Better outcomes of modified myeloablative conditioning without antithymocyte globulin versus myeloablative conditioning in cord blood transplantation for hematological malignancies: A retrospective (development) and a prospective (validation) study

Reconstitution of double-negative T cells after cord blood transplantation and its predictive value for acute graft-versus-host disease

BACKGROUND

With an increasing number of patients with hematological malignancies being treated with umbilical cord blood transplantation (UCBT), the correlation between immune reconstitution (IR) after UCBT and graft-versus-host disease (GVHD) has been reported successively, but reports on double-negative T (DNT) cell reconstitution and its association with acute GVHD (aGVHD) after UCBT are lacking.

METHODS

A population-based observational study was conducted among 131 patients with hematological malignancies who underwent single-unit UCBT as their first transplant at the Department of Hematology, the First Affiliated Hospital of USTC, between August 2018 and June 2021. IR differences were compared between the patients with and without aGVHD.

RESULTS

The absolute number of DNT cells in the healthy Chinese population was 109 (70-157)/μL, accounting for 5.82 (3.98-8.19)% of lymphocytes. DNT cells showed delayed recovery and could not reach their normal levels even one year after transplantation. Importantly, the absolute number and percentage of DNT cells were significantly higher in UCBT patients without aGVHD than in those with aGVHD within one year ( F = 4.684, P = 0.039 and F = 5.583, P = 0.026, respectively). In addition, the number of DNT cells in the first month after transplantation decreased significantly with the degree of aGVHD increased, and faster DNT cell reconstitution in the first month after UCBT was an independent protective factor for aGVHD (HR = 0.46, 95% confidence interval [CI]: 0.23-0.93; P = 0.031).

CONCLUSIONS

Compared to the number of DNT cells in Chinese healthy people, the reconstitution of DNT cells in adults with hematological malignancies after UCBT was slow. In addition, the faster reconstitution of DNT cells in the early stage after transplantation was associated with a lower incidence of aGVHD.

A predictive model combining clinical characteristics and nutritional risk factors for overall survival after umbilical cord blood transplantation

BACKGROUND

Umbilical cord blood transplantation (UCBT) is a curable therapy for hematological disease; however, the impact of nutritional status on UCBT outcomes remains controversial. To evaluate the joint effect of clinical characteristics and nutritional status on the prognosis of patients who underwent UCBT, we screened various factors to establish a predictive model of overall survival (OS) after UCBT.

METHODS

We performed an integrated clinical characteristic and nutritional risk factor analysis and established a predictive model that could be used to identify UCBT recipients with poor OS. Internal validation was performed by using the bootstrap method with 500 repetitions.

RESULTS

Four factors, including disease status, conditioning regimen, calf skinfold thickness and albumin level, were identified and used to develop a risk score for OS, which showed a positive predictive value of 84.0%. A high-risk score (≥ 2.225) was associated with inferior 3-year OS post-UCBT [67.5% (95% CI 51.1-79.4%), P = 0.001]. Then, we built a nomogram based on the four factors that showed good discrimination with a C-index of 0.833 (95% CI 0.743-0.922). The optimism-corrected C-index value of the bootstrapping was 0.804. Multivariate analysis suggested that a high calf skinfold thickness (≥ 20.5 mm) and a low albumin level (< 33.6 g/L) conferred poor disease-free survival (DFS).

CONCLUSION

The predictive model combining clinical and nutritional factors could be used to predict OS in UCBT recipients, thereby promoting preemptive treatment.

Impact of Iron overload and Iron Chelation with deferasirox on outcomes of patients with severe aplastic anemia after allogeneic hematopoietic stem cell transplantation

BACKGROUND

Patients suffering from severe aplastic anemia (SAA) need frequent blood transfusions during allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, these transfusions can result in an excess of iron in the body tissues, which can negatively impact the success of the transplant.

OBJECTIVES

This study aimed to examine the impact of pre-transplant iron overload (IO) on the outcomes of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with severe aplastic anemia (SAA). It also investigated whether iron chelation (IC) therapy was necessary to enhance transplantation outcomes in SAA patients by providing guidelines for determining when excess iron should be chelated.

STUDY DESIGN

The study consisted of two parts: Cohort 1, which was retrospective and conducted from April 2012 to December 2018, divided SAA patients receiving their first allo-HSCT into two groups based on their pre-transplant serum ferritin (SF) levels: the iron overload (IO) group (SF >1000 ng/ml, n=17) and the non-IO group (SF ≤ 1000 ng/ml, n=48). Cohort 2 was a prospective clinical trial conducted from January 2019 to July 2020. It involved SAA patients diagnosed with IO who were treated with iron chelation (IC) therapy using deferasirox (DFX) at a dose of 10-30 mg/kg. Patients were separated into two groups based on their pre-transplant SF levels: the IC success (IC^success) group (SF ≤ 1000 ng/ml, n=18) and the IC failure (IC^failure) group (SF >1000 ng/ml, n=28) groups. All participants were evaluated for the correlation between pre-transplant SF levels and transplantation outcomes. A P-value of less than 0.05 was considered statistically significant.

RESULTS

There was no significant difference in the speed of engraftment for the three lineages or in the incidence of 100-day grade II-IV acute graft-versus-host disease (aGVHD), grade III-IV aGVHD, or 3-year chronic GVHD between the two groups in both cohorts. However, in cohort 1, it was noteworthy that 1-year OS (83.3% vs. 41.2%, p < 0.001) and 3-year OS (83.3% vs. 35.3%, p < 0.001) were significantly worse in the IO group. Furthermore, 180-day TRM (14.6% vs. 47.1%, p = 0.005) and 1-year TRM (16.7% vs. 52.9%, p = 0.002) were significantly higher in the IO group. The IO group was significantly associated with inferior 3-year OS in both univariate and multivariate analyses. In cohort 2, it was found that 1-year OS (42.9% vs. 88.9%, p = 0.003) and 3-year OS (42.9% vs. 83.3%, p = 0.007) were significantly better in the IC^success group, while 180-day TRM (11.1% vs. 39.3%, p = 0.040) and 1-year TRM (11.1% vs. 57.1%, p = 0.003) were significantly lower in the IC^success group. These differences were confirmed in both univariate and multivariate analyses.

CONCLUSIONS

The study involving two cohorts showed that pre-HSCT iron overload has a negative impact on transplantation outcomes in SAA patients. Chelating excess iron with a serum ferritin level below 1000 ng/ml was found to be necessary and could potentially improve the outcomes.

Umbilical cord blood transplantation: Still growing and improving

Umbilical cord blood transplantation (UCBT) has been performed in the clinic for over 30 years. The biological and immunological characteristics of umbilical cord blood (UCB) have been re-recognized in recent years. UCB, previously considered medical waste, is rich in hematopoietic stem cells (HSCs), which are naïve and more energetic and more easily expanded than other stem cells. UCB has been identified as a reliable source of HSCs for allogeneic hematopoietic stem cell transplantation (allo-HSCT). UCBT has several advantages over other methods, including no harm to mothers and donors, an off-the-shelf product for urgent use, less stringent HLA match, lower incidence and severity of chronic graft-vs-host disease (GVHD), and probably a stronger graft-vs-leukemia effect, especially for minimal residual disease-positive patients before transplant. Recent studies have shown that the outcome of UCBT has been improved and is comparable to other types of allo-HSCT. Currently, UCBT is widely used in malignant, nonmalignant, hematological, congenital and metabolic diseases. The number of UCB banks and transplantation procedures increased exponentially before 2013. However, the number of UCBTs increased steadily in Asia and China but decreased in the United States and Europe year-on-year from 2013 to 2019. In this review, we focus on the development of UCBT over the past 30 years, the challenges it faces and the strategies for future improvement, including increasing UCB numbers, cord blood unit selection, conditioning regimens and GVHD prophylaxis for UCBT, and management of complications of UCBT.

Poor survival and prediction of prolonged isolated thrombocytopenia post umbilical cord blood transplantation in patients with hematological malignancies

Prolonged isolated thrombocytopenia (PIT) is a common complication after umbilical cord blood transplantation (UCBT). However, data on PIT prediction and impacts on transplantation outcomes for UCBT patients are rare. We retrospectively analyzed 244 patients with hematological malignancies who received single-unit UCBT at the First Affiliated Hospital of USTC between August 2018 and December 2019. Among them, PIT occurred in 49 recipients, with a crude incidence of 20.1%. In the PIT patients, the 2-year cumulative incidence of transplant-related mortality (TRM) was significantly higher, and the probabilities of 2-year overall survival, leukemia-free survival and graft-versus-host disease (GVHD)-free relapse-free survival were significantly poorer (57.1% vs. 88.6%; 53.1% vs. 81.9%; 22.4% vs. 59.8%; p < 0.001), without remarkable increases in the cumulative incidence of relapse or chronic GVHD. Importantly, the multivariate analysis revealed that lower high-resolution HLA compatibility (≤6/10), lower infused CD34⁺ cell count (≤1.78 × 10⁵ /kg), grade II-IV acute GVHD preplatelet engraftment, a lower pretransplantation platelet count (≤100 × 10⁹ /L), and a longer neutrophil engraftment time (≥17 days) were independent risk factors for PIT after UCBT. These results demonstrate that PIT is common after UCBT, predicting inferior survival and the need for more monitoring during the early phase.

[Correlation between immune reconstitution and chronic graft-versus-host disease after unrelated cord blood transplantation and sibling peripheral blood stem cell transplantation]

Objective: To explore the relationship between the reconstitution of immune cells in patients with hematological malignancies and the occurrence of chronic graft-versus-host disease (cGVHD) after treatment with unrelated cord blood transplantation (UCBT) and sibling peripheral blood stem cell transplantation (PBSCT) . Methods: A total of 124 patients undergoing allogenic hematopoietic stem cell transplantation (allo-HSCT) in the First Affiliated Hospital of University of Science and Technology of China from March 2018 to August 2019, including 96 patients with UCBT and 28 patients with PBSCT. Peripheral blood immune cells of patients with UCBT and PBSCT were detected at 1, 3, 6, 9, and 12 months after transplantation using flow cytometry, and both UCBT and PBSCT patients were divided into cGVHD and non-cGVHD groups based on whether cGVHD occurred to explore the correlation between the immune cells reconstitution of the two types of transplantation and cGVHD. Results: ①The cumulative incidence of the moderate to severe cGVHD in the UCBT group was significantly lower than that in the PBSCT group[9.38% (95% CI 3.35%-15.02%) vs 28.57% (95% CI 9.72%-43.50%) , P=0.008]; the 2-year cumulative incidence of cGVHD and moderate to severe cGVHD in the UCBT group was lower than that in the PBSCT group[15.60% (95% CI 9.20%-23.60%) vs 32.10% (95% CI 15.80%-49.70%) , P=0.047; 10.40% (95% CI 5.30%-17.50%) vs 28.60% (95% CI 13.30%-46.00%) , P=0.014]. ②The absolute counts of CD4(+)T cells in the UCBT group were higher than those in the PBSCT group at 6, 9, and 12 months after transplantation[59.00 (36.70-89.65) ×10(7)/L vs 31.40 (18.10-44.00) ×10(7)/L, P<0.001; 71.30 (49.60-101.45) ×10(7)/L vs 41.60 (25.82-56.27) ×10(7)/L, P<0.001; 83.00 (50.17-121.55) ×10(7)/L vs 44.85 (31.62-62.10) ×10(7)/L, P<0.001]; the proportions of CD4(+)T cells in the UCBT group were always higher than those in the PBSCT group (P<0.05) . The absolute counts and proportions of B cells in the PBSCT group were higher than those in the UCBT group at the first month after transplantation[0.70 (0.30-1.70) ×10(7)/L vs 0.10 (0-0.30) ×10(7)/L, P<0.001; 0.45% (0.30%-2.20%) vs 0.20% (0.10%-0.40%) , P=0.002]; the absolute counts and proportions of B cells in the UCBT group were higher than those in the PBSCT group at 9 and 12 months after transplantation[53.80 (28.00-103.20) ×10(7)/L vs 23.35 (5.07-35.00) ×10(7)/L, P<0.001; 21.45 (11.80-30.45) % vs 9.00% (3.08%-16.73%) , P<0.001. 66.70 (36.97-98.72) ×10(7)/L vs 20.85 (7.72-39.40) ×10(7)/L, P<0.001; 22.20% (14.93%-29.68%) vs 8.75% (5.80%-18.93%) , P<0.001]. The absolute counts and proportions of regulatory B (Breg) cells in the UCBT group were higher than those in the PBSCT group at 6, 9, and 12 months after transplantation[1.23 (0.38-3.52) ×10(7)/L vs 0.05 (0-0.84) ×10(7)/L, P<0.001; 5.35% (1.90%-12.20%) vs 1.45% (0-7.78%) , P=0.002. 2.25 (1.07-6.71) ×10(7)/L vs 0.12 (0-0.77) ×10(7)/L, P<0.001; 6.25% (2.00%-12.33%) vs 0.80% (0-5.25%) , P<0.001. 3.69 (0.83-8.66) ×10(7)/L vs 0.46 (0-0.93) ×10(7)/L, P<0.001; 6.15% (1.63%-11.75%) vs 1.40% (0.18%-5.85%) , P<0.001].The absolute counts and proportions of CD3(+)T cells, CD8(+)T cells, and Treg cells in the UCBT group were not significantly different from those in the PBSCT group. ③The absolute counts of B cells in the non-cGVHD group of UCBT patients were higher than those in the moderate to severe cGVHD group at 6 and 12 months after transplantation (P=0.038, P=0.043) ; the proportions of B cells in the non-cGVHD group were higher than those in the moderate to severe cGVHD group at 6 months after transplantation (P=0.049) . The absolute counts of Breg cells in the non-cGVHD group of patients with UCBT were higher than those in the moderate to severe cGVHD group at 6, 9, and 12 months after transplantation (P=0.006, P=0.028, P=0.050) ; the proportions of Breg cells in the non-cGVHD group were higher than those in the moderate to severe cGVHD group at 9 months after transplantation (P=0.038) . ④The absolute counts and proportions of B and Breg cells in the non-cGVHD group of patients with PBSCT were not statistically different than those in the moderate to severe cGVHD group. Conclusion: In the process of immune cell reconstitution, the Breg cells in the UCBT group were higher than those in the PBSCT group, and the Breg cells in the non-cGVHD group of the two types of transplantation were always higher than those in the moderate to severe cGVHD group, indicating that Breg cells can reduce the occurrence of cGVHD, revealing the possible reason for the lower incidence of cGVHD in the UCBT group.

Inflammatory monocytes promote pre-engraftment syndrome and tocilizumab can therapeutically limit pathology in patients

Unrelated cord blood transplantation (UCBT) is an effective treatment for hematopoietic disorders. However, this attractive approach is frequently accompanied by pre-engraftment syndrome (PES), severe cases of PES are associated with enhanced mortality and morbidity, but the pathogenesis of PES remains unclear. Here we show that GM-CSF produced by cord blood-derived inflammatory monocytes drives PES pathology, and that monocytes are the main source of IL-6 during PES. Further, we report the outcome of a single arm, single-center clinical study of tocilizumab in the treatment of steroid-refractory severe PES patients (www.chictr.org.cn ChiCTR1800015472). The study met the primary outcome measure since none of the patients was nonrelapse death during the 100 days follow-up. The study also met key secondary outcomes measures of neutrophil engraftment and hematopoiesis. These findings offer a therapeutic strategy with which to tackle PES and improve nonrelapse mortality.

Pre-engraftment syndrome is a major consideration during clinical application of unrelated cord blood transfusion and monocytes represent a critical cell type in immune-pathogenesis. Here the authors further establish the role of monocytes and GM-CSF in pre-engraftment syndrome and show clinical administration of tocilizumab limits pathology in pre-engraftment syndrome pathology in patients.

Incidence and risk factors of late-onset hemorrhagic cystitis after single umbilical cord blood transplantation with myeloablative conditioning regimen

OBJECTIVE

To explore the incidence and risk factors of late-onset hemorrhagic cystitis (LOHC) in patients undergoing single umbilical cord blood transplantation for hematological malignancies.

METHODS

Clinical data from 234 patients who consecutively underwent single UCBT using a myeloablative conditioning regimen without antithymocyte globulin in our center were retrospectively analyzed.

RESULTS

In total, 64 (27.4%) patients developed LOHC with a median onset time of 40.5 (range 8-154) days, and 15 (6.4%) patients gradually developed grade III-IV LOHC. The incidence of LOHC was marginally higher in adults (31.0%) than in children (23.7%) (p = 0.248). HLA matching ≤ 6/8 (HR = 2.624, 95% CI 1.112-6.191, p = 0.028) was an independent risk factor for LOHC. The overall survival of LOHC patients (59.8%, 95% CI 61.7-85.5%) was significantly lower than that of patients without LOHC (86.8%, 95% CI 79.6-91.6%) at 130 days post transplantation (p = 0.036).

CONCLUSION

Patients with less well-matched grafts have a higher incidence of LOHC. Inherent deficiencies in immunity in the context of HLA disparity and more intense pharmacologic immunosuppression after severe acute graft-versus-host disease may contribute to viral activation. Prevention and treatment of LOHC have the potential to prolong long-term survival.

Protective Effects of Cytomegalovirus DNA Copies ≧1000/mL for AML Patients in Complete Remission After Single Cord Blood Transplantation

Introduction

Current consensus recommends a protective effect of cytomegalovirus (CMV) infection on relapse after peripheral blood or bone marrow hematopoietic stem cell transplantation. However, in cord blood transplantation (CBT), studies of CMV infection, especially CMV viral load, on relapse are limited.

Patients and Methods

Wct e retrospectively analyzed the effect of CMV infection on 3-year outcomes in 249 AML patients according to CMV DNA load (DNA copies <1000/mL and DNA copies ≧1000/mL) within 100 days after CBT. Furthermore, eight-colour flow cytometry was used to detect peripheral blood lymphocyte subsets in 38 patients who received CBT in the last year, and 10 healthy volunteers were included as controls.

Results

The results showed that CMV DNA load did not affect the cumulative incidence of relapse in the whole study population. However, in patients with complete remission status before transplantation, the high CMV DNA load group showed a significantly reduction of relapse than the low CMV DNA load group (3.9% vs 14.6%, p=0.012, respectively), which was confirmed by multivariate analysis (HR 0.23; 95% CI, 0.07–0.73, p = 0.012). Surprisingly, high or low CMV DNA load did not significantly affect non-relapse mortality or overall survival (18.0% vs 17.0%, p=0.777 and 79.0% vs 74.6%, p=0.781, respectively). Besides, the absolute number of CD8⁺ T cells were increased in the high CMV DNA load group compared with the low DNA load group 1 month after CBT (0.20×10⁹/L vs 0.10×10⁹/L, p=0.021, respectively).

Conclusion

DNA copies ≧1000/mL for AML patients in complete remission was associated with a lower incidence of relapse after CBT, which might partly result from the expansion of CMV-related CD8⁺ T cells.

Conditioning regimen with a 75% dose of standard busulfan/cyclophosphamide plus fludarabine before cord blood transplantation in older patients with AML and MDS

In this retrospective study, we aimed to establish a conditioning regimen for older patients receiving cord blood transplantation (CBT). This study included 21 older patients [median age 65 (58-73) years] with acute myeloid leukemia and myelodysplastic syndrome who underwent single CBT following a conditioning regimen comprising fludarabine (FLU) 125-175 mg/m², busulfan (BU) 9.6 mg/kg, and cyclophosphamide (CY) 90 mg/kg. Twelve patients (57.1%) were considered high or very high risk according to the disease risk index. Nineteen achieved neutrophil engraftment at a median of 19 days (range 14-29 days) after CBT (cumulative incidence 90.5%). During a median observation period of 24.3 months, the overall survival (OS) rates at 100 days and 2 years were 76.2% and 47.6%, respectively, with cumulative 2-year relapse and non-relapse mortality (NRM) rates of 19.0% and 38.1%, respectively. Infectious disease was the leading cause of NRM (n = 5) and occurred within 100 day post-transplantation in two patients. This suggested that the administration of a reduced BU/CY plus FLU regimen to older patients receiving CBT enables an early recovery with high neutrophil engraftment, relapse suppression, and acceptable NRM rates.

[Comparison of umbilical cord blood transplantation and hematopoietic stem cell transplantation from HLA-matched sibling donors in the treatment of myelodysplastic syndrome-EB or acute myeloid leukemia with myelodysplasia-related changes]

目的

比较非血缘脐血干细胞移植（UCBT）与同胞HLA全相合供者造血干细胞移植（MSD-HSCT）治疗骨髓增生异常综合征伴原始细胞增多（MDS-EB）和急性髓系白血病伴骨髓增生异常相关改变（AML-MRC）的临床疗效。

方法

回顾性分析2011年2月至2017年12月接受UCBT/MSD-HSCT的MDS-EB/AML-MRC患者64例，其中MDS-EB 38例，AML-MRC 26例。

结果

①与MSD-HSCT组比较，UCBT组AML-MRC患者比例较高[52.8%（19/36）对25.0%（7/28），P=0.025]，中位年龄较低[13（1.5~52）岁对32（10~57）岁，P=0.001]。②UCBT组与MSD-HSCT组+42 d粒细胞植入率均为100%，中位植入时间分别为17.5（11~31）d、11.5（10~20）d；UCBT组+100 d血小板植入率为91.4%，中位植入时间为40（15~96）d，MSD-HSCT组+100 d血小板植入率为100.0%，中位植入时间为15（11~43）d。③UCBT组和MSD-HSCT组比较，+100 dⅡ~Ⅳ度、Ⅲ/Ⅳ度急性GVHD累积发生率、180 d移植相关死亡率、3年累积复发率、3年总生存率和3年无病生存率差异均无统计学意义（P>0.05）。④UCBT组3年慢性GVHD、重度慢性GVHD的累积发生率均低于MSD-HSCT组[28.3%（95% CI 13.4%~45.3%）对67.9%（95%CI 46.1%~82.4%），P=0.002；10.3%（95%CI 2.5%~24.8%）对50.0%（95%CI 30.0%~67.1%），P<0.001]；UCBT组3年无严重急慢性GVHD及无复发生存（GRFS）率明显高于MSD-HSCT组[55.0%（95%CI 36.0%~70.6%）对28.6%（95%CI 13.5%~45.6%），P=0.038]。

结论

UCBT治疗MDS-EB/AML-MRC患者可获得比MSD-HSCT更好的移植后生存质量。