Kenkichi Kita

Frequent expression of P‐glycoprotein/MDR1 by nasal T‐cell lymphoma cells

Background. Lethal midline granuloma is now considered to be a malignant lymphoma derived from peripheral T cells or from natural killer cells. The therapeutic outcome of nasal T‐cell lymphoma (NL) treated by conventional chemotherapy for non‐Hodgkins lymphoma is poor, although some patients have a good response to radiotherapy. To clarify the mechanisms of drug resistance, the expression of P‐glycoprotein (P‐gp)/MDR1, which is the product of the multidrug resistance (MDR) 1 gene, and MDR3 mRNA in NL cells, were examined.

De novo CD5-positive diffuse large B-cell lymphoma: clinical characteristics and therapeutic outcome.

To determine the clinical significance of CD5 expression in diffuse large B‐cell lymphoma (DLBL) without a clinical history of low‐grade B‐cell lymphoma, we have reviewed the clinical features and therapeutic outcome of 25 patients with de novo CD5‐positive DLBL, and compared the results with those of 87 patients with CD5‐negative DLBL and 22 patients with mantle cell lymphoma (MCL). The patients with de novo CD5‐positive DLBL had clinical characteristics of elderly onset (median age 63, range 37–91), and female predominance (male/female 10/15). 21 (84%) of these patients had extranodal involvement at presentation, with great variation in the sites. In comparison with the patients with CD5‐negative DLBL, the treatment outcome for the patients with de novo CD5‐positive DLBL was very poor with frequent relapse. The failure‐free survival curve was almost identical to that of patients with MCL, showing that standard chemotherapy for DLBL was not effective for most of the patients with de novo CD5‐positive DLBL. These findings suggest that de novo CD5‐positive DLBL forms a distinct subgroup of DLBL.

Survival of human leukaemic B-cell precursors is supported by stromal cells and cytokines: association with the expression of bcl-2 protein.

We searched for cytokines with the potential to support the survival of human B‐cell precursor acute lymphoblastic leukaemia (pre‐B ALL) cells. 47 patients with pre‐B ALL were classified into four stages: stage I, CD19+CD10−CD20−; stage II, CD19+CD10+CD20−; stage III, CD19+CD10+CD20+cytoplasmic μ‐heavy chain (cμ)−; stage IV, CD19+CD10+CD20+cμ+. Interleukin (IL)‐3 receptor α chain (IL‐3Rα) was expressed in all stages, whereas the expressions of IL‐7Rα and IL‐2Rα were pronounced in stages IV and II, respectively. Neither IL‐3, IL‐7 nor IL‐2 supported the survival of pre‐B ALL cells. When pre‐B ALL cells were layered on stromal, MS‐10, cells, viability of the pre‐B ALL cells increased. Addition of IL‐3 to culture containing MS‐10 cells enhanced the survival of pre‐B ALL cells in all cases, whereas addition of IL‐7 augmented the survival of pre‐B ALL cells of some cases of stage III and all cases of stage IV. The survival of pre‐B ALL cells was also supported by the conditioned media of MS‐10 cells. Stromal‐cell‐derived factor 1 (SDF‐1) supported the survival of pre‐B ALL cells. Effects of the conditioned media of MS‐10 cells were abrogated by an anti‐SDF‐1 neutralizing antibody. The extent of survival of pre‐B ALL cells supported by stromal cells and IL‐3 and IL‐7, correlated with the expression level of bcl‐2 protein. The effects of stromal cells may be in part related to SDF‐1.

Successful autologous peripheral blood stem cell transplantation for relapsed intravascular lymphomatosis

We describe a case of relapsed intravascular lymphomatosis (IVL) successfully treated with autologous PBSCT. A 59-year-old Japanese female patient with IVL who had achieved CR after six courses of biweekly CHOP therapy developed lymphoma. She achieved a second CR after six courses of modified biweekly CHOP therapy, followed by autologous PBSCH and high-dose chemotherapy (CBDCA, VP-16, MCNU, CY) with PBSCT. There has not been any evidence of recurrence 48 months after PBSCT. Our case suggests that PBSC is acceptable as a source for stem cell rescue in IVL. Bone Marrow Transplantation (2001) 27, 89–91.

(gamma) / (delta) T-cell lymphoma of the thyroid gland

To the Editor: Lymphomas of the thyroid are almost exclusively of B-cell origin.1 We report a case of thyroid lymphoma with a γ/δ T-cell phenotype. A 59-year-old Japanese woman was seen because of ...

The expression of co-stimulatory molecules and their relationship to the prognosis of human acute myeloid leukaemia : poor prognosis of B7-2-positive leukaemia

We examined the expression of co‐stimulatory molecules on leukaemic cells of 52 adult patients with acute myeloid leukaemia (AML) (34 men and 18 women) and analysed the relationship between these expressions and the patients prognosis. B7‐1 was not expressed in any of the 23 patients investigated, whereas B7‐2 was expressed in 26/52 patients (50.0%). B7‐2 was expressed in all AML patients with monocytic morphology (M4 or M5) and in 16/42 cases without monocytic morphology. CD54 was expressed in 28/37 patients examined (75.7%), and CD58 was expressed in all of the AML patients except one (M7). The overall survival of the 26 B7‐2‐positive leukaemia patients (1–24 months, median survival 11.5 months) was significantly shorter than that of the 26 B7‐2‐negative leukaemia patients (1–71+ months, median 35.1 months) (P = 0.0080). In addition, the B7‐2‐positive patients exhibited significantly shorter disease‐free survival periods compared to the B7‐2‐negative patients (P = 0.021). There was no significant difference in age, sex, haematological data and complete remission rate between the B7‐2‐positive and B7‐2‐negative patients. Our results indicated that B7‐2 is one of the most crucial factors in the prognosis of adult acute leukaemia and can be expected to have an important role in tumour immunity.

Heterogeneous fusion transcripts involving the NUP98 gene and HOXD13 gene activation in a case of acute myeloid leukemia with the t(2;11)(q31;p15) translocation

We report the characterization of a rare chromosomal translocation, a t(2;11)(q31;p15), which occurred in a patient with de novo acute myeloid leukemia (AML-M4). By 3′-RACE and RT-PCR analyses, two kinds of NUP98-HOXD13 fusion transcript were detected. In addition, we identified a novel fusion transcript, NUP98-FN1, in the same patient. Ectopic expression of the wild-type HOXD13 gene was also observed in the patient, suggesting that HOXD13 contributes to the development of this type of leukemia. The NUP98-HOXD13 fusion transcript was predicted to encode a 552 or 569-amino acid protein containing the Phe-Gly (FG) repeat region of NUP98 and the homeodomain of HOXD13. The NUP98-FN1 fusion transcript was predicted to encode a 482 or 499-amino acid protein consisting of the same N-terminal region of NUP98 and a C-terminal region of 12 amino acids derived from a previously unidentified sequence. We isolated and characterized the chromosomal breakpoints. The breakpoint at 11p15 is mapped within a LINE repetitive element in a 9 kb intron of NUP98, and more than 60% of the sequenced 3 kb region surrounding the breakpoint junction consists of repetitive elements. The other breakpoint at 2q31 is in an intron of FN1, which is located 7 kb upstream of HOXD13, and the repetitive sequence content of the breakpoint junction is low. Local sequence duplications at genomic breakpoints suggest that the t(2;11) translocation is mediated through staggered double-strand DNA breaks. These results throw light on the mechanisms responsible for the generation of t(2;11) translocation and on the processes leading to t(2;11) leukemia. Leukemia (2000) 14, 1621–1629.

Cellular characteristics of acute myeloblastic leukemia associated with t(8;21)(q22;q22). The Japanese Cooperative Group of Leukemia/Lymphoma.

A large number of AML cases is reviewed in order to clarify biological characteristics of t(8;21) AML cells. The incidence of positivities for stem cell antigens, CD34 and HLA-DR, on blasts in t(8;21) AML is higher in comparison with those in other M2 or M3 categories. Frequent expression of CD34 and HLA-DR is indicative of the stem cell derivation of t(8;21) AML cells. The non-blastic leukemic cells in t(8;21) AML tend to lose the immature phe-notype with discordant maturation such as low CD33 expression. Further, the blasts show frequent expression of the B-cell antigen, CD 19, without other B-cell antigens and immunoglobulin gene rearrangements.

Diagnostic and clinical importance of interleukin-2 receptor alpha chain expression on non-T-cell acute leukaemia cells

The expression of interleukin‐2 receptors (IL‐2R) was examined in 328 adult patients with non‐T‐cell (non‐T) acute leukaemia and blast crisis of chronic myelocytic leukaemia (CML.BC) using two monoclonal antibodies, anti‐Tac for IL‐2R α chain (IL‐2Rα) and Mikβ1 for IL‐2R β chain (IL‐2Rβ). Leukaemic cells in the following cases were positive for anti‐Tac; 28/192 of acute myelocytic leukaemia (AML), 24/44 CML‐BC, 4/28 CD19(+)CD10(‐) acute lympho‐blastic leukaemia (ALL), and 20/64 common ALL (c‐ALL). IL‐2Rβ was not detected on leukaemic cells of any case examined. Eleven of IL‐2Rα(+) AML were derived from myelodysplastic syndrome. None of the IL‐2Rα positive leukaemic cells responded to exogenous recombinant human IL‐2 (rhIL‐2) in culture. In addition, IL‐2Rα expression on non‐T leukaemic cells was closely correlated with coexpressing different lineage markers and the presence of the Philadelphia abnormality. Marked increase of serum soluble IL‐2Rα was demonstrated in the IL‐2Rα(+) patients examined. Clinically, the IL‐2Rα(+) patients showed significantly lower response to chemotherapy and poorer prognosis than IL‐2Rα(‐) patients. Our results clearly indicate the diagnostic importance of IL‐2Rα expression in non‐T acute leukaemia with a close relation to the particular cellular characteristics and the prognosis.

Expression of endothelial cell-associated molecules in AML cells.

Recently, it has been clarified that interaction between hematopoietic cells and endothelial cells is important in normal hematopoiesis and leukemogenesis. In this study, we examined the relationship between AML cells and endothelial cells by analyzing the expression profile of angiogenic factors, angiopoietin-1 (Ang-1), Ang-2, Tie-2 (a receptor for angiopoietins) and vascular endothelial growth factor (VEGF). Our results demonstrated that CD7(+)AML expressed Ang-2 mRNA frequently and integrin-family adhesion molecules (CD11c and CD18) intensively, suggesting the close correlation with endothelial cells. On the other hand, in t(8;21) AML cells, expression of Ang-2 was infrequent and expression of integrin-family adhesion molecules (CD11b, CD11c and CD18) was weak, suggesting the sparse association with endothelial cells. As for CD7(+)AML cells, despite the frequent and intense expression of endothelial cell-associated molecules (such as Ang-2, CD11c and CD18), intensity of Tie-2 expression was quite low (P < 0.05). Ang-2 expressed in CD7(+)AML cells is not considered to act in an autocrine fashion, but to work on endothelial cells to ‘feed’ leukemic cells. Although Ang-2 is recognized as a natural antagonist for Tie-2, our data presented here suggested the alternative role of Ang-2 in the relationship between endothelial cells and leukemia cells, at least in a subset of leukemia such as CD7(+)AML. These results were supported by the study using AML cell lines, KG-1 (CD7 negative) and its subline KG-1a (CD7 positive); KG-1 had mRNA expression profile of Ang-1+Ang-2−Tie-2+, while KG-1a showed Ang-1+Ang-2+Tie-2−. These difference in the expression profile of angiogenic factors between CD7(+)AML and t(8;21)AML may explain the characteristic morphological features of these leukemias (CD7(+)AML as blastic type and t(8;21)AML as differentiative type).