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Allogeneic haematopoietic cell transplantation (HCT) can cure a variety of non-malignant haematological disorders. Although transplant outcomes for selected patients with severe aplastic anaemia (SAA) and paroxysmal nocturnal haemoglobinuria (PNH) have improved, older age, allo-immunisation from transfusions, prior immunosuppressive therapy and a prolonged time from diagnosis to transplantation are associated with worse outcome. Because of its potent immunosuppressive effects, we investigated a fludarabine-based non-myeloablative conditioning regimen in patients with transfusion-dependent non-malignant haematological disorders at increased risk for graft rejection with conventional transplant conditioning. Twenty-six patients with transfusion dependent/anti-thymocyte globulin (ATG)-refractory SAA, PNH or pure red cell aplasia underwent HCT from a human leucocyte antigen (HLA)-compatible relative. Transplant conditioning consisted of cyclophosphamide (120 mg/kg) and fludarabine (125 mg/m2) with or without ATG. Ciclosporine, alone or combined with mycophenolate mofetil or methotrexate, was used as graft- versus-host disease (GVHD) prophylaxis. All patients achieved durable engraftment and transfusion-independence. Twenty-four of 26 patients are alive at a median of 21 months following transplantation. Although a high cumulative incidence of acute (65% grades II–IV, 54% grades III–IV) and chronic GVHD (56%) was observed, only one patient died from transplant-related causes (cumulative incidence 7%). These data show that HCT following fludarabine-based non-myeloablative conditioning results in durable engraftment and excellent survival in SAA and PNH patients at high risk for graft rejection. [ABSTRACT FROM AUTHOR]

Summary: Patients with acute megakaryoblastic leukaemia of Down syndrome (DS‐AMKL) have an excellent survival rate; however, patients with non‐DS‐AMKL experience poor outcomes. Therefore, this study retrospectively analysed 203 children with non‐DS‐AMKL who underwent their first haematopoietic cell transplantation (HCT) from 1986 to 2015 using a nationwide Japanese HCT registry data to assess HCT outcomes for non‐DS‐AMKL. The 5‐year overall survival (OS) and event‐free survival (EFS) rates were 43% and 38% respectively. The 5‐year OS rate was significantly higher for patients who underwent HCT in the first complete remission (CR1, 72%) than for those in the second CR (CR2, 23%) and non‐CR (16%) (p < 0.001), and for those from a human leukocyte antigen (HLA)‐matched (52%) than for those from an HLA‐mismatched donor (27%) (p < 0.001). Multivariate analysis for OS revealed that HCT in CR2 and non‐CR was a significant risk factor (hazard ratio, 5.86; 95% confidence interval, 3.56–9.53; p < 0.001). The 3‐year EFS in patients who received HCT in CR1 using reduced‐intensity conditioning (RIC, 35%) was significantly lower than in those using myeloablative conditioning (busulfan‐based, 71%; total body irradiation‐based, 58%) (p < 0.001). Risk stratification in patients with non‐DS‐AMKL should be established to determine HCT indication in CR1. [ABSTRACT FROM AUTHOR]

Summary: The impact of human leukocyte antigen (HLA) mismatching at the HLA‐A, ‐B, ‐C, and ‐DRB1 loci after unrelated bone marrow transplantation in paediatric patients with haematological malignancies has not been fully examined. Here, we analysed patients with haematological malignancies (all aged ≤15 years; n = 1330) who underwent a first unrelated bone marrow transplantation between 1993 and 2017 in Japan. The results show that although an HLA mismatch was significantly associated with a low relapse rate, it was also associated with higher non‐relapse mortality. There was a significant association between HLA mismatch and low overall survival. Locus mismatch analysis revealed that, as in adults, an HLA‐C mismatch had a significant negative impact on survival; however, in paediatric patients, an HLA‐DRB1 mismatch did not have a negative impact, although these HLA mismatch effects are weakened in recent cases. Taken together, the results suggest that an HLA‐matched donor should be the first candidate for paediatric patients; however, for patients without a matched sibling or matched unrelated donor, we can select an unrelated donor with a mismatch at HLA‐DRB1 if available. [ABSTRACT FROM AUTHOR]

Summary: 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. [ABSTRACT FROM AUTHOR]

Aplastic anaemia (AA) is defined as a pancytopenia caused by bone marrow failure, and its pathogenesis is thought to involve autoimmune processes. Several predictive markers of the response to immunosuppressive therapy (IST) have been proposed, which appear to reflect the immune pathophysiology. We prospectively investigated the presence of human leucocyte antigen (HLA)-DR15, a minor population of paroxysmal nocturnal haemoglobinuria (PNH)-type cells, and antibodies to the recently identified autoantigen postmeiotic segregation increased 1 (PMS1) in 103 children with AA enrolled in a multicentre study. In contrast to adults, children with AA did not show an increased frequency of HLA-DR15. In addition, a sensitive flow cytometric assay revealed that children with AA have a much lower prevalence of PNH-type cells (21·4%) than reported for adults with this disease. An immunoblotting assay detected anti-PMS1 antibody in 15 of 103 (14·6%) of the children. Finally, the response rate to IST was not significantly different between patients with and without DR15 (45·5% vs. 54·0%), PNH-type cells (68·2% vs. 53·1%) or anti-PMS1 antibody (40·0% vs. 59·1%). The current study did not confirm a correlation between these markers and the response to IST, suggesting that there is a difference in the pathophysiologies of adult and paediatric AA. [ABSTRACT FROM AUTHOR]

To characterize childhood acute megakaryoblastic leukaemia (AMKL), we reviewed 45 children with AMKL diagnosed between 1986 and 2005 at Nagoya University Hospital and Japanese Red Cross Nagoya First Hospital. Twenty-four patients (53%) had AMKL associated with Down syndrome (DS-AMKL) and 21 (47%) had non-DS-AMKL. The median age of the DS-AMKL patients was 21 months (range, 8–38 months) and that of non-DS-AMKL patients was 15 months (range, 2–185 months). The morphology of blast cells was categorized into three groups according to the stage of megakaryocyte maturation. The blast cells were more immature in DS-AMKL than in non-DS-AMKL in terms of morphology and immunophenotyping. Cytogenetic abnormalities of leukaemic cells were classified into seven categories: normal karyotype including constitutional trisomy 21 in DS-AMKL; numerical abnormalities only; t(1;22)(p13;q13); 3q21q26 abnormalities; t(16;21)(p11;q22); −5/del(5q) and/or −7/del(7q); and other structural changes. The outcome of children with either DS-AMKL or non-DS-AMKL is excellent. The 10-year overall survival estimate was 79% [95% confidence interval (CI): 54–90] for DS-AMKL and 76% (95% CI: 58–91) for non-DS-AMKL ( P = 0·81) with a median follow-up of 78 months (range, 20–243 months). Our study shows the diverse heterogeneity of childhood AMKL and the need for subclassification according to cytogenetic and morphological features. [ABSTRACT FROM AUTHOR]

Summary: The treatment of choice for patients with severe aplastic anaemia (SAA) includes immunosuppressive therapy (IST) with anti‐thymocyte globulin (ATG) and ciclosporin A. However, the optimal dose for rabbit ATG has yet to be established. We herein report the first prospective, randomized, multicentre study comparing two doses of rabbit ATG in patients with SAA. Patients with SAA who required initial IST in Japan (n = 89), China (n = 85) and Korea (n = 48) were enrolled between May 2012 and October 2017. A 1:1 block randomization was employed for two doses of rabbit ATG. In total, 222 patients were randomized, with 112 patients receiving 2·5 mg/kg and 110 receiving 3·5 mg/kg of rabbit ATG for 5 days. The primary endpoint was the haematological response at day 180. After 6 months, no significant difference in response rates was observed between the 2·5 and 3·5 mg/kg groups (49% vs. 48%, P = 0·894). Overall survival at 3 years was similar between the two groups [85% (95% confidence interval [CI], 76%−91%) vs. 91% (95% CI, 82%−96%); P = 0·107]. The current study revealed no significant differences in the efficacy and safety between the 2·5 and 3·5 mg/kg doses of rabbit ATG in patients with SAA. Trial registration: UMIN000011134. [ABSTRACT FROM AUTHOR]

The clinical significance of paroxysmal nocturnal haemoglobinuria ( PNH) in children with aplastic anaemia ( AA) remains unclear. We retrospectively studied 57 children with AA between 1992 and 2010. During the follow-up, five patients developed clinical PNH, in whom somatic PIGA mutations were detected by targeted sequencing. The 10-year probability of clinical PNH development was 10·2% (95% confidence interval, 3·6-20·7%). Furthermore, the detection of minor PNH clones by flow cytometry at AA diagnosis was a risk factor for the subsequent development of clinical PNH. These patients with PNH clones at AA diagnosis should undergo periodic monitoring for potential clinical PNH development. [ABSTRACT FROM AUTHOR]

We assessed the clinical utility of next-generation sequencing ( NGS)-based monitoring of minimal residual disease ( MRD) in a uniformly treated cohort of 79 patients with paediatric B-cell acute lymphoblastic leukaemia. Bone marrow samples were collected at the time of diagnosis, days 33 and 80, pre- (4-5 months) and post- (24 months) maintenance therapy time points, and at relapse. We identified leukaemia-specific CDR3 sequences in 72 of 79 patients (91%) and detected MRD in 59 of 232 samples. Although MRD was detected in 28 of 55 samples (51%) on day 33, the frequencies of MRD detection decreased to 25% (16/65) at day 80, 19% (11/58) at 4-5 months and 7·4% (4/54) at 24 months. In a univariate analysis, positive MRD results on day 80 [relative risk (RR) 95% confidence interval (CI) = 7·438 (2·561-21·6), P < 0·001], at 4-5 months [ RR (95% CI) = 10·24 (3·374-31·06), P < 0·001], and at 24 months [ RR (95% CI) = 19·26 (4·974-74·59), P < 0·001] exhibited statistically significant associations with inferior leukaemia-free survival; this was confirmed using a Cox proportional hazard model. Our study suggests the promising potential of NGS- MRD for patients with B-cell ALL. [ABSTRACT FROM AUTHOR]

The article discusses the pathological mutation of the human gene SIPA1 in patients with juvenile myelomonocytic leukemia (JMML). Although the malignancy is typically associated with constructive activation of the granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor/Ras/Raf/MEK/ERK signaling, the researchers claim that its correlation with the SIPA1 gene is unlikely.

To evaluate haematopoietic stem cell transplantation ( HSCT) in children and adolescents, we reviewed the records of 47 patients who were ≤18 years, had relapsed or refractory anaplastic large cell lymphoma, and received HSCT between 1990 and 2010. At HSCT, complete remission ( CR) was less common in allogeneic HSCT recipients ( n = 24) than in autologous HSCT recipients ( n = 23) ( P = 0·01). The autologous and allogeneic HSCT groups differed in terms of 5-year event-free survival ( EFS) (38% vs. 50%, P = 0·63), cumulative incidence of progress or relapse (49% vs. 28%, P = 0·25), and treatment-related mortality (12% vs. 25%, P = 0·40). However, these differences were not significant. Patients with non- CR at autologous HSCT had a significantly lower EFS rate (14% vs. 48%, P = 0·03). Conversely, although those with non- CR at allogeneic HSCT had a lower EFS rate, this was not significant (44% vs. 63%, P = 0·26). Reduced-intensity conditioning regimens were used for three of the 16 allogeneic HSCTs received by patients with non- CR. These three patients achieved CR, surviving 32-65 months after HSCT. These results demonstrated that allogeneic HSCT might be a treatment option for patients who do not achieve CR through conventional chemotherapy. [ABSTRACT FROM AUTHOR]

Myelodysplastic/myeloproliferative uclassifiable ( MDS/ MPN- U) is a rare myeloid neoplasm characterized by myelodysplasia and myeloproliferation at the time of initial presentation, which is usually a diagnosis of exclusion. The molecular pathogenesis of MDS/ MPN- U patients remains to be elucidated. Among five patients diagnosed with MDS/ MPN- U, three patients harboured RUNX1 ( AML1) mutations; one carried somatic mosaicism of RUNX1 mutation with JAK2V617F mutation and one had dual RUNX1 and FLT3-internal tandem duplication mutations with progression to acute myeloid leukaemia ( AML). Germline mutation of TP53 was detected as a sole genetic lesion in one patient. JAK2V617F and somatic mosaicism of KRAS and TET2 mutations co-existed in one patient. Otherwise, no alterations were detected in PTPN11, NRAS, CBL and ASXL1 genes. ETV6- PDGFRB fusion transcript was not detected in all patients. Four patients recieved haematopoietic stem cell transplantation ( HSCT); three patients relapsed and one achieved complete remission after three donor lymphocyte infusions. Our findings suggest that the mutational spectrum observed in childhood MDS/ MPN- U is quite different from that seen in juvenile myelomonocytic leukaemia and, to some extent, resemble chronic myelomonocytic leukaemia. Moreover, two patients had constitutional alterations of genes frequently found in AML. Further investigations are required to define the roles of these genetic alterations in the pathogenesis of childhood MDS/ MPN- U. [ABSTRACT FROM AUTHOR]

Summary While acute megakaryoblastic leukaemia (AMKL) occurs in children with (DS-AMKL) and without (paediatric non-DS-AMKL) Down syndrome, it can also affect adults without DS (adult non-DS-AMKL). We have analysed these subgroups of patients (11 children with DS-AMKL, 12 children and four adults with non-DS-AMKL) for the presence of molecular lesions, including mutations and chromosomal abnormalities studied by sequencing and single nucleotide polymorphism array-based karyotyping, respectively. In children, AMKL was associated with trisomy 21 (somatic in non-DS-AMKL), while numerical aberrations of chromosome 21 were only rarely associated with adult AMKL. DS-AMKL was also associated with recurrent somatic gains of 1q (4/11 DS-AMKL patients). In contrast to trisomy 21 and gains of 1q, other additional chromosomal lesions were evenly distributed between children and adults with AMKL. A mutational screen found GATA1 mutations in 11/12 DS-AMKL, but mutations were rare in paediatric non-DS-AMKL (1/12) and adult AMKL (0/4). JAK3 (1/11), JAK2 (1/11), and TP53 mutations (1/11) were found only in patients with DS-AMKL. ASXL1, IDH1/2, DNMT3A, RUNX1 and CBL mutations were not found in any of the patient group studied, while NRAS mutation was identified in two patients with paediatric non-DS-AMKL. [ABSTRACT FROM AUTHOR]

Mutations in NF1, PTPN11, NRAS, KRAS and CBL have been reported to play a pathogenetic role in juvenile myelomonocytic leukaemia (JMML), a rare myelodyplastic/myeloproliferative neoplasm occurring in children. Recently, mutations in ASXL1 were identified in chronic myelomonocytic leukaemia and other myeloid malignancies. We sequenced exon 12 of ASLX1 in 49 JMML patients, and found 2 novel heterozygous (nonsense and frameshift) mutations, one occurring as a sole lesion, the other was in conjunction with a PTPN11 mutation. ASXL1 cooperates with KDM1A in transcriptional repression and thereby ASXL1 mutations may synergize with or mimic other JMML-related mutations. [ABSTRACT FROM AUTHOR]

Summary. The in vivo cytotoxic mechanism of Epstein–Barr virus (EBV)-specific cytotoxic lymphocytes was examined in a patient who suffered with EBV-associated lymphoproliferative disease (LPD) after bone marrow transplantation (BMT). His peripheral CD8+ T-cell count was significantly increased and > 70% of these cells were EBV-specific by fluorescence-activated cell sorter (FACS) analysis for interferon-γ production. Intracellular perforin expression was markedly increased in CD8+ T cells by FACS analysis. The lymphocytes from this patient had cytotoxic activity against autologous EBV+ lymphoblastoid cell lines which were completely inhibited by concanamycin A, an inhibitor of perforin, and a anti-human leucocyte antigen (HLA)-class I monoclonal antibody. These results suggest that the cytotoxicity was mediated by the perforin, in an HLA-class I-restricted manner. We performed serial intracellular perforin analyses in another patient who also showed endogenous expansion of EBV-specific CD8+ T cells that coincided with an increased EBV-DNA load. Perforin expression in the CD8+ and CD4+ T cells paralleled the EBV-specific CD8+ T cells and EBV-DNA load, which also suggests that perforin mediates EBV-specific cytolysis in vivo and is responsible for effective immunosurveillance against EBV reactivation after BMT. Evaluation of host immunity against EBV by determining perforin expression in lymphocytes and EBV-specific lymphocytes along with quantification of EBV-DNA may be useful for predicting the clinical course of patients with EBV-associated LPD after BMT. [ABSTRACT FROM AUTHOR]

We report a favourable outcome in 15 patients with severe aplastic anaemia (SAA) who were < 20 years of age and who underwent bone marrow transplantation (BMT) from a human leucocyte antigen (HLA)-matched unrelated donor. All patients were non-responders to intensive immunosuppressive therapy (IST) and were multiply transfused. The conditioning regimen consisted of cyclophosphamide (60 mg/kg/d, on d -4 and -3), anti-thymocyte globulin (2·5 mg/kg/d, on d -5 to -2) and total body irradiation (2·5 Gy × 2/d, on d -2 and -1). Patients received cyclosporine and methotrexate for prophylaxis of graft-versus-host disease (GVHD), except for the last four who received tacrolimus instead of cyclosporine. Donor/recipient pairs were identical for HLA class I and II antigens by serological typing, but four pairs were found to have a mismatch at the HLA-A, -B or -DRB1 locus by high-resolution typing. All patients achieved rapid engraftment and are alive at 2–86 months after transplantation (median follow-up, 51 months). Moderate to severe acute GVHD occurred in 5 out of 15 patients (33%); only one patient developed extensive chronic GVHD. Considering our encouraging results, unrelated donor transplantation for SAA is recommended as a salvage therapy in non-responders to IST. [ABSTRACT FROM AUTHOR]

A total of 100 children under the age of 17 years with acquired aplastic anaemia (AA) were initially treated with immunosuppressive therapy (IST) (n = 63) or bone marrow transplantation (BMT) (n = 37) from an HLA-matched family donor. The projected 10-year survival rates were 55 ± 8% and 97 ± 3% respectively (P = 0·004). Because the IST group included 11 non-responders who were salvaged by BMT from an HLA-matched unrelated donor, we compared failure-free survival (FFS) between the groups. The probability of FFS at 10 years was 97 ± 3% for the BMT group, compared with 40 ± 8% for the IST group (P = 0·0001). Seven patients evolved to myelodysplastic syndrome (MDS) with monosomy 7 and the estimated cumulative incidence of MDS 10 years after diagnosis was 20 ± 7% in the IST group. We compared the outcome of children treated with IST during the two consecutive periods of 1983–91 (group A, n = 40) and 1991–8 (group B, n = 23) to assess the impact of combined therapy with anti-thymocyte globulin and cyclosporin. The probability of FFS at 7 years follow-up was the same in the two groups (50 ± 8% vs. 40 ± 15%, P = 0·40). We recommend BMT as first-line therapy in paediatric severe AA patients with an HLA-matched family donor. Alternative donor BMT is recommended as salvage therapy in patients who relapse or do not respond to initial IST. [ABSTRACT FROM AUTHOR]

The article focuses on association of aldehyde dehydrogenases (ALDHs) enzymes with progression of bone marrow failure (BMF) in children with idiopathic aplastic anaemia. It states that immunosuppressive therapy (IST) in children with suppressed aldehyde metabolism is negatively impacted by defects in haematopoietic stem cells (HSCs). The study concludes that endogenous aldehydes damages HSCs and leads to early-onset of BMF in children with idiopathic aplastic anaemia.

The article informs that mutation in THPO gene which encodes thrombopoietin is not associated with Aplastic Anaemia (AA). It mentions that THPO is the causative gene for congenital amegakaryocytic thrombocytopenia (CAMT). It further mentions that for the determination of THPO association, the gene sequence consisting of 12 exons were analyzed and these exons were amplified by polymerase chain reaction of genomic DNA from patients with AA. It concludes that no THPO mutations were found.