Stem cell transplantation for pediatric lymphoma: past, present and future

Hematopoietic Progenitor Cell Transplantation in Children, Adolescents, and Young Adults With Relapsed Mature B-Cell NHL

Although children, adolescents, and young adults with newly diagnosed B-cell non-Hodgkin's lymphoma enjoy excellent overall survival with current chemoimmunotherapy, those with relapsed and/or refractory disease have a dismal prognosis. Although most clinicians would agree that hematopoietic progenitor cell transplantation after reinduction therapy is frontline therapy for these patients, there is no consensus as to what type of hematopoietic progenitor cell transplantation promises the best event-free and overall survival. This review outlines the disparate types of stem cell therapy that have been used in this difficult-to-treat population as well as the role of maintenance and CAR T-cell therapy in conjunction with stem cell therapy.

An Overview on Stem Cells in Tissue Regeneration

BACKGROUND

Deteriorations in tissues and decline in organ functions, due to chronic diseases or with advancing age or sometimes due to infections or injuries, can severely compromise the quality of life of an individual. Regenerative medicine, a field of medical research focuses on replacing non-functional or dead cells or repairing or regenerating tissues and organs to restore normal functions of an impaired organ. Approaches used in regenerative therapy for achieving the objective employ a number of means which include soluble biomolecules, stem cell transplants, tissue engineering, gene therapy and reprogramming of cells according to target tissue types. Stem cells transplant and tissue regeneration methods for treating various diseases have rapidly grown in usage over the past decades or so. There are different types of stem cells such as mesenchymal, hematopoietic, embryonic, mammary, intestinal, endothelial, neural, olfactory, neural crest, testicular and induced pluripotent stem cells.

METHODS

This review covers the recent advances in tissue regeneration and highlights the application of stem cell transplants in treating many life-threatening diseases or in improving quality of life.

RESULTS

Remarkable progress in stem cell research has established that the cell-based therapy could be an option for treating diseases which could not be cured by conventional medical means till recent. Stem cells play major roles in regenerative medicine with its exceptional characteristics of self-renewal capacity and potential to differentiate into almost all types of cells of a body.

CONCLUSION

Vast number of reports on preclinical and clinical application of stem cells revealed its vital role in disease management and many pharmacological industries around the globe working to achieve effective stem cell based products.

Outcome predictors of autologous hematopoietic stem cell transplantation in children with relapsed and refractory Hodgkin lymphoma: Single-center experience in a lower-middle-income country

BACKGROUND

Children and adolescents with HL have excellent long-term survival exceeding 95% after combined modality treatment. However, about 20% will either relapse or have PRF. Salvage HDCT followed by AHSCT is considered to be the preferential treatment.

OBJECTIVE

To describe the outcome (OS and EFS) and prognostic factors in pediatric patients with relapsed or refractory HL (r/rHL) who underwent AHSCT.

METHODS

We retrospectively included 43 pediatric patients with r/rHL who underwent AHSCT from July 1, 2007, till December 31, 2016, at the Children's Cancer Hospital of Egypt. MAC regimen given was CMV.

RESULTS

Of the whole cohort, 88.4% of patients achieved CR, while 11.6% had a positive PET scan prior to transplantation. The 3-year OS and EFS were 85% and 70.6%, respectively. The 3-year OS for patients > 10 years was 94% versus 65.5% for patients 10 years of age or younger (P = 0.046). There is strong tendency toward better 3-year OS for patients with negative PET scan as compared to those with positive PET scan before AHSCT, 89.4% vs 60%, respectively (P = 0.059). This tendency is also applicable when looking at the 3-year EFS for the two groups, 78.3% vs 40%, respectively (P = 0.069).

CONCLUSION

Poor predictors of OS were younger age and positive PET scan before AHSCT. The latter, along with single modality treatment before AHSCT, were poor predictors of EFS.

Advances in cellular and humoral immunotherapy - implications for the treatment of poor risk childhood, adolescent, and young adult B-cell non-Hodgkin lymphoma

Patients with relapsed, refractory or advanced stage B non-Hodgkin lymphoma (NHL) continue to have a dismal prognosis. This review summarises current and novel cellular and immunotherapy for these high-risk populations, including haematopoietic stem cell transplant, bispecific antibodies, viral-derived cytotoxic T cells, chimeric antigen receptor (CAR) T cells, and natural killer (NK) cell therapy, as discussed at the 6th International Symposium on Childhood, Adolescent and Young Adult Non-Hodgkin Lymphoma on September 26th-29th 2018 in Rotterdam, the Netherlands, and explores the future of NK/CAR NK therapies.

Hematopoietic stem cell transplantation in children and adolescents with relapsed or refractory B-cell non-Hodgkin lymphoma

We undertook a retrospective study using the national registry data of hematopoietic stem cell transplantation (HSCT) in Japan to investigate the effect of graft source, particularly autologous or allogeneic tissue, on the treatment outcome in patients aged less than 18 years with relapsed or refractory B-cell non-Hodgkin lymphoma (B-NHL). Survival analysis was conducted on 31 autologous HSCT (auto-HSCT) and 48 allogeneic HSCT (allo-HSCT) recipients between 1990 and 2013. The 5-year survival rates were significantly lower for allo-HSCT compared to auto-HSCT recipients (32% vs. 55%; P = 0.036). Multivariate analysis of survival rates identified allogeneic graft, Burkitt histology, and lack of response to chemotherapy as poor prognostic factors for survival. The cumulative incidence of treatment-related mortality (TRM) was significantly higher in allo-HSCT compared to auto-HSCT recipients (P = 0.017), explaining the difference in survival rates. In patients with Burkitt lymphoma (BL), overall survival was significantly inferior in the group of patients undergoing HSCT within 12 months from the initial diagnosis (P = 0.039). These data indicate that treatment outcomes for HSCT in children and adolescents with B-NHL were better in autograft recipients, suggesting that greater attention should be paid to the risk of TRM, especially after allografts, for patients with BL.

Overall survival of children and adolescents with mature B cell non-Hodgkin lymphoma who had refractory or relapsed disease during or after treatment with FAB/LMB 96: A report from the FAB/LMB 96 study group

We determined the risk factors associated with poor survival in children and adolescents with de novo mature B cell non-Hodgkin lymphoma (B-NHL) who had refractory or relapsed disease during or after the French-American-British mature lymphoma B (FAB/LMB) 96 multi-agent chemotherapy. Among the 1 111 registered on study, 104 patients (9·4%) had refractory disease or disease relapse after first complete remission. Among these 104 patients, 28 (27%) patients had refractory disease and 76 (73%) had relapsed disease. The estimated 1- and 2-year overall survival (OS) (95% confidence interval) was 31·5% (23·3-41·0%) and 22·3% (15·3-31·4%), respectively. Prognostic analysis of OS using a Cox multivariate model showed that factors independently associated with OS included lactate dehydrogenase ≥2 upper normal limit [hazard ratio (HR) = 2·86 (1·57-5·2), P = 0·0006]; time to failure (>6 months) [HR = 0·59 (0·36-0·97), P = 0·038]; and failure in bone marrow [HR = 2·78 (1·65-4·68), P = 0·0001]. New therapeutic strategies are required to significantly reduce refractory disease and disease relapse in patients with newly diagnosed mature B-NHL and, more importantly, there is a critical need to develop novel retrieval approaches in patients with chemotherapy-resistant disease.

Ruxolitinib significantly enhances in vitro apoptosis in Hodgkin lymphoma and primary mediastinal B-cell lymphoma and survival in a lymphoma xenograft murine model

Hodgkin lymphoma (HL) and primary mediastinal B-cell lymphoma (PMBL) share similar molecular features by gene expression profiling. Frequent gains of chromosome 9p exhibit higher Janus Kinase 2 (JAK2) transcript levels with increased JAK2 activity, suggesting aberrant activity of JAK2 and STAT pathways. This signaling pathway alteration may in part play an important role in the pathogenesis and/or chemoradiotherapy resistance in HL and PMBL. Ruxolitinib is a potent and selective JAK1/JAK2 inhibitor, with activity against myeloproliferative neoplasms (MPNs) including those harboring the JAK2V617F mutation. We investigated the in vitro and in vivo efficacy of ruxolitinib and changes in downstream signaling pathways in HL and PMBL. We demonstrated that ruxolitinib significantly inhibited STAT signaling in both HL and PMBL with constitutively active JAK2 signaling. We also observed that ruxolitinib significantly induced in vitro anti-proliferative effects (p < 0.05) and increased programmed cell death (p < 0.05) against both HL and PMBL cells. Importantly, ruxolitinib significantly inhibited tumor progression by bioluminescence (p < 0.05) and significantly improved survival in HL (p = 0.0001) and PMBL (p < 0.0001) xenograft NSG mice. Taken altogether, these studies suggest that ruxolitinib may be a potential adjuvant targeted agent in the therapeutic approach in patients with high risk HL and PMBL.

Outcome of children and adolescents with relapsed Hodgkin lymphoma treated with high-dose therapy and autologous stem cell transplantation: the Memorial Sloan Kettering Cancer Center experience

To evaluate outcomes and prognostic markers among children with relapsed Hodgkin lymphoma (HL) treated with autologous stem cell transplant (ASCT), we conducted a retrospective analysis of 36 consecutive pediatric patients treated at Memorial Sloan Kettering Cancer Center from 1989 to 2013. With a median follow-up of 9.6 years, the 10-year overall survival (OS) and event-free survival (EFS) were 74.1 and 67.1% respectively. Absence of B-symptoms, chemotherapy-sensitive disease, and transplant date after 1997 were each associated with superior EFS [HR 0.12 (p = .0015), 0.18 (p = .0039), and 0.17 (p = .0208), respectively]. Childhood Hodgkin International Prognostic Score at relapse (R-CHIPS) was calculated in a subset of patients (n = 22) and a lower score was associated with improved OS (HR 0.29, p = .0352) and a trend toward improved EFS (HR 0.38, p = .0527). In summary, ASCT results in durable remission for the majority of pediatric patients with relapsed HL. R-CHIPS should be evaluated in larger cohorts as a potential predictive tool.

Outcome of autologous hematopoietic stem cell transplantation in children and adolescents with relapsed or refractory Hodgkin's lymphoma

This study evaluates the outcome of 66 pediatric patients with rrHL who underwent autoHSCT. Twenty-nine patients experienced early relapse, and 19 patients experienced late relapse. Of 18 newly diagnosed with HL, 13 were primary refractory disease and five had late responsive disease. At the time of transplantation, only 68% of the patients were chemosensitive. The majority of patients received BCNU + etoposide + ara-C + melphalan for conditioning (45/66), and peripheral blood (56/66) was used as a source of stem cells. After a median follow-up period of 39 months, 46 patients were alive. At five yr, the probabilities of OS, EFS, the relapse rate, and the non-relapse mortality rate were 63.1%, 54.3%, 36.4%, and 9.1%, respectively. The probability of EFS in chemosensitive and chemoresistant patients at five yr was 72.3% and 19%, respectively (p < 0.001). Multivariate analysis showed that chemoresistant disease at the time of transplantation was the only factor predicting limited both OS (hazard ratio = 4.073) and EFS (hazard ratio = 4.599). AutoHSCT plays an important role for the treatment of rrHL in children and adolescents, and survival rates are better for patients with chemosensitive disease at the time of transplantation.

Outcome of pediatric patients with lymphoma following stem cell transplant: a single institution report

Hematopoietic stem cell transplant (HSCT) is recommended for pediatric patients with relapsed/refractory lymphoma even though the evidence for this is limited. We retrospectively reviewed records of 57 patients (29 Hodgkin lymphoma [HL], 28 non-Hodgkin lymphoma [NHL]) who underwent HSCT between 1995 and 2012. All demonstrated chemoresponsiveness prior to HSCT and 44 patients had a complete response. All underwent myeloablative conditioning, 38 chemotherapy-based and 19 total body irradiation-based. Forty-one patients received autologous and 16 allogeneic HSCT. Twelve (21%) died within 100 days post-HSCT, and 25 patients relapsed at a median of 1.6 months post-HSCT. Three patients developed second malignant neoplasms. Five-year overall survival (OS) was 50.5% and event-free survival (EFS) was 43.4%. Outcomes for HL were significantly better than those for NHL (OS 61.9% vs. 38.7% [p = 0.005] and EFS 60.4% vs. 26% [p = 0.008]). In summary, approximately half of all pediatric patients with lymphoma who failed first-line therapy and demonstrated chemosensitivity to second-line therapy can be salvaged with HSCT.

Sequential myeloablative autologous stem cell transplantation and reduced intensity allogeneic hematopoietic cell transplantation is safe and feasible in children, adolescents and young adults with poor-risk refractory or recurrent Hodgkin and non-Hodgkin lymphoma

The outcome of children, adolescents and young adults (CAYA) with poor-risk recurrent/refractory lymphoma is dismal (⩽30%). To overcome this poor prognosis, we designed an approach to maximize an allogeneic graft vs lymphoma effect in the setting of low disease burden. We conducted a multi-center prospective study of myeloablative conditioning (MAC) and autologous stem cell transplantation (AutoSCT), followed by a reduced intensity conditioning (RIC) and allogeneic hematopoietic cell transplantation (AlloHCT) in CAYA, with poor-risk refractory or recurrent lymphoma. Conditioning for MAC AutoSCT consisted of carmustine/etoposide/cyclophosphamide, RIC consisted of busulfan/fludarabine. Thirty patients, 16 Hodgkin lymphoma (HL) and 14 non-Hodgkin lymphoma (NHL), with a median age of 16 years and median follow-up of 5years, were enrolled. Twenty-three patients completed both MAC AutoSCT and RIC AlloHCT. Allogeneic donor sources included unrelated cord blood (n=9), unrelated donor (n=8) and matched siblings (n=6). The incidence of transplant-related mortality following RIC AlloHCT was only 12%. In patients with HL and NHL, 10 year EFS was 59.8% and 70% (P=0.613), respectively. In summary, this approach is safe, and long-term EFS with this approach is encouraging considering the poor-risk patient characteristics and the use of unrelated donors for RIC AlloHCT in the majority of cases.

A phase I/II study of CY and topotecan in patients with high-risk malignancies undergoing autologous hematopoietic cell transplantation: the St Jude long-term follow-up

Fifty-eight consecutive children with high-risk malignancies were treated with CY, and targeted topotecan followed by autologous hematopoietic cell transplantation (AHCT) in a phase I/II Institutional Review Board-approved study. Twelve participants enrolled in phase I; 5 received dose level 1 of topotecan 3 mg/m(2) per day, with subsequent doses targeted to total systemic exposure of 100±20 ng h/mL and CY 750 mg/m(2) per day. Seven participants received dose level 2. CY dose escalation to 1 g/m(2) per day was considered excessively toxic; one died from irreversible veno-occlusive disease and two experienced reversible hepatotoxicity. These adverse events halted further dose escalation. A total of 46 participants were enrolled in phase II; results are on the 51 participants who received therapy at dose level 1, the maximum tolerated dose. Diagnoses included neuroblastoma (26), sarcoma (9), lymphoma (8), brain tumors (5), Wilms (2) and retinoblastoma (1). Twenty participants (39.3%) were in CR1 at enrollment; median age was 5.1 years. Most common non-hematological grade III-IV toxicity was gastrointestinal (n=37). Neutrophil and platelet engraftment occurred at a median of 15 and 24 days, respectively. Twenty-six (51%) participants remain alive at a median of 6.4 years after AHCT. CY 3.75 g/m(2), and targeted topotecan followed by AHCT are feasible and produce acceptable toxicity in children with high-risk malignancies.

Leukemia and lymphoma

Leukemia and lymphoma are the most common and third most common pediatric malignancies, respectively, and share cell lineages, but the clinical and imaging manifestations of these malignancies vary substantially. Along with providing pertinent details on classification, epidemiology, and treatment, this article reviews the current roles of imaging in the management of childhood leukemia and lymphoma, with attention to diagnosis, staging, risk stratification, therapy response assessment, and surveillance for disease relapse and adverse effects of therapy. Advances in functional imaging are also discussed to provide insights into future applications of imaging in the management of pediatric patients with leukemia and lymphoma.

Long-term results of AIEOP-8805 protocol for acute B-cell lymphoblastic leukemia of childhood

BACKGROUND

Acute B-cell leukemia (B-ALL) is a rare form of pediatric leukemia characterized by a very high-proliferation index, rapid clinical progression, and a high frequency of central nervous system (CNS) involvement. Commonly, it is treated in the clinical trials for Burkitt lymphoma, of which it represents the leukemic counterpart.

PROCEDURE

Children with B-ALL diagnosed between 1988 and 1999 were enrolled in the AIEOP-8805 protocol. Treatment included six high-dose chemotherapy courses. No prophylactic CNS irradiation was administered.

RESULTS

Sixty-five consecutive patients were enrolled in the study. L3 morphology was observed in 57 of 65 patients (88%). Twenty-five children (38%) had tumor mass in addition to massive bone marrow infiltration; 11 children (17%) had CNS disease at diagnosis. Sixty-two patients obtained complete morphological remission of which 13 suffered a relapse, including 3 with initial CNS involvement. Ten-year overall survival and event-free survival were 77% and 75%, respectively. Neither relevant long-term toxicity nor second malignancies were observed.

CONCLUSIONS

The AIEOP-8805 confirmed that short high-dose chemotherapy is highly effective for the treatment of B-ALL without significant long-term adverse sequelae. Therapy modifications to reduce relapse rate, such as the use of anti-CD20 monoclonal antibody and more effective CNS treatment, are being tested.

Outcome of hematopoietic stem cell transplant as salvage therapy for Hodgkin's lymphoma in adolescents and young adults at a single institution

For patients with relapsed Hodgkin's lymphoma (HL), high dose chemotherapy with stem cell rescue (HDCT-SCT) may improve survival over chemotherapy alone. We assessed the outcomes of HDCT-SCT in 37 consecutive adolescent and young adult patients with relapsed HL whose malignancy was categorized based on sensitivity to chemotherapy. We determined whether current outcomes supported the use of HDCT-SCT in all of our patients or just those patients with lower-risk characteristics such as chemosensitivity. With a median follow-up of 6.5 years, the 2-year overall survival (OS) was 89% (95% CI: 62-97%) for the chemosensitive patients (n = 21), whereas for patients with resistant disease (n = 16), OS was 53% (95% CI: 25-74%). Both autologous and allogeneic transplants were well tolerated, with 100-day treatment-related mortality under 10%. Our data show encouraging outcomes for patients with chemosensitive relapsed HL who receive hematopoietic stem cell transplant (HSCT) and support the value of the procedure even when the disease is chemoresistant.

Autologous peripheral blood stem cell transplantation in children with refractory or relapsed lymphoma: results of Children's Oncology Group study A5962

This prospective study was designed to determine the safety and efficacy of cyclophosphamide, BCNU, and etoposide (CBV) conditioning and autologous peripheral blood stem cell transplant (PBSCT) in children with relapsed or refractory Hodgkin and non-Hodgkin lymphoma (HL and NHL). Patients achieving complete remission (CR) or partial remission (PR) after 2 to 4 courses of reinduction underwent a granulocyte-colony stimulating factor (G-CSF) mobilized PBSC apheresis with a target collection dose of 5 × 10⁶ CD34(+)/kg. Those eligible to proceed received autologous PBSCT after CBV (7200 mg/m², 450-300 mg/m², 2400 mg/m²). Forty-three of 69 patients (30/39 HL, 13/30 NHL) achieved a CR/PR after reinduction. Thirty-eight patients (28 HL, 10 NHL) underwent PBSCT. All initial 6 patients who received BCNU at 450 mg/m² experienced grade III or IV pulmonary toxicity compared to none of the subsequent 32 receiving 300 mg/m² (P < .0001). The probability of overall survival (OS) at 3 years for all patients is 51% and for transplanted patients is 64%. The 3-year event-free survival (EFS) is 38% (45% for HL; 30% NHL). The 3-year EFS in transplanted patients is 66% (65% HL; 70% NHL). Initial duration of remission of ≥12 versus <12 months was associated with a significant increase in OS (3 years OS 70% versus 34%) (P = .003). BCNU at 300 mg/m(2) in a CBV regimen prior to PBSCT is well tolerated in relapsed or refractory pediatric lymphoma patients. A short duration (<12 months) of initial remission is associated with a poorer prognosis. Last, a high percentage of patients achieving a CR/PR after reinduction therapy can be salvaged with CBV and autologlous PBSCT.

Evidence of a clinical response at one yr after reduced-intensity allogeneic hematopoietic stem cell transplantation in heavily pretreated adolescents with aggressive refractory Hodgkin's lymphoma

We report results of RIC AHSCT in four adolescents with aggressive refractory HL. They all received three or four lines of therapy prior to RIC-AHSCT including autografts. At the time of RIC, they were in partial response except for one patient who had progressive chemoresistant disease. The conditioning regimen consisted of fludarabin, busulfan and ATG. They all had a matched related donor. The median follow-up was 12-16-month post-allograft. All patient transplants engrafted rapidly. The median time of hospitalization was 35 days. The median time to neutrophil recovery (>or=500/muL) was 19 days. All the patients were in complete donor chimerism at day 60. Four patients developed skin (grade <or= II) acute GvHD. All responded and all are alive. Two patients are in CR, one in PR and one relapsed six months after grafting after a PR. Each of the patients in PR received two DLI. These observations, together with the responses after DLI, suggest the presence of a graft vs. lymphoma effect in patients with advanced active HL. Prospective studies are needed to identify the patients likely to benefit most from this treatment approach.

Incidence of Viral and fungal infections following busulfan-based reduced-intensity versus myeloablative conditioning in pediatric allogeneic stem cell transplantation recipients

Reductions in the duration and nadir of neutropenia have translated into a significant decrease in bacteremia in adult recipients of allogeneic stem cell transplantation (allo-SCT) with reduced-intensity conditioning (RIC) during the first 30 days after transplantation. It remains to be determined whether RIC allo-SCT also will result in a decrease in systemic viral infections (SVIs) and invasive fungal infections (IFIs), which are more dependent on alterations in cellular immunity. We compared the incidence of SVIs and IFIs in children receiving busulfan-based RIC allo-SCT and in children receiving myeloablative conditioning (MAC) allo-SCT for various malignant and nonmalignant diseases. Allo-SCT recipients at risk for cytomegalovirus (CMV) received ganciclovir/foscarnet, and most of the patients received antifungal prophylaxis with liposomal amphotericin B until day +100. Eighty-six patients (median age, 7.5 years; 70% with malignant disease, 30% with nonmalignant disease; 80% average risk, 20% poor risk) were evaluated. The probability of developing grade II-IV acute graft-versus-host disease (aGVHD) was 29.1% (95% confidence interval [CI]=16.7%-41.6%) in RIC allo-SCT versus 40.3% (95% CI=23.9%-56.6%) in MAC allo-SCT (P=.23), and that of chronic GVHD (cGVHD) was 28.9% (95% CI=14.7%-43.0%) in RIC allo-SCT versus 28.4% (95% CI=10.5%-46.3%) in MAC allo-SCT (P=.73). The overall probability of developing an SVI was 58%, and that of developing an IFI was 15%. These probabilities did not differ significantly by conditioning intensity. In a multivariate Cox regression model, the following were identified as independent risk factors for invasive fungal infection: older age (hazard ratio [HR]=1.3; 95% CI=1.1-1.6; P=< .01), poor risk status (HR=6.5; 95% CI =1.1-37.4; P=.03), and CMV-positive recipient (high vs low CMV risk group, HR=26.7; 95% CI=3.4-210.8; P=< .01). Overall infection-related mortality was only 1.1% (1/86) for SVIs and 2.3% (2/86) for IFIs. Our data indicate that RIC allo-SCT does not carry a lower risk of SVIs and IFIs than MAC allo-SCT in pediatric recipients.

Allotransplantation in pediatric HL

In this issue of Blood, Claviez and colleagues report on the outcomes of 91 patients younger than 18 years of age who underwent an allogeneic bone marrow transplantation for HL between 1987 and 2005. The outcomes were reported to the European Group for Blood and Marrow Transplantation.

Haematopoietic SCT for children and adolescents with relapsed and refractory Hodgkin's lymphoma

Despite the generally excellent prognosis of children and adolescents with Hodgkin's lymphoma (HL), approximately 15% of patients relapse. Salvage therapy options include further chemo-radiotherapy and autologous or allogeneic haematopoietic SCT (HSCT). Autologous HSCT following high-dose chemotherapy, the standard treatment for adult patients with relapsed HL, is also effective in paediatric patients, but randomized trials showing its superiority to conventional therapy are lacking. Although patients with late relapse (>12 months after completion of therapy) may be cured with conventional therapy, those with progressive disease or early relapse (3-12 months) are considered candidates for autologous HSCT. According to patient selection criteria, overall and disease-free survival rates after autologous HSCT are 43-95% and 31-70%, respectively. Short time to relapse and refractory disease at the time of autologous HSCT remain the most important risk factors. Data on allogeneic HSCT in children with HL are scarce. Broader use has been hampered for a long time mainly by high non-relapse mortality, offsetting the advantage of a graft-vs-lymphoma effect. Data suggest that young patients with recurring disease following autologous HSCT, as well as some patients with multiple relapses and selected patients with refractory lymphoma, might benefit from allogeneic HSCT, but relapse remains the major challenge.

Prolongation of cardiac allograft survival by syngeneic hematopoietic stem/progenitor cell transplantation in mice

INTRODUCTION

Organ transplantation is a rapidly developing field, being the only effective treatment for end-stage organ disease. However, the associated immunosuppressant therapy has numerous direct and indirect adverse effects. Hematopoietic stem cell transplantation (HSCT), via immune reconstitution, offers an alternative method of treatment. In this study, we determined the cardiac allograft survival in mice treated with syngeneic HSCT or hematopoietic progenitor cell transplantation (HPCT).

METHODS

BALB/c and C57BL/6 mice were randomly divided into three groups. Mice in Group A (n=7) were untreated while those in Group B (n=8) and C (n=7) were treated with HPCT and HSCT, respectively. Cervical heterotopic cardiac transplantation models were established in all groups and cardiac grafts were observed throughout. Regulatory T (Treg) cell expression in peripheral blood was analyzed by flow cytometry. We recorded the cardiac allograft survival time and constructed Kaplan-Meier survival curves.

RESULTS

The number of Treg cells in Group B was significantly higher than that in Group C (P<0.05). The survival time of mice from each group differed significantly according to Kaplan-Meier/log-rank analysis (P<0.01). A total of 62.5% of the grafts in Group B showed long-term survival (>100 days); all the mice in Group A died within 9 days, compared with 59 days in Group C.

CONCLUSION

We conclude that syngeneic HSCT and HPCT can prolong cardiac allograft survival in mice. These two methods could be promising ways to induce immune tolerance in future organ transplantation.

Banking on cord blood stem cells

Umbilical cord blood gifted to non-profit public cord blood banks is now routinely used as an alternative source of haematopoietic stem cells for allogeneic transplantation for children and adults with cancer, bone marrow failure syndromes, haemoglobinopathies and many genetic metabolic disorders. Because of the success and outcomes of public cord banking, many companies now provide private cord banking services. However, in the absence of any published transplant evidence to support autologous and non-directed family banking, commercial cord banks currently offer a superfluous service.