Efficacy of azithromycin in preventing lethal graft-versus-host disease

Acute graft-versus-host disease (GVHD) following allogeneic bone marrow transplantation (BMT) is initiated by donor T lymphocytes that recognize histocompatibility antigens presented by recipient dendritic cells (DCs). Current approaches to reduce GVHD are focused on suppressing donor T lymphocyte responses to alloantigens. However, these strategies may be inadequate in the setting of allogeneic transplants (particularly histoincompatible transplants), may increase the risk of tumour relapse and are associated with high rates of opportunistic infections. We hypothesized that inhibition of recipient DCs might suppress GVHD. We recently demonstrated in vitro that azithromycin, a macrolide antibiotic, also acts as a nuclear factor (NF)-κB inhibitor of murine DCs and inhibits their maturation and functions, including allogeneic responses. We investigated whether azithromycin could prevent alloreactions in a murine histoincompatibility model. Oral administration of azithromycin to recipient mice for 5 days during major-histoincompatible BMT suppressed lethal GVHD significantly, whereas ex-vivo lymphocyte function was not affected by the drug. These data suggest that azithromycin has potential as a novel prophylactic drug for lethal GVHD.

The effect of azithromycin on the maturation and function of murine bone marrow-derived dendritic cells

Dendritic cells (DCs) are professional antigen-presenting cells capable of initiating primary/adaptive immune responses and tolerance. DC functions are regulated by their state of maturation. However, the molecular pathways leading to DC development and maturation remain poorly understood. We attempted to determine whether inhibition of nuclear factor kappa B (NF-κB), which is one of the pivotal pathways underlying these processes, could induce immunophenotypic and functional changes in lipopolysaccharide-induced mature DCs derived from murine bone marrow. A comparative in vitro study of five clinically used drugs that are known to inhibit NF-κB demonstrated that azithromycin, a macrolide antibiotic, significantly inhibited expression of co-stimulatory molecules (CD40 and CD86) and major histocompatibility complex (MHC) class II by DCs. It also reduced Toll-like receptor 4 expression, interleukin-12 production and the allostimulatory capacity of DCs. These data suggest that azithromycin, as not only an NF-κB inhibitor but also an antibiotic, has potential as a novel drug for manipulation of allogeneic responses.

Expression of ADAMTS4 in Ewing's sarcoma

Ewing's sarcoma (EWS) is a malignant bone tumor that frequently occurs in teenagers. Genetic mutations which cause EWS have been investigated, and the most frequent one proved to be a fusion gene between EWS gene of chromosome 22 and the FLI1 gene of chromosome 11. However, a limited numbers of useful biological markers for diagnosis of EWS are available. In this study, we identified ADAMTS4 (a disintegrin and metalloproteinase with thrombospondin motifs) as a possible tumor marker for EWS using the retrovirus-mediated signal sequence trap method. ADAMTS4 is a secreted protein of 837 amino acids with a predicted molecular mass of 98-100 kDa. It is a member of metalloprotease family, is expressed mainly in cartilage and brain, and regulates the degradation of aggrecans. ADAMTS4 has been suggested to be involved in arthritic diseases and gliomas. Herein, we show that ADAMTS4 mRNA was expressed in all primary EWS samples and all EWS-derived cell lines examined, while its expression was detected only in small subpopulations of other solid tumors. Furthermore, ADAMTS4 expression was found to be regulated by EWS-FLI1 fusion gene-dependent manner. We also demonstrated that ADAMTS4 protein was highly expressed in tumor samples of the patients with EWS by using immunohistochemistry. These results suggest that ADAMTS4 is a novel tumor marker for EWS.

Optimal positive airway pressure predicts oral appliance response to sleep apnoea

Patients with less severe obstructive sleep apnoea (OSA) are usually prescribed oral appliances and/or smaller optimal nasal continuous positive airway pressure (P(nCPAP)) in nCPAP therapy. We hypothesised that OSA patients with greater P(nCPAP) would not respond favourably to oral appliances. Oral appliances were inserted in nCPAP users after washing-out the nCPAP effect. Follow-up polysomnography was undertaken with the adjusted oral appliance in place. The predictability of P(nCPAP) was evaluated with receiver-operating characteristic (ROC) curves. The median baseline apnoea/hypopnoea index (AHI) was reduced with the oral appliance from 36 to 12 events.h(-1) in 35 patients. When responders were defined as patients showing a follow-up AHI of <5 events.h(-1) with >50% reduction in baseline AHI, the area under the ROC curve for P(nCPAP) was 0.76. The best cut-off value of P(nCPAP) turned out to be 10.5 cmH(2)O with a high negative predictive value (0.93) and a low negative likelihood ratio (0.18). OSA patients with a P(nCPAP) of >10.5 cmH( 2)O are unlikely to respond to oral appliance therapy. This prediction is clinically helpful to both OSA patients and medical personnel in discussing oral appliances as a temporary substitute and/or alternative for nCPAP.

Haemodynamic changes in the liver under balloon occlusion of a portal vein branch: evaluation with single-level dynamic computed tomography during hepatic arteriography

AIM

To assess haemodynamic changes in the liver under temporary occlusion of an intrahepatic portal vein.

MATERIALS AND METHODS

Between February 2000 and October 2004, 16 patients with hepatobiliary disease underwent single-level dynamic computed tomography during hepatic arteriography (SLD-CTHA) under temporary balloon occlusion of an intrahepatic portal vein. All patients needed percutaneous transhepatic portography for therapy of their disease. SLD-CTHA was undertaken to clarify the time-attenuation curve influenced by portal vein occlusion, and it was performed continuously over a period of 30s. The difference in absolute attenuation of the liver parenchyma in segments with occluded and non-occluded portal vein branches was determined by means of the CT number, and the difference in absolute attenuation of the occluded and non-occluded portal veins themselves was also evaluated.

RESULTS

SLD-CTHA demonstrated a demarcated hyperattenuation area in the corresponding distribution of the occluded portal vein branch. The attenuation of the liver parenchyma supplied by the occluded portal vein was significantly higher than that in the non-occluded area (p<0.01). The balloon-occluded portal branch enhancement in 15 of 16 cases (94%) appears due to arterio-portal communications. Failure to evaluate a remaining case for portal branch enhancement was due to absence of a visualized portal branch in the section.

CONCLUSION

Under temporary occlusion of an intrahepatic portal vein, hepatic angiography produced enhancement of the occluded portal branches and their corresponding parenchymal distribution; this finding is considered consistent with the presence of arterio-portal communications.

High CD4/CD45RO+ and CD8/CD45RO+ frequencies in children with vaccine-modified measles

BACKGROUND

Despite availability and wide vaccine coverage, measles infections still occur especially in developing countries. An outbreak of measles occurred among previously immunized older Ghanaian children who had milder clinical symptoms with measles-specific IgG antibodies that could have been attributed to secondary vaccine failure, suggesting that the infection was vaccine-modified measles (VMM).

METHODS

Two-color immunophenotyping of the peripheral blood mononuclear cells was performed at acute, recovery and convalescence phases for 19 VMM patients (mean age 6.2 +/- 3.5 years) using flow cytometry, and compared with that of 20 healthy, sex- and age-matched controls.

RESULTS

The results showed a significantly higher memory helper (CD4(+)/CD45RO(+)) cell frequency and increased suppressor cell (CD8(+)/CD45R0(+)) frequency in VMM patients compared to healthy controls. There were no complications and all the patients recovered completely.

CONCLUSIONS

These findings show that the mild symptoms in patients with VMM may have correlated with the increase of memory T cells, which is in sharp contrast with previous reports on acute measles infection. This may suggest that the intact immunologic memory cells could have been crucial for the resolution of VMM.

Cryptic insertion and translocation or nondividing leukemic cells disclosed by FISH analysis in infant acute leukemia with discrepant molecular and cytogenetic findings

Of 51 infants with acute leukemia, 13 (25%) had contradictory findings on 11q23/MLL rearrangements that were analyzed by cytogenetic and Southern blot methods: seven had rearranged MLL and normal karyotype, four had rearranged MLL and abnormal karyotype with no 11q23 translocation, and two had germline MLL and 11q23 translocations. Fluorescent in situ hybridization (FISH) analysis using an MLL probe that was performed to elucidate the discrepancy disclosed the presence of normal dividing cells and nondividing leukemic cells in the same bone marrow in five patients, and cryptic insertion or translocation in another five. Subsequent FISH and reverse transcription-polymerase chain reaction analysis identified the MLL-AF10, MLL-AF4, or MLL-AF1q fusions that were produced by the cryptic rearrangements in four of the five patients. In the remaining three patients, the breakpoint of 11q23 translocation was located distal to the MLL locus in one, and the discrepancy was unresolved in two. Thus, FISH should complement cytogenetic analysis when cytogenetic and molecular genetic findings are contradictory in infant leukemia, and when infant leukemia does not show 11q23 translocations or other specific translocations including t(7;12), t(1;22), etc that are recurrently found in infant leukemia.

Polio vaccine virus-associated meningoencephalitis in an infant with transient hypogammaglobulinemia

The case of an infant with transient hypogammaglobulinemia who developed meningoencephalitis, retinitis and sensorineural hearing loss is presented. The neurovirulent variant of the Sabin type 2 oral poliovirus vaccine was detected in cerebrospinal fluid and stool.

Characterization of nuclear factors that bind to the human thymidylate synthase gene in HL-60 cells differentiated by all-trans retinoic acid treatment

HL-60 cells differentiate into granulocyte-like cells by all-trans retinoic acid (ATRA) treatment, and the cellular proliferation is markedly reduced during the differentiation. To elucidate the molecular mechanisms of the growth arrest during the cellular differentiation, we examined the regulated expression of the thymidylate synthase (TS) gene. Northern blot analysis revealed that the expression of the TS gene was almost suppressed in the differentiated HL-60 cells. The change in the levels of nuclear factors, NF-TS2 and NF-TS3, that bind to the 5'-terminal regulatory region of the human TS gene was examined during the differentiation of the HL-60 cells. The amount of NF-TS2 did not change significantly during the differentiation, whereas that of NF-TS3 clearly increased as the cells differentiated. We previously reported that NF-TS2 and NF-TS3 bind to the sequence around the initiation codon ATG of the human TS gene. Further analyses revealed that the DNA sequences of NF-TS2 and NF-TS3 are very similar, and the first and second positions of the ATG triplet codon are important for the formation of rigid DNA-protein complexes. The present findings concerning the binding site and changes during the differentiation induced by ATRA treatment are very similar to those previously reported on the differentiation induced by 1,25-dihydroxyvitamin D3 treatment. These findings suggest that NF-TS3 is involved in regulating the expression of the human TS gene during the differentiation of HL-60 cells, regardless of the terminal cell type: macrophage-like cells or granulocyte-like cells.

Mutations/deletions of the WT1 gene, loss of heterozygosity on chromosome arms 11p and 11q, chromosome ploidy and histology in Wilms' tumors in Japan

Incidence rates of Wilms' tumor (WT) markedly differ in East Asian and Caucasian children. In the present study, we examined WT1 deletions/mutations and loss of heterozygosity (LOH) on 11p and 11q in a large number of WTs and compared our findings with those from 4 series of Caucasian WTs. Incidence rates of the subtle WT1 mutation in 3 of the 5 series of sporadic and unilateral WTs including ours were 4.3-6.2% and similar. However, gross homozygous WT1 deletion was more frequent in our series than in some others. In addition, our series tended to show a higher incidence of LOH limited to 11p13 and a lower incidence of LOH including 11p15 than the Caucasian one. These findings indicate some genetic differences in WT between the 2 regions. One of the 4 Caucasian series reported a correlation of germinal WT1 mutation with the predominantly stromal histology. The present study not only confirms the correlation of germinal WT1 deletion/mutation with predominant stromal histology but also establishes a correlation with somatic WT1 deletion/mutations with predominant stromal histology. While WTs with WT1 abnormalities usually showed pseudodiploidy and predominant stromal histology, those without WT1 abnormalities showed various chromosome numbers and histologic subtypes.

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.

A pivotal role of Rho GTPase in the regulation of morphology and function of dendritic cells

Dendritic cell (DC) is the most potent activator of CD4+ T cells and has unique dendrites and veils. To explore the function of Rho in DC, exoenzyme C3 from Clostridium botulinum was used as a specific inhibitor of Rho. Treatment of DC with C3 (DC/C3) resulted in profound morphological changes by losing dendrites and emerging of shrunk membrane processes that were in parallel with marked reduction of polymerized actin in the marginal area. Inactivation of Rho-associated coiled coil-containing kinase (p160ROCK) by a specific ROCK inhibitor Y-27632 also led to disappearance of dendrites of DC with retaining large membrane expansions. In scanning electron microscopy, untreated DCs interacted with CD4+ T cells more efficiently than DC/C3. Conjugate formation assay showed that the number of DCs associated with CD4+ T cells was 2-fold higher in untreated DCs than that of DC/C3. Alloantigen-presenting capacity of DC/C3 was significantly suppressed in a dose-dependent manner. Because C3 treatment did not affect the surface expression of HLA, costimulatory, and adhesion molecules of DC, we examined cytokine production of DC and naive CD4+ T cells to further elucidate the inhibitory mechanism of MLR. Unexpectedly, DC/C3 increased IL-12 production after LPS stimulation. Naive CD4+ T cells cocultured with DC/C3 produced the increased percentage of IFN-gamma-producing cells, whereas the percentage of IL-2-producing T cells was decreased. These results demonstrate that Rho GTPase in DC controls both characteristic shape and immunogenic capacity.

Successful unrelated BMT in a patient with Kostmann syndrome complicated by pre-transplant pulmonary 'bacterial' abscesses

Kostmann syndrome, severe congenital neutropenia, is often associated with life-threatening bacterial infections. A 5-year-old girl with Kostmann syndrome developed pulmonary abscesses. She was refractory to granulocyte colony-stimulating factor and antibiotics. She underwent unrelated HLA-matched BMT. Myeloablative conditioning consisted of 12-Gy TBI with lung shielding, antithymocyte globulin, etoposide, and cyclophosphamide. After successful engraftment, the pulmonary abscesses resolved by day 75 post-transplant. Although the option of transplantation is not established in the setting of unrelated HLA-matched BMT in Kostmann syndrome, this case may provide useful information. Furthermore, pre-transplant pulmonary bacterial abscesses may not be a contraindication for BMT in some patients with Kostmann syndrome.

Differential responsiveness of cord and adult blood monocytes to hepatocyte growth factor

Monocytes as antigen-presenting cells play an important role in host defence. There are several cytokines affecting monocyte function. We demonstrate that both adult and cord blood monocytes constitutively express hepatocyte growth factor (HGF) receptor, MET. HGF significantly down-regulated MET expression of adult blood monocytes, compared with cord blood monocytes, when cultured either in RPMI-1640 containing 10% FBS or serum-free medium. Surface levels of MET correlated with c-met mRNA levels both in adult and cord blood when cultured. MET expression was down-regulated by treating with actinomycin D or cycloheximide. HGF stimulated DNA synthesis of adult monocytes, but not cord blood. HGF enhanced antigen-presenting capacity of adult blood monocytes but not cord blood monocytes. HGF up-regulated HLA class I expression in adult monocytes but not in cord blood monocytes. The current results suggest that the failure of cord blood monocytes to respond to HGF may be responsible, in large part, for their functional immaturity.

Frequent increase of DNA copy number in the 2q24 chromosomal region and its association with a poor clinical outcome in hepatoblastoma: cytogenetic and comparative genomic hybridization analysis

In a cytogenetic and comparative genomic hybridization (CGH) study of 38 hepatoblastomas, we found gain of 1q in 17 tumors (44.7%), that of 2 / 2q in 14 (36.8%), that of 20 / 20q in 9 (23.7%) and that of 8 / 8q in 8 (21.0%), loss of 4q in 4 (10.5%) and no DNA copy changes with normal karyotype or no mitotic cells in 11 (28.9%). Eleven tumors with 2 / 2q gain detected by CGH had a total chromosome 2 gain, a partial 2q gain, or a total chromosome 2 gain with an augmented partial 2q region; the common region for DNA copy gain was 2q24. Two-color fluorescence in situ hybridization (FISH) analyses using probes covering the centromere of chromosome 2 or HOXD13 (2q31) confirmed the CGH findings, and showed that the common region for gain in 2q was centromeric to HOXD13. Event-free survival (EFS) +/- standard error (SE) at 5 years was lowest in patients with 2q gain [37 +/- 15%], highest in those with no DNA copy changes [82 +/- 12%], and intermediate in those with DNA copy changes other than 2q gain [74 +/- 13%] (P = 0.0549). Multivariate analysis showed that 2q gain was an independent factor predicting a poor outcome. These findings suggest the presence of a growth-promoting gene or an oncogene in the 2q24 chromosome band, and a tumor suppressor gene in terminal 4q, which have important roles in the development and progression of hepatoblastoma.

Functional immaturity of cord blood monocytes as detected by impaired response to hepatocyte growth factor

BACKGROUND

Monocytes as antigen-presenting cells play an important role in host defense and transplantation. However, there are little reports on cord blood monocytes, and the role of monocytes in cord blood transplantation is largely unknown.

METHODS AND RESULTS

There are several cytokines affecting monocyte function. These include interferon-gamma, interleukin-4, interleukin-10, granulocyte macrophage-colony stimulating factor and hepatocyte growth factor (HGF). We investigated the effect of these cytokines on antigen-presenting capacity (APC) of cord and adult blood monocytes. Using either mononuclear cells or purified CD4+ T cells as responder cells, HGF enhanced APC of adult monocytes most effectively among these cytokines. In contrast, cord blood monocytes failed to respond to HGF. As HLA, costimulatory and adhesion molecules may affect APC function, we examined these antigens of monocytes following HGF stimulation. The HGF upregulated integrin alpha5 subunit (CD49e) and intercellular adhesion molecule-1 (CD54) was expressed in adult blood monocytes, but not in cord blood. In kinetic studies, HGF downregulated c-met protein/HGF receptor expression of adult monocytes in lower concentrations and at shorter incubation time as compared with that of cord blood.

CONCLUSIONS

The results suggest that impaired response of cord blood monocytes to HGF may be responsible, in large part, for their functional immaturity.

Plasma levels of natriuretic peptides in relation to doxorubicin-induced cardiotoxicity and cardiac function in children with cancer

BACKGROUND

Anthracyclines are effective anticancer drugs for childhood cancer with dose-limiting cardiotoxicity. Children who have received anthracyclines thus need periodical cardiac evaluation. The plasma levels of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) have been shown to increase in proportion to severity of cardiac dysfunction. We examined whether plasma levels of ANP and BNP, in addition to echocardiographic evaluation, can be used as specific markers for doxorubicin-induced cardiotoxic effects in children.

PROCEDURE

Consecutively, 34 patients (18 boys and 16 girls) who had previously received doxorubicin-containing chemotherapy were enrolled in this study. Plasma ANP and BNP were assayed simultaneously at the time of first cardiac function evaluation by echocardiography.

RESULTS

Of the 34 patients, 8 (23.5%) had left ventricular dysfunction as assessed by echocardiography. Both ANP and BNP plasma levels in these patients were significantly elevated in comparison with healthy controls (P < 0.01) or patients with normal cardiac function (P < 0.05). It should be also noted that ANP and BNP levels were correlated significantly with cardiac systolic function, but not with diastolic function.

CONCLUSIONS

These results suggest that plasma ANP and BNP levels could be markers for doxorubicin-induced cardiotoxicity in children. Measurement of natriuretic peptide levels during treatment may allow earlier-identification of individuals at risk for severe cardiac damage.

Is the sleep initiating process affected by psychological factors?

The aim of this study was to investigate the effects of psychological factors on sleep initiating process. The Y-G personality test (Y-G), Lazarus-type stress coping inventory (SCI), Zung self-rating depression scale, General health questionnaire, and Sleep health questionnaire were administered to 418 subjects (mean age = 21.13 +/- 8.76 years), and the data were analyzed by multiple regression analysis (stepwise variable reduction method). Self-rating depression scale; Co-Em, Pla, Sel scale in SCI; C, N, O, Co scale in Y-G were significantly included in the final model. The results showed that psychological factors, such as depression, emotion-focused coping behaviour, prudent planning to solve problems, low self-control, small changes of feeling, nervousness, subjectiveness, and cooperativeness are associated with difficulty initiating sleep.

Transient renal tubular acidosis in a neonate following transplacental acetazolamide

Renal tubular acidosis (RTA) was observed in a preterm boy shortly after birth. His mother had glaucoma and had been treated during pregnancy with oral acetazolamide, a carbonic anhydrase inhibitor. When RTA developed, acetazolamide was detected in his serum demonstrating transplacental acetazolamide passage.

Successful immunization following cord blood transplantation in a child with Diamond-Blackfan anemia

Cord blood transplantation (CBT) has been increasingly used to treat patients with hematological diseases, but active immunizations for patients have not been described. Patients certainly need immunizations following CBT, since transplanted cord blood is naive. The authors previously reported successful hematopoietic reconstitution following cord blood transplantation from an HLA-matched sibling in a transfusion-dependent child with Diamond-Blackfan anemia. No graft-versus-host disease, either acute or chronic, has been observed so far. Here, the authors report that immunological recovery of the patient has been rapid shortly after CBT and immunization has been done successfully. Vaccines (diphtheria, pertussis, tetanus, rubella, measles, and BCG) were administered during 22-34 months post-transplant. Seroconversion to these vaccines was excellent without significant adverse effects. These results indicate that both toxoid and live vaccines have been safely administered in the patient who underwent related cord blood transplantation.

Abnormalities of primitive myeloid progenitor cells expressing granulocyte colony-stimulating factor receptor in patients with severe congenital neutropenia

To define the basis for faulty granulopoiesis in patients with severe congenital neutropenia (SCN), the expression of granulocyte colony-stimulating factor receptor (G-CSFR) in primitive myeloid progenitor cells and their responsiveness to hematopoietic factors were studied. Flow cytometric analysis of bone marrow cells based on the expression of CD34, Kit receptor, and G-CSFR demonstrated a reduced frequency of CD34(+)/Kit(+)/ G-CSFR(+) cells in patients with SCN. The granulocyte-macrophage colony formation of CD34(+)/Kit(+)/G-CSFR(+) cells in patients was markedly decreased in response to G-CSF alone and to the combination of stem cell factor, the ligand for flk2/flt3, and IL-3 with or without G-CSF in serum-deprived semisolid culture. In contrast, no difference in the responsiveness of CD34(+)/Kit(+)/G-CSFR(-) cells was noted between patients with SCN and subjects without SCN. These results demonstrate that the presence of qualitative and quantitative abnormalities of primitive myeloid progenitor cells expressing G-CSFR may play an important role in the impairment of granulopoiesis in patients with SCN. (Blood. 2000;96:4366-4369)

Homing-associated cell adhesion molecule (H-CAM/CD44) on human CD34+ hematopoietic progenitor cells

Human CD34+ hematopoietic progenitor cells (HPCs) express CD44 and can directly adhere to hyaluronate (HA) via CD44. Furthermore, CD44 may also be involved in the regulation of CD34+ HPC proliferation and development. The expression of CD44 molecules on CD34+ hematopoietic progenitor cells is significantly lower on bone marrow (BM) CD34+ cells compared with circulating CD34+ cells in cord blood and peripheral blood. Myeloid and erythroid progenitor cells are found predominantly in CD34+ CD44+ cell fractions. More interestingly, CD34+ CD44- cells expressing B-lymphocyte-associated CD10 and CD19 would represent unique B-lymphocyte committed precursors in the BM, which might undergo apoptotic cell death in the early steps of B-cell differentiation.

Activation-induced T cell death occurs at G1A phase of the cell cycle

Peripheral negative selection of cycling T cells after TCR engagement and deletion of activated T cells after an immune response occur by an apoptotic process termed activation-induced cell death (AICD). The cross-linking of TCR-CD3 complex with anti-CD3 monoclonal antibody led to significant apoptotic cell death in peripheral blood T cells. To further define cell cycle restriction points for triggering AICD in T cells, we evaluated the association between cell cycle progression and death signal transduction. Simultaneous DNA / RNA quantification analysis revealed that T cells entering G1A phase of the cell cycle may acquire sensitivity to AICD. The activation of caspase-3 was induced when T cells entered G1A phase. Up-regulation of cyclin-dependent kinases (Cdk4 and Cdk6) and cyclin D3 was initiated in TCR-stimulated T cells entering G1A phase and expression of these markers steadily increased as T cells progressed from G1A into G1B phase. Interestingly, caspase-3 inhibitors could inhibit the up-regulation of these G1 cell cycle regulators and induce G0 / G1A arrest as well as the inhibition of AICD. On the basis of these results, AICD signals are most likely transduced into TCR-stimulated T cells entering G1A phase. T cells that fail to progress from G1A into G1B phase undergo AICD.

The reconstitution of CD45RBhiCD4+ naive T cells is inversely correlated with donor age in murine allogeneic haematopoietic stem cell transplantation

A high incidence of opportunistic infections after unrelated bone marrow transplantation has been reported. Delayed lymphocyte recovery may be associated with opportunistic infections. Immune reconstitution is influenced by recipient age and graft-vs-host disease (GVHD). In fact, children develop GVHD less frequently than adults. However, the role of donor age is largely unknown. We examined the effect of donor age on lymphocyte reconstitution after transplant. Three-month-old BALB/c recipient mice were lethally irradiated and transplanted with allogeneic haematopoietic stem cells from A/J donor mice of different ages, ranging from 0 d to 12 months. The recovery of absolute lymphocyte counts and those of CD3+ T cells, CD4+ T cells and CD45RBhi CD4+ naive T cells in the early post-transplant period correlated inversely with donor age. Recipient mice transplanted with haematopoietic stem cells from younger donors showed significantly higher survival rates and mitogenic responses than adult donors. As T cells, especially CD4+ naive T cells, play an important role in host defence, faster recovery of CD4+ naive T cells in younger donors may contribute to reduced mortality in the early post-transplant period. The results suggest that it could be better to choose a younger donor if sufficient cell dose is available.

Neonatal (cord blood) T cells can competently raise type 1 and 2 immune responses upon polyclonal activation

In the neonate, cellular immunity has generally been hypothesized as being incompetent. Accumulating evidence from several recent studies, together with our present report, contradicts this hypothesis. T-helper cell and T cytotoxic type 1 and 2 (Th1/Th2 and Tc1/Tc2, respectively) cytokine responses to polyclonal T cell receptor (TCR) activation were assessed in medium-term cultures of human cord blood T cells using intracellular cytokine staining, which could measure the frequencies of cytokine-producing cells. In this study, we examined the responses of cord blood CD4(+) and CD8(+) T cells in regard to the production of interferon (IFN)-gamma and interleukin (IL)-4 and compared the responses with those obtained from T cells of healthy adults. We found that the responses in cord blood T cells activated with TCR stimulation were comparable to those of their adult counterparts. Moreover, the Th/Tc cells that developed in cord blood were as competent as adult cells for both IFN-gamma and IL-4 secretion. In addition, IL-12 production, which is critical for both Th1 and Tc1 responses, was equally comparable in the two groups. The production of two major cross-regulatory cytokines, tumor necrosis factor-alpha and IL-10, was similarly comparable and not significantly different between the two groups. Taken together, these results indicate that, though naive, the neonatal T cell is competent to respond to TCR-mediated stimulation and to produce both type 1 and type 2 cytokines.

Somnolence syndrome in a child following 1200-cGy total body irradiation in an unrelated bone marrow transplantation

Neurological complications may occur following intensive chemotherapy and hematopoietic cell transplantation. Postirradiation somnolence syndrome has been observed in children with acute lymphoblastic leukemia who received central nervous system preventive therapy with 1800-2400 cGy cranial irradiation. The authors report a 16-year-old boy with chronic myelogenous leukemia in chronic phase, who developed symptoms compatible with the somnolence syndrome (SS) 6 weeks following HLA-matched unrelated bone marrow transplantation (BMT). The preparative regimen consisted of 1200 cGy total body irradiation (TBI), cytosine arabinoside and cyclophosphamide. The patient developed lethargy and low-grade fever, with intermittent rhythmical delta activity in electroencephalograph. He recovered spontaneously without specific therapy 3 weeks after developing symptoms. This is the first report describing that as low as 1200 cGy TBI can induce SS in a child. After allogeneic BMT, some patients develop neurological symptoms. The authors suggest that somnolence syndrome should be included in differential diagnosis in these patients.

Prognostic factors in childhood acute lymphoblastic leukemia in Japan. Japan Association of Childhood Leukemia Study

A retrospective analysis of children with acute lymphoblastic leukemia (ALL) was performed to evaluate the current status of diagnosis and treatment of ALL in Japanese children. Clinical records of 670 children with ALL were collected and analyzed; these children had been diagnosed between 1991 and 1995 at the 53 institutions in 4 areas participating in the Japan Association of Childhood Leukemia Study. It was found that T-cell ALL was significantly less frequent in Tokai and Hokkaido than in Kansai and Chu-Shikoku. The overall induction rate was 92.4%. The estimated 7-year overall survival rate and event-free survival (EFS) rate were 76.0% +/- 1.9% and 61.4% +/- 2.1%, respectively. EFS rates were significantly different among the geographic areas. In female patients with B-cell precursor (B-pre) ALL and white blood cell counts at diagnosis (WBCsdiag) below 50.0 x 10(9)/L, favorable outcomes were significant. Favorable outcomes were not significant in B-pre ALL patients with a WBCdiag above 50.0 x 10(9)/L or in T-cell ALL patients. The EFS rate for infants was significantly worse than that for patients over 1 year of age. In B-pre ALL, but not in T-cell ALL, it was found that the higher the WBCdiag, the worse the EFS rate. Multivariate analysis showed that the following factors were significantly unfavorable for EFS: the Philadelphia chromosome, an translocations associated with chromosome 11q23, an acute unclassified leukemia, mixed-lineage leukemia, a WBCdiag above 100.0 x 10(9)/L, and male gender. Hyperdiploidy (> 50 chromosomes) was significantly favorable for EFS. For further tailoring of treatment and to improve the outcome in childhood ALL, a prospective large-scale study should be undertaken in Japan.

Effects of bright light pre-exposure on sleep onset process

This study investigated the effects on the sleep onset process of enhanced cerebral cortex activity caused by bright light pre-exposure. Seven healthy young adults were exposed for 40 min before sleep onset, 2500 lx of bright light and 10 lx of dim light. Other factors that affect sleep onset (e.g. circadian phase) were experimentally controlled. Five stages of hypnagogic electroencephalogram (EEG) were scored. The latency of each EEG stage was longer at bright light than at dim light conditions, suggesting that activation of brain activity by bright light pre-exposure strongly regulates the sleep onset process.

Detection of methylthioadenosine phosphorylase (MTAP) and p16 gene deletion in T cell acute lymphoblastic leukemia by real-time quantitative PCR assay

Methylthioadenosine phosphorylase (MTAP) deficiency in tumors can be therapeutically exploited for selective therapy. Many tumors lacking MTAP have been found to homozygously delete the chromosome 9p region containing the p16 tumor suppressor gene. Several methods have been used to detect chromosome 9p deletions in primary tumors. However, the accurate diagnosis of chromosome 9p deletions has been hampered by the presence of contaminating normal cells. In search of an accurate and sensitive diagnostic method, we have developed the real-time polymerase chain reaction assay using the TaqMan chemistry for quantitative detection of MTAP and p16 gene deletions. The assay's feasibility was tested with peripheral blood leukocytes (PBL) from 29 patients with adult T cell leukemia (ATL) previously analyzed with Southern blot analysis and validated on 39 PBL or bone marrow samples from childhood T cell acute lymphoblastic leukemia (T-ALL). Homozygous deletions of MTAP and p16 genes were detected respectively in six (20.7%) and eight (27.6%) of 29 ATL samples and in 15 (38.5%) and 23 (59%) of 39 T-ALL samples. The results correlated well with those of Southern blot analysis. It is of significance that the newly developed method can successfully detect homozygous deletions of these genes in samples containing as low as 33% blast cells. This rapid and sensitive method may be useful in searching for candidates for selective therapy targeting MTAP deficiency.

mRNA expression of variant Fas molecules in acute leukemia cells

Fas (Apo-1/CD95) is a cell membrane receptor involved in apoptotic cell death. Soluble variant forms (sFas) lacking the transmembrane domain due to alternative splicing have been identified. Up-regulation of sFas expression is reportedly implicated in prereceptorial blockage of Fas-induced apoptosis in a dose-dependent manner. We examined mRNA expression of Fas and sFas in fresh leukemia cells. All leukemia cells expressed both mRNAs of full-length Fas (FasFull) and sFas with deletion of exon6 (FasDel6). The ratio of FasFull/FasDel6 mRNA expression was not always correlated with Fas-mediated growth inhibition. Interestingly, in a 6-year-old boy with acute myelogenous leukemia, blast cells obtained at onset and at the time of bone marrow relapses expressed distinct amounts of FasDel6 mRNA. Furthermore, the level of FasDel6 expression appeared to be correlated with Fas-resistance in leukemia blasts. In addition, sFas protein levels were elevated in patients' sera at onset with subsequent return to normal levels after complete remission. These results indicated that sFas could be synthesized and released by leukemia blasts and suggested that up-regulation of Fas variant transcript might render leukemia blasts resistant to Fas-mediated growth inhibition in certain cases.

Epitopes and functional responses defined by a panel of anti-Fas (CD95) monoclonal antibodies

Fas (CD95) is a cell surface glycoprotein that mediates apoptotic cell death when cross-linked with agonistic anti-Fas monoclonal antibodies (MAbs) or the endogenous Fas ligand. In this study, we investigated the in vitro biological properties of a panel of anti-human Fas MAbs. We found that five anti-Fas MAbs of IgG1 subclass (B.E28, B.G30, B.L25, DX2, and B.G34) induced marked apoptotic cell death in Fas-expressing leukemia cells, although this killing was delayed when compared to the cytolytic effect mediated by the prototypic anti-Fas MAb of IgM subclass (clone CH-11). On the other hand, four clones (ZB4, B.G27, B.D29, and B.K14) efficiently blocked apoptotic cell death induced by the CH-11 MAb or Fas ligand. The ability of these MAbs to inhibit cell death appeared to correlate with their relative affinity for the Fas molecule. Furthermore, different clones recognized the same epitope and elicited different effects (induction or inhibition of cell killing); conversely, different clones elicited the same effect but recognized different epitopes. These results suggest that the different biological effects of anti-Fas MAbs would not be mediated in an epitope-restricted manner. The relative binding affinity might correlate to some extent with the biological properties of the MAb.

A randomised dose-comparison trial of granisetron in preventing emesis in children with leukaemia receiving emetogenic chemotherapy

This randomised study was performed to assess the anti-emetic efficacy and tolerability of two-dose regimens of granisetron in children with leukaemia. 49 children with leukaemia were treated with three consecutive courses of high-dose methotrexate or cytarabine regimen. During the first course, patients were evaluated regarding the emetogenicity of each regimen. They were randomised in a crossover manner to receive 20 or 40 micrograms/kg of granisetron before the second and third course of chemotherapy. Neither emesis nor severe appetite loss were observed in over 80% of patients within the first 24 h in all treatment groups. There was no significant difference in the anti-emetic efficacy between the two-dose regimens of granisetron. However, complete protection was achieved less frequently on days 2 and 3. Older children and girls appeared to be less well protected. No adverse events attributable to granisetron were observed. Granisetron dose regimens of 20 and 40 micrograms/kg are, comparably, well tolerated and effective in controlling chemotherapy-induced emesis in the first 24 h, though this protection fails thereafter, particularly in older patients and girls.

Comparative mechanism and toxicity of tetra- and dithiomolybdates in the removal of copper

Tetrathiomolybdate (TTM) can be used as a specific chelator to remove copper (Cu) accumulating in the form bound to metallothionein (MT) in the livers of Wilson disease patients and Long-Evans rats with a cinnamon-like coat color (LEC rats). However, an adverse effect, hepatotoxicity, was observed occasionally on its clinical application. The mechanism underlying the adverse effect of TTM has been studied in comparison with dithiomolybdate (DTM), and a safer and more effective therapy by TTM was proposed based on the mechanism. The activity of glutamic-pyruvic transaminase (GPT) in serum was shown to increase significantly on the treatment of Wistar rats with sulfide produced through hydrolytic degradation of TTM and DTM, the latter being more easily degraded. The hydrolytic degradation of TTM was enhanced under acidic conditions. Cu in Cu-containing enzymes such as Cu,Zn-superoxide dismutase (SOD) in liver and ceruloplasmin (Cp) in plasma was decreased by excessive thiomolybdates, the Cu being found in the plasma in the form of a Cu/thiomolybdate/albumin complex. The decreased amounts of Cu in SOD and Cp were explained by the sequestration of Cu from their chaperones by thiomolybdates rather than the direct removal of Cu from the enzymes. Although both TTM and DTM remove Cu from MT, DTM is not appropriate as a therapeutic agent for Wilson disease due to its easy hydrolysis and production of sulfide.

Human dendritic cells express the thrombopoietin receptor, c-Mpl

Human thrombopoietin (TPO) is a haemopoietic growth factor that is essential for the growth and development of megakaryocytes. However, c-Mpl, the TPO receptor, has been detected in human leukaemic cell lines with a myelomonocytic phenotype. These results raise the possibility that dendritic cells (DC), a putative myeloid lineage cell, may also express c-Mpl and respond to TPO. In haemopoietic stem cell transplantation, DC could induce graft-versus-host disease by its strong antigen-presenting capacity. In this study we have examined the effect of TPO on differentiation and the antigen-presenting capacity of DC. To differentiate DC, cord blood CD34+ cells were cultured in the presence of a cytokine cocktail either in serum-free medium or RPMI1640 containing 10% fetal bovine serum. Flow cytometric analysis and immunocytochemical staining demonstrated that c-Mpl was expressed on DC. Furthermore, the expression of c-Mpl mRNA was detected in DC by RNase protection assay. However, when TPO was added to the culture system there were no significant changes in the differentiation and mixed leucocyte-stimulating capacity of DC. These findings suggest that TPO may be administered following cord blood transplantation without significant augmentation of antigen presentation mediated by DC.

Possible involvement of bcl-2 in regulation of cell-cycle progression of haemopoietic cells by transforming growth factor-beta1

Transforming growth factor-beta1 (TGF-beta1) acts directly on haemopoietic progenitor cells to regulate their growth. To investigate a possible link between the action of TGF-beta1 and cell death regulators such as bcl-2, we utilized Ba/F3 cells, the interleukin-3 (IL-3)-dependent growth of which could be modulated by TGF-beta1, as well as haemopoietic progenitor cells. We demonstrate here that up-regulation of bcl-2 protein (Bcl-2) as well as that of an inhibitor of cyclin/cyclin-dependent kinase complex, p27, was associated with TGF-beta1-induced deceleration of the cell-cycling of haemopoietic progenitor cells and Ba/F3 cells. The data from cell-cycle analysis of Ba/F3 cells showed that TGF-beta1 retarded the G1 to S phase transition. Analysis of cells with the potential to express Bcl-2 in an inducible manner indicated that up-regulation of Bcl-2 was sufficient for not only an increase in the level of p27 but also to inhibit the cell growth. Using c-kit-overexpressing cells, we observed that the potential of TGF-beta1 to up-regulate the expression of Bcl-2 and p27 could be counteracted by the c-kit ligand, stem cell factor. These results demonstrate that Bcl-2 exerts an essential function in the regulation of G1 to S phase transition of haemopoietic cells by TGF-beta1.

CD3-mediated T cell activation is inhibited by anti-CD44 monoclonal antibodies directed to the hyaluronan-binding region

The CD44 molecule has been shown to play a role in T cell adhesion and activation. We have investigated the ability of five anti-CD44 monoclonal antibodies (MoAb) including 15C6, 18A3, BU75 (Ancell), J173 (Immunotech), and L178 (Becton Dickinson) to regulate T cell activation. Three MoAb: 15C6, BU75, and J173 were found to selectively inhibit DNA synthesis, interleukin-2 (IL-2) receptor expression, and G1-->S transition of the cell cycle in T cells stimulated with anti-CD3 MoAb. None of anti-CD44 MoAb had influence on T cell proliferation induced by IL-2 or phorbol 12-myristate 13-acetate plus ionomycin. Inhibition of the CD3 pathway by anti-CD44 MoAb occurred by binding of MoAb directly to T cells without the involvement of monocytes or Fc receptors. In addition, the inhibitory anti-CD44 MoAb clearly suppressed intracellular calcium mobilization in T cells stimulated with anti-CD3 MoAb. Interestingly, the ability of anti-CD44 MoAb to inhibit T cell activation was well correlated with their capability to block the binding of hyaluronan (HA) to CD44 molecules. These results suggest that anti-CD44 MoAb directed to HA-binding site could selectively inhibit CD3-mediated T cell activation. Furthermore, CD44-mediated inhibitory signals would be linked to the blocking of early CD3-mediated signal transduction.

[Smooth muscle myosin of SM1 and SM2 isoforms expressing human neuroblastoma cell line of MP-N-MS]

Human neuroblastoma (NB) cell lines have at least three morphological appearance of neuroblastic (N-type), substrate-adhessive (S-type) and intermediate(I) cells. Our previous study revealed S-type cells expressed alpha-smooth muscle actin, desmin and/or basic-calponin, indicating the plausible smooth muscle cell characteristics of S-type cells. In this study, a new human NB cell line, MP-N-MS, was established from bone marrow metastasis of a one year and six-month old girl with advanced NB, originating from right adrenal gland. Morphology of this cell line is composed of S-type cells. MP-N-MS was identified as a NB cell line by surface membrane antigen analysis and MYCN gene amplification. EWS-FLI1 and EWS-ERG chimeric products, observed in Ewing family tumors, were not detected by RT-PCR (reverse transcriptase-polymerase chain reaction). In cytoskeletal protein analysis, alpha-smooth muscle actin and basic calponin of smooth muscle cell markers were detected. Furthermore, smooth myosin of SM1 isoform was identified in MP-N-MS cell line by immunofluorescence, Western blot and RT-PCR, whereas smooth myosin of SM2 was detected by RT-PCR. MP-N-MS is the first cell line, showing SM1 and SM2 isoforms. The presence of smooth muscle myosin of SM1 and SM2 isoforms in MP-N-MS demonstrated the mature smooth muscle phenotype of this NB cell line, and the ability of NB cells to differentiate into smooth muscle cell.

Expression of homing-associated cell adhesion molecule (H-CAM/CD44) on human CD34+ hematopoietic progenitor cells

We investigated the expression of CD44 molecule on CD34+ hematopoietic progenitor cells. Significantly lower expression of CD44 was observed on bone marrow (BM) CD34+ cells compared with circulating CD34+ cells in cord blood and peripheral blood. Using fluorescence-activated cell sorting, human CD34+ BM cells were fractionated into CD44+ and CD44- populations. Immunofluorescence analysis revealed that the majority of CD34+CD44- cells expressed B-lymphocyte-associated CD10 and CD19 antigens, whereas only a part of CD34+CD44+ cells were positive for CD19. Myeloid and erythroid progenitor cells were found predominantly in CD34+ CD44+ cell fractions. In short-term suspension cultures, cell proliferation and G1-->S transition in the cell cycle were enhanced in CD34+CD44+ cells. In contrast, a large part of CD34+CD44- cells underwent apoptotic cell death. Although co-culture with BM stromal cells could partially prevent CD34+CD44- cells from undergoing apoptosis, significant increase of apoptotic cells was consistently observed. Furthermore, CD34+CD44- cells plated on BM stromal cells could differentiate into CD34-CD44-CD10-CD19+ cells. These findings suggest that CD34+CD44- cells expressing CD19 would represent unique B-lymphocyte-committed precursors in BM, which might undergo apoptotic cell death in the early steps of B-cell differentiation.