During childhood, anemia includes a group of anemia of unknown etiology, although the contribution of congenital and familial factors is strongly suspected. This group includes Diamond-Blackfan anemia (DBA), Fanconi's anemia (FA) and amegakaryocytic thrombocytopenia (AMT), which are included in the conventionalclassification, and as to hypoplastic anemia, so called ill-defined dyshematopoiesis (IDD), which is the transient type. The author pathophysiologically analyzed these types of childhood anemia with respect to red cell membrane components, such as protein, lipid and sugar. The peanut lectin (PNA) agglutination test showed a persistent positive agglutinated reaction to PNA not only in peripheral red cells but also in the bone marrow erythroblasts of the anemic children as well as some of the cord-blood cells, but was not observed in other anemic children. This abnormality may have contributed to red cell-membrane sugar chain anomalies. When analyzed by HPLC, the sugar chains derived from erythrocyte membrane showed the O-linked sugar-chain (O-glycan) peak wave pattern as observed with red cells treated with sialic acid-cleaving enzyme (vibrio cholerae : VC), making them test positive for PNA agglutination. These sugar chain anomalies showed similar properties to the immature chain of cord-blood red cells or to the loss of sialic acid from O-glycan in VC-treated red cells in which an incomplete sugar chain of sialic acid was lost. Therefore, the abnormal sugar chain expressed on red cell membranes may have induced anemia in these patients. DBA may have membrane sugar chain-forming anomaly at the level of CFU-E. If such anomaly also occurs at the levels of CFU-GM and CFU-Meg, FA, AMT or IDD may develop. The results of this study suggest that hypoplastic anemia with sugar chain anomaly (HASA) may be established as a group of anemia.

View full abstract

The cloning of chromosome translocation breakpoints has enabled the identification of several genes contributing to hematologic malignancies. The ETV6/TEL gene at 12p13, cloned from a CMML patient sample with t (5; 12), is presumed to code a putative transcription factor with HLH and ets DNA binding domain. ETV6 resembles the MLL gene in terms of promiscous genes; seven partner genes (i.e., PDGFR-β, MN1, ABL, AML-1, STL, MDS1/EVI1, and JAK2) are cloned and the fusion transcripts are characterized. ETV6-AML1 fusion is detected in about 30% of childhood B-cell ALL cases, and the cryptic t (12; 21) carrying the fusion is now the most common translocation among childhood leukemias. In t (9; 12) childhood ALL, ETV6 is fused to JAK2, a gene of tyrosine kinase involved in the JAK-STAT signal transduction pathway. While the presumed function of these fusion proteins is to activate tyrosine kinase in some translocation, another possibility is raised that the tumor suppression function may be impaired by the concomitant translocation and deletion of ETV6 in certain leukemias. The distribution of genomic breakpoints suggests this unique property of genomic structure. Further studies of genomic structure are needed to reveal the mechanism of translocation and deletion of 12p13.

View full abstract

We examined the fibrinolytic activities of neonates, especially in the early neonatal period, and we found cases with short euglobulin clot lysis time (ELT); 8 of 66 cord plasma, 1 of 13 1-day-old plasma and 2 of 15 3-day-old plasma samples. Then, we distinguished the cases with short ELT from the other cases with normal ELT in neonates and investigated further fibrinolytic parameters. Some of the cases with short ELT showed high levels of plasma tissue-type plasminogen activator (tPA) antigen and low levels of plasma plasminogen activator inhibitor (PAI) activity. Especially, cord plasma with short ELT showed significant differences in tPA antigen and PAI activity from those with normal ELT. These findings indicate that tPA and PAI-1 have important roles in shortening ELT in neonates.

View full abstract

It is known that activated T cells show the elevation of telomerase activity and the expression of Fas ligand (FasL). In this study, we investigated the inhibitory effects of pooled human immunoglobulin (PHIG) and dexamethazone (DEX) on peripheral blood mononuclear cells stimulated with streptococcus pyrogenic exotoxin-A (SPE-A), known a bacterial superantigen, through measuring the telomerase activity of the cells and soluble FasL concentration in the culture supernatants. When PHIG was added simultaneously with SPE-A in vitro, both the telomerase activity and soluble FasL concentration were suppressed significantly. But no inhibitory effect was observed when the addition of PHIG was postponed over 12 hr after SPE-A stimulation. On the other hand, telomerase activity was not significantly inhibited by the addition of DEX, but sFasL concentration was suppressed by the addition of DEX until 48 hr after SPE-A stimulation. It was suggested that the clinical effect of PHIG or DEX might be mediated by the inhibition of telomerase activity and Fas-FasL systems to such diseases as induced by excessive immune reactions.

View full abstract

Between August 1994 and July 1995, we experienced 17 episodes of a-Streptococcal (α-Str) sepsis after chemotherapy for childhood malignancy. The patients consisted of 7 boys and 7 girls (multiple episodes in three patients). Their primary diseases were diagnosed as acute lymphocytic leukemia (5 cases in 4 patients), acute non-lymphocytic leukemia (8 cases in 6 patients), non-Hodgkin's lymphoma (two cases), neuroblastoma (one case) and rhabdomyosarcoma (one case). Thirteen cases occurred after high-dose cytarabine therapy (HD-AraC), and adult respiratory distress syndrome was seen in three cases. Piperacillin (PIPC) and cefotaxim (CTX) showed good chemosensitivity for these α-Str. Since August 1995, we started alternative prophylactic antibiotic therapy with PIPC and CTX after HD-AraC. Thereafter, α-Str sepsis did not occur after HD-AraC, leading to the consideration that prophylactic antibiotic therapy is effective for the prevention of α-Str sepsis after HD-AraC.

View full abstract

The sequential combination of MTX and Ara-C at a 2-hr interval (S-AC) has been known to have a strong cell-killing effect for multidrug-resistant leukemic cells (MDR cells). This study aimed to clarify whether or not cyclosporin A (CyA) and cepharanthin (CR) have the effect of further enhancing the cytotoxicity of S-AC in vitro. According to the S-AC procedure, MTX and Ara-C were added to a liquid culture of MDR cells (K562/VCR, K562/ADM and CEM/MTX), followed by the addition of CyA or CR at different time (at the same time as MTX, at the same time as Ara-C, at 1 hr after Ara-C). After 72 hr incubation, the cytotoxic index (CI) was determined using the MTT dye method. Another experiment was undertaken to clarify whether or not pretreatment with INF-γ and TNF-α increases the drug sensitivity of drug-resistant cells such as K562/VCR and CEM/MTX. The addition of CyA to S-AC resulted in a significant enhancement of cytotoxicity for all MDR-cell lines. CR also showed the same effect, but less than CyA. Both IFN-γ and TNF-α increased the drug sensitivity of K562/VCR for vincristine and CEM/MTX for MTX, respectively, to a sensitive level.

View full abstract

We report on a six-year-old boy who was admitted to our hospital because of high fever and exanthema. He was found to have acute myelomonocytic leukemia (AMMoL) (FAB-M4) without bone marrow basophilia. A cytogenetic analysis of bone marrow blasts revealed t (6; 9) (p23; q34). He was treated with induction therapy consisting of cytarabine, mitoxantrone and etoposide, and attained complete remission. After 8 courses of intensification therapy, chemotherapy was completed. However, 2 months later he relapsed, and the disease became resistant to chemotherapy. He died of sepsis 20 months after the diagnosis. DEK-CAN chimeric mRNA was detected both at the time of diagnosis and during hematologic remission by reverse transcriptase-polymerase chain reaction. The poor clinical outcome of our case was compatible to with previous reports of leukemia with t (6; 9). More intensive treatment, including bone marrow transplantation in the first remission, should be considered to improve the prognosis of this type of leukemia. The etiology and clinical features of t (6; 9) acute leukemia are also discussed.

View full abstract

We report on three children with refractory leukemia who underwent transplants with CD34-positive bone marrow cells from HLA two-loci mismatched related donors. The first patient was a 4-year-old girl with acute myeloid leukemia with t (16 ; 21). She received the transplant during second complete remission. The second patient was a 7-year-old boy with B-cell acute lymphoblastic leukemia. He received the transplant during the refractory phase. The third patient was a 15-year-old boy with acute monocytic leukemia. He was transplanted in refractory phase. The conditioning regimen consisted of busulfan, melphalan and total body irradiation. The CD34-positive marrow cells were separated using an immunomagnetic cell-separation system (Isolex50®). The number of infused CD34-positive cells was 2.18×10⁶/kg, 2.80×10⁶/kg and 0.32×10⁶/kg, respectively. All three patients achieved engraftment without severe acute graft-versus-host disease (GVHD). The first patient is alive and well in hematological remission 26 months after transplantation. The second patient relapsed on day 68 after transplantation and died from multiple organ failure on day 97. The third patient died from cytomegalovirus pneumonia on day 54. CD34-positive marrow cell transplantation from HLA-mismatched related donors may be a useful method that provides hematopoietic engraftment without severe GVHD. But the increased risk of relapse and viral infection remain to be solved, and overcoming these problems is crucial to establish this method.

View full abstract

We report two cases of acute lymphoblastic leukemia (ALL) that were difficult to diagnose, because the patients presented only cytopenia without the appearance of distinct blast cells in peripheral blood and bone marrow for more than five months. The first case was a 23-month-old girl. She was noted to have bicytopenia and admitted to our hospital when she had a fever. She did not present an obvious increase of blast cells at the time of admission. However, after seven months, blast cells increased suddenly and she developed typical manifestations of ALL. The second case was a 26-month-old boy. He was kept under observation in another hospital because he presented bicytopenia like the first case. After five months, he had overt ALL. These two cases corresponded to the PreALL described previously. ALL preceded by a cytopenic phase seems to have a good prognosis. The cases which we experienced were common ALL, and responded well to chemotherapy, which resulted in complete remission. One case in which chromosome analysis was carried out showed hyperdiploidy, known as a good prognostic factor.

View full abstract