Markedly improved outcomes and acceptable toxicity in adolescents and young adults with acute lymphoblastic leukemia following treatment with a pediatric protocol: a phase II study by the Japan Adult Leukemia Study Group.

The superiority of the pediatric protocol for adolescents with acute lymphoblastic leukemia (ALL) has already been demonstrated, however, its efficacy in young adults remains unclear. The ALL202-U protocol was conducted to examine the efficacy and feasibility of a pediatric protocol in adolescents and young adults (AYAs) with BCR-ABL-negative ALL. Patients aged 15-24 years (n=139) were treated with the same protocol used for pediatric B-ALL. The primary objective of this study was to assess the disease-free survival (DFS) rate and its secondary aims were to assess toxicity, the complete remission (CR) rate and the overall survival (OS) rate. The CR rate was 94%. The 5-year DFS and OS rates were 67% (95% confidence interval (CI) 58-75%) and 73% (95% CI 64-80%), respectively. Severe adverse events were observed at a frequency that was similar to or lower than that in children treated with the same protocol. Only insufficient maintenance therapy significantly worsened the DFS (hazard ratio 5.60, P<0.001). These results indicate that this protocol may be a feasible and highly effective treatment for AYA with BCR-ABL-negative ALL.

Dichotomy of all-trans retinoic acid inducing signals for adult T-cell leukemia.

We previously reported that all-trans retinoic acid (ATRA) inhibits growth in human T-cell leukemia virus type 1 (HTLV-1)-positive T-cell lines and fresh cells from patients with adult T-cell leukemia. However, the mechanism of this inhibition is not clear. In the present study, we observed that NF-kappaB transcriptional activity as well as cell growth decreased significantly in HTLV-1-positive T-cell lines in the presence of ATRA. Furthermore, we observed that ATRA reduced HTLV-1 proviral DNA, HTLV-1 genes (gag, tax, or pol mRNA) using the real-time quantitative polymerase chain reaction. SIL-2R was reduced by ATRA in both protein level (culture supernantant) and mRNA level in HTLV-1-positive T-cell lines. Interestingly, ATRA significantly inhibited RT activity similar to azidothimidine (AZT) in HTLV-1-positive T-cell lines. Moreover, AZT inhibited proviral DNA but not NF-kappaB transcriptional activity, and sIL-2R on HTLV-1; however, ATRA inhibited of NF-kappaB, proviral DNA and sIL-2R on HTLV-1. These results suggested that the decrease in sIL-2R induced by ATRA may be caused by the actions of a NF-kappaB inhibitor acting on the NF-kappaB/sIL-2R signal pathway. These results suggested that ATRA could have two roles, as a NF-kappaB inhibitor and as an RT inhibitor.

A mechanism of apoptosis induced by all-trans retinoic acid on adult T-cell leukemia cells: a possible involvement of the Tax/NF-kappaB signaling pathway.

In this study, five single clones were randomly established by limiting dilution method from each of the HTLV-I positive T cell lines - HUT 102 and ATL-2, and examined for the all-trans retinoic acid (ATRA) sensitivity, respectively. For each clone, we found a significant correlation between the reduction in 3[H]-thymidine incorporation and the reduction in CD25 expression (r=0.701, P<0.05) following treatment with 10(-5) M ATRA for 48 h. Agarose gel electrophoresis revealed DNA fragmentation of the cell lines treated with ATRA, indicative of apoptosis. These results suggested that the tax gene in the HTLV-I genome might be a key molecule involved in cell proliferation and CD25 expression. Thereafter, we transfected the tax gene in the expression vector (pCMV-Tax-neo) into the HTLV-I(-) T cell line Jurkat and examined the effects of ATRA on cell growth. The results showed that ATRA sensitivity was acquired by the Jurkat cells transfected with the tax gene expression vector, but not in those transfected with the control vector. We also observed NF-kappaB transcriptional activity on Jurkat cells transfected with the tax gene by CAT assay in the presence or absence of ATRA. NF-kappaB transcriptional activity was decreased significantly on Jurkat cells transfected with the tax gene after ATRA treatment. Taken together, these results indicate that ATRA may affect or block the Tax/NF-kappaB signaling pathway in ATL cells.

Serum KL-6 levels in patients with pulmonary complications after allogeneic bone marrow transplantation.

KL-6, a mucinous high-molecular weight glycoprotein expressed on type 2 pneumocytes, has been shown to be elevated in the serum and bronchoalveolar lavage fluid of patients with interstitial pneumonitis (IP). We measured the serum levels of KL-6 in patients after they had undergone allogeneic bone marrow transplantation (BMT) to determine whether KL-6 could be a clinically useful indicator for the development of IP. The serum concentrations of KL-6 were determined by a sandwich-type enzyme-linked immunosorbent assay using an anti-KL-6 monoclonal antibody. A total of 1028 samples were tested from 76 patients (78 transplantations) who received BMTs. The KL-6 values were markedly elevated in patients with pulmonary complications, but not in those with acute and chronic graft-versus-host disease, hemorrhagic cystitis, herpes encephalitis, sepsis, and veno-occlusive disease. The serum levels of KL-6 from patients with pulmonary complications were significantly higher than from those without pulmonary complications (P < .001) and those with other complications (P < .001). Of the 12 patients with pulmonary complications, 6 had idiopathic IP (IIP). The levels were not high at the onset of IIP. Four of 6 IIP patients showed marked elevations of KL-6 levels in parallel with the severity of IP and died of respiratory failure without response to treatment. Assessment of serum KL-6 levels might not be useful for the early diagnosis of IP, but may be a useful indicator for monitoring the severity of IP after BMT.

Exogenous PML/RARα Fusion Gene Responds to All-trans Retinoic Acid Results in Differentiation of the Human B Cell Line.

The interaction of an exogenous PML/RARα fusion gene, associated with acute promyelocytic leukemia, with all-trans retinoic acid (ATRA) was examined in B-lymphoid cell lines. RPMI8866 cells were transfected with PML/RARα cDNA in the expression vector pGD and two stable transformants (RPMI8866Y-4 and RPMI8866Y-17) were established by selection with G418. ATRA inhibited the growth of those stable transformants, as assessed by [(3)H]-thymidine incorporation, but had no effect on the growth of control cells stably transformed with neomycin resistant gene alone. ATRA also increased expression of CD38 and immunoglobulin production in RPMI8866Y-4 cells but not in control cells. When these results are taken together, it can be observed that the exogenous PML/RARα fusion gene responds to ATRA, which results in cell differentiation of the human B cell line.

Transient eosinophilia by HIV infection.

We describe a case of early human immunodeficiency virus infection characterized by transient eosinophilia without an elevated immunoglobulin E concentration, allergic symptoms, or atopic dermatitis. Possible mechanisms of the eosinophilia are discussed.

Establishment of a myeloid cell line, YM711, characterized by retinoid resistance.

A myeloid cell line (YM711) was established by transfecting exogenous PML/RARalpha cDNA into peripheral blood stem cells. The cells were positive for CD33, CD34, CD38, CD13, CD14, and CD11b. Cytochemical examination revealed YM711 cells to be positive for peroxidase, alpha-naphtyl butyrate esterase, and acid phosphatase as well. Karyotypic analysis showed them to be nearly tetraploid (92 XXYY). Reverse-transcription polymerase chain reaction showed that, although PML/RARalpha mRNA was detected in YM711, these cells could not be differentiated by all-trans retinoic acid (ATRA). We therefore designated the YM711 cell line as being ATRA resistant. Because YM711 expressed multi drug resistance 1 (MDR-1) mRNA and p-glycoprotein cell surface protein, we assessed whether verapamil and ATRA would induce the differentiation of YM711 cells; they did not. An increased expression of cellular retinoic acid-binding protein (CRABP)-II was also detected on YM711 cells compared with that of HL-60. These results suggest that high level of expression of CRABP-II may contribute to be the mechanism of ATRA resistance. This cell line may be useful in evaluating the mechanism of resistance to retinoid.

Thiol compounds rescue growth inhibition by retinoic acid on HTLV-I (+) T lymphocytes; possible mechanism of retinoic-acid-induced growth inhibition of adult T-cell leukemia cells.

We demonstrated significant growth inhibition by retinoic acid (RA) of HTLV-I (+) T-cell lines (ATL-2 and HUT102), but not HTLV-I (-) T-cell lines (MOLT-4 and Jurkat). We hypothesized that the mechanism of growth inhibition by RA depends on an imbalance in redox potential. To examine the effect of exogenous thiol compounds for the growth of HTLV-I (+) T-cell lines by RA, HTLV-I (+) T-cell lines were cultured with several thiol compounds (thioredoxin, L-cystine, and GSH), following addition of 13-cis RA or ATRA, respectively, in cultured with thiol free medium. Unexpectedly, thiol compounds alone did not restore growth inhibition of HTLV-I (+) T-cell lines. However, when those cells were preincubated with thiol compounds for 24 hours, no growth inhibition by 13-cis RA or ATRA was observed. These results suggest that thiol compounds are associated strongly with sensitivity to RA of HTLV-I (+) T cells, but not of HTLV-I (-) T cells and that thiol compounds serve an important role on HTLV-I (+) T cells.

Inhibition of proliferation and CD25 down-regulation by retinoic acid in human adult T cell leukemia cells.

The effects of retinoic acid (RA) on the cell growth and expression of interleukin-2 (IL-2) receptors (IL-2R alpha/p55, Tac, CD25) by the human T lymphotropic virus type I (HTLV-I)-positive T cell lines, HUT102 and ATL-2 were investigated. Incubation of these cells for 48 h with either 13-cis retinoid acid (13-cis RA) or all-trans retinoic acid (ATRA) resulted in marked inhibition of cell growth, determined by 3H-thymidine incorporation, and in down-regulation of CD25 expression, determined by flow cytometry. Four HUT102 cell clones were established by limiting dilution, and 13-cis RA was shown to inhibit cell growth and CD25 expression in three of these clones (HUT102-M5, -M6 and -M7), but not in the fourth (-M8). RA did not induce growth inhibition or down-regulation of CD25 in the HTLV-I-negative T cell lines (Jurkat and MOLT-4) and in normal lymphocytes that had been stimulated with phytohemagglutinin or phorbol 12-myristate 13-acetate. We have shown that RA markedly inhibited both the cell growth and the expression of CD25 in some HTLV-I-positive T cell clones, but not in normal lymphocytes. These results suggest that RA may be suitable for the treatment of patients with adult T cell leukemia (ATL).

Soluble intercellular adhesion molecule-1 levels of patients with acute myeloid leukemia after allogeneic bone marrow transplantation.

Concentrations of serum-soluble intercellular adhesion molecule-1 (ICAM-1) were measured for 10 patients with or without chronic graft versus host disease after allogeneic bone marrow transplantation. Levels of soluble ICAM-1 were higher among patients with chronic graft versus host disease than among those without it, a statistically significant difference. The results indicated that measurement of serum-soluble ICAM-1 is useful for prediction of chronic graft versus host disease.

[Inhibition of proliferation by retinoic acid on adult T cell leukemia cells].

We observed the effects of the retinoic acid (13-cis retinoic acid; 13-cis RA, and all-trans retinoic acid; ATRA) for the cell growth and the expression of CD 25 on peripheral blood mononuclear cells (PBMC) from 17 patients with adult T cell leukemia (ATL). Fourteen had acute type, 1 had chronic type, and 2 had smoldering type of ATL. We divided those patient into 3 groups (hyper-sensitive, sensitive and resistant group) by determined with reduction rate of [3H]-thymidine incorporation obtained before and after treatment with 13 -cis RA or ATRA respectively. Growth inhibition was not observed in normal PBMC by 13 -cis RA or ATRA. However, no down-regulation of CD 25 expression was observed on PBMC in all patients and normal individuals after treatment with 13-cis RA or ATRA. In the aspect of growth inhibition on PBMC in ATL patients, we tried to clarify the mechanism of the phenomenon. In agarose gel electrophoresis, extracted genomic DNA from retinoic acid treated PBMC in hyper-sensitive and sensitive ATL patients showed multimer DNA fragmentation pattern. On the other hand, genomic DNA from PBMC after treatment with retinoic acid in resistant ATL patients and normal individuals showed high molecular DNA pattern without fragmentation. Taken together, it is suggested that retinoic acid could induce growth inhibition of PBMC in some ATL patients resulting in DNA fragmentation, apoptosis. We deeply consider that retinoic acid may be an useful agent for ATL patients in clinical aspect.

Elevated levels of soluble ICAM-1 in serum of patients with acute myeloid leukemia undergoing bone marrow transplantation.

Serum soluble ICAM-1 concentrations were measured in 10 patients with or without chronic graft-vs.-host disease (GVHD) after allogeneic bone marrow transplantation. The serum soluble ICAM-1 levels in the patients with chronic GVHD were significantly higher than that in the patients without chronic GVHD. The data indicated that serum soluble ICAM-1 is a useful parameter for predicting chronic GVHD.

Inhibition of growth and induction of apoptosis by all-trans retinoic acid in lymphoid cell lines transfected with the PML/RAR alpha fusion gene.

The interaction of an exogenous PML/RAR alpha fusion gene associated with acute promyelocytic leukaemia, with all-trans retinoic acid (ATRA) was examined in two lymphoid cell lines. L1210 and MOLT-4 cells were transfected with PML/RAR alpha cDNA in the expression vector pGD and stable transformants (L1210PML/RAR alpha and MOLT-4PML/RAR alpha) were selected with G418. ATRA inhibited the growth of these stable transformants, as assessed by [3H]thymidine incorporation, in a dose-dependent manner, but had no effect on the growth of control cells stably transformed with neomycin resistant gene alone. ATRA also induced apoptosis, as assessed by fragmentation of genomic DNA, in L121OPML/RAR alpha and MOLT-4PML/RAR alpha cells but not in control cells. The exogenous PML/RAR alpha fusion gene therefore probably mediates the effects of ATRA on cell growth and apoptosis in these cell lines.