Allogeneic stem cell transplantation in children with acute lymphoblastic leukemia after isolated central nervous system relapse: our experiences and review of the literature.

The prognosis of patients with acute lymphoblastic leukemia (ALL) and central nervous system (CNS) relapse has historically been very poor. Although chemo-radiotherapy has improved outcomes, some patients still have a poor prognosis after CNS relapse. Therefore, allogeneic hematopoietic stem cell transplantation (allo-SCT) has recently become an option for treatment of CNS leukemia; however, information, particularly on the long-term outcome of transplant recipients, is limited. We performed allo-SCT in eight pediatric patients with ALL (n=7) or T-cell type non-Hodgkin's lymphoma (n=1), who had isolated CNS relapse. All patients survived for a median of 70.5 (range, 13-153) months after SCT. Sequelae developed late in some patients: mental retardation (IQ=47) in one patient, severe alopecia in two patients, limited chronic graft-versus-host-disease in three patients, and amenorrhea and/or hypothyroidism in three patients. Except for a pre-school child with post transplant CNS relapse, six out of seven patients show normal school/social performance. Our results clearly indicate a high cure rate of isolated CNS relapse by allo-SCT in pediatric lymphoid malignancies; however, there needs to be further studies to determine which are the appropriate candidates for transplantation and what is the best transplant regimen to achieve high cure rate and maintain good quality of life.

Numerous nonclonal chromosomal aberrations arising in residual recipient hematopoietic cells following allogeneic bone marrow transplantation.

A young female patient in a second remission of acute lymphoblastic leukemia underwent bone marrow transplantation after total body irradiation and high-dose cytarabine from her HLA-matched brother. Following successful engraftment, mixed chimerism was seen 75 days post transplant. The karyotype contained numerous abnormalities in residual recipient cells. Chromosomes 1, 7, 13, and X were significantly more affected than other chromosomes. The high-frequency breakpoints identified were 1p22.2, 5q31.2, and 13q14.2. Some karyotypes specific for leukemia, such as t(9;22)(q34.1;q11.2) and t(8;21)(q22.2;q22.2), not seen with the original disease, were also present. As the frequency of aberrant chromosomes increased markedly with time, donor leukocytes were infused 14 months after BMT, which effectively eradicated the abnormal karyotypes.

Lack of clinical utility of minimal residual disease detection in allogeneic stem cell recipients with childhood acute lymphoblastic leukemia: multi-institutional collaborative study in Japan.

The clinical utility of minimal residual disease (MRD) measurements following allogeneic stem cell transplantation (SCT) in childhood ALL is controversial. We therefore performed a multi-institutional study of MRD in bone marrow samples taken before SCT and at 1, 3, 6 and 12 months after SCT. Case-specific clonal rearrangements of IgH and TCR genes and expression levels of Wilms' tumor 1 (WT1) mRNA were determined by PCR or RT-PCR methods. In total, 95 cases met all criteria for analysis of informative IgH/TCR markers and quantitative WT1 mRNA expression levels. During the 2-year (median 414 days) study period, 20 patients relapsed. Although the proportion of patients with a positive IgH/TCR result before SCT was significantly reduced at 1 month after treatment (P<0.001), attesting the efficacy of SCT, serial measurements of IgH/TCR rearrangements did not correlate with leukemic relapse. Clonal switch was demonstrated in 11 of the 14 patients with bone marrow relapse, indicating that the poor predictive power of the MRD assay most likely reflected the loss of PCR targets. WT1 expression was not related to either MRD detection by IgH/TCR assays or to clinical leukemic relapse. The clinical value of serial MRD monitoring would be limited in ALL patients undergoing SCT.

A novel infant acute lymphoblastic leukemia cell line with MLL-AF5q31 fusion transcript.

Infant acute lymphoblastic leukemia (ALL) is characterized by the presence of the proB phenotype (CD10(-)/CD19(+)), poor prognosis and frequent rearrangement of the mixed lineage leukemia (MLL) gene. The most frequent rearrangement is t(4;11)(q21;q23), the role of whose product, the MLL-AF4 fusion transcript, has been extensively studied in leukemogenesis. In a cell line of infant leukemia with MLL rearrangement denoted KP-L-RY, panhandle PCR amplification of cDNA revealed the presence of a fusion transcript, MLL-AF5q31, indicating that AF5q31 is also a partner gene of MLL. In this fusion transcript the MLL exon 6 is fused in frame to the 5' side of the putative transactivation domain of AF5q31. The AF5q31 protein is a member of the AF4/LAF4/FMR2-related family of proteins, which have been suggested to play a role in hematopoietic cell growth and differentiation. The MLL-AF5q31 fusion transcript, although probably rare, appears to be associated with the pathogenesis of infant ALL like MLL-AF4. Co-expression of HoxA9 and Meis1 genes in the KP-L-RY cell line indicated possible functional similarity between MLL-AF4 and MLL-AF5q31. Further understanding of the function of AF5q31 as well as the specific leukemogenic mechanism of MLL-AF5q31 awaits future studies.

Epstein-Barr virus-associated T-lymphoproliferative disease with hemophagocytic syndrome, followed by fatal intestinal B lymphoma in a young adult female with WHIM syndrome. Warts, hypogammaglobulinemia, infections, and myelokathexis.

A rare association of Epstein-Barr virus-associated T- and B-lymphoproliferative disease (EBV(+) T- and EBV(+) B-LPD) in a patient with WHIM (warts, hypogammaglobulinemia, infections, and myelokathexis) syndrome is reported. A 26-year-old Japanese female, who had been treated for WHIM syndrome since early childhood, developed hemophagocytic syndrome associated with EBV(+) T-LPD at the lymph nodes and spleen. The disease rapidly resolved in response to prednisolone therapy. However, 6 weeks later, fatal EBV(+) B lymphoma unresponsive to chemotherapy occurred in the intestine and other organs. Caution must be exercised that the patient with WHIM syndrome may be at risk for EBV-LPD.

Epithelial cell proliferation and apoptosis in the developing murine palatal rugae.

Epithelial cell proliferation and apoptosis during morphogenesis of the murine palatal rugae (PR) were examined histochemically by using anti-bromodeoxyuridine (BrdU) and the terminal deoxynucleotidyl transferase-mediated UTP nick-end-labelling (TUNEL) technique. Formation of the PR rudiment was observed as an epithelial placode in fetuses at 12.5 days post-coitus (dpc). During the PR formation, BrdU-positive cells were detected mainly in the epithelium of the interplacode and interprotruding areas in fetuses administered BrdU maternally at 2 h before killing. TUNEL-positive cells were detected only at the epithelial placode area in 12.5-14.5 dpc. At 16.5-18.5 dpc, the BrdU-positive cells were decreased in number in the epithelial cells at the interprotruding area of the PR. Only a few TUNEL-positive cells were observed in the protruding area of the PR at 16.5 dpc. These results suggest that cell proliferation and apoptosis in the palatal epithelium are involved spatiotemporally in the murine PR morphogenesis.

Superior outcome of infant acute myeloid leukemia with intensive chemotherapy: results of the Japan Infant Leukemia Study Group.

This study analyzed data on 35 infants with acute myeloid leukemia (AML) who were treated with intensive chemotherapy between 1995 and 1998 in Japan. The incidence of boys, younger age (< 6 months old), and hyperleukocytosis at onset was high in patients with the M4/M5 subtype (n = 23) in the French-American-British classification, compared with the non-M4/M5 subtype (n = 12). Thirteen (56%) and 16 (70%) patients with the M4/M5 subtype also showed 11q23 translocations and MLL gene rearrangements, respectively, whereas only one patient with the non-M4/M5 subtype had this rearrangement. All 35 patients were treated with the ANLL91 protocol consisting of etoposide, high-dose cytarabine, and anthracyclines. Overall survival and the event-free survival (EFS) rates at 3 years of all patients were 76% (95% confidence interval [CI], 61.3%-90.7%) and 72% (95% CI, 56.4%-87.9%), respectively. EFS showed no significant difference between 2 subgroups divided by age, gender, presence of the MLL gene rearrangements, and white blood cell count at onset; EFS in patients with the M4/M5 subtype tended to be better than those with the non-M4/M5 subtype. Although all 6 patients who underwent allogeneic stem cell transplantation (SCT) have been in complete remission, no benefit of SCT was confirmed. These findings suggest that the intensive chemotherapy with the ANLL91 protocol might have been responsible for the observed good outcome of infant AML, even without SCT. The presence of the MLL gene rearrangements or the age at onset had no impact on the outcome of infant AML.

Recent developments in the management of haemophagocytic lymphohistiocytosis.

Over the past two decades, the underlying pathophysiology of haemophagocytic lymphohistiocytosis (HLH) (synonyms: haemophagocytic syndrome, macrophage activation syndrome) has been well recognised. Cytokine storm plays a major role, which derives from an inappropriate immune reaction caused by proliferating and activated T-cell or natural killer (NK) cells associated with macrophage activation and inadequate apoptosis of immunogenic cells. Many biological parameters reflecting activity of disease or response to treatment have been identified, in particular, serum ferritin has been confirmed to be one of the markers for HLH. The common types of HLH consist of non-hereditary (acquired) infection-associated disease such as Epstein-Barr virus (EBV)-haemophagocytic lymphohistiocytosis (HLH) and hereditary (familial) disease such as FHL, in which, at the molecular level, dysfunctional perforin was clarified. Regarding the therapeutic strategies, prompt differential diagnosis of underlying disease is essential and choice of treatment should be based on the risk (low or high) of prognosis, where either cyclosporin A, steroids or iv. immunoglobulin (IVIG) may be indicated as initial treatment for low-risk patients, with etoposide-containing regimens for high-risk patients. Significant improvement of prognosis has been obtained by incorporating intensive supportive care at the disease onset and prompt introduction of immunosuppressants to control cytokine storm. Subsequent immunochemotherapy and haemopoietic stem cell transplantation have contributed significantly to further improve survival of hereditary and refractory HLH patients.

Myelodysplastic syndrome in childhood: a retrospective study of 189 patients in Japan.

We report a retrospective analysis of children with myelodysplastic syndrome (MDS) diagnosed between 1990 and 1997 in Japan. In total, 189 patients were enrolled: 122 cases of primary MDS (26 RA, 18 RAEB, 25 RAEBt, 53 CMML/JMML), 24 cases with constitutional predisposition to MDS, and 43 cases of therapy-related MDS (t-MDS). The frequency of pediatric MDS was estimated to be 7.7% of all leukemias. Cytogenetic abnormalities were observed in 41% of primary MDS and 90% of t-MDS cases. The 4-year survival rate, estimated by Kaplan-Meier analysis, for primary RA was 78.9%, while other types of MDS and JMML had rates lower than 40%, and t-MDS showed an even more unfavorable prognosis. In primary MDS, the survival rate of patients with cytogenetic abnormalities was significantly lower. Among prognostic variables by IPSS, only the cytogenetic pattern was useful for predicting outcome in childhood MDS. There was no apparent advantage to chemotherapy for RA, and the survival rate in patients with primary RA, JMML, or t-MDS receiving stem cell transplantation was significantly higher. More precise designs of our diagnostic and classification systems, as well as therapeutic trials in large-scale prospective studies, are necessary for further improvements in MDS outcome.

[AML(M7) associated with t(16;21)(p11;q22) showing relapse after unrelated bone marrow transplantation and disappearance of TLS/FUS-ERG mRNA].

A 3-year-old boy with poorly prognostic acute megakaryoblastic leukemia (AML M7) showing t(16;21)(p11;q22) karyotype underwent unrelated bone marrow transplantation (U-BMT) during his first hematological remission. The conditioning regimen consisted of BU, VP-16 and L-PAM. Engraftment was smooth, but the patient developed grade I acute GVHD. During hematological remission before U-BMT, the TLS/FUS-ERG chimeric transcript of t(16;21)(p11;q22) was consistently detectable as minimal residual disease (MRD) by RT-PCR. However, after U-BMT it soon became undetectable. There was no detectable MRD until 7 months after U-BMT, but bone marrow relapse occurred 10 months after U-BMT. We consider that U-BMT is a promising treatment for t(16;21)(p11;q22) AML. However, an intensified conditioning regimen or modification of GVHD prophylaxis is needed.

Isolation and characterization of a human thiamine pyrophosphokinase cDNA.

A human thiamine pyrophosphokinase cDNA clone (hTPK1) was isolated and sequenced. When the intact hTPK1 open reading frame was expressed as a histidine-tag fusion protein in Escherichia coli, marked enzyme activity was detected in the bacterial cells. The hTPK1 mRNA was widely expressed in various human tissues at a very low level, and the mRNA content in cultured fibroblasts was unaffected by the thiamine concentration of the medium. The chromosome localization of the hTPK1 gene was assigned to 7q34.

Syntheses and evaluation of quinoline derivatives as novel retinoic acid receptor alpha antagonists.

In the course of studies on novel retinoids, we have designed and synthesized a series of quinoline derivatives. One of them, 4-[5-[8-(1-methylethyl)-4-phenyl-2-quinolinyl]-1H-2-pyrrolyl]benzoic acid (12f) shows potent RARalpha-selective antagonistic activity.

Requirement for etoposide in the treatment of Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis.

PURPOSE: We sought to identify the clinical variables most critical to successful treatment of Epstein-Barr virus (EBV)-associated hemophagocytic lymphohistiocytosis (HLH). PATIENTS AND METHODS: Among the factors tested were age at diagnosis (< 2 years or > or = 2 years), time from diagnosis to initiation of treatment with or without etoposide-containing regimens, timing of cyclosporin A (CSA) administration during induction therapy, and the presence or absence of etoposide. RESULTS: By Kaplan-Meier analysis, the overall survival rate for the entire cohort of 47 patients, most of whom had moderately severe to severe disease, was 78.3% +/- 6.7% (SE) at 4 years. The probability of long-term survival was significantly higher when etoposide treatment was begun less than 4 weeks from diagnosis (90.2% +/- 6.9% v 56.5% +/- 12.6% for patients receiving this agent later or not at all; P <.01, log-rank test). Multivariate analysis with the Cox proportional hazards model demonstrated the independent prognostic significance of a short interval from EBV-HLH diagnosis to etoposide administration (relative risk of death for patients lacking this feature, 14.1; 95% confidence interval, 1.16 to 166.7; P =.04). None of the competing variables analyzed had significant predictive strength in the Cox model. However, concomitant use of CSA with etoposide in a subset of patients appears to have prevented serious complications from neutropenia during the first year of treatment. CONCLUSION: We conclude that early administration of etoposide, preferably with CSA, is the treatment of choice for patients with EBV-HLH.

Existence of retinoic acid-receptor-independent retinoid X-receptor-dependent pathway in myeloid cell function.

We previously reported that ER-27191 (4-[4,5,7,8,9,10-hexahydro-7,7,10,10-tetramethyl-1-(3-pyridylmethyl)anthra[1,2-b]pyrrol-3-yl]benzoic acid) is a potent antagonist of retinoic acid receptor (RAR), and ER-35795 ((2E,4E,6E)-7-[1-(1-methylethyl)-8-chloro-1,2,3,4-tetrahydroquinolin-6-yl]-6-fluoro-3-methyl-2,4,6-nonatrienoic acid) is a novel retinoid X receptor (RXR)-specific agonist. By using these compounds, we investigated whether distinct RAR-dependent and RXR-dependent pathways operate to mediate the diverse activities of retinoids, particularly, the effects of the RXR pathway on cellular function. ER-27191 completely antagonized HL60 cell differentiation induced by all-trans-retinoic acid (atRA). However, the differentiation induced by the ER-35795 was not antagonized at all by the RAR antagonist, but was inhibited by an RXR homodimer antagonist (LGD100754, (2E,4E,6Z)-7-(3-n-propoxy-5,6,7,8-tetrahydro-5,5,8,8-tetramethylnaphthalen-2-yl)-3-methylocta-2,4,6-trienoic acid). Its agonistic action on RXR/RAR heterodimer, on the other hand, was neutralized by the RAR antagonist. During HL60 cell differentiation, atRA induced RARbeta mRNA, while the RXR had no effect. Interestingly, a functional RXR-pathway was also seen in lipopolysaccharide-induced inhibition of mouse splenocyte proliferation. These results strongly suggest the existence of a pharmacological RXR-dependent pathway that is activated by a ligand that can bind to RXR.