Miharu Yabe

11p15 translocations involving the NUP98 gene in childhood therapy-related acute myeloid leukemia/myelodysplastic syndrome

In a survey of childhood therapy‐related acute myeloid leukemia/myelodysplastic syndrome (t‐AML/MDS) in Japan, we found 11p15 translocations in 5 (6%) of 81 children with t‐AML/MDS. t(11;17)(p15;q21), t(11;12)(p15;q13), t(7;11)(p15;p15), inv(11)(p15q22), and add(11)(p15) were each found in one patient. Southern blotting and/or RT‐PCR analyses revealed rearrangements of the NUP98 gene in tumor samples of all five patients. Rearrangements of DDX10 were detected in t‐AML/MDS cells with inv(11), and rearrangements of HOXA9 were detected in t‐AML cells with t(7;11). The 17q21 breakpoint of t(11;17) and the 12q13 breakpoint of t(11;12)(p15;q13) coincided with the loci of the HOXB and HOXC gene families, respectively. Therefore, it is reasonable to speculate that one of the HOXB genes and one of the HOXC genes were fused to NUP98 by t(11;17) and t(11;12), respectively, in t‐AML/MDS cells. We propose that NUP98 may be a target gene for t‐AML/MDS, and that t‐AML/MDS with a fusion of NUP98 and HOX or DDX10 genes may be more frequent in children than in patients of other age groups. Genes Chromosomes Cancer 26:215–220, 1999.

Fatal interstitial pulmonary disease in a patient with dyskeratosis congenita after allogeneic bone marrow transplantation

Chronic restrictive lung disease in a 9-year-old boy with dyskeratosis congenita (DC) 7 years after allogeneic bone marrow transplantation (BMT) is described. When he was 1 year and 10 months old, severe aplastic anemia developed. He received a marrow transplant from his HLA serologically identical, but HLA-DP mismatched brother. He developed grade II acute graft-versus-host disease (GVHD) and thereafter chronic GVHD of progressive type, and was treated with both prednisolone and azathioprine resulting in clinical improvement. Thereafter he complained of dyspnea, and bilateral noncircumscribed interstitial shadows on chest CT scan were present. His pulmonary function showed restrictive changes. Prednisolone was not effective and he died of respiratory failure. Post-mortem examination confirmed interstitial fibrosis, lymphocytic infiltration of the bronchioles and alveoli with luminal fibrosis. There was no evidence of chronic GVHD in the skin and the liver. These findings raise the possibility that this pulmonary complication was associated with DC itself.

Variant ALDH2 is associated with accelerated progression of bone marrow failure in Japanese Fanconi anemia patients

Fanconi anemia (FA) is a severe hereditary disorder with defective DNA damage response and repair. It is characterized by phenotypes including progressive bone marrow failure (BMF), developmental abnormalities, and increased occurrence of leukemia and cancer. Recent studies in mice have suggested that the FA proteins might counteract aldehyde-induced genotoxicity in hematopoietic stem cells. Nearly half of the Japanese population carries a dominant-negative allele (rs671) of the aldehyde-catalyzing enzyme ALDH2 (acetaldehyde dehydrogenase 2), providing an opportunity to test this hypothesis in humans. We examined 64 Japanese FA patients, and found that the ALDH2 variant is associated with accelerated progression of BMF, while birth weight or the number of physical abnormalities was not affected. Moreover, malformations at some specific anatomic locations were observed more frequently in ALDH2-deficient patients. Our current data indicate that the level of ALDH2 activity impacts pathogenesis in FA, suggesting the possibility of a novel therapeutic approach.

Mutations in the Gene Encoding the E2 Conjugating Enzyme UBE2T Cause Fanconi Anemia

Fanconi anemia (FA) is a rare genetic disorder characterized by genome instability, increased cancer susceptibility, progressive bone marrow failure (BMF), and various developmental abnormalities resulting from the defective FA pathway. FA is caused by mutations in genes that mediate repair processes of interstrand crosslinks and/or DNA adducts generated by endogenous aldehydes. The UBE2T E2 ubiquitin conjugating enzyme acts in FANCD2/FANCI monoubiquitination, a critical event in the pathway. Here we identified two unrelated FA-affected individuals, each harboring biallelic mutations in UBE2T. They both produced a defective UBE2T protein with the same missense alteration (p.Gln2Glu) that abolished FANCD2 monoubiquitination and interaction with FANCL. We suggest this FA complementation group be named FA-T.

Correlation of Clinical Features With the Mutational Status of GM-CSF Signaling Pathway-Related Genes in Juvenile Myelomonocytic Leukemia

Mutations in RAS, neurofibromatosis type 1 (NF1), and PTPN11, constituents of the granulocyte-macrophage colony-stimulating factor signaling pathway, have been recognized in patients with juvenile myelomonocytic leukemia (JMML). We assessed 71 children with JMML for NRAS, KRAS, and PTPN11 mutations and evaluated their clinical significance. Of the 71 patients, three had been clinically diagnosed with neurofibromatosis type 1, and PTPN11 and NRAS/KRAS mutations were found in 32 (45%) and 13 (18%) patients, respectively. No simultaneous aberrations were found. Compared with patients with RAS mutation or without any aberrations, patients with PTPN11 mutation were significantly older at diagnosis and had higher fetal Hb levels, both of which have been recognized as poor prognostic factors. As was expected, overall survival was lower for patients with the PTPN11 mutation than for those without (25 versus 64%; p = 0.0029). In an analysis of 48 patients who received hematopoietic stem cell transplantation, PTPN11 mutations were also associated with poor prognosis for survival. Mutation in PTPN11 was the only unfavorable factor for relapse after hematopoietic stem cell transplantation (p = 0.001). All patients who died after relapse had PTPN11 mutation. These results suggest that JMML with PTPN11 mutation might be a distinct subgroup with specific clinical characteristics and poor outcome.

Allogeneic haematopoietic cell transplantation from alternative donors with a conditioning regimen of low-dose irradiation, fludarabine and cyclophosphamide in Fanconi anaemia

A pilot study was undertaken using a fludarabine‐based conditioning regimen to improve haematopoietic cell transplantation (HCT) from alternative donors in 27 Fanconi anaemia (FA) patients. Patients were conditioned with 150–180 mg/m2 of fludarabine, 40 mg/kg of cyclophosphamide, 5–10 mg/kg of antithymocyte globulin, and 300–450 cGy of thoracoabdominal/total body irradiation. One patient who received unrelated cord blood transplantation failed to engraft, another patient died of sepsis. The 1‐year overall survival was 96·3% (95% CI, 89–100). This conditioning regimen exerted an immunosuppressive effect that enabled durable engraftment in alternative donor HCT without severe toxicity.

Gonadal shielding to irradiation is effective in protecting testicular growth and function in long-term survivors of bone marrow transplantation during childhood or adolescence

An increasing number of long-term surviving bone marrow transplantation (BMT) recipients have recovered from their primary disease but are at risk of developing failure of endocrine organs. We investigated 30 recipients who underwent allogeneic BMT during childhood or adolescence. Testicular growth and function were evaluated by serial measurement of testicular volume, basal luteinizing hormone (LH), basal follicle-stimulating hormone (FSH) and testosterone levels and by gonadotropin-releasing hormone (GnRH) provocative test. Puberty started spontaneously in all patients. However, all except four patients had normal testosterone levels with elevated LH, indicating partial Leydig cell dysfunction. Standard deviation scores of testicular volume at last evaluation were statistically lower in those who had received irradiation without gonadal shield compared to those with (−2.04±0.45 vs −0.30±1.17, respectively, P<0.005), suggesting damage of testicular germinal epithelium owing to gonadal irradiation. Serial measurement of testicular volume showed a tendency of growth to stop at 10 ml in those without gonadal shield. Among the 30 patients, only one patient has fathered a child after reaching spontaneous puberty. These results suggest that gonadal shield is effective to protect testicular growth and function, although the attainment of fertility is difficult to achieve.

Multivariate analysis of risk factors for hemorrhagic cystitis after hematopoietic stem cell transplantation.

Summary:To establish the most appropriate prophylactic therapy and risk factors for predicting hemorrhagic cystitis (HC) after stem cell transplantation (SCT), we retrospectively analyzed the clinical records of 450 transplant patients treated from 1982 to 2002. In all, 81 patients developed early- and/or late-onset HC (early=29, late=48, both=4). For the incidence of early-onset HC, administration of cyclophosphamide (CY) (p=0.0079, odds ratio (OD)=5.109, 95% confidence interval (CI)=1.533–17.030), busulfan (BU) (p=0.0015, OD=3.336, 95% CI=1.584–7.027), BU+CY (p=0.0001, OD=4.369, 95% CI=2.055–9.292), antithymocyte globulin (p=0.0009, OD=3.368, 95% CI=1.642–6.911), nonradiation (p=0.0163, OD=2.564, 95% CI=0.181–0.841), 2-mercaptoethane sodium sulfonate (Mesna) (p=0.0001, OD=7.519, 95% CI=2.847–19.858), and bladder irrigation (p=0.0001, OD=4.950, 95% CI=2.328–10.523) were risk factors. By Fishers exact test, the combination of BU and Mesna was a more significant risk factor (P<0.001) than Mesna alone (p=0.008) compared to the administration of neither agent. By multivariate analysis, prophylactic administration of Mesna (p=0.0105, OD=5.301, 95% CI=1.477–19.026) and bladder irrigation (p=0.0001, OD=9.469, 95% CI=3.872–23.156) were significant risk factors of early-onset HC. We conclude that (i) high-dose BU as well as CY is a cause of HC, (ii) protective bladder irrigation has an opposite effect, and (iii) Mesna possibly has a toxic effect on bladder mucosa.

The Kinetics of Immune Reconstitution after Cord Blood Transplantation and Selected cd34+ Stem Cell Transplantation in Children: Comparison with Bone Marrow Transplantation

The present study compares immune reconstitution after allogeneic cord blood transplantation (CBT) and CD34+ stem cell transplantation (CD34-SCT) with that after bone marrow transplantation (BMT). Eighty-eight children who underwent CBT (20 patients), BMT (58), and CD34-SCT (10) were enrolled, and lymphocytes and T-, B-, and natural killer—lymphocyte subsets were monitored for more than 5 years after transplantation. CBT recipients showed significant increases in (1) total lymphocyte counts (P < .001), (2) CD4+/CD8+ cell ratios (P < .01), (3) CD4+ and CD4+CD45RA+ cells (P < .001), (4) CD8+CD11b+ cells (P < .001), and (5) CD19+ and CD19+CD5+ cells (P < .0001) and marked decreases in the frequencies of CD8+ and CD8+CD11b- cells (P < .0001). CD34-SCT recipients showed lower lymphocyte counts in the first 6 months and an emergence of lymphocyte and CD4+CD45RA+ cells at approximately 9 months and 1 year. Both CBT and CD34-SCT recipients showed increased frequencies of CD56+ cells at 1 month (CD34-SCT versus BMT, P < .001) but decreased frequencies after 6 months (CBT versus BMT, P < .001). Lymphoproliferative responses to exogenous interleukin 2 were constantly lower in CBT and CD34-SCT recipients than in BMT recipients.These results suggest that the delay in immune reconstitution after CBT in the early phase was mainly qualitative and related to the immaturity of cells, whereas the delay in CD34-SCT was mainly quantitative in the first several months. Int J Hematol. 2003;77:399-407.

Changes in thyroid function after bone marrow transplant in young patients.

Abstract Background : Changes in thyroid function among young patients who received bone marrow transplantation (BMT) were evaluated.