Criteria for and outcomes of allogeneic haematopoietic stem cell transplant in children, adolescents and young adults with acute lymphoblastic leukaemia in first complete remission

A comprehensive comparison between TBI vs non-TBI-based conditioning regimen in pediatric patients with acute lymphoblastic leukemia: A systematic review and meta-analysis

INTRODUCTION

We aimed to evaluate the efficacy, safety, and latent toxicity of total body irradiation (TBI)-based conditioning regimens compared to non-TBI regimens for pediatric patients (under 18 years old) with acute lymphoblastic leukemia (ALL) undergoing allogeneic hematopoietic stem cell transplantation (HSCT).

METHODS

A systematic search was performed on MEDLINE, Scopus, WOS, and PMC. Also, a search for grey literature was performed on Google Scholar and relevant articles' references were included. Relevant articles which met the inclusion criteria were retrieved up to October 31th, 2022. CMA version 2 was used for the quantitative synthesis of the data.

RESULTS

Eight studies on efficacy and safety of TBI and non-TBI as a conditioning regimen were analyzed and six comparative studies on late toxicity were investigated. The meta-analysis revealed a hazard ratio (HR) of 1.508 (95% CI 0.96-2.35) for overall survival (OS) in instances of non-TBI conditioning. Also, an HR of 1.503 (95% CI 1.006-2.25) for disease-free- survival (DFS) favoring TBI-based conditioning. Late complications were reported to be significantly higher in the TBI conditioning regimen group than in the non-TBI group.

CONCLUSION

It appears that non-TBI regimens are as effective as TBI regimens in pediatrics with ALL regarding OS. Occurrence of latent toxicity is higher with TBI conditioning regimen. Conversely, TBI-based regimens are superior to non-TBI conditioning regimens regarding DFS. Considering all aspects, non-TBI conditioning regimens can be an alternative treatment option for pediatric ALL undergoing HSCT.

Mycobacterium abscessus pulmonary disease presenting with spontaneous pneumomediastinum and subcutaneous emphysema in childhood acute lymphoblastic leukemia: a case report and literature review

INTRODUCTION

Mycobacterium abscessus is a rapidly growing mycobacterium commonly identified in adults with underlying pulmonary diseases but is rarely observed in children. A better understanding of this pathogen in children is essential.

CASE PRESENTATION

We report the case of a 49-month-old female child without previous underlying pulmonary diseases but with acute lymphoblastic leukemia (ALL). The patient was complicated with pneumonia during chemotherapy, which was primarily characterized by spontaneous pneumomediastinum and subcutaneous emphysema on chest computed tomography (CT). M. abscessus sequences were detected by metagenomic next-generation sequencing in bronchoalveolar lavage fluid. With mechanical ventilation, closed thoracic drainage, and anti-infective therapy for 6 months, the patient's infection was controlled. The patient completed 2.5 years of treatment for ALL, and the drugs were discontinued. The patient currently remains in complete hematologic remission.

DISCUSSION

We reviewed the literature on 33 children with M. abscessus pulmonary disease. These children mostly had underlying immunodeficiency. Chest CT most often showed nodular shadows, consolidation, and bronchiectasis. Spontaneous pneumomediastinum and subcutaneous emphysema were not reported as major manifestations.

CONCLUSION

Spontaneous pneumomediastinum and subcutaneous emphysema were our patient's main characteristics on chest CT, and this study enriches the knowledge regarding possible imaging changes in M. abscessus pulmonary disease in children. This case report reflects good clinical experience in maintaining the balance between chemotherapy and anti-infective therapy in childhood ALL.

Recent advances of nanodrug delivery system in the treatment of hematologic malignancies

Although the survival rate of hematological malignancies (HM) has increased in recent years, the unnecessary adverse effect to the body is usually generated by the traditional chemotherapy for HM due to the lack of specificity to tumor tissue. Nanodrug delivery systems have exhibited unique advantages in targetability, stability and reducing toxicity, attracting wide concern, which is expected to be the prevalent alternative for the treatment of HM. In this review, we systemically introduced the current therapeutic strategies and the categories of HM. Subsequently, five key factors including circulation, targeting, penetration, internalization and release involving in tailoring nanoparticles were demonstrated, followed by the introduction of the development of nanodrug delivery-traditional synthetic nanomaterilas, biomimetic cell membrane coating nanomaterials, cell-based nanomaterials as well as immunotherapy combined with nanodrug. Afterwards, the recent advances of nanodrug delivery system for the treatment of HM were introduced. Moreover, the challenge and prospect of nanodrug delivery system in treating HM were discussed. The promising drug delivery system will provide new therapeutic avenues for the treatment of HM.

Adolescent and young adult (AYA) versus pediatric patients with acute leukemia have a significantly increased risk of acute GVHD following unrelated donor (URD) stem cell transplantation (SCT): the Children's Oncology Group experience

Adolescent and young adult (AYA) patients with acute leukemia (AL) have inferior outcomes in comparison to younger patients, and are more likely to develop acute and chronic GVHD than younger children following HLA matched sibling donor stem cell transplant (SCT). We compared the incidence of grade II-IV acute GVHD, chronic GVHD, and survival in AYA (age 13-21 years) to younger children (age 2-12 years) who received an unrelated donor SCT for acute leukemia on Children's Oncology Group trials between 2004-2017. One hundred and eighty-eight children and young adults ages 2-21 years underwent URD SCT. Sixty-three percent were aged 2-12 and 37% were age 13-21. Older age was a risk factor for grade II-IV acute GVHD in multivariate analysis with a hazard ratio (HR) of 1.95 [95% confidence interval (CI) 1.23-3.10], but not for chronic GVHD, HR 1.25 [95% CI 0.57-2.71]. Younger patients relapsed more often (34.5 ± 4.4% vs. 22.8 ± 4.0%, p = 0.032), but their Event-Free Survival (42.6 ± 4.7% vs. 51.8 ± 6.1%, p = 0.18) and Overall Survival at 5 years (48.5 ± 4.9% vs. 51.5 ± 6.4%, p = 0.56) were not different than AYA patients. AYA patients who receive an URD SCT for acute leukemia are significantly more likely to develop grade II-IV acute GVHD, though survival is similar.

Haploidentical hematopoietic stem cell transplantation may improve long-term survival for children with high-risk T-cell acute lymphoblastic leukemia in first complete remission

Background:

The role of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in children with high-risk (HR) T-cell acute lymphoblastic leukemia (T-ALL) in first complete remission (CR1) is still under evaluation. Moreover, relapse is the main factor affecting survival. This study aimed to explore the effect of allo-HSCT (especially haploidentical HSCT [haplo-HSCT]) on improving survival and reducing relapse for HR childhood T-ALL in CR1 and the prognostic factors of childhood T-ALL in order to identify who could benefit from HSCT.

Methods:

A total of 74 newly diagnosed pediatric T-ALL patients between January 1, 2012 and June 30, 2018 were enrolled in this retrospective study. Patients were stratified into the low-risk chemotherapy cohort (n = 16), HR chemotherapy cohort (n = 31), and HR transplant cohort (n = 27). Characteristics, survival outcomes, and prognostic factors of all patients were then analyzed.

Results:

Patient prognosis in the HR chemotherapy cohort was significantly worse than that in the low-risk chemotherapy cohort (5year overall survival [OS]: 58.5% vs. 100%, P = 0.003; 5-year event-free survival [EFS]: 54.1% vs. 83.4%, P = 0.010; 5-year cumulative incidence of relapse [CIR]: 45.2% vs. 6.3%, P = 0.011). In HR patients, allo-HSCT improved the 5-year EFS and CIR compared to that of chemotherapy (5-year EFS: 80.1% vs. 54.1%, P = 0.041; 5-year CIR: 11.6% vs. 45.2%, P = 0.006). The 5-year OS was higher in the HR transplant cohort than that in the HR chemotherapy cohort (81.0% vs. 58.5%, P = 0.084). Minimal residual disease re-emergence was an independent risk factor for 5-year OS, EFS, and CIR; age ≥10 years was an independent risk factor for OS and EFS; and high white blood cell count was an independent risk factor for EFS and CIR.

Conclusion:

Allo-HSCT, especially haplo-HSCT, could effectively reduce relapse of children with HR T-ALL in CR1.

Radiation-Free myeloablative allogeneic hematopoietic stem cell transplantation for adult acute lymphoblastic leukemia: A comparison of outcomes between patients with and without central nervous system involvement

For patients with acute lymphoblastic leukemia (ALL) undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT), total body irradiation (TBI) has been particularly advocated as a part of the conditioning regimen in case of extramedullary involvement in sanctuary sites such as the central nervous system (CNS), to ensure greater tissue penetration. In resource-limited countries lacking TBI facilities; however, ALL patients undergo radiation-free myeloablative conditioning, though its impacts on post-HSCT outcomes of the patients with pre-HSCT CNS involvement have not been analyzed. In this 14-year series of 278 adult (> 18 y) ALL patients undergoing TBI-free busulfan/cyclophosphamide conditioning allo-HSCT, we found that the long-term probabilities of overall survival, disease free survival, relapse and non-relapse mortality were not significantly different between CNS-involved and CNS-spared patients. Moreover, there was no statistically significant difference in the incidence of post-HSCT CNS relapse between CNS-involved and CNS-spared patients. Pre-HSCT cranial radiation therapy (CRT) showed no significant preventive effect on the likelihood of post-HSCT CNS relapse. Through multivariable regression analysis, grade III-IV acute graft-versus-host disease (GvHD), extensive chronic GvHD and post-HSCT relapse were ascertained as independent determinants of mortality (Adj.R² = 53.9 %, F_(12,265) = 28.1, P < 0.001), while other parameters including Philadelphia translocation, pre-HSCT CNS involvement and CRT were found to have no independent effect. Although this study was not an attempt to compare TBI-based vs. non-TBI conditioning, the TBI-free myeloablative allo-HSCT was shown to be feasible and an option for adult ALL patients with CNS involvement, considering the comparable outcomes between patients with and without CNS involvement.

Why Do Children with Acute Lymphoblastic Leukemia Fare Better Than Adults?

It is a new and exciting time for acute lymphoblastic leukemia (ALL). While nearly 50 years ago, only one in nine children with ALL survived with chemotherapy, nowadays nearly 90% of children have a chance of long-term survival. Adults with ALL, as well as the special category of adolescents and young adult (AYA) patients, are catching up with the new developments seen in children, but still their prognosis is much worse. A plethora of factors are regarded as responsible for the differences in treatment response, such as age, ethnicity, disease biology, treatment regimens and toxicities, drug tolerance and resistance, minimal residual disease evaluation, hematopoietic stem cell transplantation timing and socio-economic factors. Taking these factors into account, bringing pediatric-like protocols to adult patient management and incorporating new agents into frontline treatment could be the key to improve the survival rates in adults and AYA.

High preharvest donor Foxp3 mRNA level predicts late relapse of acute lymphoblastic leukaemia after haematopoietic stem cell transplantation

Objectives

The curative effect of allogeneic haematopoietic stem cell transplantation (HSCT) for acute leukaemia is due in part to the donor T cell–mediated graft‐versus‐leukaemia immune reaction (GvL). Several studies have suggested that donor CD25+CD4+Foxp3+regulator T cells (Tregs) may decrease graft‐versus‐host disease (GvHD) without abrogating GVL. This notion may need modification in acute lymphoblastic leukaemia (ALL).

Methods

Foxp3 mRNA level was measured by qPCR in preharvest donor blood CD4+ T cells. The study comprised 45 patients with ALL in 1st or 2nd CR who received myeloablative HSCT using T‐replete bone marrow grafts.

Results

Relapse occurred in 17 patients median 363 days after HSCT. The relapse risk was estimated by Cox univariate and multivariate proportional hazard regression. The proportionality assumption was met by analysing the preharvest donor Foxp3 mRNA level as a time‐dependent covariate. Early relapse was not modified by the Foxp3 mRNA level. However, a higher Foxp3 mRNA level was associated with a significantly increased relapse risk after day 363 after transplantation, compatible with inhibition of GvL. In contrast, a higher preharvest donor CD4+ T‐cell concentration was associated with reduced relapse risk.

Conclusion

A higher preharvest donor Foxp3 mRNA level may be predictive of late ALL relapse after HSCT.

The impact of donor type on the outcome of pediatric patients with very high risk acute lymphoblastic leukemia. A study of the ALL SCT 2003 BFM-SG and 2007-BFM-International SG

Allogeneic HSCT represents the only potentially curative treatment for very high risk (VHR) ALL. Two consecutive international prospective studies, ALL-SCT-(I)BFM 2003 and 2007 were conducted in 1150 pediatric patients. 569 presented with VHR disease leading to any kind of HSCT. All patients >2 year old were transplanted after TBI-based MAC. The median follow-up was 5 years. 463 patients were transplanted from matched donor (MD) and 106 from mismatched donor (MMD). 214 were in CR1. Stem cell source was unmanipulated BM for 330 patients, unmanipulated PBSC for 135, ex vivo T-cell depleted PBSC for 62 and cord-blood for 26. There were more advanced disease, more ex vivo T-cell depletion, and more chemotherapy based conditioning regimen for patients transplanted from MMD as compared to those transplanted from MSD or MD. Median follow up (reversed Kaplan Meier estimator) was 4.99 years, median follow up of survivals was 4.88, range (0.01–11.72) years. The 4-year CI of extensive cGvHD was 13 ± 2% and 17 ± 4% (p = NS) for the patients transplanted from MD and MMD, respectively. 4-year EFS was statistically better for patients transplanted from MD (60 ± 2% vs. 42 ± 5%, p < 0.001) for the whole cohort. This difference does not exist if considering separately patients treated in the most recent study. There was no difference in 4-year CI of relapse. The 4-year NRM was lower for patients transplanted from MD (9 ± 1% vs. 23 ± 4%, p < 0.001). In multivariate analysis, donor-type appears as a negative risk-factor for OS, EFS, and NRM. This paper demonstrates the impact of donor type on overall results of allogeneic stem cell transplantation for very-high risk pediatric acute lymphoblastic leukemia with worse results when using MMD stem cell source.

Allogeneic Stem Cell Transplantation from HLA-Mismatched Donors for Pediatric Patients with Acute Lymphoblastic Leukemia Treated According to the 2003 BFM and 2007 International BFM Studies: Impact of Disease Risk on Outcomes

Allogeneic hematopoietic stem cell transplantation (HSCT) is beneficial for pediatric patients with relapsed or (very) high-risk acute lymphoblastic leukemia (ALL) in remission. A total of 1115 consecutive patients were included in the ALL SCT 2003 BFM study and the ALL SCT 2007 I-BFM study and were stratified according to relapse risk (standard versus high versus very high risk of relapse) and donor type (matched sibling versus matched donor versus mismatched donor). A total of 148 patients (60% boys; median age, 8.7 years; B cell precursor ALL, 75%) were transplanted from mismatched donors, which was defined as either less than 9/10 HLA-compatible donors or less than 5/6 unrelated cord blood after myeloablative conditioning regimen (total body irradiation based, 67%) for high relapse risk (HRR; n = 42) or very HRR (VHRR) disease (n = 106). The stem cell source was either bone marrow (n = 31), unmanipulated peripheral stem cells (n = 28), T cell ex vivo depleted peripheral stem cells (n = 59), or cord blood (n = 25). The median follow-up was 5.1 years. The 4-year rates of overall survival (OS) and event-free survival were 56% ± 4% and 52% ± 4%, respectively, for the entire cohort. Patients transplanted from mismatched donors for HRR disease obtained remarkable 4-year OS and event-free survival values of 82% ± 6% and 80% ± 6%, respectively, whereas VHRR patients obtained values of 45% ± 5% and 42% ± 5% (P < .001), respectively. The cumulative incidence of relapse was 29% ± 4% and that of nonrelapse mortality 19% ± 3%. The cumulative incidence of limited and extensive chronic graft-versus-host disease was 13% ± 3% and 15% ± 4%, respectively, among the 120 patients living beyond day 100. Multivariate analysis showed that OS was lower for transplanted VHRR patients (P = .002; hazard ratio [HR], 3.62; 95% confidence interval [CI], 1.60 to 8.20) and for patients beyond second complete remission (CR2) versus first complete remission (P < .001; HR, 3.68; 95% CI, 1.79 to 7.56); relapse occurred more frequently in patients with VHRR disease (P = .026; HR, 3.30; 95% CI, 1.16 to 9.60) and for those beyond CR2 (P = .005; HR, 4.16; 95% CI, 1.52 to 10.59). Nonrelapse mortality was not significantly higher for cytomegalovirus-positive recipients receiving cytomegalovirus-negative grafts (P = .12; HR, 1.96; 95% CI, .84 to 4.58). HSCT with a mismatched donor is feasible in pediatric ALL patients but leads to inferior results compared with HSCT with better matched donors, at least for patients transplanted for VHRR disease. The results are strongly affected by disease status. The main cause of treatment failure is still relapse, highlighting the urgent need for interventional strategies after HSCT for patients with residual leukemia before and/or after transplantation.

Recent advances and novel treatment paradigms in acute lymphocytic leukemia

This is an exciting time in the treatment of acute lymphoblastic leukemia (ALL) given the advances in the relapsed/refractory setting. The development of antibody treatments (including antibody drug conjugates with toxins) offers a different treatment approach compared with conventional chemotherapy regimens. Moreover, the use of bispecific T-cell-engager antibodies (BiTEs) such as blinatumomab harness the cytotoxic activity of T cells against CD19-positive lymphoblasts. Another strategy involves the use of chimeric antigen receptor (CAR) T cells. CAR T cells have demonstrated promising results in the relapsed/refractory setting. However, the use of BiTEs and CAR T cells is also associated with a distinct set of adverse reactions that must be taken into account by the treating physician. Apart from the above strategies, the use of other targeted therapies has attracted interest. Namely, the discovery of the Philadelphia (Ph)-like signature in children and young adults with ALL has led to the use of tyrosine kinase inhibitors (TKI) in these patients. The different drugs and strategies that are being tested in the relapsed/refractory ALL setting pose a unique challenge in identifying the optimum sequence of treatment and determining which approaches should be considered for frontline treatment.

Haploidentical hematopoietic stem cell transplantation for paediatric high-risk T-cell acute lymphoblastic leukaemia

Paediatric HR T-cell ALL demonstrates dismal prognosis with chemotherapy, and poor outcomes could be improved with allo-SCT. HID-SCT is an almost immediately available choice; however, few studies have focused on the outcomes of HID-SCT for paediatric HR T-ALL. Forty-eight consecutive HR T-ALL children who underwent HID-SCT were included. Survival outcomes and factors predictive of outcomes were retrospectively analysed. Of the 48 patients, 35 were in CR1, 10 in CR2, and three in relapse. The cumulative incidence of grade 3/4 aGVHD was 10.4% and that of extensive cGVHD was 28.4%. The CIR at three yr was 30.8% and that of NRM at three yr was 14.7%. At a median follow-up of 20.0 (range 2.5-124.2) months, the three-yr LFS was 54.4%. Children who received transplants during CR1 had a better LFS (65.7% vs. 26.0%, p = 0.008) and a lower relapse rate (19.8% vs. 56.7%, p = 0.014) compared to those during non-CR1. HID-SCT is feasible for HR T-ALL children, and survival outcomes are better when performed in CR1 compared to non-CR1. Prospective clinical trials would be needed to confirm that.

Comparison of survival of adolescents and young adults with hematologic malignancies in Osaka, Japan

The survival gap between adolescents and young adults (AYAs) with hematological malignancies persists in many countries. To determine to what extent it does in Japan, we investigated survival and treatment regimens in 211 Japanese AYAs (15-29 years) in the Osaka Cancer Registry diagnosed during 2001-2005 with hematological malignancies, and compared adolescents (15-19 years) with young adults (20-29 years). AYAs with acute lymphoblastic leukemia (ALL) had a poor 5-year survival (44%), particularly young adults (29% vs. 64% in adolescents, p = 0.01). Additional investigation for patients with ALL revealed that only 19% of young adults were treated with pediatric treatment regimens compared with 45% of adolescents (p = 0.05). Our data indicate that we need to focus on young adults with ALL and to consider establishing appropriate cancer care system and guidelines for them in Japan.

Increased μ-Calpain Activity in Blasts of Common B-Precursor Childhood Acute Lymphoblastic Leukemia Correlates with Their Lower Susceptibility to Apoptosis

Childhood acute lymphoblastic leukemia (ALL) blasts are characterized by inhibited apoptosis promoting fast disease progress. It is known that in chronic lymphocytic and acute myeloid leukemias the reduced apoptosis is strongly related with the activity of calpain-calpastatin system (CCS) composed of cytoplasmic proteases—calpains—performing the modulatory proteolysis of key proteins involved in cell proliferation and apoptosis, and of their endogenous inhibitor—calpastatin. Here, the CCS protein abundance and activity was for the first time studied in childhood ALL blasts and in control bone marrow CD19⁺ B cells by semi-quantitative flow cytometry and western blotting of calpastatin fragments resulting from endogenous calpain activity. Significantly higher μ-calpain (CAPN1) gene transcription, protein amounts and activity (but not those of m-calpain), with calpastatin amount and transcription of its gene (CAST) greatly varying were observed in CD19⁺ ALL blasts compared to control cells. Significant inverse relation between the amount/activity of calpain and spontaneous apoptosis was noted. Patients older than 10 years (considered at higher risk) displayed increased amounts and activities of blast calpain. Finally, treatment of blasts with the tripeptide calpain inhibitors II and IV significantly and in dose-dependent fashion increased the percentage of blasts entering apoptosis. Together, these findings make the CCS a potential new predictive tool and therapeutic target in childhood ALL.

Exploring the Cancer Experiences of Young Adults in the Context of Stem Cell Transplantation

BACKGROUND

Cancer is the leading cause of nonaccidental morbidity and mortality among young adults (YAs) in the United States. Stem cell transplantation (SCT), a treatment modality for a variety of YA malignancies, often requires prolonged hospitalization and immune-compromising treatment regimens. Stem cell transplantation may isolate YAs physically and emotionally, contributing to uncertainty about treatment processes, outcomes, and long-term sequelae. Studies in this population suggest that uncertainty can contribute to difficulty accomplishing basic developmental tasks. Few studies have examined the experiences of YAs in active cancer treatment, particularly those undergoing SCT.

OBJECTIVES

This study explored the cancer experiences of YAs aged 18 to 25 years leading up to SCT and explored how YAs construct issues of uncertainty related to the transplantation experience.

METHODS

Interviews with 14 YAs conducted within 24 hours of admission to undergo SCT were analyzed using thematic analysis from a medical ethnographic perspective.

RESULTS

Themes emerged within 2 domains: relational and psychoemotional. The relational theme of "altered relationships" included the subthemes of "moving from" and "moving toward." The psychoemotional theme of the "power of perspective" included the subthemes of "optimism," "acknowledgment of death," "informational empowerment," and "developing a new outlook."

CONCLUSIONS

Our findings offer new insights into the YA experience in the context of active cancer treatment, specifically how the cancer experience impacts relationships and how this experience is influenced by YAs' perspectives.

IMPLICATIONS FOR PRACTICE

This study provides a foundation for addressing the psychosocial needs of YAs hospitalized for SCT, paying particular attention to the development of specific interventions.

Transcriptome Analysis of Minimal Residual Disease in Subtypes of Pediatric B Cell Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is the most common childhood cancer and the leading cause of cancer-related death in children and adolescents. Minimal residual disease (MRD) is a strong, independent prognostic factor. The objective of this study was to identify molecular signatures distinguishing patients with positive MRD from those with negative MRD in different subtypes of ALL, and to identify molecular networks and biological pathways deregulated in response to positive MRD at day 46. We compared gene expression levels between patients with positive MRD and negative MRD in each subtype to identify differentially expressed genes. Hierarchical clustering was applied to determine their functional relationships. We identified subtype-specific gene signatures distinguishing patients with positive MRD from those with negative MRD. We identified the genes involved in cell cycle, apoptosis, transport, and DNA repair. We also identified molecular networks and biological pathways dysregulated in response to positive MRD, including Granzyme B, B-cell receptor, and PI3K signaling pathways.

Treatment of pediatric acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is the most common pediatric oncologic diagnosis, and advances in its treatment have led to progressive improvements in survival. The 4 main components of therapy are remission induction, consolidation, maintenance, and central nervous system-directed therapy, and usually last 2 to 3 years. Treatment intensity based on risk-based stratification is the cornerstone of treatment. Patients with features of more favorable disease are spared the more toxic effects of chemotherapy, whereas more aggressive regimens are reserved for those with higher-risk disease. Prognosis of relapsed pediatric ALL depends primarily on duration of remission and site of relapse.

Treatment of adolescent and young adults with acute lymphoblastic leukemia

The primary objective of this review was to update and discuss the current concepts and the results of the treatment of acute lymphoblastic leukemia (ALL) in adolescents and young adults (AYA). After a brief consideration of the epidemiologic and clinicobiologic characteristics of ALL in the AYA population, the main retrospective comparative studies stating the superiority of pediatric over adult-based protocols were reviewed. The most important prospective studies in young adults using pediatric inspired or pediatric unmodified protocols were also reviewed emphasizing their feasibility at least up to the age of 40 yr and their promising results, with event-free survival rates of 60–65% or greater. Results of trials from pediatric groups have shown that the unfavourable prognosis of adolescents is no more adequate. The majority of the older adolescents with ALL can be cured with risk-adjusted and minimal residual disease-guided intensive chemotherapy, without stem cell transplantation. However, some specific subgroups, which are more frequent in adolescents than in children (e.g., early pre-T, iAMP21, and BCR-ABL-like), deserve particular attention. In summary, the advances in treatment of ALL in adolescents have been translated to young adults, and that explains the significant improvement in survival of these patients in recent years.

Upregulation of NKG2D ligands in acute lymphoblastic leukemia and non-Hodgkin lymphoma cells by romidepsin and enhanced in vitro and in vivo natural killer cell cytotoxicity

BACKGROUND AIMS

There is a critical need to prevent and/or treat hematological relapse after allogeneic hematopoietic stem cell transplantation. The activating NKG2D receptor expressed on natural killer (NK) cells, when engaged by its corresponding ligands (MIC A/B), activates NK cells to become cytotoxic against malignant cells.

METHODS

We incubated acute lymphoblastic leukemia and non-Hodgkin lymphoma cells for 24 h with 10 ng/mL of romidepsin. Flow cytometry was performed to demonstrate changes in surface expression of NKG2D ligands MIC A/B. In vitro and in vivo cytotoxicity was measured by means of modified Europium assay, and non-obese diabetic/severe combined immunodeficiency mice were xenografted with RS 4:11 cells.

RESULTS

We demonstrated an approximately 50, 200, 1300 and 180-fold increase in the number of cells positive for the surface expression of MIC A/B in RS 4:11 (P < 0.001), REH (P < 0.001), Ramos (P < 0.001) and Jurkat cells (P < 0.001), respectively. We further demonstrated a significant increase in NK cell-mediated in vitro cytotoxicity against RS 4:11 (P < 0.004), Ramos (P < 0.05), Jurkat (P < 0.001) and REH cells (P < 0.01), respectively. Romidepsin-mediated NK cytotoxicity was blocked by pre-incubating NK cells with anti-NKG2D-Fc in RS 4:11 (P < 0.03) and Ramos cells (P < 0.01), respectively. Finally, non-obese diabetic/severe combined immunodeficiency mice xenografted with RS 4:11 cells had a significant increase in survival (P < 0.02) in mice treated with romidepsin and interleukin-2-activated NK cells compared with each of these other treatment groups.

CONCLUSIONS

Romidepsin significantly enhanced in vitro and in vivo NK cell cytotoxicity mediated in part by increased MIC A/B expression on malignant cells. This translational approach of the use of romidepsin and interleukin-2-activated NK cells should be considered in patients with relapsed/refractory leukemia or lymphoma.

New frontiers in pediatric Allo-SCT

The inaugural meeting of 'New Frontiers in Pediatric Allogeneic Stem Cell Transplantation' organized by the Pediatric Blood and Transplant Consortium (PBMTC) was held at the American Society of Pediatric Hematology and Oncology Annual Meeting. This meeting provided an international platform for physicians and investigators active in the research and utilization of pediatric Allo-SCT in children and adolescents with malignant and non-malignant disease (NMD), to share information and develop future collaborative strategies. The primary objectives of the conference included: (1) to present advances in Allo-SCT in pediatric ALL and novel pre and post-transplant immunotherapy; (2) to highlight new strategies in alternative allogeneic stem cell donor sources for children and adolescents with non-malignant hematological disorders; (3) to discuss timing of immune reconstitution after Allo-SCT and methods of facilitating more rapid recovery of immunity; (4) to identify strategies of utilizing Allo-SCT in pediatric myeloproliferative disorders; (5) to develop diagnostic and therapeutic approaches to hematological complications post pediatric Allo-SCT; (6) to enhance the understanding of new novel cellular therapeutic approaches to pediatric malignant and non-malignant hematological disorders; and (7) to discuss optimizing drug therapy in pediatric recipients of Allo-SCT. This paper will provide a brief overview of the conference.

Relationship between cytomegalovirus (CMV) reactivation, CMV-driven immunity, overall immune recovery and graft-versus-leukaemia effect in children

The interplay between immune recovery, cytomegalovirus (CMV)-reactivation, CMV-driven immunity and graft-versus-leukaemia effect (GVL) was analysed in 108 children (median age: 8 years) who underwent haematopoietic-stem cell transplantation (HSCT) for acute leukaemia. Follow-up was 2 years unless death or relapse occurred. CMV-polymerase chain reaction (PCR) was programmed weekly until month +3 post-HSCT. Immunomonitoring consisted of sequential lymphocyte subset enumerations and analyses of T-cell proliferative and γ-interferon responses to CMV and to adenovirus. In the 108 recipients, the 2-year relapse rate (RR) was 25% (median time to onset 4·5 months; range: 24 d-17 months). CMV reactivation occurrence was 31% (median time to onset 26 d). Donor/recipient CMV serostatus did not influence RR. Among the 89 recipients disease-free after day +120, i) early CMV-reactivation before day +30 was more frequent (P = 0·01) in the relapse recipient group opposed to the non-relapse group. ii) CD8(+) /CD28(-) and CD4(+) CD45RA(-) T-cell expansions induced by CMV did not influence RR, iii) Recovery of anti-CMV and also anti-adenovirus immunity and of naïve CD4(+) T-cells was faster in the non-relapse group (P = 0·008; 0·009 and 0·002 respectively). In contrast to adult acute myeloid leukaemia, CMV reactivation was associated with increased RR in this paediatric series. Accelerated overall immune recovery rather than CMV-driven immunity had a favourable impact on RR.