Umbilical cord blood transplantation and unmanipulated haploidentical hematopoietic SCT for pediatric hematologic malignances

Prior cytomegalovirus reactivation may lead to worse bacterial bloodstream infection outcomes in HSCT patients

BACKGROUND

Cytomegalovirus (CMV) reactivation is common after transplantation, and may further augment natural killer (NK) cell activity, which has a protective role through both innate and adaptive immune responses. Bacterial bloodstream infections (BBSIs) are a common cause of morbidity and mortality in patients following allo-HSCT. Therefore, we hypothesized that CMV reactivation might play a role in the outcomes of patients with BBSI after allo-HSCT.

OBJECTIVES

We investigated the role of CMV reactivation in the clinical outcomes of patients with BBSI after allo-HSCT.

STUDY DESIGN

A total of 101 BBSI patients (45 non-CMV reactivation [NCR] and 56 CMV reactivation [CR]) were included in the study following allo-HSCT. Clinical and laboratory findings were reviewed, and differences were tested using the Chi-square (χ2) test. Multivariate Cox regression analysis was used to calculate hazard ratios for between-group comparisons of clinical outcomes.

RESULTS

CMV reactivation had a negative prognostic impact on the clinical outcomes of BBSI patients following allo-HSCT with regard to the 1-year overall survival time (HR, 3.583; 95% CI, 1.347-9.533; P = 0.011). In 56 BBSI patients with CMV reactivation following allo-HSCT, the 1-year mortality among those in whom CMV was reactivated first (CRF) was significantly elevated (56.5% vs. 18.2%, P = 0.003) compared with patients in whom the BBSIs occurred first (BOF).

CONCLUSIONS

CMV reactivation in BBSI patients is related to higher mortality 1-year after allo-HSCT. Further studies on a larger cohort are needed to better understanding the mechanism of CMV reactivation influence.

Epidemiology, treatment patterns, and disease burden of cytomegalovirus in hematopoietic cell transplant recipients in selected countries outside of Europe and North America: A systematic review

BACKGROUND

Cytomegalovirus (CMV) disease impacts morbidity and mortality in hematopoietic cell transplant (HCT) recipients. This systematic review summarized data on the epidemiology, management, and burden of CMV post-HCT outside of Europe and North America.

METHODS

The MEDLINE, Embase, and Cochrane databases were searched for observational studies and treatment guidelines in HCT recipients across 15 selected countries from Asia-Pacific, Latin America, and Middle East (search period: 1 January 2011-17 September 2021). Outcomes included incidence of CMV infection/disease, recurrence, risk factors, CMV-related mortality, treatments, refractory, resistant CMV, and burden.

RESULTS

Of 2708 references identified, 68 were eligible (67 studies and one guideline; 45/67 studies specific to adult allogeneic HCT recipients). The rates of CMV infection and disease within 1 year of allogeneic HCT were 24.9%-61.2% (23 studies) and 2.9%-15.7% (10 studies), respectively. Recurrence occurred in 19.8%-37.9% of cases (11 studies). Up to 10% of HCT recipients died of CMV-related causes. In all countries, first-line treatment for CMV infection/disease involved intravenous ganciclovir or valganciclovir. Conventional treatments were associated with serious adverse events such as myelosuppression (10.0%) or neutropenia only (30.0%, 39.8%) and nephrotoxicity (11.0%) (three studies), frequently leading to treatment discontinuation (up to 13.6%). Refractory CMV was reported in 2.9%, 13.0%, and 28.9% of treated patients (three studies) with resistant CMV diagnosed in 0%-10% of recipients (five studies). Patient-reported outcomes and economic data were scarce.

CONCLUSION

The incidence of CMV infection and disease post-HCT is high outside of North America and Europe. CMV resistance and toxicity highlight a major unmet need with current conventional treatments.

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

BACKGROUND

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

RESULTS

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

CONCLUSIONS

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

Adult and Cord Blood-Derived High-Affinity gB-CAR-T Cells Effectively React Against Human Cytomegalovirus Infections

Human cytomegalovirus (HCMV) reactivations are associated with lower overall survival after transplantations. Adoptive transfer of HCMV-reactive expanded or selected T cells can be applied as a compassionate use, but requires that the human leukocyte antigen-matched donor provides memory cells against HCMV. To overcome this, we developed engineered T cells expressing chimeric antigen receptors (CARs) targeted against the HCMV glycoprotein B (gB) expressed upon viral reactivation. Single-chain variable fragments (scFvs) derived from a human high-affinity gB-specific neutralizing monoclonal antibody (SM5-1) were fused to CARs with 4-1BB (BBL) or CD28 (28S) costimulatory domains and subcloned into retroviral vectors. CD4⁺ and CD8⁺ T cells obtained from HCMV-seronegative adult blood or cord blood (CB) transduced with the vectors efficiently expressed the gB-CARs. The specificity and potency of gB-CAR-T cells were demonstrated and compared in vitro using the following: 293T cells expressing gB, and with mesenchymal stem cells infected with a HCMV TB40 strain expressing Gaussia luciferase (HCMV/GLuc). BBL-gB-CAR-T cells generated with adult or CB demonstrated significantly higher in vitro activation and cytotoxicity performance than 28-gB-CAR-T cells. Nod.Rag.Gamma (NRG) mice transplanted with human CB CD34⁺ cells with long-term human immune reconstitution were used to model HCMV/GLuc infection in vivo by optical imaging analyses. One week after administration, response to BBL-gB-CAR-T cell therapy was observed for 5/8 mice, defined by significant reduction of the bioluminescent signal in relation to untreated controls. Response to therapy was sporadically associated with CAR detection in spleen. Thus, exploring scFv derived from the high-affinity gB-antibody SM5-1 and the 4-1BB signaling domain for CAR design enabled an in vitro high on-target effect and cytotoxicity and encouraging results in vivo. Therefore, gB-CAR-T cells can be a future clinical option for treatment of HCMV reactivations, particularly when memory T cells from the donors are not available.

Predictive impact of residual disease detected using multiparametric flow cytometry on risk stratification of paediatric acute myeloid leukaemia with normal karyotype

INTRODUCTION

Residual disease (RD) detected using multiparametric flow cytometry (MFC) is an independent predictive variable of relapse in acute myeloid leukaemia (AML). However, RD thresholds and optimal assessment time points remain to be validated.

MATERIAL AND METHODS

We investigated the significance of RD after induction therapy in paediatric AML with normal karyotype between June 2008 and June 2018. Bone marrow samples from 73 patients were collected at the end of the first (BMA-1) and second (BMA-2) induction courses to monitor RD using MFC.

RESULTS

Presence of RD after BMA-1 and/or BMA-2 correlated with poor relapse-free (RFS) and overall survival at 0.1% RD cutoff level. Receiver operating characteristic curve showed that RD cutoff levels of 1.3% and 0.5% after BMA-1 and BMA-2, respectively, predicted events with the highest sensitivity and specificity. In multivariable analysis, RD after BMA-2 was the strongest independent risk predictor for poor RFS (hazard ratio 2.934; 95% confidence interval: 1.106-7.782; P = .031).

CONCLUSIONS

Our study therefore suggests that an RD level ≥0.5% after BMA-2 has a significant predictive impact on the prognosis of AML patients having normal karyotype and thus guide the stratification of treatment strategies.

Unmanipulated haploidentical hematopoietic stem cell transplantation is an excellent option for children and young adult relapsed/refractory Philadelphia chromosome-negative B-cell acute lymphoblastic leukemia after CAR-T-cell therapy

Although chimeric antigen receptor T-cell (CAR-T) therapy produces a high complete remission rate among patients with relapsed/refractory B-cell acute lymphoblastic leukemia, relapse remains an urgent issue. It is uncertain whether consolidative haploidentical-allogeneic hematopoietic stem cell transplantation (haplo-HSCT) is suitable for achieving sustainable remission. Therefore, we aimed to assess the efficacy and safety of bridging CAR-T therapy to haplo-HSCT. Fifty-two patients with relapsed/refractory Philadelphia chromosome-negative B-cell acute lymphoblastic leukemia who underwent haplo-HSCT after CAR-T therapy were analyzed. The median time from CAR-T therapy to haplo-HSCT was 61 days. After a median follow-up of 24.6 months, the 1-year probabilities of event-free survival, overall survival, and cumulative incidence of relapse were 80.1% (95% confidence interval (CI), 69.0-90.9), 92.3% (95% CI, 85.0-99.5), and 14.1% (95% CI, 10.7-17.4), respectively, while the corresponding 2-year probabilities were 76.0% (95% CI, 64.2-87.7), 84.3% (95% CI, 74.3-94.3), and 19.7% (95% CI, 15.3-24.0), respectively. No increased risk of 2-year cumulative incidence of graft-versus-host disease, treatment-related mortality, or infection was observed. A pre-HSCT measurable residual disease-positive status was an independent factor associated with poor overall survival (hazard radio: 4.201, 95% CI: 1.034-17.063; P = 0.045). Haplo-HSCT may be a safe and effective treatment strategy to improve event-free survival and overall survival after CAR-T therapy.

Wilms' tumor gene 1 is an independent prognostic factor for pediatric acute myeloid leukemia following allogeneic hematopoietic stem cell transplantation

BACKGROUND

Sequential monitoring of Wilms' tumor gene 1 (WT1) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) could predict relapse in adult acute myeloid leukemia (AML). However, the prognostic role of WT1 in pediatric AML after allo-HSCT is unclear. Thus, we determined to see whether sequential monitoring of WT1 after allo-HSCT could predict relapse in AML children.

METHODS

Pediatric AML patients receiving allo-HSCT from January 21, 2012 to December 20, 2018 at the Peking University Institute of Hematology were included in this study. WT1 expression level was determined by TaqMan-based reverse transcription-polymerase chain reaction. WT1 sequential monitoring was performed 1, 2, 3, 4.5, 6, 9, and 12 months post-transplantation and at 6-month intervals thereafter. The primary end point was relapse. The secondary end points included disease-free survival (DFS), overall survival (OS), and non-relapse mortality (NRM). Kaplan-Meier analysis was used for DFS and OS estimates, while competing risk analysis was used for estimating relapse and NRM.

RESULTS

Of the 151 consecutive patients included, the median age was 10 years (range, 1-17). The optimal cutoff value of WT1 within 1 year after allo-HSCT to predict relapse was 0.8% (80 WT1 copies/104 ABL copies), with a sensitivity of 60% and specificity of 79%. Compared with WT1 expression < 0.8%, WT1 expression ≥0.8% indicated significantly higher 5-year cumulative incidence of relapse (CIR, 35.1% vs. 11.3%; P = 0.001), lower 5-year disease-free survival (DFS, 60.4% vs. 80.8%; P = 0.009), and lower 5-year overall survival (OS, 64.9% vs. 81.6%; P = 0.038) rates. Multivariate analyses showed that WT1 was an independent risk factor for relapse (HR 2.89; 95% confidence interval (CI), 1.25-6.71; P = 0.014). Both the CIR (5-year CIR: 8.3% vs. 11.3%; P = 0.513) and DFS (5-year DFS: 91.7% vs. 80.8%; P = 0.208) were comparable between patients achieving minimal residual disease (MRD) negativity after preemptive interferon-α (IFN-α) treatment and those without MRD after allo-HSCT, which were better than those of MRD-positive patients without preemptive therapies.

CONCLUSIONS

Sequential monitoring of WT1 could predict relapse in pediatric AML after allo-HSCT. WT1-directed immunotherapy may have the potential to prevent relapse and improve survival.

The incidence, risk factors, and outcomes of acute graft-vs-host disease in pediatric T-cell-replete haploidentical hematopoietic stem cell transplantation

The specific description, risk factors, and outcomes of aGVHD in pediatric haplo-HSCT using TCR protocols without PT-Cy have not been well described previously. We evaluated the incidence, risk factors, and outcomes of aGVHD in 350 consecutive pediatric patients receiving TCR haplo-HSCT without PT-Cy according to the Glucksberg and NIH aGVHD classifications between January 2015 and December 2017 at Peking University Institute of Hematology. The cumulative incidences of grade I, II, III, and IV aGVHD were 28%, 29.7%, 8.3%, and 5.1%, respectively. The type of aGVHD onset was classic in 243 patients (97.2%), and persistent/recurrent/late-onset aGVHD was in seven patients (2.8%). None of the considered variables significantly influenced the incidence of grade III-IV aGVHD. The 3-year OS, DFS, cumulative incidence of NRM, and relapse in malignant disease between severe aGVHD (III-IV) group and grade 0-II aGVHD group were 61.5% vs 77.2% (P = .027), 58.6% vs 75.1% (P = .014), 19.8% vs 5.3% (P = .002), and 21.6% vs 19.6% (P = .59), respectively; in non-malignant diseases, the 3-year OS, DFS, and NRM were 81.8% vs 97.4% (P = .05), 81.8% vs 97.4% (P = .05), and 18.2% vs 2.6% (P = .05), respectively. Under the protocol of pediatric TCR haplo-HSCT without PT-Cy, the persistent/recurrent/late-onset aGVHD was rare, and the incidence of severe aGVHD was acceptable and significantly contributed to NRM and lower survival in both malignant disease and non-malignant diseases.

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.

Incidence, Risk Factors, and Outcomes of Chronic Graft-versus-Host Disease in Pediatric Patients with Hematologic Malignancies after T Cell-Replete Myeloablative Haploidentical Hematopoietic Stem Cell Transplantation with Antithymocyte Globulin/Granulocyte Colony-Stimulating Factor

The specific description, risk factors, and outcomes of chronic graft-versus-host disease (cGVHD) in pediatric patients with hematologic malignancies after T cell-replete (TCR) myeloablative haploidentical hematopoietic stem cell transplantation (haplo-HSCT) with antithymocyte globulin (ATG)/granulocyte colony-stimulating factor (G-CSF) have not been previously well described. We retrospectively analyzed the incidence, risk factors, and outcomes of cGVHD documented according to the 2014 National Institutes of Health consensus criteria (NIH-CC) in 292 consecutive pediatric patients with hematologic malignancies after TCR myeloablative haplo-HSCT with ATG/G-CSF between January 2015 and December 2017. A total of 170 patients experienced cGVHD. The 3-year cumulative incidence of total cGVHD and mild, moderate, and severe cGVHD was 57.9%, 27.5%, 18.8%, and 11.9%, respectively. Multivariate analysis showed that acute GVHD (aGVHD) grade II-IV (hazard ratio, 1.578; P = .002) was an independent risk factor for cGVHD. Compared to patients without cGVHD, patients with cGVHD demonstrated a lower 3-year relapse (17.6% versus 27.2%; P = .009), a similar 3-year nonrelapse mortality (NRM) (5.9% versus 5.4%; P = .79), and better 3-year disease-free survival (DFS) (77.8% versus 66.9%; P = .007) and overall survival (OS) (81.3% versus 68.6%; P = .001), particularly those with mild or moderate cGVHD; however, no significant impact of severe cGVHD on relapse, NRM, DFS, or OS was seen. In conclusion, the incidence of severe cGVHD in pediatric patients with hematologic malignancies after TCR myeloablative haplo-HSCT with ATG/G-CSF was acceptable. Previous aGVHD grade II-IV was a risk factor for the occurrence of cGVHD. Only mild or moderate cGVHD was associated with a lower risk of relapse, translating into improved DFS and OS in pediatric patients with hematologic malignancies after TCR myeloablative haplo-HSCT with ATG/G-CSF.

Haploidentical- versus identical-sibling transplant for high-risk pediatric AML: A multi-center study

Background

Human leukocyte antigen‐identical sibling donor (ISD)‐hematopoietic stem cell transplantation (SCT) is a potentially curative treatment for high‐risk pediatric acute myeloid leukemia (AML). A haploidentical donor (HID) is readily available to almost all children. Previous studies have demonstrated that patients with HID‐SCT had similar outcomes compared to ISD‐SCT for pediatric and adult AML. However, the role of HID‐SCT in high‐risk pediatric AML is unclear.

Methods

To compare the overall survival of high‐risk AML children who underwent either HID‐SCT or ISD‐SCT, we analyzed 179 cases of high‐risk AML patients under 18 years of age treated with either ISD‐SCT (n = 23) or HID‐SCT (n = 156). Granulocyte colony‐stimulating factor plus anti‐thymocyte globulin‐based regimens were used for HID‐SCT. We also analyzed the subgroup data of AML patients at first complete remission (CR1) before SCT with known cytogenetic risk.

Results

The numbers of adverse cytogenetic risk recipients were 8 (34.8%) and 13 (18.8%) in the ISD‐SCT group and the HID‐SCT group, and the number of patients with disease status beyond CR1 were 6 (26.1%) and 14 (20.3%) in the two groups. The cumulative rates of grades II‐IV acute graft‐versus‐host disease (GVHD) were 13.0% in the ISD‐SCT group and 34.8% in the HID‐SCT group (P = 0.062), with a three‐year cumulative rates of chronic GVHD at 14.1% and 34.9%, respectively (P = 0.091). The relapse rate in the ISD‐SCT group was significantly higher than that in the HID‐SCT group (39.1% vs. 16.4%, P = 0.027); with non‐relapse mortality at 0.0% and 10.6% (P = 0.113), respectively. The three‐year overall survival rates were 73.0% for the ISD‐SCT group and 74.6% for the HID‐SCT group (P = 0.689). In subgroup analysis, the three‐year relapse rate in the ISD‐SCT group was higher than that in the HID‐SCT group (50.0% vs. 9.2%, P = 0.001) and the three‐year DFS in the ISD‐SCT group (50.0%) was lower than that in the HID‐SCT group (81.2%) (P = 0.021).

Conclusions

Unmanipulated HID‐SCT achieved DFS and OS outcomes comparable to those of ISD‐SCT for high‐risk pediatric AML patients with potentially higher rate but manageable GVHD.

Hematopoietic stem cell transplantation with unrelated cord blood or haploidentical donor grafts in adult patients with secondary acute myeloid leukemia, a comparative study from Eurocord and the ALWP EBMT

Survival of patients with secondary acute myeloid leukemia (sAML) is poor. Cord blood transplantation (UCBT) and non-T-cell-depleted stem cell transplantation from haploidentical donors (HAPLO) are both strategies that have shown encouraging results in patients who do not have an human leukocyte antigen (HLA)-matched sibling or unrelated donor. We retrospectively analyzed outcomes of 409 adults with sAML receiving either UCBT (n = 163) or HAPLO (n = 246) in EBMT centers. Myelodysplastic syndrome (MDS) or myeloproliferative disorder (MPD) was the antecedent diagnosis in 79% of UCBT and 85% of HAPLO recipients. In multivariate analysis, UCBT was associated with higher risk of grade II-IV acute GVHD (HR 1.9, p = 0.009) and lower GHVD-free-relapse-free-survival (GRFS) (HR 1.57, p = 0.007) compared to HAPLO. Chronic-GVHD, RI, NRM, LFS, and OS were not statistically different between the two. Early disease stage at transplant was independently associated with lower RI and NRM and higher OS and LFS. These results indicate that HAPLO is associated with better GRFS and lower aGvHD compared to UCBT in patients with sAML and that UCBT can be a valid alternative for sAML patients who lack a matched sibling, a proper haploidentical or an unrelated donor.

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.

Association between C-reactive protein levels in the first 1-3 days post-transplant and allogeneic immune reactions

AIM

The purpose of this study was to determine whether C-reactive protein (CRP) in the first 1-3 days post-transplant could predict allogeneic immune reactions, including engraftment syndrome or acute graft-versus-host disease (GVHD), in pediatric haploidentical stem cell transplantation.

PATIENTS & METHODS

The study population comprised 175 consecutive pediatric patients. Receiver operating characteristic analysis was performed to identify the cut-off CRP value.

RESULTS

The high-CRP group (≥20.1 mg/l) was associated with an increased occurrence of engraftment syndrome (hazard ratio [HR] = 2.046; p = 0.008), II-IV acute GVHD (HR = 2.203; p = 0.001) and severe GVHD (HR = 6.371; p = 0.004).

CONCLUSION

Our data suggest that higher CRP during the first 1-3 days post-transplant could be a predictor of allogeneic immune reactions.

Higher dose of CD34+ peripheral blood stem cells is associated with better survival after haploidentical stem cell transplantation in pediatric patients

Haploidentical stem cell transplantation (SCT) is increasingly used to treat pediatric patients with malignant or nonmalignant hematological disorders. The CD34+ dose of bone marrow or peripheral blood stem cells (PBSCs) has been shown to be an important determinant of the transplant outcome in adults under various preparative regimens. However, knowledge of the effect of the CD34+ dose in pediatric haploidentical SCT is limited. We analyzed the data of 348 pediatric patients (aged 2-18 years) with acute or chronic leukemia, myelodysplastic syndrome (MDS), and other hematological disorders that received a transplant between 2002 and 2012. The results of multivariate analysis showed that PBSC CD34+ counts greater than 1.01 × 10⁶  kg^-1 improved platelet engraftment, improved overall survival, and reduced nonrelapse mortality. In contrast, a higher PBSC CD34+ dose did not affect the incidence of acute or chronic graft-versus-host disease, including engraftment syndrome. These data suggest that a PBSC CD34+ dose greater than 1.01 × 10⁶  kg^-1 is optimal for pediatric haploidentical SCT.

Improved clinical outcomes of rhG-CSF-mobilized blood and marrow haploidentical transplantation compared to propensity score-matched rhG-CSF-primed peripheral blood stem cell haploidentical transplantation: a multicenter study

The effects of haploidentical rhG-CSF-mobilized blood and marrow transplantation (HBMT) on hematological malignances are well established. Previous prospective single-center studies have demonstrated better survival after HBMT versus haploidentical rhG-CSF-mobilized peripheral blood stem cell transplantation (HPBSCT) for acute leukemia (AL) not in remission (NR) or in more than the second complete remission (>CR2). To test the hypothesis that HBMT is still superior to HPBSCT for patients with AL, multiple myeloma (MM), or non-Hodgkin lymphoma (NHL) in CR1/CR2 and for patients with chronic myeloid leukemia in the first and second chronic phase lacking a matched donor, we designed a propensity score method-based multicenter study. Hematopoietic recovery, acute graft-versus-host disease (aGVHD), and chronic GVHD were comparable between the HBMT group (n=168) and the HPBSCT group (n=42). No significant differences were found in non-relapse mortality rate (20.17%±3.58% and 27.24%±7.16%, P=0.18) or relapse rate (19.96%±3.72% and 28.49%±8.25%, P=0.32) between the HBMT group and the HPBSCT group. HBMT recipients had better overall survival (65.0%±4.2% and 54.2%±8.3%, P=0.037) and disease-free survival (59.9%±4.6% and 44.3%±8.7%, P=0.051). Multivariate analysis showed that HPBSCT was associated with poorer DFS (HR (95%CI), 1.639 (0.995-2.699), P=0.052). Our comparisons showed that HBMT was superior to HPBSCT as a post-remission treatment for patients lacking an identical donor.

Comparison of outcomes after umbilical cord blood and unmanipulated haploidentical hematopoietic stem cell transplantation in children with high-risk acute lymphoblastic leukemia

Allogeneic hematopoietic stem cell transplantation (HSCT) is an effective therapy for children with high-risk acute lymphoblastic leukemia (ALL). Human leukocyte antigen (HLA)-haploidentical HSCT (haplo-HSCT) or umbilical cord blood transplantation (UCBT) are both important alternative sources of stem cells for those without an HLA-identical sibling donor or unrelated matched donor. We aimed to compare the therapeutic effects of single UCBT and unmanipulated haplo-HSCT in high-risk ALL children (n = 129). Hematopoietic recovery was significantly faster in haplo-HSCT recipients than in UCBT recipients. The 2-year cumulative incidences of relapse in the haplo-HSCT and UCBT groups were 16.1% and 24.1%, respectively (p = 0.169). The 2-year cumulative incidences of non-relapse mortality in the haplo-HSCT and UCBT groups were 12.8% and 18.8%, respectively (p = 0.277). The 2-year probabilities of overall survival in the haplo-HSCT and UCBT groups were 82.0% and 69.6%, respectively (p = 0.071), and the 2-year probability of disease-free survival in the haplo-HSCT group was higher than in the UCBT group (71.0% vs. 57.2%, p = 0.040). However, several variables (such as leukocyte count and cytogenetics at diagnosis) were different between the groups, and a possible center effect should also be considered. In addition, only mild and moderate chronic graft-versus-host disease (GVHD) was associated with significantly improved survival compared to those without chronic GVHD in multivariate analysis. Thus, our results show that both unmanipulated haplo-HSCT and UCBT are valid for high-risk ALL children lacking a HLA matched donor, and both strategies expand the donor pool for children in need.

How do we choose the best donor for T-cell-replete, HLA-haploidentical transplantation?

In haploidentical stem cell transplantations (haplo-SCT), nearly all patients have more than one donor. A key issue in the haplo-SCT setting is the search for the best donor, because donor selection can significantly impact the incidences of acute and chronic graft-versus-host disease, transplant-related mortality, and relapse, in addition to overall survival. In this review, we focused on factors associated with transplant outcomes following unmanipulated haplo-SCT with anti-thymocyte globulin (ATG) or after T-cell-replete haplo-SCT with post-transplantation cyclophosphamide (PT/Cy). We summarized the effects of the primary factors, including donor-specific antibodies against human leukocyte antigens (HLA); donor age and gender; killer immunoglobulin-like receptor-ligand mismatches; and non-inherited maternal antigen mismatches. We also offered some expert recommendations and proposed an algorithm for selecting donors for unmanipulated haplo-SCT with ATG and for T-cell-replete haplo-SCT with PT/Cy.

Infusion-related febrile reaction after haploidentical stem cell transplantation in children is associated with higher rates of engraftment syndrome and acute graft-versus-host disease

The clinical significance and prognostic impact of IRFR in pediatric recipients of haploidentical SCT are not clearly understood. Therefore, we attempted to determine how IRFR affects clinical outcomes in children. Clinical data from 100 consecutive pediatric patients (60 boys and 40 girls; median age, 12 yr [range, 2-18 yr] after haploidentical SCT between January 2010 and December 2012 were collected retrospectively. IRFR was described as unexplained fever (>38 °C) within 24 h after the infusion of haploidentical PBSCs. Thirty-eight (38.0%) cases met the criteria for IRFR. ES was found in 24 (63.2%) of the 38 children with IRFR, with the median time of developing ES of +9 (7-16) days, while only 15 (25.4%) of the 59 children without IRFR were found with ES (p < 0.001). Similarly, the cumulative incidence rates of grade II-IV aGVHD were 50.0% in the IRFR group and 29.3% (p = 0.012) in the non-febrile group. Multivariate analysis identified IRFR as the risk factor for ES and aGVHD. In the haploidentical setting, IRFR is associated with the development of ES and aGVHD. We attempted to determine how IRFR affects clinical outcomes in children after haploidentical SCT. Thirty-eight children comprised the IRFR group, and 59 were in the control (non-IRFR) group. High incidence of ES was observed in children with the occurrence of IRFR. Similarly, the incidence of stage I-IV and II-IV aGVHD was significantly higher in the febrile group. Multivariate analysis showed IRFR to be the risk factor for ES and aGVHD.

Fighting against hematological malignancy in China: from unique system to global impact

During recent decades, substantial progress has been made in clinical strategies for treating hematological malignancies. Not only did China benefit from the global progression in the management of acute promyelocytic leukemia, risk-stratification-directed strategies for acute or chronic leukemia and haploidentical hematopoietic stem cell transplantation, the unique system developed by Chinese doctors has also become inspiration for refining global clinical practice. The multicenter trials and collaborations adhering to international standards might further strengthen the global impact and lead the way in specific fields of research worldwide.

Hematopoietic cell transplantation and cellular therapeutics in the treatment of childhood malignancies

Hematopoietic cell transplantation (HCT) represents the most common and effective form of immunotherapy for childhood malignancies. The role of the graft-versus-leukemia effect in allogeneic HCT has been well established in childhood malignancies, but is also associated with short-term and long-term morbidity. HCT may be ineffective in some settings at obtaining control of the malignancy, and as such, cannot be used as a universal cancer immunotherapy. Novel therapies using dendritic cell vaccinations, tumor-infiltrating lymphocytes, and chimeric antigen receptor T cells are being evaluated as potential adjuvants to HCT.