower incidence of bronchiolitis obliterans syndrome compared with HLA-matched sibling donor transplantation in patients with hematologic malignancies: Benefit from ATG?

Background

Haploidentical donor stem cell transplantation (HID-SCT) based on antithymocyte globulin (ATG) for graft-versus-host disease (GVHD) prophylaxis had achieved a similar incidence of chronic graft-versus-host disease (cGVHD) with human leukocyte antigen (HLA)-matched sibling donor stem cell transplantation (MSD-SCT). However, bronchiolitis obliterans syndrome (BOS), which serves as pulmonary cGVHD, was rarely compared between HID and MSD transplantation.

Methods

One thousand four hundred five patients with hematologic malignancies who underwent allogeneic SCT were enrolled in this retrospective study. Based on donor type, we divided the patients into three groups: HID, MSD, and match unrelated donor (MUD) groups. The cumulative incidences and risk factors of BOS were analyzed.

Results

The 5-year cumulative incidence of BOS was 7.2% in the whole population. HID transplantation had a lower 5-year cumulative incidence of BOS than MSD transplantation (4.1% vs. 10.0%, p &lt; 0.001) and a similar incidence with MUD transplantation (4.1% vs. 6.2%, p = 0.224). The 5-year cumulative incidence of BOS was lower in the ATG group than that in the non-ATG group in both the whole and MSD populations (4.6% vs. 11.2%, p &lt; 0.001, and 4.1% vs. 11.2%, p = 0.042, respectively). The 5-year incidence of BOS in mixed grafts [peripheral blood stem cell (PBSC) plus bone marrow] group was also lower than that in the PBSC group (4.2% vs. 9.1, p = 0.001). Multivariate analysis showed that HID, ATG, and mixed grafts were protective factors for BOS [odds ratio (OR) 0.3, 95% CI 0.2–0.6, p &lt; 0.001; OR 0.3, 95% CI 0.2–0.7, p = 0.001; OR 0.3, 95% CI 0.1–0.8, p = 0.013], and acute graft-versus-host disease (aGVHD) and cGVHD were independent risk factors for BOS (OR 2.1, 95% 1.1–4.3, p = 0.035; OR 10.1, 95% CI 4.0–25.0, p &lt; 0.001).

Conclusions

HID transplantation had a lower incidence of BOS than MSD transplantation, which might be associated with ATG and mixed grafts.

Effect of pediatric- versus adult-type chemotherapy regimens on outcomes of allogeneic hematopoietic stem cell transplants for adult T-cell acute lymphoblastic leukemia in first complete remission

The optimal chemotherapy regimen pre-transplantation for adult T-cell acute lymphoblastic leukemia (T-ALL) patients remains unknown. Here, we compared the transplant outcomes in 127 subjects receiving pediatric- (N = 57) or adult-type (N = 70) regimens pre-transplant. The corresponding 3-year cumulative incidences of relapse (CIR) was 7% (95% CI: 3-11%) and 29% (95% CI: 23-35%; P = 0.02), leukemia-free survivals (LFS) was 86% (95% CI: 81-91%) and 57% (95% CI: 51-63%; P = 0.003), overall survivals (OS) was 88% (95% CI: 84-92%) and 58% (95% CI: 52-64%; P = 0.002), the 1-year NRM was 4% (95% CI: 1-7%) and 9% (95% CI: 4-14%; P = 0.40). Multivariate analysis showed that pediatric-type regimen was associated with lower CIR (Hazard Ratio [HR] = 0.31 [95% CI: 0.09-1.00]; P = 0.05), better LFS (HR = 0.34 [95% CI: 0.15-0.78]; P = 0.01) and OS (HR = 0.30 [95% CI: 0.13-0.72]; P = 0.01). Our results suggested that adult T-ALL patients undergoing allo-HSCT might benefit from pediatric-type chemotherapy.

Post-remission measurable residual disease directs treatment choice and improves outcomes for patients with intermediate-risk acute myeloid leukemia in CR1

Objectives

This study retrospectively investigated in which cycle measurable residual disease (MRD) is associated with prognosis in patients in first complete remission (CR1) of intermediate-risk acute myeloid leukemia (AML).

Methods

The study enrolled 235 younger patients with intermediate-risk AML. MRD was evaluated by multiparameter flow cytometry after the 1st, 2nd, and 3rd chemotherapy cycles (MRD1–3, respectively).

Results

No significant association was detected after the 1st and 2nd cycles. However, the 5-year incidence of relapse was higher in the MRD3-positive group (n = 99) than in the negative group (n = 136) (48.7% vs. 13.7%, P = 0.005), while 5-year disease-free survival (DFS) and overall survival (OS) were lower in the MRD3-positive group than in the negative group (43.2% vs. 81.0% and 45.4% vs. 84.1%; P = 0.003 and 0.005, respectively). Allogeneic hematopoietic stem cell transplantation led to a lower 5-year relapse, and higher DFS and OS rates than chemotherapy in the MRD3-positive group (22.3% vs. 71.5%, 65.9% vs. 23.0%, and 67.1% vs. 23.9%; P < 0.001, 0.002, and 0.022, respectively), but did not affect the MRD-negative group.

Conclusions

MRD3 could serve as an indicator for post-remission treatment choice and help improve outcomes for intermediate-risk AML in CR1.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12185-022-03441-6.

Outcomes of allogeneic haematopoietic stem cell transplantation for paediatric patients with MLL-rearranged acute myeloid leukaemia

Background

The presence of mixed-lineage leukaemia rearrangement (MLL-r) in paediatric patients with acute myeloid leukaemia (AML) is a poor prognostic predictor. Whether allogeneic haematopoietic stem cell transplantation (allo-HSCT) is beneficial in such cases remains unclear.

Methods

We evaluated the outcomes and prognostic factors of allo-HSCT in 44 paediatric patients with MLL-r AML in the first complete remission (CR1) between 2014 and 2019 at our institution.

Results

For all the 44 patients, the 3-year overall survival (OS), event-free survival (EFS), and cumulative incidence of relapse (CIR) were 74.5%, 64.1%, and 29.1%, respectively. Among them, 37 (84.1%) patients received haploidentical (haplo)-HSCT, and the 3-year OS, EFS, and CIR were 73.0%, 65.6%, and 26.4%, respectively. The 100-day cumulative incidence of grade II–IV acute graft-versus-host disease (aGVHD) post-transplantation was 27.3%, and that of grade III–IV aGVHD was 15.9%. The overall 3-year cumulative incidence of chronic graft-versus-host disease (cGVHD) post-transplantation was 40.8%, and that of extensive cGVHD was 16.7%. Minimal residual disease (MRD)-positive (MRD +) status pre-HSCT was significantly associated with lower survival and higher risk of relapse. The 3-year OS, EFS, and CIR differed significantly between patients with MRD + pre-HSCT (n = 15; 48.5%, 34.3% and 59%) and those with MRD-pre-HSCT (n = 29; 89.7%, 81.4% and 11.7%). Pre-HSCT MRD + status was an independent risk factor in multivariate analysis.

Conclusions

Allo-HSCT (especially haplo-HSCT) can be a viable strategy in these patients, and pre-HSCT MRD status significantly affected the outcomes.

Current status and prospects of hematopoietic stem cell transplantation in China

Hematopoietic stem cell transplantation (HSCT) is a highly effective and unique medical procedure for the treatment of most hematological malignancies. The first allogeneic transplantation was performed by E. Donnall Thomas in 1957. Since then, the field has evolved and expanded worldwide. The first successful allogenic HSCT (allo-HSCT) in China was conducted in 1981. Although the development of allo-HSCT in China lagged, China has since made considerable contributions to the process of HSCT worldwide, with more than 10,000 HSCTs performed annually. In particular, haploid HSCT (haplo-HSCT) technology represented in the Beijing Protocol has demonstrated similar efficacy to human leukocyte antigen-matched HSCT and has gradually become the pre-dominant choice for allo-HSCT in China. Currently, the number of haplo-HSCT procedures exceeds 5000 per year, and the Beijing Protocol has been greatly improved by implementing updated individualized strategies for controlling complications, relapse, and infection management. In addition, innovative haplo-HSCT technologies developed by different medical transplantation centers, such as Soochow, Zhejiang, Fujian, Chongqing, and Anhui, have emerged, providing inspiration for the refinement of global practice. This review will focus on the current activity in this field and highlight important trends that are vital in China's allo-HSCT process, examining the current viewpoint and future directions.

Efficacy and safety of CD19 CAR-T cell therapy for acute lymphoblastic leukemia patients relapsed after allogeneic hematopoietic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an effective therapy for B-cell acute lymphoblastic leukemia (B-ALL). Although allo-HSCT can be curative for some B-ALL patients, relapse still occurs in some patients following allo-HSCT. Conventional chemotherapies show poor efficacy in B-ALL patients who have relapsed following allo-HSCT. In the past decade, chimeric antigen receptor T-cell (CAR-T) therapy has shown to be efficacious for B-ALL patients. In particular, autologous CD19 CAR-T therapy results in a high remission rate. However, there are challenges in the use of CD19 CAR-T therapy for B-ALL patients who have relapsed following allo-HSCT, including the selection of CAR-T cell source for manufacturing, post-CAR-T graft-versus-host disease (GVHD) risk, maintenance of long-term efficacy after remission through CAR-T therapy, and whether a consolidative second transplant is needed. In this review, we describe the current status of CAR-T therapy for B-ALL patients who have relapsed following allo-HSCT, the advantages and disadvantages of various CAR-T cell sources, the characteristics and management of GVHD following CAR-T therapy, and the risk factors that may affect long-term efficacy.

Haploidentical transplantation has a superior graft-versus-leukemia effect than HLA-matched sibling transplantation for Ph- high-risk B-cell acute lymphoblastic leukemia

Background:

Compared with human leukocyte antigen (HLA)-matched sibling donor (MSD) transplantation, it remains unclear whether haploidentical donor (HID) transplantation has a superior graft-versus-leukemia (GVL) effect for Philadelphia-negative (Ph–) high-risk B-cell acute lymphoblastic leukemia (B-ALL). This study aimed to compare the GVL effect between HID and MSD transplantation for Ph– high-risk B-ALL.

Methods:

This study population came from two prospective multicenter trials (NCT01883180, NCT02673008). Immunosuppressant withdrawal and prophylactic or pre-emptive donor lymphocyte infusion (DLI) were administered in patients without active graft-versus-host disease (GVHD) to prevent relapse. All patients with measurable residual disease (MRD) positivity posttransplantation (post-MRD+) or non-remission (NR) pre-transplantation received prophylactic/pre-emptive interventions. The primary endpoint was the incidence of post-MRD+.

Results:

A total of 335 patients with Ph– high-risk B-ALL were enrolled, including 145 and 190, respectively, in the HID and MSD groups. The 3-year cumulative incidence of post-MRD+ was 27.2% (95% confidence interval [CI]: 20.2%–34.7%) and 42.6% (35.5%–49.6%) in the HID and MSD groups (P = 0.003), respectively. A total of 156 patients received DLI, including 60 (41.4%) and 96 (50.5%), respectively, in the HID and MSD groups (P = 0.096). The 3-year cumulative incidence of relapse was 18.6% (95% CI: 12.7%–25.4%) and 25.9% (19.9%–32.3%; P = 0.116) in the two groups, respectively. The 3-year overall survival (OS) was 67.4% (95% CI: 59.1%–74.4%) and 61.6% (54.2%–68.1%; P = 0.382), leukemia-free survival (LFS) was 63.4% (95% CI: 55.0%–70.7%) and 58.2% (50.8%–64.9%; P = 0.429), and GVHD-free/relapse-free survival (GRFS) was 51.7% (95% CI: 43.3%–59.5%) and 37.8% (30.9%–44.6%; P = 0.041), respectively, in the HID and MSD groups.

Conclusion:

HID transplantation has a lower incidence of post-MRD+ than MSD transplantation, suggesting that HID transplantation might have a superior GVL effect than MSD transplantation for Ph– high-risk B-ALL patients.

Trial registration:

ClinicalTrials.gov: NCT01883180, NCT02673008.

Intestinal microbiota score could predict survival following allogeneic hematopoietic stem cell transplantation

Intestinal microbiota is an important prognostic factor for allogeneic hematopoietic stem cell transplantation (allo-HSCT), but its role in predicting survival has not been determined. Here, stool samples at day 15 ± 1 posttransplant were obtained from 209 patients at two centers. Microbiota was examined using 16S rRNA sequencing. The microbiota diversity and abundance of specific bacteria (including Lachnospiraceae, Ruminococcaceae, Erysipelotrichaceae, and Enterobacteriaceae) were assigned a value of 0 or 1 depending on whether they were positive or negative associated with survival, respectively. An accumulated intestinal microbiota (AIM) score was generated, and patients were divided into low- and high-score groups. A low score was associated with a better 3-year cumulative overall survival (OS) as well as lower mortality than a high score (88.5 vs. 43.9% and 7.1 vs. 35.8%, respectively; both P < 0.001). In multivariate analysis, a high score was found to be an independent risk factor for OS and transplant-related mortality (hazard ratio = 5.68 and 3.92, respectively; P < 0.001 and 0.003, respectively). Furthermore, the AIM score could serve as a predictor for survival (area under receiver operating characteristic curve = 0.836, P < 0.001). Therefore, the intestinal microbiota score at neutrophil recovery could predict survival following allo-HSCT.

A Comparison of the Clinical Outcomes of Haploidentical Transplantation and Other Graft Sources in Acute Lymphoblastic Leukemia: A Systematic Review and Meta-Analysis

BACKGROUND

Most likely due to the availability of potential stem cell sources, there appears to be a growing usage of haploidentical (haplo) donors for cases of acute lymphoblastic leukemia involving high-risk features or relapse.

PATIENTS AND METHODS

This study compared the outcomes of stem cell transplantations (SCTs) using haplo and other stem cell sources, namely, matched sibling donors (MSDs), matched unrelated donors (MUDs), and cord blood transplantations (CBTs). Literature searches were conducted of the MEDLINE and Embase databases from inception to December 2020.

RESULTS

Twenty-eight studies were examined (17 retrospective and 11 prospective). There were no significant differences in the overall survival of haplo and those of the other stem-cell sources. For haplo versus matched donor (MSD or MUD), the pooled odds ratio (OR) was 0.94 (95% CI, 0.79-1.12; I², 22%); while for haplo versus CBT, the OR was 1.24 (95% CI, 0.78-1.96; I², 28%). The cumulative relapse incidence was significantly higher for MSD than haplo (OR, 0.69; 95% CI, 0.48-0.99; I², 48%). Both grade II-IV acute and long-term graft-versus-host disease (GVHD) were significantly higher for haplo than MSD (OR, 1.78; 95% CI, 1.15-2.74; I², 28%; and OR, 1.33; 95% CI, 1.00-1.77; I², 14%, respectively). The other clinical outcomes did not demonstrate any statistical differences.

CONCLUSION

The outcomes of patients treated with haplo-SCT appear comparable with those of the SCTs using other sources. The higher probability of developing GVHD supports the need for a novel method to harness T-cell alloreactivity.

How I Use Measurable Residual Disease in the Clinical Management of Adult Acute Lymphoblastic Leukemia

Over the last decade the use of measurable residual disease (MRD) diagnostics in adult acute lymphoblastic leukemia (ALL) has expanded from a limited number of study groups in Europe and the United States to a world-wide application. In this review, we summarize the advantages and drawbacks of the current available techniques used for MRD monitoring. Through the use of three representative case studies, we highlight the advances in the use of MRD in clinical decision-making in the management of ALL in adults. We acknowledge discrepancies in MRD monitoring and treatment between different countries, reflecting differing availability, accessibility and affordability.

Role of allogeneic haematopoietic stem cell transplantation in the treatment of adult acute lymphoblastic leukaemia in the era of immunotherapy

ABSTRACT

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is currently the standard of care for adult acute lymphoblastic leukemia (ALL) patients. In recent years, with the continuous development of immunotherapy, such as chimeric antigen receptor T cells, blinatumomab, and inotuzumab ozogamicin, a series of vital clinical studies have confirmed its high response rate and favorable outcomes for ALL. Although the emergence of immunotherapy has expanded relapsed or refractory (r/r) ALL patients' opportunities to receive allo-HSCT, allo-HSCT is associated with potential challenges. In this review, the role of allo-HSCT in the treatment of adult ALL in the era of immunotherapy will be discussed.

Effect of donor characteristics on T cell-replete haploidentical stem cell transplantation over the last 10 years at a single institution

One of the most complex issues with haploidentical stem cell transplantation (haplo-SCT) is donor selection, given that multiple haploidentical donors are often available for a given recipient. To develop evidence-based guidance for donor selection in the setting of anti-thymocyte globulin-based haplo-SCT, we performed a prospective cohort study of 512 patients with haematological malignancies who had haplo-SCT to determine which donor variables were most important in favouring transplant outcomes. Increasing donor age was associated with poorer overall survival (OS) [hazard ratio (HR) 1·08, P = 0·044]. Female donors to male recipients was significantly associated with higher non-relapse mortality (NRM; HR 2·05, P = 0·006). Furthermore, increasing donor age had a higher risk of Grades 3-4 acute graft-versus-host disease (aGVHD; HR 1·17, P = 0·005), female donors to male recipients was associated with a higher risk of Grades 2-4 aGVHD (HR 1·50, P = 0·022). Sibling donors had superior OS, disease-free survival, and NRM than parental donors in patients aged <35 years. However, sibling donors had higher NRM than offspring donors in patients aged ≥35 years. A younger donor, usually a young sibling in younger recipients (aged <35 years) or a young offspring in older patients (aged ≥35 years) and avoiding female donors to male recipients should be preferred when multiple haploidentical donors are available.

Haploidentical vs. sibling, unrelated, or cord blood hematopoietic cell transplantation for acute lymphoblastic leukemia

Haploidentical HCT is the preferred alternate donor approach for adults with ALL.

Haploidentical transplantation had similar survival compared with fully HLA-matched donor HCT but with reduced GVHD.

The role of haploidentical hematopoietic cell transplantation (HCT) using posttransplant cyclophosphamide (PTCy) for acute lymphoblastic leukemia (ALL) is being defined. We performed a retrospective, multivariable analysis comparing outcomes of HCT approaches by donor for adults with ALL in remission. The primary objective was to compare overall survival (OS) among haploidentical HCTs using PTCy and HLA-matched sibling donor (MSD), 8/8 HLA-matched unrelated donor (MUD), 7 /8 HLA-MUD, or umbilical cord blood (UCB) HCT. Comparing haploidentical HCT to MSD HCT, we found that OS, leukemia-free survival (LFS), nonrelapse mortality (NRM), relapse, and acute graft-versus-host disease (aGVHD) were not different but chronic GVHD (cGVHD) was higher in MSD HCT. Compared with MUD HCT, OS, LFS, and relapse were not different, but MUD HCT had increased NRM (hazard ratio [HR], 1.42; P = .02), grade 3 to 4 aGVHD (HR, 1.59; P = .005), and cGVHD. Compared with 7/8 UD HCT, LFS and relapse were not different, but 7/8 UD HCT had worse OS (HR, 1.38; P = .01) and increased NRM (HR, 2.13; P ≤ .001), grade 3 to 4 aGVHD (HR, 1.86; P = .003), and cGVHD (HR, 1.72; P ≤ .001). Compared with UCB HCT, late OS, late LFS, relapse, and cGVHD were not different but UCB HCT had worse early OS (≤18 months; HR, 1.93; P < .001), worse early LFS (HR, 1.40; P = .007) and increased incidences of NRM (HR, 2.08; P < .001) and grade 3 to 4 aGVHD (HR, 1.97; P < .001). Haploidentical HCT using PTCy showed no difference in survival but less GVHD compared with traditional MSD and MUD HCT and is the preferred alternative donor HCT option for adults with ALL in complete remission.

The consensus from The Chinese Society of Hematology on indications, conditioning regimens and donor selection for allogeneic hematopoietic stem cell transplantation: 2021 update

The consensus recommendations in 2018 from The Chinese Society of Hematology (CSH) on indications, conditioning regimens and donor selection for allogeneic hematopoietic stem cell transplantation (allo-HSCT) facilitated the standardization of clinical practices of allo-HSCT in China and progressive integration with the world. There have been new developments since the initial publication. To integrate recent developments and further improve the consensus, a panel of experts from the CSH recently updated the consensus recommendations, which are summarized as follows: (1) there is a new algorithm for selecting appropriate donors for allo-HSCT candidates. Haploidentical donors (HIDs) are the preferred donor choice over matched sibling donors (MSDs) for patients with high-risk leukemia or elderly patients with young offspring donors in experienced centers. This replaces the previous algorithm for donor selection, which favored MSDs over HIDs. (2) Patients with refractory/relapsed lymphoblastic malignancies are now encouraged to undergo salvage treatment with novel immunotherapies prior to HSCT. (3) The consensus has been updated to reflect additional evidence for the application of allo-HSCT in specific groups of patients with hematological malignancies (intermediate-risk acute myeloid leukemia (AML), favorable-risk AML with positive minimal residual disease, and standard-risk acute lymphoblastic leukemia). (4) The consensus has been updated to reflect additional evidence for the application of HSCT in patients with nonmalignant diseases, such as severe aplastic anemia and inherited diseases. (5) The consensus has been updated to reflect additional evidence for the administration of anti-thymocyte globulin, granulocyte colony-stimulating factors and post-transplantation cyclophosphamide in HID-HSCT.

Comparison of 2 Different Doses of Antithymocyte Globulin in Conditioning Regimens for Haploidentical Hematopoietic Stem Cell Transplantation

OBJECTIVES

Antithymocyte globulin is extensively used for prophylaxis of graft-versus-host disease in patients undergoing haploidentical hematopoietic stem cell transplantation. However, different doses of antithymocyte globulin are administered in clinical practice. This study aimed to identify the optimal dose of antithymocyte globulin (thymoglobulin) in haploidentical hematopoietic stem cell transplantation.

MATERIALS AND METHODS

We retrospectively analyzed the effects of 10 mg/kg (2.5 mg/kg on days -5 to -2) versus 7.5 mg/kg thymoglobulin (2.5 mg/kg on days -4 to -2) on patients receiving haploidentical hematopoietic stem cell transplantation with myeloablative conditioning.

RESULTS

We observed significant differences between the 2 treatment groups with regard to cumulative incidence of grade II to IV acute graft-versus-host disease (15.3% vs 14.6%; P = .93) and 3-year chronic graft-versus-host disease (12.1% vs 14.3%; P = .77). The probabilities of 3-year overall survival (68.9% vs 73.5%; P = .98) and graft-versus-host disease-free/relapse-free survival (66.7% vs 53.1%; P = .14) were comparable between the 2 groups. However, there was a trend for lower cumulative incidence of hemorrhagic cystitis in the 7.5 mg/kg treatment group compared with the 10 mg/kg treatment group (40.7% vs 24.4%; P = .07).

CONCLUSIONS

For patients who received a reduced dose of antithymocyte globulin (7.5 vs 10 mg/kg), there was no impaired effect on prophylaxis of graft-versus-host disease, with a trend of reduced incidence of hemorrhagic cystitis. Further studies of the 7.5 mg/kg dose of antithymocyte globulin are warranted for patients receiving haploidentical hematopoietic stem cell transplantation.

Upfront transplantation may have better outcomes than pretransplant cytoreductive therapy for treating patients with MDS-EB-1 or MDS-EB-2

Whether patients with myelodysplastic syndrome (MDS) undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT) benefit from pretransplant cytoreductive therapy remains controversial. Our study compared the outcomes of upfront transplantation with those of pretransplant cytoreductive therapy in the patients who received transplantation and those who dropped out due to cytoreductive therapy-related adverse effects. Patients with MDS-EB-1 or MDS-EB-2 were enrolled and divided into three groups based on therapy pretransplantation: upfront transplantation (upfront, n = 54), induction chemotherapy (CT, n = 66) and hypomethylating agents (HMA, n = 37) alone. One hundred fifty-seven patients were enrolled and 124 received allo-HSCT, with 5.6%, 28.8% and 29.7% of drop-out rate of transplantation in upfront, CT and HMA groups (P = .030), respectively. Overall therapy-related mortality (TRM), cytoreductive therapy and transplant-related mortality was 13.0%, 32.4% and 28.4% (P = .028), and 5-year overall survival (OS) was 73.6%, 43.4% and 46.9% (P = .033). Multivariate analysis showed that CT and HMA were risk factors for TRM and OS, and transplantation was a protective factor for OS. In transplant patients, 3-year cumulative incidence of relapse was 10.6%, 20.4% and 20.3% (P = .033), 5-year TRM was 14.5%, 20.0% and 17.6% (P = .651), OS was 77.3%, 64.3% and 68.8% (P = .047) and DFS was 74.0%, 63.0% and 65.8% (P = .042). Multivariate analysis showed that CT was a risk factor for DFS, while CT, HMA and poor karyotype were risk factors for relapse. Results suggested that pretransplant cytoreductive therapy was not associated with better outcomes in the patients who had undergone transplantation. Therefore, upfront transplantation may be preferable for MDS patients.

[Comparison of the clinical outcomes of haploidentical and matched-sibling donor stem cell transplantation for T cell acute lymphoblastic leukemia in complete remission]

目的

比较亲缘单倍型造血干细胞移植（HIDT）和同胞相合造血干细胞移植（MSDT）治疗完全缓解期（CR）急性T淋巴细胞白血病（T-ALL）的疗效。

方法

回顾性分析2012年5月至2017年5月间在河北燕达陆道培医院接受HIDT（81例）和MSDT（17例）的CR期T-ALL患者的临床特点和预后。

结果

HIDT组、MSDT组移植后100 d Ⅱ～Ⅳ度急性GVHD发生率分别为51.9％（95％CI42.0％～64.0％）、29.4％（95％CI 14.1％～61.4％）（P＝0.072），Ⅲ/Ⅳ度急性GVHD发生率分别为9.8％（95％CI 5.1％～19.1％）、11.8％（95％CI 3.2％～43.3％）（P＝1.000），巨细胞病毒（CMV）血症发生率分别为53.1％（95％CI 43.3％～65.2％）、29.4％（95％CI 14.1％～61.4％）（P＝0.115），EB病毒（EBV）血症发生率分别为35.8％（95％CI 26.8％～47.9％）、11.8％（95％CI 3.2％～43.3％）（P＝0.048）。HIDT、MSDT两组移植后5年总生存（OS）率分别为60.5％（95％CI 5.4％～49.0％）、68.8％（95％CI 11.8％～40.0％）（P＝0.315），无白血病生存（LFS）率分别为58.0％（95％CI 5.5％～46.5％）、68.8％（95％CI11.8％～40.0％）（P＝0.258），累积复发率分别为16.1％（95％ CI 9.8％～26.4％）、11.8％（95％ CI3.2％～43.3％）（P＝0.643），非复发死亡率（NRM）分别为25.9％（95％CI 17.9％～37.5％）、19.4％（95％CI6.9％～54.4％）（P＝0.386）。

结论

对于CR期T-ALL患者，当缺乏合适供者时，HIDT可作为替代选择。

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.

Haploidentical stem cell transplantation vs matched unrelated donor transplantation in adults with hematologic malignancies: a systematic review and meta-analysis

OBJECTIVES

Haploidentical hematopoietic stem cell transplantation (Haplo-SCT) and matched unrelated donor transplantation (MUD-SCT) are two important options when a matched sibling donor (MSD) is unavailable. Several studies comparing Haplo-SCT and MUD-SCT have reported inconsistent clinical outcomes. Therefore, it is necessary to synthesize the existing evidence regarding outcomes of stem cell transplantations comparing Haplo-SCT with MUD-SCT.

METHODS

We searched for titles of articles in MEDLINE (PubMed), Cochrane library, EMBASE database that compared transplantation with Haplo-SCT versus MUD-SCT. To compare clinical outcomes between Haplo-SCT and MUD-SCT, we performed a meta-analysis of 17 studies and reported the pooled odd ratios (OR) of 6 endpoints including overall survival (OS), progression free survival (PFS), non-relapse mortality (NRM), relapse rate (RR), acute graft-versus-host disease (aGVHD) and chronic graft- versus-host disease (cGVHD).

RESULTS

We found that Haplo-SCT was associated with a comparable OS (pooled OR of 0.99, 95% Confidence Interval (CI) 0.86-1.14), PFS (OR 1.00, 95% CI 0.88-1.15), NRM (OR 0.83, 95% CI 0.65-1.04) and RR (OR 1.08, 95% CI 0.95-1.22) compared to MUD-SCT. We also found a significantly decreased risk of aGVHD (OR 0.74, 95% CI 0.62-0.88) and cGVHD (OR 0.50, 95% CI 0.38-0.66) in Haplo-SCT group.

CONCLUSION

Results of this meta-analysis demonstrates that Haplo-SCT achieves comparable clinical outcomes compared to MUD-SCT in terms of OS, PFS, TRM and RR, but is better than MUD-SCT in terms of decreased aGVHD and cGVHD risk. Haplo-SCT is a valid option for patient needing urgent transplantation.

Overt gastrointestinal bleeding following haploidentical haematopoietic stem cell transplantation: incidence, outcomes and predictive models

Gastrointestinal bleeding (GIB) accounts for a significant proportion of life-threatening bleeding cases occurring after allogeneic haematopoietic stem cell transplantation (allo-HSCT). However, data on GIB after haploidentical HSCT (haplo-HSCT) are not available. A total of 3180 patients received haplo-HSCT at Peking University People's Hospital from January 2015 to November 2019, and GIB occurred in 188 of these patients (incidence of 5.9%). Platelet counts <30 × 10⁹/L, viral hepatitis, acute kidney injury (AKI), gastrointestinal disease or bleeding before HSCT and sinusoidal obstruction syndrome (SOS) were determined to be significant risk factors for the occurrence of GIB after haplo-HSCT. Grade III-IV acute graft-versus-host disease (aGVHD), AKI, thrombotic microangiopathy (TMA), disseminated intravascular coagulation (DIC) and gastrointestinal disease or bleeding before HSCT were significantly related to mortality in patients with GIB after haplo-HSCT. The predictive models developed for the occurrence and mortality of GIB performed well in terms of discrimination, and they might assist clinicians with personalised strategies for GIB prevention and treatment in patients after haplo-HSCT.

T-Cell-Replete Versus ex vivo T-Cell-Depleted Haploidentical Haematopoietic Stem Cell Transplantation in Children With Acute Lymphoblastic Leukaemia and Other Haematological Malignancies

Allogeneic haematopoietic stem cell transplantation (HSCT) represents a potentially curative option for children with high-risk or refractory/relapsed leukaemias. Traditional donor hierarchy favours a human leukocyte antigen (HLA)-matched sibling donor (MSD) over an HLA-matched unrelated donor (MUD), followed by alternative donors such as haploidentical donors or unrelated cord blood. However, haploidentical HSCT (hHSCT) may be entailed with significant advantages: besides a potentially increased graft-vs.-leukaemia effect, the immediate availability of a relative as well as the possibility of a second donation for additional cellular therapies may impact on outcome. The key question in hHSCT is how, and how deeply, to deplete donor T-cells. More T cells in the graft confer faster immune reconstitution with consecutively lower infection rates, however, greater numbers of T-cells might be associated with higher rates of graft-vs.-host disease (GvHD). Two different methods for reduction of alloreactivity have been established: in vivo T-cell suppression and ex vivo T-cell depletion (TCD). Ex vivo TCD of the graft uses either positive selection or negative depletion of graft cells before infusion. In contrast, T-cell-repleted grafts consisting of non-manipulated bone marrow or peripheral blood grafts require intense in vivo GvHD prophylaxis. There are two major T-cell replete protocols: one is based on post-transplantation cyclophosphamide (PTCy), while the other is based on anti-thymocyte globulin (ATG; Beijing protocol). Published data do not show an unequivocal benefit for one of these three platforms in terms of overall survival, non-relapse mortality or disease recurrence. In this review, we discuss the pros and cons of these three different approaches to hHSCT with an emphasis on the significance of the existing data for children with acute lymphoblastic leukaemia.

Haploidentical Hematopoietic Stem Cell Transplantation Versus Umbilical Cord Blood Transplantation in Hematologic Malignancies: A Systematic Review and Meta-Analysis

Haploidentical hematopoietic stem cell transplantation (Haplo-SCT) and umbilical cord blood transplantation (UCBT) are two important alternatives when a matched sibling donor is unavailable. Several studies have reported inconsistent clinical outcomes comparing Haplo-SCT and UCBT. Therefore, it is necessary to synthesize the existing evidence regarding outcomes of stem cell transplantations comparing Haplo-SCT with UCBT. We searched article titles that compared transplantation with Haplo-SCT and UCBT in MEDLINE (PubMed), Cochrane library, and EMBASE database. To compare clinical outcomes between Haplo-SCT and UCBT, we performed a meta-analysis of 12 studies and reported the pooled odds ratios (ORs) of 6 end points including overall survival (OS), progression-free survival (PFS), nonrelapse mortality (NRM), relapse rate (RR), acute graft-versus-host disease (aGVHD), and chronic graft-versus-host disease (cGVHD). We found that Haplo-SCT was associated with a significantly superior OS (pooled OR of 0.74, 95% confidence interval [CI] 0.68 to 0.80) and PFS (0.77, 95% CI 0.72 to 0.83), as well as a lower NRM (0.72, 95% CI 0.64 to 0.80) and aGVHD (0.87, 95% CI 0.77 to 0.98) compared to the UCBT group. We also found a significantly increased risk of cGVHD in Haplo-SCT group (1.40, 95% CI 1.22 to 1.62). In terms of RR, Haplo-SCT was comparable to UCBT (0.91, 95% CI 0.79 to 1.05). Results of this meta-analysis demonstrate that Haplo-SCT results in better clinical outcomes compared to UCBT in terms of OS, PFS, TRM, and aGVHD, but is inferior to UCBT in terms of increased cGVHD risk. Further prospective comparisons between Haplo-SCT and UCBT are needed.

[Clinical study of anti-human T cell porcine immunoglobulin with recombinant human tumor necrosis factor-α receptor II: IgG Fc in the treatment of 35 cases of grade III/IV acute graft-versus-host disease after allo-HSCT]

Objective: To evaluate the efficacy and safety of anti-human T lymphocyte porcine immunoglobulin (P-ATG) with recombinant human tumor necrosis factor-α receptor Ⅱ:IgG Fc fusion protein (rhTNFR∶Fc, Etanercept) on grade Ⅲ/Ⅳ acute graft-versus-host disease (aGVHD) after allogenic hematopoietic stem cell transplantation (allo-HSCT) . Methods: Thirty-five patients with Grade Ⅲ/Ⅳ aGVHD who received P-ATG with etanercept therapy after allo-HSCT were retrospectively analyzed. P-ATGs (5 mg·kg(-1)·d(-1)) were administrated for 3 to 5 days, and then 5mg/kg was sequentially administrated, QOD to BIW. Etanercepts were administrated 25 mg, twice a week (12.5 mg, BIW for pediatric patients) . Results: Among the 35 patients with grade Ⅲ/Ⅳ aGVHD, 21 were males and 14 females, with a median age of 10 (3-54) years. A total of 19 cases of acute myeloid leukemia, 13 of acute lymphoblastic leukemia, 1 of severe aplastic anemia, 1 of myelodysplastic syndrome, and 1 of mixed phenotypic acute leukemia were noted. The overall response (OR) rate of P-ATG with etanercept was 85.7% (30/35) , with complete response (CR) and partial response (PR) rates of 34.3% (12/35) and 51.4% (18/35) , respectively, on day 28. The OR rate of grade Ⅲ aGVHD group was higher than of grade IV aGVHD group [100% (19/19) vs. 68.8% (11/16) , P=0.004]. On day 56, the OR rate became 77.2% (27/35) , with CR and PR rates of 62.9% (22/35) and 14.3% (5/35) , respectively. The OR rate of grade Ⅲ aGVHD group was also higher than of grade Ⅳ aGVHD group [89.5% (17/19) vs. 62.5% (10/16) , P=0.009]. Thirty-five patients had no adverse effects such as fever, chills, and rash during the P-ATG infusion, and no obvious liver and kidney function damage was observed after treatment. The main treatment-related complication was infection. The reactivation rates of CMV and EBV were 77.1% (27/35) and 22.9% (8/35) , respectively, and the bacterial infection rate was 48.6% (17/35) . With a median follow-up time of 13 (1-55) months after HSCT, the 1-year and 2-year OS rates were (68.1±8.0) % and (64.3±8.4) % , respectively. The 1-year OS rate of grade Ⅲ aGVHD group was superior to grade Ⅳ aGVHD group [ (84.2±8.4) % vs. (47.6±13.1) % , χ(2)=3.38, P=0.05]. Conclusion: This study demonstrated that P-ATG with etanercept was effective and safe in treating grade Ⅲ-Ⅳ aGVHD after allo-HSCT.

Recent progress in haploidentical transplantation: is this the optimal choice for alternative donor transplantation?

PURPOSE OF REVIEW

This article is intended to review recent trends and improvements in haploidentical transplantation to understand its current status and future direction.

RECENT FINDINGS

The noninferiority of haploidentical donors compared with other donor sources, including HLA-matched related or unrelated donors, has been demonstrated in patients with various hematological diseases. The development of graft-versus-host-disease (GVHD) prophylaxis using posttransplant cyclophosphamide has effectively reduced transplant-related mortality caused by GVHD, graft rejection, and other related complications. Novel GVHD prophylactic methods and other supportive strategies are under intense investigation to reduce the risk of infections and retain graft-versus-leukemia/lymphoma effects after transplantation.

SUMMARY

Recent progress in haploidentical stem cell transplantation has broadened the availability of donor sources for patients with hematological diseases. It is important to compare and examine the impact of donor sources on transplant outcomes to achieve a better understanding about the appropriate donor choice for each patient.

Anti-Ro52 Autoantibodies Are Related to Chronic Graft-vs.-Host Disease After Allogeneic Hematopoietic Stem Cell Transplantation

Chronic graft-vs.-host disease (cGVHD) remains a major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Previous studies have shown that autoantibodies play an important role in the development of cGVHD. Anti-nuclear autoantibodies (ANA) is the most frequently detected autoantibodies in patients with cGVHD, but the role of anti-Ro52 autoantibodies (anti-Ro52) in cGVHD remains largely unknown. In this study, we analyzed autoantibodies from 84 patients after allo-HSCT, including 42 with active cGVHD and 42 without cGVHD. Autoantibodies were found in 36 (42.9%) patients. Among these autoantibody-positive patients, 28 (77.8%) patients had active cGVHD. The most frequent autoantibodies in patients with active cGVHD were ANA (50.0%), anti-Ro52 (28.6%) and anti-mitochondrial autoantibodies type 2 (4.8%). We further explored the association between anti-Ro52 and cGVHD. Patients with active cGVHD had higher anti-Ro52 levels than patients without cGVHD (P < 0.05). The increases of anti-Ro52 levels were more significant in patients with moderate/severe cGVHD compared to those of patients without cGVHD (P < 0.05). Stratified and multivariable logistic regression analysis demonstrated that moderate/severe cGVHD was an independent risk factor for the levels of anti-Ro52 (P < 0.01). ROC analysis confirmed anti-Ro52 as a risk factor for progression of skin cGVHD. Moreover, the anti-Ro52 levels were highly correlated with the levels of B cell-activating factor (BAFF) and IgG1 antibodies. Our study demonstrates that anti-Ro52 is associated with cGVHD. The increased levels of anti-Ro52 were associated with higher levels of BAFF and IgG1 antibodies, suggesting a mechanistic link between elevated anti-Ro52 levels and aberrant B cell homeostasis.

Haploidentical related donor vs matched sibling donor allogeneic hematopoietic stem cell transplantation for acute myeloid leukemia and myelodysplastic syndrome aged over 50 years: A single-center retrospective study

Allogeneic hematopoietic stem cell transplantation (allo‐HSCT) is a potentially curative therapeutic option for patients with acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS). Increasing data suggest that haploidentical donor (HID) transplantation achieve comparable outcomes with HLA‐matched sibling donor (MSD) in adult AML/MDS. This retrospective study compared the outcomes of AML or MDS patients age ≥50 years underwent HID and MSD transplantation. One hundred and fifty‐six patients were enrolled in this study, including 75 HID and 81 MSD transplantation. The 100‐day cumulative incidence of II‐IV° acute graft‐versus‐host disease (GVHD) was 33.3 ± 5.4% vs 22.2 ± 4.6%, respectively, in HID and MSD groups (P = .066), and III‐IV° acute GVHD was not significantly different between two groups (5.3%±2.6% vs 6.2%±2.7%, respectively, P = .823). The 2‐year cumulative incidence of limited and extensive chronic GVHD was not statistically different in HID and MSD groups (20.9 ± 5.5% vs 18.9 ± 4.8% and 13.0 ± 4.7% vs 19.7 ± 5.0%, P = .889 and P = .269, respectively). The 2‐year cumulative incidences of relapse (27.0 ± 5.6% vs 22.7 ± 5.1%, P = .509), 2‐year overall survival (63.0 ± 5.8% vs 66.7 ± 5.4%, P = .454), 2‐year transplant‐related mortality (17.2 ± 4.6% vs 17.4 ± 4.4%, P = .847), 2‐year progression‐free survival (59.3 ± 5.8% vs 64.5 ± 5.4%, P = .437), 2‐year GVHD‐free relapse‐free survival (42.6 ± 5.9% vs 40.9 ± 5.6%, P = .964) were not significantly different in the two groups. The present data showed equivalent outcomes in AML or MDS patients age ≥50 years underwent HID and MSD transplantation.

Graft-vs-Host Disease-Induced Hyperthyroidism in a Recipient of Allogeneic Hematopoietic Stem Cell Transplantation: A Case Report

BACKGROUND

Hyperthyroidism after hematopoietic stem cell transplantation (HSCT) is rare, and only a few cases have been reported. What is more important, the fundamental mechanisms of hyperthyroidism after HSCT remained unclear.

CASE

A 28-year-old man received an HLA haploidentical related-donor HSCT for acute myeloid leukemia and developed hyperthyroidism 31 months after HSCT. He presented with periodic paralysis as the initial symptom, his serum levels of free triiodothyronine (fT3), free thyroxine (fT4), and anti-thyroid autoantibodies increased, and thyroid-stimulating hormone level decreased. As a result, he was diagnosed with hyperthyroidism. Although systemic symptoms, signs, and laboratory findings of graft-vs-host disease (GVHD) were absent, thyroid histopathologic examination revealed thyroid follicular destruction and infiltrations of lymphocytes, which mainly consisted of CD20⁺ B lymphocytes and CD4⁺ and CD3⁺ T lymphocytes by immunohistochemistry. These were in accordance with the pathologic features of GVHD. The symptom of periodic paralysis resolved after treatment with prednisolone and methimazole for 1 month. The treatments lasted for 4 months, and the plasma levels of fT3, fT4, TSH, and anti-thyroid peroxidase normalized. He did not relapse after drug withdrawal with observation for 24 months to date.

CONCLUSIONS

To the best of our knowledge, the present case was the first to be confirmed with thyroid-specific GVHD-induced hyperthyroidism after allogeneic HSCT.

Reduced-intensity versus Myeloablative Conditioning Regimens for Younger Adults with Acute Myeloid Leukemia and Myelodysplastic Syndrome: A systematic review and meta-analysis

Background: Historically, reduced-intensity conditioning (RIC) was recommended to be performed for older patients who were considered ineligible for myeloablative conditioning (MAC) before allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, the evidence regarding the optimal conditioning intensity in younger patients with AML or MDS is weak and contradictory.

Methods: PubMed, Medline, Embase, and other online sources were searched from the initial period to February 25, 2020. Odds ratios and 95% confidence intervals were calculated to estimate pooling effects.

Results: Four randomized controlled trials (RCTs) about conditioning intensity involving 633 patients were included. There were no significant differences of 1/2/4/5 years progression-free survival (PFS) and relapse incidence (RI) between two conditioning intensities. Overall survival (OS) was similar at 1/2/4 years, but patients receiving RIC had a higher OS at 5 years. Additionally, RIC were associated with lower non-relapse mortality, less grade II-IV and grade III-IV acute graft-versus-host disease (GVHD), and lower incidence of chronic GVHD compared with MAC regimens. Subgroup analysis showed similar OS and RI for AML patients, and there was a trend towards lower NRM and grade II-IV aGVHD in RIC group. Available data for MDS indicated that OS, PFS, and RI were comparable. For intermediate-risk patients, there was no evidence that RIC is inferior to MAC. However, for high-risk patients, MAC tends to perform better.

Conclusions: Based on the above results, it might be concluded that RIC is a feasible treatment option for adults with AML or MDS younger than 66 years, particularly those with intermediate-risk disease. Future RCTs incorporating of risk stratifications are warranted to guide the optimal decision under certain conditions.

Comparison of haplo-SCT and chemotherapy for young adults with standard-risk Ph-negative acute lymphoblastic leukemia in CR1

Abstract

Human leukocyte antigen (HLA) haploidentical stem cell transplantation (haplo-SCT) as a postremission treatment for standard risk Philadelphia chromosome-negative acute lymphoblastic leukemia (SR Ph-ALL) in the first complete remission (CR1) has not been defined. In this multicenter, phase 3 study (NCT02042690), of the 131 consecutive Ph-ALL young adult patients (YA, aged 18–39 years) without high-risk features who achieved CR1, 114 patients without HLA-matched donors received consolidation with an adult chemotherapy regimen (n = 55) or haplo-SCT (n = 59). In the landmark analysis, haplo-SCT resulted in a lower 2-year cumulative incidence of relapse (CIR, 12.8% vs 46.7%, P = 0.0017) and superior 2-year leukemia-free survival (LFS, 80.9% vs 51.1%, P = 0.0116) and 2-year overall survival (OS, 91.2% vs 75.7 [64.8–93.2] %, P = 0.0408) than chemotherapy. In the time-dependent multivariate analysis with propensity score adjustment, postremission treatment (haplo-SCT vs chemotherapy) was an independent risk factor for the CIR (HR 0.195, 95% CI 0.076–0.499, P = 0.001), LFS (HR 0.297, 95% CI 0.131–0.675, P = 0.003), and OS (HR 0.346, 95% CI 0.140–0.853, P = 0.011). In all subgroups, CIR was lower in haplo-SCT. Myeloablative haplo-SCT with ATG+G-CSF might be one of the preferred therapies for YA patients with standard-risk Ph-ALL.

Trial registration

ClinicalTrials.gov. Registered on 23 January 2014, https://clinicaltrials.gov/ct2/show/NCT02042690

Hematopoietic Cell Transplantation for Philadelphia Chromosome Negative Adult Acute Lymphoblastic Leukemia in the Modern Era of Immune Therapy

PURPOSE OF REVIEW

This review will discuss the data and controversies related to HCT in the front-line and relapsed/refractory setting in the context of newly available targeted immunotherapies.

RECENT FINDINGS

Recent studies in adult Ph-negative ALL support the use of measurable residual disease (MRD) response to front-line therapy to guide consolidation. As such, most MRD-negative patients do not require front-line HCT. Blinatumomab benefits patients with B-ALL with MRD+ complete response (CR) and can be used as a bridge to HCT; whether HCT is still required in this setting is an area of ongoing inquiry. Blinatumomab and inotuzumab result in high rates of MRD negative CR in adults with relapsed/refractory ALL and allow more patients with relapsed disease to receive HCT. Chimeric antigen receptor T cell (CAR-T) therapies may serve as a bridge to HCT or as a stand-alone therapy for relapsed/refractory patients; data suggests there may be greater benefit to consolidating CAR-T with HCT in HCT-naïve adults. The decision to incorporate consolidative allogeneic HCT into front-line therapy should be primarily guided by MRD status and the ALL regimen utilized. Targeted immunotherapies result in high MRD-negative CR rates, allowing more adults with relapsed/refractory ALL to be successfully bridged to HCT; early incorporation of these therapies may also prove valuable in reducing the need for HCT in the front-line setting by increasing MRD negative CR rates.

Treatment and unmet needs in steroid-refractory acute graft-versus-host disease

Acute graft-versus-host disease (aGVHD) is a common complication of allogeneic hematopoietic stem cell transplantation (alloHCT) and is a major cause of morbidity and mortality. Systemic steroid therapy is the first-line treatment for aGVHD, although about half of patients will become refractory to treatment. As the number of patients undergoing alloHCT increases, developing safe and effective treatments for aGVHD will become increasingly important, especially for those whose disease becomes refractory to systemic steroid therapy. This paper reviews current treatment options for patients with steroid-refractory aGVHD and discusses data from recently published clinical studies to outline emerging therapeutic strategies.

Comparison of hemorrhagic and ischemic stroke after allogeneic hematopoietic stem cell transplantation

Stroke is an important complication following allogeneic hematopoietic stem cell transplantation (allo-HSCT). Nevertheless, few studies have been published to analyzed the occurrence and prognosis of stroke after allo-HSCT. From January 2007 to December 2018 in Peking University People's Hospital, 6449 patients received HSCT and there were 2.3% of patients diagnosed with stroke after allo-HSCT (hemorrhagic: 1.0%, ischemic: 1.3%). The median time to hemorrhagic and ischemic stroke after HSCT was 161 days and 137 days, respectively. In total, 8.4% of patients experienced neurological sequelae. The outcome was much worse in patients with stroke than in control subjects. The comparison of prognosis showed no statistical differences between patients with hemorrhagic stroke and those with ischemic stroke. Significant risk factors for hemorrhagic stroke were pretransplant central nervous system leukemia (CNSL), and delayed platelet engraftment. Risk factors associated with the occurrence of ischemic stroke included high-risk disease, prior venous thromboembolism (VTE), grade III-IV acute graft-versus-host disease (aGVHD), and thrombotic microangiopathy (TMA). Haplo-identical transplantation was not a risk factor for stroke and had no impact on the prognosis compared with HLA-matched HSCT. Altogether, these results show that stroke is a severe complication after allo-HSCT. The prognosis of posttransplant stroke did not differ between hemorrhagic and ischemic stroke.

A gut microbiota score predicting acute graft-versus-host disease following myeloablative allogeneic hematopoietic stem cell transplantation

Although studies have reported that intestinal microbiota are associated with acute graft-versus-host disease (aGVHD), they lacked a satisfactory method for predicting aGVHD. We collected stool and blood samples at day 15 posttransplant from 150 patients from two centers who underwent myeloablative conditioning allogeneic hematopoietic stem cell transplantation (allo-HSCT). Stool microbiota were detected by 16S ribosomal RNA gene sequencing; inflammatory factors and T lymphocytes were detected by multiplex immunoassays and flow cytometry, respectively. A gut microbiota score (GMS) from a LASSO (least absolute shrinkage and selection operator) model was developed and validated to predict aGVHD. In the discovery cohort, the GMS could predict II-IV aGVHD (area under the receiver operating characteristic [ROC] curve [AUC] = 0.904, P < .0001). Furthermore, the validation model was consistent with the discovery set (AUC = 0.887, P < .0001). Regulatory T/T-helper 17 (Treg/Th17) cells ratio in the low GMS subgroup was higher compared with the high GMS (P = .012), and the validation set is consistent with the discovery set (P = .003). In addition, high cytokine levels were associated with high GMS. In conclusion, the GMS at neutrophil engraftment could predict aGVHD, and it was a potential and novel method. The GMS was associated with the inflammatory factor and Treg/Th17 balance.

Haploidentical versus HLA-matched sibling transplantation for refractory acute leukemia undergoing sequential intensified conditioning followed by DLI: an analysis from two prospective data

BACKGROUND

Compared with HLA-matched sibling donor (MSD) transplant, the outcomes of haploidentical donor (HID) transplant for refractory acute leukemia need to be further explored. In this study, we compared the outcomes of HID with MSD for refractory acute leukemia.

PATIENTS AND METHODS

This study population came from two prospective multicenter trials (NCT01883180, NCT02673008). Two hundred and seventy-eight patients with refractory acute leukemia were enrolled in this study, including 119 in HID group and 132 in MSD group. Sequential intensified conditioning was employed in all patients, and donor lymphocyte infusion (DLI) was administered in patients in the absence of active GVHD and according to minimal residual disease (MRD) from day + 60 post-transplantation for preventing relapse.

RESULTS

The complete remission of leukemia by day + 30 post-transplant were 94% and 93%, respectively, in HID and MSD groups (p = .802). The 1-year incidence of grades II-IV acute GVHD was 62% and 54% (p = .025), and 3-year incidence of chronic GVHD was 55% and 55% (p = .789), respectively, in two groups. HID transplant had lower incidence of first episode of MRD positivity and relapse than MSD transplant (28% vs 45%, p = .006; 26% vs 38%, p = .034). There was higher infection-related mortality in HID than MSD (8% vs 2%, p = .049) within the first 100 days' post-transplant. The 5-year overall survival was 46% and 42% (p = .832), respectively; the 5-year disease-free survival was 43% and 39% (p = .665), in HID and MSD groups, respectively.

CONCLUSIONS

HID transplant has lower relapse, but higher infection-related mortality and similar survival rates in refractory acute leukemia by the strategy of sequential intensified conditioning followed by DLI compared with MSD transplant.

Outcomes of Allogeneic Hematopoietic Cell Transplantation after Salvage Therapy with Blinatumomab in Patients with Relapsed/Refractory Acute Lymphoblastic Leukemia

Historically, outcomes of adult patients with relapsed acute lymphoblastic leukemia (ALL) who fail to enter remission with conventional chemotherapy are very poor. Blinatumomab, a bispecific CD3/CD19 antibody, has shown remarkable activity in relapsed/refractory (r/r) ALL. Although allogeneic hematopoietic cell transplant (HCT) is the recommended consolidation therapy for patients with r/r ALL who respond to salvage therapy, HCT and toxicity outcomes for those who received blinatumomab salvage and HCT remain largely unknown. We treated 89 patients with r/r ALL with blinatumomab, of whom 43 patients (48%) achieved remission. Here we describe our single-center experience in the subset of patients who responded to blinatumomab salvage therapy for eradication of either gross (n = 24) or minimal residual disease (n = 11) before HCT. Overall survival at 1 and 2 years after allogeneic HCT was 77% and 52%, respectively. Leukemia-free survival at 1 and 2 years were 65% and 40%, respectively. Additionally, with blinatumomab administration pre-HCT, no unusual toxicities such as delayed neutrophil/platelet engraftment or graft failure were observed. Acute grades II to IV graft-versus-host disease (GVHD) at day +100 post-HCT was at 43% and 2-year chronic GVHD was 36%, both comparable with historic control subjects. Finally, results of our subset analysis based on pre-HCT minimal residual disease (MRD) status indicated no significant difference in survival outcomes among patients undergoing transplant in MRD-negative status and the entire cohort. In conclusion, based on results of this study, blinatumomab may be considered as a safe and effective agent for r/r ALL patients before HCT.

Haploidentical transplantation might have superior graft-versus-leukemia effect than HLA-matched sibling transplantation for high-risk acute myeloid leukemia in first complete remission: a prospective multicentre cohort study

This study aimed to investigate graft-versus-leukemia (GVL) of haploidentical donor (HID) compared with HLA-matched sibling donor (MSD) for high-risk acute myeloid leukemia (H-AML) in first complete remission (CR1). One hundred and eighty-nine patients with H-AML in CR1 were enrolled in this multicentre prospective cohort study. Patients were assigned to groups transplanted with HID (n = 83) or MSD (n = 106) based on donor availability (biological randomization). The primary endpoint was the incidence of MRD positivity posttransplantation (post-MRD+). All post-MRD+ patients received preemptive interventions. The cumulative incidences of post-MRD+ were 18 and 42% in HID and MSD groups, respectively, (p < 0.001). Fifty-two patients received preemptive DLI, including 13 (16%) in HID and 39 cases (37%) in MSD groups (p = 0.001). Among HID and MSD groups, the 3-year cumulative incidence of relapse were 14 and 24% (p = 0.101); the 3-year cumulative incidence of treatment-related mortality were 15 and 10% (p = 0.368); the 3-year overall survival rates were 72 and 68% (p = 0.687); the 3-year disease-free-survival were 71 and 66% (p = 0.579); the 3-year graft-versus-host disease and relapse free survival were 63 and 43% (p = 0.035), respectively. HID might have a stronger GVL than MSD in H-AML patients. HID transplantation as postremission therapy should be recommended as one of the optimal choices for H-AML patients in CR1.

Granulocyte Colony-Stimulating Factor-Primed Unmanipulated Haploidentical Blood and Marrow Transplantation

Granulocyte colony-stimulating factor (G-CSF), a growth factor for neutrophils, has been successfully used for stem cell mobilization and T cell immune tolerance induction. The establishment of G-CSF-primed unmanipulated haploidentical blood and marrow transplantation (The Beijing Protocol) has achieved outcomes for the treatment of acute leukemia, myelodysplastic syndrome, and severe aplastic anemia with haploidentical allografts comparable to those of human leukocyte antigen (HLA)-matched sibling donor transplantation. Currently, G-CSF-mobilized bone marrow and/or peripheral blood stem cell sources have been widely used in unmanipulated haploidentical transplant settings. In this review, we summarize the roles of G-CSF in inducing T cell immune tolerance. We discuss the recent advances in the Beijing Protocol, mainly focusing on strategies that have been used to improve transplant outcomes in cases of poor graft function, virus infections, and relapse. The application of G-CSF-primed allografts in other haploidentical modalities is also discussed.

Two dose levels of rabbit antithymocyte globulin as graft-versus-host disease prophylaxis in haploidentical stem cell transplantation: a multicenter randomized study

BACKGROUND

The optimal dose of rabbit antithymocyte globulin (ATG, ImtixSangstat) minimizing infections without increasing graft-versus-host disease (GVHD) is unknown in T cell-replete, G-CSF-primed haploidentical hematopoietic stem cell transplantation (haplo-HSCT).

METHODS

Four hundred and eight patients were enrolled in this multicenter study to evaluate the effect of 7.5 mg/kg and 10.0 mg/kg rabbit ATG on viral infections and GVHD prophylaxis after haplo-HSCT. The primary endpoint was EBV DNAemia within 1 year posttransplantation.

RESULTS

The 1-year incidence of EBV DNAemia was 20.7% (95% confidence interval, 15.4-26.5) and 40.0% (33.3-46.6) in the 7.5 mg/kg and 10.0 mg/kg groups, respectively (P < 0.001). The 100-day cumulative incidence of grade II to IV aGVHD was 27.1% (21.1-33.4) and 25.4% (19.6-31.5) in the 7.5 mg/kg and 10.0 mg/kg ATG groups, respectively (P = 0.548). The 2-year incidence of chronic GVHD was 34.6% (27.8-41.4) and 36.2% (29.1-43.2) in the 7.5 mg and 10.0 mg groups (P = 0.814). The 1-year incidence of CMV DNAemia was 73.4% (67.2-79.4) and 83.4% (77.5-87.9) in the 7.5 mg/kg and 10.0 mg/kg groups (P = 0.038). The 3-year overall survival posttransplantation was 69.5% (63.2-75.8) and 63.5% (56.2-70.8), and the disease-free survival was 62.2% (55.3-69.1) and 60.3% (53.0-67.6) in the 7.5 mg/kg and 10.0 mg/kg groups, respectively (OS: P = 0.308; DFS: P = 0.660). The counts of EBV- and CMV-specific cytotoxic T cells (CTLs) were higher in the 7.5 mg/kg group than in the 10.0 mg/kg group early posttransplantation.

CONCLUSIONS

Compared with 10.0 mg/kg, 7.5 mg/kg ATG for GVHD prophylaxis was associated with reduced EBV and CMV infections without increased incidence of GVHD in haplo-HSCT, probably by affecting EBV- and CMV-specific CTLs.

TRIAL REGISTRATION

clinicaltrials.gov, NCT01883180 . Registered 14 June 2013.

Haploidentical Transplantation with Post-Transplant Cyclophosphamide versus Unrelated Donor Hematopoietic Stem Cell Transplantation: A Systematic Review and Meta-Analysis

Hematopoietic stem cell transplantation (HSCT) is the standard treatment for patients with high-risk hematologic malignancies. Only approximately 25% of siblings are HLA-matched, and thus alternative donors-unrelated or haploidentical-are usually the only options available. This meta-analysis aimed to compare haploidentical HSCT with post-transplantation cyclophosphamide and unrelated donor (URD) HSCT. We searched the PubMed and Cochrane databases for pertinent studies indexed between 2008 and 2018. Twenty observational studies (with a total of 1783 haploidentical HSCT recipients and 6077 URD HSCT recipients) were included. Results for overall survival, graft-versus-host disease (GVHD), nonrelapse mortality (NRM), and relapse incidence were pooled. Measures of association used were hazard ratios and risk differences. The median age was 51 years for haploidentical transplant recipients and 52 years for URD transplant recipients. Peripheral blood stem cell (PBSC) grafts were more frequent in the URD transplant recipients (85%) than in the haploidentical transplant recipients (31%). Overall survival was not different between the 2 groups. NRM was lower for haploidentical transplantation. All forms of GVHD (acute grades II-IV and III-IV and moderate, severe, and extensive chronic) were lower with haploidentical donor HSCT. The risk of chronic GVHD was fairly proportional to the differential use of PBSC grafts across studies, however. All included studies were retrospective, representing the major limitation of this meta-analysis. In conclusion, haploidentical HSCT for hematologic malignancies achieved the same overall survival as URD HSCT, with a lower incidence of GVHD and NRM. The increased frequency of PBSC use in the unrelated donor group could partially explain the higher cGVHD rate. Haploidentical transplantation with post-transplantation cyclophosphamide should strongly be considered as the first option for adult patients with hematologic malignancies who do not have matched sibling donors in experienced centers. This systematic review has been registered at PROSPERO (65790).

Intestinal Microbiota Can Predict Acute Graft-versus-Host Disease Following Allogeneic Hematopoietic Stem Cell Transplantation

The intestinal microbiome plays an important role in the development of acute graft-versus-host disease (aGVHD). However, whether intestinal microbiota can predict the development of aGVHD has been reported only rarely. Here we conducted a prospective study of microbiota in 141 patients after allogeneic hematopoietic stem cell transplantation. We found lower microbiota diversity in the aGVHD group compared with the non-aGVHD group at day 0 and day 15 ± 1 (P = .018 and .009, respectively). Diversity was negatively associated with conditioning intensity (P = .017, day 0; P = .045, day 15) and β-lactam antibiotic administration (P = .004, day 15). Intensified conditioning and β-lactam antibiotics were associated with a lower regulatory T (Treg)/T helper 17 (Th17) cell ratio at day 15 (P = .030 and .047, respectively). At day 15, the levels of the inflammatory factors (tumor necrosis factor α, interleukin [IL]-6, IL-17A, IL-1β, and lipopolysaccharide) were higher in the intensified conditioning group compared with the standard group (P < .05). The accumulated intestinal microbiota (AIM) score was defined as microbiota diversity and gradient of the 4 bacterials (Lachnospiraceae, Peptostreptococcaceae, Erysipelotrichaceae, and Enterobacteriaceae) at day 15 post-transplantation. The AIM score was positively correlated with aGVHD grade (r = .481, P < .001), and the AIM score could be predictive of the development of aGVHD (grade II-IV aGVHD: area under the curve [AUC], .75, P < .001; grade III-IV aGVHD: AUC, .84, P < .001). These findings suggest that intestinal microbiota and conditioning might induce aGVHD by inflammatory factors and the Treg/Th17 balance. The constitution of the intestinal microbiota at neutrophil engraftment may predict the development of aGVHD.

Prophylaxis and treatment of relapse after haploidentical stem cell transplantation: What is known vs unknown?

In recent years, the human leukocyte antigen-haploidentical stem cell transplantation (haplo-SCT) approach is an attractive option for patients who require transplantation, but relapse is still the main reason that affects the curative effect of transplantation. Some studies have shown that haplo-SCT is superior to sibling or unrelated matching donor transplantation in preventing leukemia relapse after transplantation. In this review, we discussed the known and unknown aspects of relapse post haplo-SCT. Encouragingly, haplo-SCT experienced lower or similar incidence of relapse. But there is currently a lack of multicenter prospective studies evaluating the outcomes of different haplo-SCT strategies. The combination of common prophylactic strategies and pre-emptive interventions might help prevent relapse after transplantation. Novel methods such as target drugs therapy and chimeric antigen receptor T cell therapy may be useful in treatment of relapse.