Reduced intensity conditioning in unrelated donor transplantation for refractory cytopenia in childhood

Childhood myelodysplastic syndromes: Is cytoreductive therapy useful before allogeneic hematopoietic stem cell transplantation?

For most patients with childhood myelodysplastic syndrome (cMDS), allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains the only curative option. In the case of increased blasts (cMDS-IB), the benefit of pretransplant cytoreductive therapy remains controversial. In this multicenter retrospective study, the outcomes of all French children who underwent allo-HSCT for cMDS reported in the SFGM-TC registry between 2000 and 2020 were analyzed (n = 84). The median age at transplantation was 10.2 years. HSCT was performed from matched sibling donors (MSD) in 29% of the cases, matched unrelated donors (MUD) in 44%, haploidentical in 6%, and cord blood in 21%. Myeloablative conditioning was used in 91% of cases. Forty-eight percent of patients presented with cMDS-IB at diagnosis (median BM blasts: 8%). Among them, 50% received pretransplant cytoreductive therapy. Five-year overall survival (OS), cumulative incidence of nonrelapse mortality (NRM), and relapse were 67%, 26%, and 12%, respectively. Six-month cumulative incidence of grade II-IV acute graft-versus-host disease was 46%. Considering the whole cohort, age under 12, busulfan/cyclophosphamide/melphalan conditioning or MUD were associated with poorer 5-year OS. In the cMDS-IB subgroup, pretransplant cytoreductive therapy was associated with a better OS in univariate analysis. This seems to be mainly due to a decreased NRM since no impact on the incidence of relapse was observed. Overall, those data may argue in favor of cytoreduction for cMDS-IB. They need to be confirmed on a larger scale and prospectively.

The different faces of GATA2 deficiency: implications for therapy and surveillance

GATA2 deficiency is one of the most common genetic predispositions to pediatric myelodysplastic syndrome (MDS) in children and adolescents. The wide spectrum of disease comprises, among others, hematological, immunological and pulmonary manifestations, as well as occasionally distinct organ anomalies. Due to the elevated risk of progression, nearly all individuals with GATA2-related MDS eventually undergo a hematopoietic stem cell transplantation (HSCT) at some point in their lives. Nevertheless, the optimal timing, method, and even the indication for HSCT in certain cases are still matter of debate and warrant further research. In this article, we report five patients with different hematological and immunological manifestations of GATA2 deficiency ranging from immunodeficiency and refractory cytopenia of childhood without chromosomal aberrations to relapsed MDS-related acute myeloid leukemia. We discuss the adopted strategies, including intensity of surveillance, indication and timing of HSCT, based on morphological, clinical and molecular markers, as well as individual patient needs. We conclude that a better characterization of the natural disease course, a better understanding of the prognostic significance of somatic aberrations and a thorough evaluation of patients´ perspectives and preferences are required to achieve a personalized approach aimed at improving the care of these patients.

Decitabine-containing conditioning improved outcomes for children with higher-risk myelodysplastic syndrome undergoing allogeneic hematopoietic stem cell transplantation

Myelodysplastic syndrome (MDS) is a rare clonal hematopoietic disorder in children. The risk stratification system and treatment strategy for adults are unfit for children. The role of hypomethylating agents (HMAs) in higher-risk childhood MDS has not been identified. This study aimed to investigate the outcomes of hematopoietic stem cell transplantation (HSCT) in children with higher-risk MDS at one single center. A retrospective study was conducted in children with higher-risk MDS undergoing HSCT between September 2019 and March 2023 at Blood Diseases Hospital CAMS. The clinical characteristics and transplantation information were reviewed and analyzed. A total of 27 patients were analyzed, including 11 with MDS with excess blasts (MDS-EB), 14 with MDS-EB in transformation (MDS-EBt) or acute myeloid leukemia with myelodysplasia-related changes (AML-MRC), and 2 with therapy-related MDS/AML (t-MDS/AML). Eight patients harbored monosomy 7. Before transplantation, induction therapy was administered to 25 patients, and 19 of them achieved bone marrow blasts <5% before HSCT. The stem cell source was unmanipulated-related bone marrow or peripheral blood stem cells for nineteen patients and unrelated cord blood for eight. All patients received decitabine-containing and Bu/Cy-based myeloablative conditioning; 26 patients achieved initial engraftment. The cumulative incidences of grade II-IV and grade III-IV acute graft-versus-host disease (GvHD) at 100 days were 65.4% and 42.3%, respectively. The incidence of cGvHD was 38.5%. The median follow-up was 26 (range 4-49) months after transplantation. By the end of follow-up, two patients died of complications and two died of disease progression. The probability of 3-year overall survival (OS) was 84.8% (95%CI, 71.1 to 98.5%). In summary, decitabine-containing myeloablative conditioning resulted in excellent outcomes for children with higher-risk MDS undergoing allogeneic HSCT.

Pediatric Bone Marrow Failure: A Broad Landscape in Need of Personalized Management

Irreversible severe bone marrow failure (BMF) is a life-threatening condition in pediatric patients. Most important causes are inherited bone marrow failure syndromes (IBMFSs) and (pre)malignant diseases, such as myelodysplastic syndrome (MDS) and (idiopathic) aplastic anemia (AA). Timely treatment is essential to prevent infections and bleeding complications and increase overall survival (OS). Allogeneic hematopoietic stem cell transplantation (HSCT) provides a cure for most types of BMF but cannot restore non-hematological defects. When using a matched sibling donor (MSD) or a matched unrelated donor (MUD), the OS after HSCT ranges between 60 and 90%. Due to the introduction of post-transplantation cyclophosphamide (PT-Cy) to prevent graft versus host disease (GVHD), alternative donor HSCT can reach similar survival rates. Although HSCT can restore ineffective hematopoiesis, it is not always used as a first-line therapy due to the severe risks associated with HSCT. Therefore, depending on the underlying cause, other treatment options might be preferred. Finally, for IBMFSs with an identified genetic etiology, gene therapy might provide a novel treatment strategy as it could bypass certain limitations of HSCT. However, gene therapy for most IBMFSs is still in its infancy. This review summarizes current clinical practices for pediatric BMF, including HSCT as well as other disease-specific treatment options.

Thiotepa-fludarabine-treosulfan conditioning for 2nd allogeneic HCT from an alternative unrelated donor for patients with AML: a prospective multicenter phase II trial

Therapeutic options for patients with AML relapsing after allogeneic HCT range from chemotherapy or hypomethylating agents with or without donor lymphocyte infusions to a 2nd allogeneic HCT. Available data are based on retrospective single center or registry studies. The aim of this multicenter trial was to investigate prospectively intensive conditioning with Thiotepa, Fludarabine and Treosulfan (TFT) for 2nd allogeneic HCT from an alternative unrelated donor in patients with AML relapse > 6 months after a 1st allogeneic HCT. Primary endpoint was disease-free survival (DFS) at one year after 2nd HCT. 50 patients median age 53.5 years, in CR/PR (34%) or active relapse (66%) were included. 33 of 38 patients (86.8%) with available data achieved CR 100 days post transplant. 23 patients were alive and free of relapse at primary endpoint one year after 2nd HCT (DFS rate 0.46, 95%-CI (0.32-0.61). Three-year rates of DFS, relapse, non-relapse mortality, and overall survival were 0.24, 95%-CI (0.13-0.36); 0.36 (0.25-0.52); 0.40 (0.29-0.57); and 0.24 (0.13-0.37). Second HCT with TFT conditioning is feasible and has high anti-leukemic efficacy in chemosensitive or refractory AML relapse after prior allogeneic HCT. Still, relapse rates and NRM after 2nd allogeneic HCT remain a challenge. The trial is registered in the German Clinical Trials Registry (number DRKS00005126).

The effect of decitabine-combined minimally myelosuppressive regimen bridged allo-HSCT on the outcomes of pediatric MDS from 10 years' experience of a single center

Background

Myelodysplastic syndrome (MDS) is a rare disease in children and the treatment option before the allogeneic hematopoietic stem cell transplantation (allo-HSCT) is rarely reported. Our main objective was to report our single-center experience with the DNA-hypomethylating agent, decitabine-combined minimally myelosuppressive regimen (DAC + MMR) bridged allo-HSCT in children with MDS.

Methods

Twenty-eight children with de novo MDS who underwent allo-HSCT between 2011 and 2020 were enrolled. Patients were divided into subgroups (refractory cytopenia of childhood [RCC] and advanced MDS [aMDS]) and treated by HSCT alone or pre-transplant combination treatment based on risk stratification. The patients’ clinical characteristics, treatment strategies and outcomes were retrospectively evaluated.

Results

Twenty patients with aMDS had received pre-transplant treatment (three were treated with decitabine alone, thirteen with DAC + MMR, and four with acute myeloid leukemia type [AML-type] induction therapy). DAC + MMR was well tolerated and the most common adverse events were myelosuppression and gastrointestinal reaction. DAC + MMR had shown an improved marrow complete remission (mCR) compared with AML-type chemotherapy (13/13, 100% versus 2/4, 50%, P = 0.044). The median follow-up for total cohort was 53.0 months (range, 2.3-127.0 months) and the 4-year overall survival (OS) was 71.4 ± 8.5%. In the subgroup of aMDS, pretreatment of DAC + MMR resulted in a much better survival rate than AML-type chemotherapy (84.6 ± 10.0% versus 0.0 ± 0.0%, P < 0.001).

Conclusions

The DAC + MMR bridged allo-HSCT may be recommended as a novel and effective approach.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03376-1.

Prospective validation of the provisional entity of refractory cytopenia of childhood, proposed by the World Health Organization

In 2008, the World Health Organization proposed a new entity of childhood myelodysplastic syndrome (MDS), which was referred to as refractory cytopenia of childhood (RCC). However, whether this morphological classification reflects clinical outcomes remains unclear. We performed a prospective evaluation of bone marrow morphology in 252 children with acquired bone marrow failure between 2009 and 2013. Of 252 patients, 63 were diagnosed with aplastic anaemia (AA), 131 with RCC without multilineage dysplasia (RCC-w/o-MLD) and 58 with RCC with MLD (RCC-MLD). One patient with AA, three with RCC-w/o-MLD and nine with RCC-MLD presented with chromosomal abnormalities at diagnosis (P = 0·001). The response rates to immunosuppressive therapy (IST) at 6 months and the cumulative incidence of clonal evolution at 5 years did not significantly differ among the three groups. A multivariate analysis revealed that the morphological classification of RCC-MLD was a significant risk factor for secondary graft failure after haematopoietic cell transplantation (HCT) (P = 0·003). In view of these findings, RCC could be divided into two categories, RCC-w/o-MLD and RCC-MLD, because children with this condition exhibited a distinct morphology, frequent chromosomal abnormalities at diagnosis and a high frequency of secondary graft failure after HCT.

Pediatric Myelodysplastic Syndromes

Pediatric myelodysplastic syndromes (MDS) comprise less than 5% of childhood malignancies. Approximately 30% to 45% of pediatric MDS cases are associated with an underlying genetic predisposition syndrome. A subset of patients present with MDS/acute myeloid leukemia (AML) following intensive chemotherapy for an unrelated malignancy. A definitive diagnosis of MDS can often only be rendered pending a comprehensive clinical and laboratory-based evaluation, which frequently includes ancillary testing in a reference laboratory. Clinical subtypes, the current diagnostic schema, and the results of more recently performed next-generation sequencing studies in pediatric MDS are discussed here.

Unmanipulated haploidentical hematopoietic stem cell transplantation for children with myelodysplastic syndrome

Myelodysplastic syndrome (MDS) is a heterogeneous group of clonal disorders and is rare in children. Allogeneic hematopoietic stem cell transplantation (HSCT) is commonly used in children with MDS with excess blasts and in patients with refractory cytopenia of childhood (RCC) associated with monosomy 7, complex karyotype, severe neutropenia, or transfusion dependence. We recruited 27 children with MDS who received haploidentical hematopoietic stem cell transplantation (haplo-HSCT). At transplantation, 10 patients had RCC, 12 patients had advanced MDS (RAEB and RAEB-T), and 5 patients had myelodysplasia-related acute myeloid leukemia (MDR-AML). All patients received granulocyte colony-stimulating factor (G-CSF)-mobilized bone marrow cells and peripheral blood stem cells. At a median follow-up of 24.1 months (range: 2.0-74.5 months) after HSCT, the estimated probabilities of 3-year disease-free survival (DFS) and overall survival (OS) were both 81.9% (95% CI, 66.8-100.0%). The estimated 3-year incidences of relapse (CIR) and non-relapse mortality (NRM) were both 7.4% (95% CI, 1.2%-21.4%). The 100-day cumulative incidence of grade II-IV aGVHD was 52.6% (95% CI, 42.9-62.3%), while that of grade III-IV aGVHD was 11.1% (95% CI, 5.1-17.1%). The 3-year cumulative incidences of overall and extensive cGVHD were 42.3% (95% CI, 19.8%-57.5%) and 21.1% (95% CI, 2.5%-63.2%), respectively. Univariate analysis showed that chronic GVHD significantly affected OS and DFS. Haploidentical HSCT may be an effective treatment option with easier donor availability for pediatric patients with MDS.

Outcome of allogeneic hematopoietic stem cell transplantation for hypoplastic myelodysplastic syndrome

The prognosis of patients with hypoplastic myelodysplastic syndrome (hMDS) after receiving allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains unclear. This study aimed to evaluate the outcomes of patients with hMDS after allo-HSCT. Between September 2013 and October 2019, a total of 20 consecutive patients with hMDS and 1 patient with clonal cytopenia of undermined significance (CCUS) who underwent allo-HSCT, which included procedures with 9 matched sibling donors, 2 matched unrelated donors, 4 mismatched unrelated donors and 6 haploidentical donors, were enrolled in this study. The median time for myeloid engraftment was 11 days (range 9-17 days), and that for platelet engraftment was 10 days (range 7-17 days). The cumulative incidence (CI) of myeloid and platelet recovery was 95.2 ± 6.0% and 90.5 ± 7.3%, respectively. The CI rates were 40.0 ± 11.3% for grades II-III acute graft-versus-host disease (GVHD), 36.8 ± 11.5% for chronic GVHD and 23.8 ± 9.6% for nonrelapse mortality. No patients experienced relapse. Sixteen surviving patients were followed up for a median of 1113 days (range 110-2305 days), and the overall survival and relapse-free survival rates were both 72.7 ± 10.6%. This limited retrospective analysis suggests that patients with hMDS had a favorable survival after allo-HSCT.

Conditioning regimen for allogeneic bone marrow transplantation in children with acquired bone marrow failure: fludarabine/melphalan vs. fludarabine/cyclophosphamide

Fludarabine/cyclophosphamide-based conditioning regimens are standard in bone marrow transplantation (BMT) for acquired bone marrow failure in children, however, graft failure may occur. Using the data from a nationwide transplantation registry, we compared the outcomes of children aged <16 years with acquired aplastic anemia and refractory cytopenia of childhood who underwent allogeneic BMT with either fludarabine/melphalan (n = 71) or fludarabine/cyclophosphamide (n = 296) between 2000 and 2016. The fludarabine/melphalan regimen provided excellent outcomes, with 3-year overall survival and failure-free survival rates of 98% and 97%, respectively. The 83% 3-year failure-free survival in the fludarabine/cyclophosphamide group was significantly inferior (P = 0.002), whereas the overall survival did not differ between the two groups. Late graft failure was the most common cause of treatment failure in the fludarabine/cyclophosphamide group, which experienced a significantly higher incidence of late graft failure than the fludarabine/melphalan group (11% vs. 3%; P = 0.035). Multivariate analyses showed that the fludarabine/melphalan regimen was associated with a better failure-free survival (hazard ratio [HR] 0.12; P = 0.005) and lower risk of late graft failure (HR 0.16; P = 0.037). Fludarabine/melphalan-based conditioning regimen can be a promising option for children with acquired bone marrow failure receiving BMT.

Improved outcomes of allogeneic hematopoietic stem cell transplantation including haploidentical transplantation for childhood myelodysplastic syndrome

This retrospective study aimed to investigate the outcomes of allogeneic hematopoietic stem cell transplantation (HSCT) for childhood myelodysplastic syndrome (MDS). Thirty-six patients (low-grade MDS, 24; advanced MDS, 12) received HSCT at the Asan Medical Center over two decades (early period, 1997-2007; recent period, 2008-2017). The transplantation outcomes were analyzed according to disease status, conditioning regimen, various donor types, and period of HSCT. During a median follow-up of 5.6 (range, 1.4-21.1) years, the probability of overall survival (OS) and failure-free survival was 77% and 69%, respectively. The cumulative incidence of transplantation-related mortality (TRM) was 12%. Significantly reduced TRM and improved OS were observed in patients who received HSCT during the recent period vs. the early period (TRM, 4% vs. 30%, P = 0.021; OS, 87% vs. 50%, P = 0.006). Comparable outcomes were observed for HSCT from haploidentical family donors vs. HLA-identical donors (TRM, 10% vs. 14%, P= 0.837; OS, 86% vs. 79%, P = 0.625). This study identified the improved outcomes of allogeneic HSCT for childhood MDS over time, in addition, the feasible outcomes of haploidentical HSCT suggested its use as an attractive alternative in the future procedures.

Myelodysplastic syndromes in children

PURPOSE OF REVIEW

Myelodysplastic syndromes (MDSs) are rare disorders in children, showing peculiar clinical manifestations and biological features. This review will summarize biological, genetic and clinical features of childhood MDS and will provide an update of the algorithm of treatment of the different disease variants.

RECENT FINDINGS

The most recent classification of MDS includes refractory cytopenia of childhood (RCC), advanced and therapy-related MDS. Importantly, in children, these clonal hematopoietic disorders may be often associated with inherited bone marrow failure syndromes, this representing a challenge for diagnostic work-up and treatment. Moreover, germline syndromes predisposing to develop MDS/acute myeloid leukemia have been recently identified, such as those caused by mutations in GATA2, ETV6, SRP72 and SAMD9/SAMD9-L.

SUMMARY

Treatment of childhood MDS varies according to specific disease features; allogeneic hematopoietic stem cell transplantation (HSCT) using a Human Leukocyte antigen (HLA)-identical donor, whenever available, represents the treatment of choice for most of these children. HSCT is indicated in MDS with excess of blasts, or in therapy-related MDS. For RCC patients, HSCT is recommended for RCC associated with monosomy 7, or complex karyotype and for patients showing severe neutropenia or transfusion dependence. Novel approaches of HSCT from an HLA-haploidentical relative after selective graft manipulation allow reducing transplant-related complications.

How I treat myelodysplastic syndromes of childhood

Pediatric myelodysplastic syndromes (MDSs) are a heterogeneous group of clonal disorders with an annual incidence of 1 to 4 cases per million, accounting for less than 5% of childhood hematologic malignancies. MDSs in children often occur in the context of inherited bone marrow failure syndromes, which represent a peculiarity of myelodysplasia diagnosed in pediatric patients. Moreover, germ line syndromes predisposing individuals to develop MDS or acute myeloid leukemia have recently been identified, such as those caused by mutations in GATA2, ETV6, SRP72, and SAMD9/SAMD9-L Refractory cytopenia of childhood (RCC) is the most frequent pediatric MDS variant, and it has specific histopathologic features. Allogeneic hematopoietic stem cell transplantation (HSCT) is the treatment of choice for many children with MDSs and is routinely offered to all patients with MDS with excess of blasts, to those with MDS secondary to previously administered chemoradiotherapy, and to those with RCC associated with monosomy 7, complex karyotype, severe neutropenia, or transfusion dependence. Immune-suppressive therapy may be a treatment option for RCC patients with hypocellular bone marrow and the absence of monosomy 7 or a complex karyotype, although the response rate is lower than that observed in severe aplastic anemia, and a relevant proportion of these patients will subsequently need HSCT for either nonresponse or relapse.

Myelodysplastic and myeloproliferative disorders of childhood

Myelodysplastic syndrome (MDS) and myeloproliferative disorders are rare in children; they are divided into low-grade MDS (refractory cytopenia of childhood [RCC]), advanced MDS (refractory anemia with excess blasts in transformation), and juvenile myelomonocytic leukemia (JMML), each with different characteristics and management strategies. Underlying genetic predisposition is recognized in an increasing number of patients. Germ line GATA2 mutation is found in 70% of adolescents with MDS and monosomy 7. It is challenging to distinguish RCC from aplastic anemia, inherited bone marrow failure, and reactive conditions. RCC is often hypoplastic and may respond to immunosuppressive therapy. In case of immunosuppressive therapy failure, hypercellular RCC, or RCC with monosomy 7, hematopoietic stem cell transplantation (HSCT) using reduced-intensity conditioning regimens is indicated. Almost all patients with refractory anemia with excess blasts are candidates for HSCT; children age 12 years or older have a higher risk of treatment-related death, and the conditioning regimens should be adjusted accordingly. Unraveling the genetics of JMML has demonstrated that JMML in patients with germ line PTPN11 and CBL mutations often regresses spontaneously, and therapy is seldom indicated. Conversely, patients with JMML and neurofibromatosis type 1, somatic PTPN11, KRAS, and most of those with NRAS mutations have a rapidly progressive disease, and early HSCT is indicated. The risk of relapse after HSCT is high, and prophylaxis for graft-versus-host disease and monitoring should be adapted to this risk.

Brincidofovir clearance of acyclovir-resistant herpes simplex virus-1 and adenovirus infection after stem cell transplantation

Infections with adenovirus (AdV) and herpesviruses can result in considerable morbidity and mortality in pediatric hematopoietic stem cell transplant (SCT) recipients. Herpes simplex virus (HSV) reactivations are usually prevented by acyclovir (ACV) prophylaxis, whereas cidofovir (CDV) has been used off indication to manage AdV infections. We report a child with myelodysplastic syndrome undergoing multiple SCT, who experienced HSV-1 disease including severe mucositis and herpetic whitlow, as well as high viral load AdV DNAemia. Both ACV and CDV were ineffective; however, viral loads were decreased with brincidofovir, resulting in viral clearance. A subsequent Epstein-Barr virus disease with relevant meningoencephalitis responded to rituximab.

Response to treatment with azacitidine in children with advanced myelodysplastic syndrome prior to hematopoietic stem cell transplantation

Advanced myelodysplastic syndrome harbors a high risk of progression to acute myeloid leukemia and poor prognosis. In children, there is no established treatment to prevent or delay progression to leukemia prior to hematopoietic stem cell transplantation. Azacitidine is a hypomethylating agent, which was shown to slow progression to leukemia in adults with myelodysplastic syndrome. There is little data on the efficacy of azacitidine in children. We reviewed 22 pediatric patients with advanced myelodysplastic syndrome from a single center, diagnosed between January 2000 and December 2015. Of those, eight patients received off-label azacitidine before hematopoietic stem cell transplantation. A total of 31 cycles were administered and modification or delay occurred in four of them due to cytopenias, infection, nausea/vomiting, and transient renal impairment. Bone marrow blast percentages in azacitidine-treated patients decreased significantly from a median of 15% (range 9-31%) at the start of treatment to 5.5% (0-12%, P=0.02) before hematopoietic stem cell transplantation. Following azacitidine treatment, four patients (50%) achieved marrow remission, and none progressed. In contrast, three untreated patients (21.4%) had progressive disease characterized by >50% increase in blast counts or progression to leukemia. Azacitidine-treated patients had significantly increased 4-year event-free survival (P=0.04); predicted 4-year overall survival was 100% versus 69.3% in untreated patients (P=0.1). In summary, azacitidine treatment prior to hematopoietic stem cell transplantation was well tolerated in pediatric patients with advanced myelodysplastic syndrome, led to partial or complete bone marrow response in seven of eight patients (87.5%), and correlated with superior event-free survival in this cohort.

Treatment of graft failure with TNI-based reconditioning and haploidentical stem cells in paediatric patients

Graft failure is a life‐threatening complication after allogeneic haematopoietic stem cell transplantation (HSCT). We report a cohort of 19 consecutive patients (median age: 8·5 years) with acute leukaemias (n = 14) and non‐malignant diseases (n = 5) who experienced graft failure after previous HSCT from matched (n = 3) or haploidentical donors (n = 16) between 2003 and 2012. After total nodal irradiation (TNI)‐based reconditioning combined with fludarabine, thiotepa and anti‐T cell serotherapy, all patients received T cell‐depleted peripheral blood stem cell grafts from a second, haploidentical donor. Median time between graft failure and retransplantation was 14 d (range 7–40). Sustained engraftment (median: 10 d, range 9–32) and complete donor chimerism was observed in all evaluable patients. 5 patients additionally received donor lymphocyte infusions. Graft‐versus‐host disease (GvHD) grade II and III occurred in 1 patient each (22%); no GvHD grade IV was observed. 2 patients had transient chronic GvHD. The regimen was well tolerated with transient interstitial pneumonitis in one patient. Treatment‐related mortality after one year was 11%. Event‐free survival and overall survival 3 years after retransplantation were 63% and 68%. Thus, a TNI‐based reconditioning regimen followed by transplantation of haploidentical stem cells is an option to rescue patients with graft failure within a short time span and with low toxicity.

A Cytokine-Based Diagnostic Program in Pediatric Aplastic Anemia and Hypocellular Refractory Cytopenia of Childhood

BACKGROUND

Distinguishing hypocellular refractory cytopenia of childhood (RCC) from aplastic anemia (AA) is challenging. Thus far, no studies have compared the cytokine profiles in patients with AA to those with hypocellular RCC. In the present study, we addressed whether thrombopoietin (TPO) and interleukin 17 (IL-17) plasma levels are useful for differentiating between the two diseases.

METHODS

We measured the endogenous plasma concentrations of TPO and IL-17 in 29 patients with AA, 34 patients with hypocellular RCC, and 31 healthy controls using sensitive enzyme-linked immunosorbent assays.

RESULTS

The TPO and IL-17 plasma levels were significantly lower in patients with hypocellular RCC than in patients with AA (P < 0.001 and P = 0.007, respectively). The multivariate logistic regression analysis identified moderate disease severity, TPO levels of <1,369.8 pg/ml (TPO-low group, n = 32; odds ratio (OR), 13.40; 95% confidence intervals (CI), 3.001-51.254; P < 0.001), and IL-17 levels of <22.2 pg/ml (IL-17-low group, n = 33; OR, 4.11; 95% CI, 1.033-19.404; P = 0.031) as independent factors discriminating hypocellular RCC from AA. Importantly, 25 (78.1%) of 32 patients in the TPO-low group and 25 (75.8%) of 33 patients in the IL-17-low group were diagnosed as having hypocellular RCC. Moreover, 22 (71%) of 31 patients in the TPO-high group and 21 (70%) of 30 patients in the IL-17-high group were diagnosed as having AA.

CONCLUSIONS

TPO and IL-17 levels are useful for differentiating hypocellular RCC from AA. Prospective studies are required to confirm our findings.

Missing Cells: Pathophysiology, Diagnosis, and Management of (Pan)Cytopenia in Childhood

Peripheral blood cytopenia in children can be due to a variety of acquired or inherited diseases. Genetic disorders affecting a single hematopoietic lineage are frequently characterized by typical bone marrow findings, such as lack of progenitors or maturation arrest in congenital neutropenia or a lack of megakaryocytes in congenital amegakaryocytic thrombocytopenia, whereas antibody-mediated diseases such as autoimmune neutropenia are associated with a rather unremarkable bone marrow morphology. By contrast, pancytopenia is frequently associated with a hypocellular bone marrow, and the differential diagnosis includes acquired aplastic anemia, myelodysplastic syndrome, inherited bone marrow failure syndromes such as Fanconi anemia and dyskeratosis congenita, and a variety of immunological disorders including hemophagocytic lymphohistiocytosis. Thorough bone marrow analysis is of special importance for the diagnostic work-up of most patients. Cellularity, cellular composition, and dysplastic signs are the cornerstones of the differential diagnosis. Pancytopenia in the presence of a normo- or hypercellular marrow with dysplastic changes may indicate myelodysplastic syndrome. More challenging for the hematologist is the evaluation of the hypocellular bone marrow. Although aplastic anemia and hypocellular refractory cytopenia of childhood (RCC) can reliably be differentiated on a morphological level, the overlapping pathophysiology remains a significant challenge for the choice of the therapeutic strategy. Furthermore, inherited bone marrow failure syndromes are usually associated with the morphological picture of RCC, and the recognition of these entities is essential as they often present a multisystem disease requiring different diagnostic and therapeutic approaches. This paper gives an overview over the different disease entities presenting with (pan)cytopenia, their pathophysiology, characteristic bone marrow findings, and therapeutic approaches.

Allogeneic hematopoietic stem cell transplantation in pediatric myelodysplastic syndromes: a multicenter experience from Argentina

BACKGROUND

Allogeneic hematopoietic stem cell transplantation (AHSCT) represents the only curative treatment for the majority of pediatric patients with Myelodysplastic Syndrome (MDS). We aimed to evaluate overall survival (OS), disease-free survival (DFS), non-relapse mortality (NRM) and relapse incidence in children who underwent AHSCT for MDS in six institutions from Argentina.

PROCEDURE

A retrospective analysis of 54 AHSCT was carried out in 52 patients (mean age: 9 years; range: 2-19; 35 males).

RESULTS

MDS subtypes were refractory cytopenia of childhood (RCC) (n: 26, 50%), refractory anemia with excess blasts (RAEB) (n: 9, 18%), RAEB in transformation (RAEB-T) (n: 8, 15%) and juvenile myelomonocytic leukemia (JMML) (n: 9, 17%). At time of transplant, seven (13%) patients transformed to acute myeloid leukemia (AML) and two patients with RCC to RAEB. Donors were related in 32 cases (59%) and the stem cells source was: bone marrow (63%), peripheral blood (26%), and umbilical cord blood (11%). Five-year DFS and OS were 50% and 55% respectively; and for patients with JMML, 57% and 67% respectively. Cumulative incidence of NRM and relapse were 27% and 21% respectively. In the multivariate analysis, umbilical cord blood (HR 4.07; P = 0.025) and age ≥ 9 years at transplantation (HR 3.28; P = 0.017) were associated with lower OS; age and graft-versus-host disease (GVHD) had a higher NRM.

CONCLUSIONS

In our series, more than half of the patients achieved long term OS with AHSCT. Less toxic conditioning regimens or more intensive GVHD prophylaxis could lead to better results in some children.

Bone marrow immunophenotyping by flow cytometry in refractory cytopenia of childhood

Refractory cytopenia of childhood is the most common type of childhood myelodysplastic syndrome. Because the majority of children with refractory cytopenia have a normal karyotype and a hypocellular bone marrow, differentiating refractory cytopenia from the immune-mediated bone marrow failure syndrome (very) severe aplastic anemia can be challenging. Flow cytometric immunophenotyping of bone marrow has been shown to be a valuable diagnostic tool in differentiating myelodysplastic syndrome from non-clonal cytopenias in adults. Here, we performed the first comprehensive flow cytometric analysis of immature myeloid, lymphoid cells and erythroid cells, and granulocytes, monocytes, and lymphoid cells in bone marrow obtained from a large prospective cohort of 81 children with refractory cytopenia. Children with refractory cyotopenia had a strongly reduced myeloid compartment, but not as severe as children with aplastic anemia. Furthermore, the number of flow cytometric abnormalities was significantly higher in children with refractory cytopenia than in healthy controls and in children with aplastic anemia, but lower than in advanced myelodysplastic syndrome. We conclude that flow cytometric immunophenotyping could be a relevant addition to histopathology in the diagnosis of refractory cytopenia of childhood. (The multi-center studies EWOG-MDS RC06 and EWOG-MDS 2006 are registered at clinicaltrials.gov identifiers 00499070 and 00662090, respectively).

Childhood myelodysplastic syndrome

Myelodysplastic syndrome (MDS) comprises of a heterogeneous group of bone marrow disorders resulting from a clonal stem cell defect characterised by cytopenias despite a relatively hypercellular marrow, ineffective hematopoiesis, morphological dysplasia in the marrow elements, no response to hematinics such as iron, B12 or folic acid and risk of progression to leukemia. Myelodysplastic syndrome in childhood is extremely rare and accounts for less than 5% of all hematopoietic neoplasms in children below the age of 14 y. The primary MDS in children, also known as de novo MDS differs from secondary MDS which generally follows congenital or acquired bone marrow (BM) failure syndromes as well as from therapy related MDS, commonly resulting from cytotoxic therapy. MDS associated with Down syndrome which accounts for approximately one-fourth of cases of childhood MDS is now considered a unique biologic entity synonymous with Down syndrome-related myeloid leukemia and is biologically distinct from other cases of childhood MDS. Refractory cytopenia of childhood (RCC) is the commonest type of MDS. Genetic changes predisposing to MDS in childhood remain largely obscure. Monosomy 7 is by-far the commonest cytogenetic abnormality associated with childhood MDS; however most cases of RCC show a normal karyotype. Complex cytogenetic abnormalities and trisomy 8 and trisomy 21 are also occasionally observed. The most effective and curative treatment is Hematopoietic stem cell transplantation and this is particularly effective in children with the monosomy 7 genetic defect as well as those displaying complex karyotype abnormalities provided it is instituted early in the course of the disease.

Early hematopoietic stem cell transplant is associated with favorable outcomes in children with MDS

BACKGROUND

Although hematopoietic stem cell transplantation (HSCT) is the treatment of choice for childhood myelodysplastic syndrome (MDS), there is no consensus regarding patient or disease characteristics that predict outcomes.

PROCEDURE

We reviewed 37 consecutive pediatric MDS patients who received myeloablative HSCT between 1990 and 2010 at a single center.

RESULTS

Twenty had primary MDS and 17 had secondary MDS. Diagnostic cytogenetics included monosomy 7 (n = 21), trisomy 8 (n = 7) or normal/other (n = 8). According to the modified WHO MDS classification, thirty had refractory cytopenia and seven had refractory anemia with excess blasts. IPSS scores were: low risk (n = 1), intermediate-1 (n = 15), and intermediate-2 (n = 21). OS and DFS at 10 years in the entire cohort was 53% and 45%. Relapse at 10 years was 26% and 1 year TRM was 25%. In multivariate analysis, factors associated with improved 3 years DFS were not receiving pre-HSCT chemotherapy (RR = 0.30, 95% CI 0.10-0.88; P = 0.03) and a shorter interval (<140 days) from time of diagnosis to transplant (RR = 0.27, 95% CI 0.09-0.80; P = 0.02). Three years DFS in patients who did not receive pre-HSCT chemotherapy and those who had a shorter interval to transplant (n = 16) was 80%.

CONCLUSION

These results suggest that children with MDS should be referred for allogeneic HSCT soon after diagnosis and that pre-HSCT chemotherapy does not appear to improve outcomes.

Allogeneic hematopoetic stem cell transplantation in pediatric myelodysplastic syndromes: improved outcomes for de novo disease

We report 23 consecutive pediatric patients with MDS who received allogeneic HSCT on IRB approved protocols between 1992 and 2009 at Children's Memorial Hospital (Chicago, IL). Nine patients had de novo MDS, whereas 14 patients had treatment-related MDS. All patients had a documented cytogenetic abnormality, and monosomy 7/7q- was seen in 12 patients (52%). Fourteen of 23 patients received a myeloablative conditioning regimen; RIC regimens were used for the remaining nine. Five patients relapsed post-transplant, including four patients who received RIC transplant and four patients with treatment-related MDS. For the entire group, estimated five-yr RFS and OS were 47% and 50%, respectively. Treatment-related MDS was associated with decreased RFS in comparison with de novo MDS (33% vs. 70%, p = 0.05). Five-year OS rates reached 80% for those with de novo MDS. RIC regimens were associated with decreased three-yr RFS in comparison with myeloablative regimens (22% vs. 68%, p = 0.02). There was no correlation of survival with blast count at diagnosis, IPSS score, cytogenetic abnormality, donor type, or HLA match. Larger series are needed to confirm prognostic factors so that higher-risk patients can be targeted with novel approaches.

Classification of childhood aplastic anemia and myelodysplastic syndrome

Hypoplastic BM disorders in children and adolescents comprise a broad spectrum of disorders. Acquired severe aplastic anemia (SAA), refractory cytopenia of childhood (RCC), a subtype of myelodysplastic syndrome (MDS), and inherited BM failure (IBMF) disorders are the main and most difficult hematological differential diagnoses. Whereas IBMF disorders can often be diagnosed by their clinical features and/or underlying genetic aberrations, the morphological distinction between SAA and hypocellular RCC has been controversial. The histopathological pattern of RCC consists of islands of immature erythroid precursors accompanied by sparsely distributed granulocytic cells. Megakaryocytes are significantly decreased or absent and, rarely, micromegakaryocytes are detected on immunohistochemistry. Because fatty tissue between areas of hematopoiesis can mimic SAA, 2 biopsies are recommended to facilitate the detection of representative BM spaces. Recent data indicate that the response to immunosuppressive therapy is inferior in RCC compared with SAA. Furthermore, approaches to allogeneic hematopoietic transplantation differ. Controlled prospective clinical studies in patients with hypoplastic BM failure disorders will require comprehensive guidelines for diagnosing SAA, RCC, and the different IBMF disorders.

Analysis of risk factors influencing outcome in children with myelodysplastic syndrome after unrelated cord blood transplantation

We describe 70 children with myelodysplastic syndrome (MDS) (refractory cytopenia (n=31) and refractory anemia with excess blasts (n=30) or blasts in transformation (n=9)) who received umbilical cord blood (UCB) transplantation with a single UCB unit and a myeloablative conditioning regimen. Approximately 20% of children had secondary MDS. Median age at transplantation was 7 years and the median follow-up was 3 years. The day-60 probability of neutrophil recovery was 76%; recovery was faster after transplantation of matched or 1-locus mismatched UCB, irradiation-containing conditioning regimen, cell dose >6 × 10(7)/kg and monosomy 7. Risks of treatment failure (recurrent disease or death) were lower in patients with monosomy 7 and transplantations after 2001. The 3-year disease-free survival (DFS) was 50% for transplantations after 2001 compared with 27% for the earlier period (P=0.018). Transplantations after 2001 occurred within 6 months after diagnosis and used UCB units with higher cell dose. DFS was highest in patients with monosomy 7 (61%) compared with other karyotypes (30%), P=0.017. These data suggest that transplantation of mismatched UCB graft is an acceptable alternative for children without a matched sibling or suitably matched unrelated adult donor.

Unrelated donor bone marrow transplantation for myelodysplastic syndrome in children

We describe long-term disease-free survival (DFS) after unrelated donor bone marrow transplantation (BMT) for myelodysplastic syndrome (MDS) in 118 patients aged ≤18 years. Forty-six patients had refractory cytopenia (RC), 55 refractory anemia with excess blasts (RAEB), and 17 refractory anemia with excess blasts in transformation (RAEB-t). Transplant-related mortality was higher after mismatched BMT (relative risk [RR] 3.29, P = .002). Disease recurrence was more likely with advanced stages of MDS at the time of BMT: RAEB (RR 6.50, P = .01) or RAEB-t (RR 11.00, P = .004). Treatment failure (recurrent disease or death from any cause; inverse of DFS) occurred in 68 patients. Treatment failure was higher after mismatched BMT (RR 2.79, P = .001) and in those with RAEB-t (RR 2.38, P = .02). Secondary MDS or chemotherapy prior to BMT was not associated with recurrence or treatment failure. Similarly, cytogenetic abnormalities were not associated with transplant outcomes. Eight-year DFS for patients with RC after matched and mismatched unrelated donor BMT was 65% and 40%, respectively. Corresponding DFS for patients with RAEB and RAEB-t was 48% and 28%, respectively. When a matched adult unrelated donor is available, BMT should be offered as first-line therapy, and children with RC can be expected to have the best outcome.

Review of chronic graft-versus-host disease in children after allogeneic stem cell transplantation: nursing perspective

This review presents a summary of the research literature related to the incidence and risk factors for chronic graft-versus-host disease in children following allogeneic hematopoietic stem cell transplantation. The range of incidence of chronic graft-versus-host disease in children found in this review was large, from 0% to 46%. Incidence of chronic graft-versus-host disease was influenced by sample size, time posttransplantation, and stem cell source. Characteristics of the person (eg, child's age and gender) and disease/treatment (eg, sources of transplant) are associated with chronic graft-versus-host disease in children after stem cell transplantation. Person and disease/treatment characteristics provide a framework for understanding the factors associated with chronic graft-versus-host disease symptom experiences in children after stem cell transplantation. Timely assessment of presenting chronic graft-versus-host disease symptoms is critical for treatment and prognosis. Nursing interventions should focus on educating children and parents about the signs and symptoms of chronic graft-versus-host disease. The summary of supportive nursing care for children with chronic graft-versus-host disease provides important information to tailor effective management strategies for children with chronic graft-versus-host disease.

Unrelated donor umbilical cord blood transplantation in pediatric myelodysplastic syndrome: a single-center experience

Myelodysplastic syndromes (MDS) respond poorly to chemotherapy. Between 1995 and 2006, 23 pediatric patients with MDS were transplanted with unrelated donor umbilical cord blood (UUCB) at our center. The median age was 11.1 years (range: 1.1-19.7), median weight was 38.6 kg (range: 9.6-62.6), 61% of patients were male, and median time from diagnosis to transplant was 6.6 months (range: 2.0-61.4). Patients were followed for a median of 5.3 years (range: 1.6-12.4 years) posttransplant. MDS stage was refractory anemia (RA) in 12, refractory anemia with excess blasts (RAEB) in 8, and refractory anemia with excess blasts in transformation (RAEB-T) in 3 patients; 18 (78%) patients had primary MDS. Monosomy 7 was present in 17(74%) patients. Patients with acute myelogenous leukemia (AML) were excluded. Preparative regimen was total body irradiation (TBI) based in 18 (78%) patients. Graft-versus-host-disease (GVHD) prophylaxis was cyclosporine (CsA)/steroids (19 patients) or CsA/mycophenolate mofetil (MMF; 4 patients). Grafts were HLA matched at Class I (A and B) at low resolution and Class II (DRB1) at the allelic level, resulting in 16 (70%) 4/6 and 7 (30%) 5/6 matched transplants. The grafts contained a median of 4.0 x 10(7) (range: 1.7-12.6) total nucleated cells (TNC)/kg precryopreservation; 3.6 x 10(7) (range: 1.0-12.0) TNC/kg and 1.7 x 10(5) (range: 0.2-28.5) CD34+ cells/kg were infused. Cumulative incidence of neutrophil engraftment (absolute neutrophil count [ANC] >500/microL) at day 42 and day 100 was 73.9% (95% confidence interval [CI] 55.1%-92.7%) and 91.3% (95% CI 71.3%-100.0%) respectively, and that of platelet engraftment (50 K) at 180 days was 69.6% (95% CI 49.8%-89.4%). Three patients had graft failure whereas 3 patients (13%) engrafted slowly (after day 42). Three patients developed acute GVHD (aGVHD) grades II-IV with a cumulative incidence at 100 days of 13% (95% CI 0.0%-27.1.0%). Four patients relapsed with a cumulative incidence of relapse at 3 years of 13.0% (95% CI 0.0%-27.1%). Cumulative incidence of nonrelapse mortality (NRM) at 1 year was 27% (95% CI 8.0%-46.0%). Ten patients died: 3 graft failure, 4 relapse, 2 infections (1 adenovirus, 1 toxoplasmosis), and 1 Epstein-Barr virus (EBV) lymphoproliferative disorder. Probabilities of event-free survival (EFS) at 1 and 3 years were 69.6% (95% CI 46.6%-84.2%) and 60.9% (95% CI 38.3%-77.4%), respectively. Factors associated with better EFS were age < or = 11 years (P = .05) and weight < or = 38 kg (P = .03). These results, especially in younger patients with monosomy 7 positive MDS, are equivalent to published matched allogeneic bone marrow data. UUCB should be actively considered for pediatric MDS patients lacking matched related or unrelated adult donors.

Allogeneic stem cell transplantation for myelodysplastic syndromes in children: a report from the Spanish Working Party for Blood and Marrow Transplantation in Children (GETMON)

INTRODUCTION

Experience with the use of allogeneic hemopoietic stem transplantation (AHSCT) in pediatric myelodisplastic syndrome (MDS) in Spain is reviewed.

METHODS AND PATIENTS

Twenty-four children with MDS were analyzed retrospectively. Median age of the patients was 10 years. Twenty patients received a bone marrow graft and 4 an unrelated cord blood (UCB) transplant; 12 bone marrow grafts were from a matched related donor (MRD) and 8 from a matched unrelated donor (MUD). Conditioning regimen consisted of chemotherapy alone in 17 patients (busulfan and cyclophosphamide +/- melfalan) Seven patients received TBI and cyclophosphamide.

RESULTS

Ten patients died from transplant-related toxicity and 4 had relapse or disease progression post-AHSCT. Nine patients are alive and event-free with a median follow-up of 120 months. EFS rate in the MRD group was 0.48 (SE 0.13) versus 0.25 (SE 0.12) in the MUD/UCB group (p = .07). Lansky score in survivors is >or=90%.

CONCLUSIONS

In this historical series of children with MDS, in spite of severe transplant-related toxicity, encouraging EFS outcomes have been achieved after AHSCT with good quality of life.

Successful treatment of stem cell graft failure in pediatric patients using a submyeloablative regimen of campath-1H and fludarabine

Graft failure is a significant cause of morbidity and mortality after hematopoietic stem cell transplantation (HSCT). We used a nonmyeloablative conditioning regimen consisting of the lympho-depleting humanized CD52-antibody Campath-1H and fludarabine to rescue 12 consecutive children age 9 months to 17 years with engraftment failure after initial myeloablative HSCT. Primary diagnoses included lymphohematologic malignancies (n=6), severe combined immunodeficiency syndrome (SCID) (n=4), and metabolic diseases (n=2). The same stem cell donor was used as for the primary graft: mismatched family member (n=7), matched unrelated donor (n=4), or matched related donor (n=1). The patients received doses of CD34+ cells that did not significantly differ from those used in the initial, failed transplant. At a median follow-up of 51 months (range, 4 to 84 months), 6 of 6 patients with nonmalignant diseases and 4 of 6 patients with malignancy were alive. Two patients died, 1 patient from pulmonary toxicity and 1 from relapse, at 51 days and 8 months posttransplantation, respectively. All 12 patients initially achieved sustained neutrophil engraftment and complete donor chimerism by day 28. Six patients received donor lymphocyte infusion (DLI) after "rescue" therapy to maintain donor chimerism. At 6 months, 4 patients had complete donor cell engraftment, 4 had 15% to 89% stable donor chimerism, and 3 had developed secondary graft failure. This conditioning regimen was generally well tolerated; 4 of the 12 patients never became neutropenic, and 9 never became thrombocytopenic. Only 1 patient developed graft-versus-host disease (GVHD; grade 1), and none had chronic GVHD. Thus, the regimen that we describe can be used with minimal toxicity to effectively overcome graft failure after myeloablative HSCT in children.

Myelodysplastic syndrome in children and adolescents

Myelodysplastic syndromes (MDS) are clonal disorders characterized by ineffective hematopoiesis and subsequent frequent development of acute myeloid leukemia (AML). In children and adolescents, MDS are uncommon disorders, accounting for less than 5% of hematopoietic malignancy, with great heterogeneity in presentation and clinical course. The genetic changes predisposing children to MDS are largely obscure. Monosomy 7 is the most common chromosomal abnormality, often occurring as a sole abnormality. The recent pediatric modification of the World Health Organization (WHO) classification has greatly facilitated the diagnostic process. Refractory cytopenia (RC) is the most common MDS subtype in children, occurring in about half of all MDS cases. There is consensus that the relationship between MDS with increased blast count and de novo AML is better defined by biological and clinical features than by blast count. Because monosomy 7 is the only chromosomal abnormality strongly suggestive of MDS, children presenting with a low blast count and other chromosomal aberrations or normal karyotype must be closely observed before a diagnosis of MDS can be established. With an increasing number of children surviving primary cancer with chemotherapy or radiation therapy, the incidence of secondary therapy-related MDS is rising. The MDS risk is also increased in patients with inherited bone marrow failure disorders; this relationship provides valuable insights into MDS biology. Allogeneic hematopoietic stem cell transplantation (HSCT) from a matched related or suitable unrelated donor is the choice for most children with MDS and can rescue a large proportion of patients.

Indications and donor selections for allogeneic stem cell transplantation in children with hematologic malignancies

Allogeneic stem cell transplantation (SCT) is the only curative approach for many patients with advanced or high-risk leukemia. Advances in supportive care and management of graft-versus-host disease have resulted in improvements in outcomes of related and unrelated donor SCT, creating controversies as to which strategy might be the optimal therapy for individual patients. This article discusses the indications and donor selection strategies for SCT in patients with malignant hematologic disease.