Haploidentical hematopoietic stem cell transplantation as promising therapy in the improved survival of pediatric patients with leukemias and myelodysplasias

BACKGROUND Haploidentical hematopoietic stem cell transplantation(Haplo-HSCT)is often performed in children with hematologic malignancies.Faced with the gap in the literature regarding the approach to experiences related to Haplo-HSCT with pediatric patients with leukemias and myelodysplasias aged up to 18 years,there was an interest in exploring the clinical outcomes of patients undergoing this treatment.AIM To identify and summarize the scientific contributions available on Haplo-HSCT performed in the last 10 years in children and adolescents with myeloid and lymphoid leukemias and myelodysplasias,aged up to 18 years.METHODS This is a descriptive systematic review.We extracted data including characteristics of participants,health condition,characteristics of the donation,conditioning regimen,recurrent clinical complications and clinical outcomes.The Virtual Health Library Brazil,PubMed,EMBASE,and SciELO platforms were used,finding a total of 1052 studies.After the eligibility criteria and complete reading of the texts,18 articles were included for analysis.RESULTS The total sample of all study cohorts was 1825 patients,mostly male,the highest reported median age was 15.0 years and the lowest was 1.2 years.Acute graftversus-host disease and chronic graft-versus-host disease were observed in almost all studies.Relapse,graft rejection and delayed immune recovery were identified as major clinical challenges.Pre-transplant minimal positive residual disease was identified in 288 patients.Infections are also among the main clinical complications,viral,bacterial and fungal infections being reported.It is observed that in the 5-year interval,the lowest rates of EFS and overall survival(OS)were 29.5%and 68.0%,respectively.While,the highest rates of EFS and OS,in the same interval,were 80.1%and 81.0%.CONCLUSION Haplo-HSCT represents a promising therapy,considering the potential number of possible donors and the conditioning and treatment platforms that can be offered.The results obtained show that this type of transplant has a strong antileukemic effect,with generally favorable OS rates.Overcoming relapse as the first cause of transplant failure is the great clinical challenge.

Overview of the progress on haploidentical hematopoietic transplantation

Allogeneic hematopoietic stem cell transplant(HSCT) remains the only potentially curative option for variety of hematologic disorders. Lack of a suitable fully HLAmatched donor limits this option for many patients. Without a suitable related or unrelated HLA-matched donor,umbilical cord blood and haploidentical family members provide a potential source of stem cells. Timely donor availability makes haploidentical donors an attractive alternative donor source. Initial attempts at haploidentical HSCT was associated with significantly increased mortality owing to high rates of graft rejection and severe graftversus-host disease caused by major donor-recipient HLAdisparity. However, over the past decade, outcomes of haploidentical HSCT have improved significantly. Here, we review the advantages and challenges of haploidentical transplantation. We also discuss new developments to attempt to overcome the challenges to a successful haploidentical transplantation.

Disease Risk Comorbidity Index for Patients Receiving Haploidentical Allogeneic Hematopoietic Transplantation

We aimed to develop a disease risk comorbidity index(DRCI)based on disease risk index(DRI)and Hematopoietic Cell Transplantation-Specific Comorbidity Index(HCT-CI)in patients receiving haploidentical hematopoietic stem cell transplantation(haplo-HSCT).We identified the prognostic factors of disease-free survival(DFS)in a training subset(n=593),then assigned a weighted score using these factors to the remaining patients(validation subset;n=296).The multivariable model identified two independent predictors of DFS:DRI and HCT-CI before transplantation.In this scoring system,we assigned a weighted score of 2 to very high-risk DRI,and assigned a weighted score of 1 to high-risk DRI and intermediate-and high-risk HCT-CI(i.e.,haplo-DRCI).In the validation cohort,the three-year DFS rate was 65.2%(95%confidence interval(CI),58.2%–72.2%),55.8%(95%CI,44.9%–66.7%),and 32.0%(95%CI,5.8%–58.2%)for the low-,intermediate-,and high-risk group,respectively(P=0.005).Haplo-DRCI can also predict DFS in disease-specific subgroups,particularly in acute leukemia patients.Increasing score was also significantly predictive of increased relapse,increased non-relapse mortality(NRM),decreased DFS,and decreased overall survival(OS)in an independent historical cohort(n=526).These data confirmed that haplo-DRCI could effectively risk stratify haplo-HSCT recipients and provide a tool to better predict who will best benefit from haplo-HSCT.

Hematopoiesis reconstitution and anti-tumor effectiveness of Pai-Neng-Da capsule in acute leukemia patients with haploidentical hematopoietic stem cell transplantation

BACKGROUND With the rapid development of haploidentical hematopoietic stem cell transplantation(haplo-HSCT),primary poor graft function(PGF)has become a lifethreatening complication.Effective therapies for PGF are inconclusive.New Chinese patent medicine Pai-Neng-Da(PND)Capsule exerts dual effect in promoting hematopoiesis recovery and regulating immunity.Still,the application of PND capsule in hematopoietic stem cell transplantation,especially in the haplo-HSCT setting,has not yet been reported.AIM To evaluate the role of PND capsule in acute leukemia patients with haplo-HSCT.METHODS We retrospectively collected data of acute leukemia patients who underwent haplo-HSCT at the Affiliated People’s Hospital of Ningbo University between April 1,2015 and June 30,2020.Twenty-nine consecutive patients received oral PND capsule from the sixth day to the first month after haplo-HSCT were included in the PND group.In addition,31 patients who did not receive PND capsule during haplo-HSCT were included in the non-PND group.Subsequently,we compared the therapeutic efficacy according to the western medical evaluation indexes and Chinese medical symptom scores,and the survival between the PND group and the non-PND group,using the chi-square test,Fisher’s exact test,and the Kaplan-Meier method.RESULTS The duration of platelet engraftment was shorter in the PND group than in the non-PND group(P=0.039).The PND group received a lower frequency of red blood cells and platelet transfusions than the non-PND group(P=0.033 and P=0.035,respectively).In addition,PND capsule marginally reduced the rate of PGF(P=0.027)and relapse(P=0.043).After 33(range,4-106)months of follow-up,the 3-year relapse-free survival(P=0.046)and progression-free survival(P=0.049)were improved in the PND group than in the non-PND group.Also,the therapeutic efficacy of the PND group according to Chinese medical symptom scores was significantly better than that of the non-PND group(P=0.022).Moreover,the adverse events caused by PND capsule were mild.Nevertheless,there were no significant differences in the duration of neutrophil engraftment,the risk of infection within 100 days after haplo-HSCT,the acute graft-versus-host disease,or the 3-year overall survival between the two groups.CONCLUSION PND capsule could promote hematopoiesis reconstitution,improve the therapeutic efficacy of Chinese medical symptom scores,present anti-tumor effectiveness,and prolong the survival of acute leukemia patients with haplo-HSCT.

Haploidentical Allogeneic Hematopoietic Stem Cell Transplantation for Thymoma-associated Severe Aplastic Anemia: a Case Report

THYMOMA, a relatively rare epithelial neoplasm with unique clinical and pathologic features, is the most usual diagnosis for a mass located in the mediastinum. It is often associated withautoimmune disorders. The myastnema gravls ano pure red cell aplasia are the most common disorders, with the incidences of 40% and 5%, respectively, while the incidence of aplastic anemia is only about 0-1.4%. 1 Thymectomy is hard to perform on patients with severe aplastic anemia（SAA） due to severe pancytopenia.

Haploidentical stem cell transplantation used in treating primary plasma cell leukemia: a case report

Here we report a successful protocol in treatment of a patient with primary plasma cell leukemia (PPCL) using haploidentical stem cell transplantation (hi-HSCT). During first complete remission after routine chemotherapy, the patient received autologous blood stem cell transplantation, but he had relapse later. He gained a second CR after chemotherapy and underwent hi-HSCT from his daughter, who had HLA mismatched at three loci. Recovery of hemopoiesis was found at day 14 and complete donor chimerism was confirmed by PCR-STR on day 34, 95 and 238. The patients have survived disease-free for 56 months since hi-HSCT, without serious graft-versus-host-disease.

Effect of NK cells on GVHD in H-2 haploidentical bone marrow transplantation in mice

To study the effect of natural killer （NK） cells on graft-versus-host disease （GVHD） after H-2 haploidentical bone marrow transplantation （BMT） in mice. Methods ：Murine model of H-2 haploidentical BMT was established by using Balb/c （H- 2d） mouse as recipient, and Balb/c （H-2d）×C57BL/6 （H-2b） （H-2db） mouse as donor. Lethally irradiated Balb/c （H-2d） mice were transplanted with the bone marrow cells from Balb/c（H-2d）×C57BL/6（H-2b） （H-2db） mice containing donor spleen cells and/or NK cells. GVHD and survival rates were studied by observation of clinical manifestations and pathological changes. Results：In the group of bone marrow ＋spleen cells, GVHD was induced in 90% mice; but in the group plus with low amount of NK cells, GVHD was induced in 20% mice; and in the group transplanted with high amount of NK cells, GVHD was induced only in 10% mice. Compared to the group transplanted only with BM plus spleen cells, the incidences of GVHD in the latter two groups decreased significantly （P 〈 0.01） and the survival rates at different periods of 15, 30, 45 and 60 days increased obviously （P 〈 0.01）. Conclusion： In mouse H-2 haploidentical BMT, alloreactive NK cells can reduce the incidence of GVHD and increase the survival rate.

Efficacy of rituximab-containing regimens on post-transplantation lymphoproliferative disorder following haploidentical hematopoietic stem cell transplantation:a report of 3 cases

Objective To evaluate the efficacy of rituximab-containing regimens on post - transplantation lympho-proliferative disorder ( PTLD ) following haploidentical hematopoietic stem cell transplantation ( HSCT) . Methods The clinical data of 3 cases of PTLD after haploidentical HSCT were analyzed retrospectively. Time

Haploidentical hematopoietic stem-cell transplantation for acute myeloid leukemia in first relapse after complete remission by standard induction chemotherapy

Objective To investigate the therapeutic effects of haploidentical hematopoietic stem - cell transplantation ( Haplo - PBSCT) for acute myeloid leukemia in first relapse after complete remission by standard induction chemotherapy. Methods Eighty - nine cases of AML in first relapse after complete remission by standard DA

Impact of payment source, referral site, and place of residence on outcomes after allogeneic transplantation in Mexico

BACKGROUND The impact of social determinants of health in allogeneic transplant recipients in low-and middle-income countries is poorly described.This observational study analyzes the impact of place of residence,referring institution,and transplant cost coverage(out-of-pocket vs government-funded vs private insurance)on outcomes after allogeneic hematopoietic stem cell transplantation(alloHSCT)in two of Mexico's largest public and private institutions.AIM To evaluate the impact of social determinants of health and their relationship with outcomes among allogeneic transplant recipients in Mexico.METHODS In this retrospective cohort study,we included adolescents and adults≥16 years who received a matched sibling or haploidentical transplant from 2015-2022.Participants were selected without regard to their diagnosis and were sourced from both a private clinic and a public University Hospital in Mexico.Three payment groups were compared:Out-of-pocket(OOP),private insurance,and a federal Universal healthcare program“Seguro Popular”.Outcomes were compared between referred and institution-diagnosed patients,and between residents of Nuevo Leon and out-of-state.Primary outcomes included overall survival(OS),categorized by residence,referral,and payment source.Secondary outcomes encompassed early mortality,event-free-survival,graft-versus-host-relapse-free survival,and non-relapse-mortality(NRM).Statistical analyses employed appropriate tests,Kaplan-Meier method,and Cox proportional hazard regression modeling.Statistical software included SPSS and R with tidycmprsk library.RESULTS Our primary outcome was overall survival.We included 287 patients,n=164 who lived out of state(57.1%),and n=129 referred from another institution(44.9%).The most frequent payment source was OOP(n=139,48.4%),followed by private insurance(n=75,26.1%)and universal coverage(n=73,25.4%).No differences in OS,event-free-survival,NRM,or graft-versus-host-relapse-free survival were observed for patients diagnosed locally vs in another institution,nor patients who lived in-state vs out-of-state.Patients who covered transplant costs through private insurance had the best outcomes with improved OS(median not reached)and 2-year cumulative incidence of NRM of 14%than patients who covered costs OOP(Median OS and 2-year NRM of 32%)or through a universal healthcare program active during the study period(OS and 2-year NRM of 19%)(P=0.024 and P=0.002,respectively).In a multivariate analysis,payment source and disease risk index were the only factors associated with overall survival.CONCLUSION In this Latin-American multicenter study,the site of residence or referral for alloHSCT did not impact outcomes.However,access to healthcare coverage for alloHSCT was associated with improved OS and reduced NRM.

Everyone has a donor:contribution of the Chinese experience to global practice of haploidentical hematopoietic stem cell transplantation

Human leukocyte antigen (HLA)-matched donors for hematopoietic stem cell transplantation (HSCT) have long been scarce in China. Haploidentical (haplo) donors are available for the vast majority of patients, but toxicity has limited this approach. Three new approaches for haplo-HSCT originated from Italy, China, and USA in 1990 and have been developed to world-renowned system up to now. The Chinese approach have been greatly improved by implementing new individualized conditioning regimens, donor selection based on non-HLA systems, risk-directed strategies for graft-versus-host disease and relapse, and infection management. Haplo-HSCT has exhibited similar efficacy to HLA-matched HSCT and has gradually become the predominant donor source and the first alternative donor choice for allo-HSCT in China. Registry-based analyses and multicenter studies adhering to international standards facilitated the transformation of the unique Chinese experience into an inspiration for the refinement of global practice.This review will focus on how the new era in which "everyone has a donor" will become a reality in China.

Optimizing antithymocyte globulin dosing in haploidentical hematopoietic cell transplantation:long-term follow-up of a multicenter,randomized controlled trial

Given that randomized studies testing the long-term impact of antithymocyte globulin(ATG)dosing are scarce,we report the results of an extended follow-up from the original trial.In our prospective,multicenter,randomized trial,408 leukemia patients 14–65 years of age who underwent haploidentical hematopoietic cell transplantation(haplo-HCT)under our original“Beijing Protocol”were randomly assigned one-to-one to ATG doses of 7.5 mg/kg(n=203,ATG-7.5)or 10 mg/kg(n=205,ATG-10.0)at four sites.Extended follow-up(median 1968 d(range:1300–2710 d)indicated comparable 5-year probabilities of moderate-to-severe chronic graft-versus-host disease(GVHD)(hazard ratio(HR):1.384,95%confidence interval(CI):0.876–2.189,P=0.164),nonrelapse mortality(HR:0.814,95%CI:0.526–1.261,P=0.357),relapse(HR:1.521,95%CI:0.919–2.518,P=0.103),disease-free survival(HR:1.074,95%CI:0.783–1.473,P=0.658),and GVHD-free/relapse-free survival(HR:1.186,95%CI:0.904–1.555,P=0.219)between groups(ATG-7.5 vs.ATG-10.0).The 5-year rate of late effects did not differ significantly.However,the cytomegalovirus/Epstein-Barr virus-related death rate was much higher in the ATG-10.0 cohort than in the ATG-7.5 cohort(9.8%vs.1.5%;P=0.003).In summary,patients undergoing haplo-HCT benefit from 7.5 mg/kg ATG compared to 10.0 mg/kg ATG based on a balance between GVHD and infection control.ATG(7.5 mg/kg)is potentially regarded as the standard regimen in the platform.These results support the optimization of ATG use in the“Beijing Protocol”,especially considering the potential economic advantage in developing countries.

The role of collateral related donors in haploidentical hematopoietic stem cell transplantation

A key issue in the haploiedntical hematopoietic stem cell transplantation(haplo-HSCT) setting is the search for the best donor, because donor selection can significantly impact the clinical outcomes. We aimed to identify the role of collateral related donors(CRDs) in donor selection for haplo-HSCT through comparing the clinical outcomes between CRDs(n = 60) and maternal donors(MDs, n = 296), which were the last choice of donor selection in immediate related donors(IRDs). The cumulative incidence of graft-versus-host disease was comparable between CRDs and MDs. The 5-year cumulative incidence of relapse and non-relapse mortality was 22.0%(95% CI, 11.3%–32.7%) versus 17.4%(95% CI, 13.0%–21.8%)(P = 0.455) and 25.0%(95% CI, 13.9%–36.1%) versus 23.1%(95% CI, 18.2%–28.0%)(P = 0.721) for the CRDs and MDs, respectively. The 5-year probabilities of disease-free survival and overall survival was 53.2%(95% CI, 40.4%–66.0%) versus 59.5%(95% CI, 53.8%–65.2%)(P = 0.406) and 56.5%(95% CI,43.8%–69.2%) versus 61.8%(95% CI, 56.1%–67.5%)(P = 0.458) for the CRDs and MDs, respectively.Female donor/male recipient(FDMR) CRDs were associated with the poorest clinical outcomes, and the clinical outcomes of non-FDMR CRDs were comparable to those of MDs. In summary, our results showed that CRDs did not showed superiority over MDs. Thus, IRDs should be the first choice of donor selection, and CRDs could only be the donors for those without IRDs.

Long-term follow-up of haploidentical transplantation in relapsed/refractory severe aplastic anemia:a multicenter prospective study

In recent decades,haploidentical stem cell transplantation(haplo-SCT)to treat severe aplastic anemia(SAA)has achieved remarkable progress.However,long-term results are still lacking.We conducted a multicenter prospective study involving SAA patients who underwent haplo-SCT as salvage therapy.Long-term outcomes were assessed,mainly focusing on survival and quality of life(QoL).Longitudinal QoL was prospectively evaluated during pretransplantation and at 3 and 5 years posttransplantation using the SF-36 scale in adults and the PedsQL 4.0 scale in children.A total of 287 SAA patients were enrolled,and the median follow-up was 4.56 years(range,3.01–9.05 years)among surviving patients.During the long-term follow-up,268 of 275 evaluable patients(97.5%)obtained sustained full donor chimerism,and 93.4%had complete hematopoietic recovery.The estimated overall survival and failure-free survival for the whole cohort at 9 years were 85.4%±2.1%and 84.0%±2.2%,respectively.Age(≥18 years)and a poorer performance status(ECOG>1)were identified as risk factors for survival outcomes.For Qo L recovery after haplo-SCT,we found that QoL progressively improved from pretransplantation to the 3-year and 5-year time points with statistical significance.The occurrence of chronic graft versus host disease was a risk factor predicting poorer QoL scores in both the child and adult cohorts.At the last followup,74.0%of children and 72.9%of adults returned to normal school or work.These inspiring long-term outcomes suggest that salvage transplantation with haploidentical donors can be routine practice for SAA patients without human leukocyte antigen(HLA)-matched donors.

Comparison of the clinical outcomes of hematologic malignancies after myeloablative haploidentical transplantation with G-CSF/ATG and posttransplant cyclophosphamide:results from the Chinese Bone Marrow Transplantation Registry Group(CBMTRG)

This study compared G-CSF/ATG and PTCy in myeloablative haploidentical hematopoietic stem cell transplantation(haploHSCT)for hematologic malignancies between January 2013 and March 2018 reporting to the Chinese Bone Marrow Transplantation Registry Group(CBMTRG).For each PTCy,G-CSF/ATG subjects(1:4)were selected using the nested case-pair method.In total,220 patients including 176 in G-CSF/ATG group and 44 in PTCy group were analyzed.The incidences of 30-day neutrophil engraftment(88.6%vs.96.6%,P=0.001),90-day platelet engraftment(84.1%vs.94.2%,P=0.04),the median time to neutrophil engraftment(17 days vs.12 days,P=0.000)and platelet engraftment(22 days vs.17 days,P=0.001)were significantly inferior in PTCy group.The incidences of grades 2–4 and 3–4 acute graft-versus-host disease(GVHD),chronic GVHD and severe chronic GVHD were comparable.Among G-CSF/ATG and PTCy groups,the 3-year progression-free survival,overall survival,cumulative incidences of nonrelapse mortality and relapse was 74.3%vs.61%(P=0.045),78.3%vs.65.2%(P=0.039),12%vs.27.3%(P=0.008),and 14.9%vs.11.7%(P=0.61),respectively.G-CSF/ATG can achieve better engraftment,PFS and OS,and lower incidence of NRM compared to PTCy in myeloablative haplo-HSCT for hematologic malignancies.

Immunosuppression for 6-8 weeks after modified donor lymphocyte infusion reduced acute graft-versus-host disease without influencing graft-versus-leukemia effect in haploidentical transplant

Background In haploidentical hematopoietic stem cell transplantation （HSCT）, the duration of graft-versus-host disease （GVHD） prophylaxis after modified donor lymphocyte infusion （DLI） was the only risk factor of DLI-associated grades 3-4 acute GVHD. However, the successful application of modified DLI depended not only on the reduction of severe GVHD, but also on the preservation of graft-versus-leukemia （GVL） effect. Therefore, this study was performed to compare the impact of prophylaxis for 6-8 weeks and prophylaxis for 〈6 weeks on GVL effect after modified DLI in haploidentical HSCT. Methods A total of 103 consecutive patients developing hematological relapse or minimal residual disease （MRD）-positive status after haploidentical HSCT and receiving modified DLI were investigated retrospectively. Fifty-two patients received prophylaxis for 6-8 weeks after modified DLI; the remaining 51 patients received prophylaxis for 〈6 weeks. Results First, compared with prophylaxis for 〈6 weeks, prophylaxis for 6-8 weeks reduced incidence of relapse in total patients （26.6% vs. 69.0%, P 〈0.001）. Besides, prophylaxis for 6-8 weeks also reduced incidence of relapse in 54 patients developing hematological relapse post-transplant （P=0.018） and in 49 patients developing MRD-positive status post-transplant （P 〈0.001）. Second, prophylaxis for 6-8 weeks reduced incidence of acute GVHD （P 〈0.05）, reduced the therapeutic application of immunosuppressive agents （P=0.019）, but increased the incidence of chronic GVHD （P〈0.05）. Third, prophylaxis for 6-8 weeks improved overall survival and disease-free survival in total patients, as well as in patients developing hematological relapse post-transplant and in patients developing MRD-positive status post-transplant （P 〈0.05）. Conclusions In haploidentical HSCT, prophylaxis for 6-8 weeks after modified DLI does not reduce GVL effect, but reduces the incidence of DLI-associated acute GVHD compared with prophylaxis for 〈6 weeks. This strategy will probably improve the safety and efficacy of modified DLI further.

HLA-mismatched/haploidentical hematopoietic stem cell transplantation： a field in which Chinese doctors are making great contributions

Allogeneic hematopoietic stem cell transplantation .（allo-HSCT） is one of the best, or even the only,option for the cure of leukemia, especially for patients with high risk factors . However, it is limited by the shortage of suitable donors, because only 25%-30% patients can find a human leukocyte antigen （HLA）-identical sibling donor. Although much progress has been made in finding a suitable unrelated donor or unrelated cord blood （uCB） due to the expansion of the worldwide unrelated donor program,

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.

Efficacy and Safety of Unmanipulated Haploidentical Related Donor AIIogeneic Peripheral Blood Stem Cell Transplantation in Patients with Relapsed/Refractory Acute Myeloid Leukemia

Background： Studies of haploidentical-related donor （HRD） stem cell transplantation using a combination of peripheral blood stem cells （PBSCs） and bone marrow as the graft have reported encouraging results for patients with hematological diseases. However, few studies specifically reported transplantation of only PBSCs from HRDs among patients with relapsed or refractory acute myeloid leukemia （AML）. Here, the long-term outcomes and side effects of unmanipulated HRD PBSC transplantation （HRD-PBSCT） for relapsed/refractory AML were analyzed. Methods： We performed a retrospective analysis of the outcomes in relapsed/refractory AML patients who underwent PBSCT from HRDs （n = 36）. Results： Thirty-one （86.1%） patients in the HRD-PBSCT group achieved platelet recovery. The cumulative incidence of acute graft-versus-host disease （aGVHD） in the HRD-PBSCT group was 40.00%, and the cumulative incidence of grades 2-4 aGVHD in this group was 13.33%. A total of 13 patients in the HRD-PBSCT group had recurrent disease at a median of 183 days after transplantation （range： 10-1700 days）, reaching cumulative incidences of relapse of 50.28% at 5 years. On multivariate analysis, donor age and patient age 〉40 years were independent risk factors for inferior disease-free survival or overall survival （P 〈 0.05）. The results of the present study demonstrate rapid and complete neutrophil engraftment, a low incidence of grade 2-4 aGVHD, and promising survival rates in patients after HRD-PBSCT. Thus, granulocyte colony-stimulating factor-primed PBSCs may be a reliable graft source in unmanipulated HRD-HSCT under myeloablative conditioning when no matched sibling donor is available. Conclusions： Our results support the feasibility, effectiveness, and tolerability of PBSCs as a graft source in unmanipulated HRD transplantation under myeloablative conditioning in patients with leukemia.

Haploidentical hematopoietic stem cell transplantation for pediatric patients with chronic active Epstein-Barr virus infection:a retrospective analysis of a single center

Background This study aimed to evaluate the feasibility and clinical effect of haploidentical hematopoietic stem cell transplantation(haplo-HSCT)for the treatment of pediatric patients with chronic active Epstein-Barr virus infection(CAEBV).Methods Children with CAEBV who did not have matched donors and underwent haplo-HSCT in Beijing Children's Hospital,Capital Medical University,from October 2016 to June 2020 were analyzed retrospectively.Data relating to the clinical manifestations,engraftment,and prognosis of the children were extracted from medical records.Results Twenty-five patients,including 16 males and 9 females,with an onset age of 5.0±2.6 years and a transplantation age of 6.9±2.9 years,were enrolled irnhis study.The mean time from diagnosis to transplantation was 3.8(2.0-40.2)months.The mean observation time was 19.0±12.0 months.Three patients received the reduced intensity conditioning regimen,and the remaining patients all received the modified myeloablative conditioning regimen.By the end of the follow-up,23 patients were characterized by disease-free survival(DFS),22 were characterized by event-free survival(EFS).and two died.One of the patients died of thrombotic microangiopathy(TMA),and another died of graft versus host disease(GVHD);this patient discontinued the treatment for economic reasons.The 3-year overall survival(OS)rate was estimated to be 92.0%±5.4%,and the 3-year EFS rate was estimated to be 87.4%±6.8%.All active patients survived after HSCT event-free.Acute GVHD degrees 1-3 were observed in ten patients(40.0%),and degree IV was observed in six(24.0%),who were all cured except for one patient.Chronic GVHD was observed in nine(36.0%),and most of these cases were mild.The incidence of TMA and veno-occlusive disease(VOD)was 28.0%and 4.0%.Conclusions Haploidentical hematopoietic stem cell transplantation is safe and effective in the treatment of pediatric CAEBV and can be used as an alternative therapy without matched donors or emergency transplantation.Patients with active disease before HSCT also benefited from haplo-HSCT.Haplo-HSCT requires careful monitoring for complications,such as GVHD and TMA.Early detection of TMA and timely treatment can reduce mortality and can improve the survival rate.