Hiroshi Shiku

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.

Attenuation of Interleukin 2 Signal in the Spleen Cells of Complex Ganglioside-lacking Mice

T cell development and function in complex ganglioside-lacking (GM2/GD2 synthase gene-disrupted) mice were analyzed. GM1, asialo-GM1, and GD1b were representative gangliosides expressed on T cells of the wild type mice and completely deleted on those of the mutant mice. The sizes and cell numbers of the mutant mice spleen and thymus were significantly reduced. Spleen cells from the mutant mice showed clearly reduced proliferation compared with the wild type when stimulated by interleukin 2 (IL-2) but not when treated with concanavalin A or anti-CD3 cross-linking. Expression levels of IL-2 receptor α, β, and γ were almost equivalent, and up-regulation of α chain after T cell activation was also similar between the mutant and wild type mice. Activation of JAK1, JAK3, and SAT5 after IL-2 treatment was reduced, and c-fos expression was delayed and reduced in the mutant spleen cells, suggesting that the IL-2 signal was attenuated in the mutant mice probably due to the modulation of IL-2 receptors by the lack of complex gangliosides.

Involvement of T-cell subsets and natural killer (NK) cells in the growth suppression of murine fibrosarcoma cells transfected with interleukin-12 (IL-12) genes

A 3‐methylcholanthrene‐induced fibrosarcoma cell line of BALB/c origin, CMS5j, was co‐transfected with cDNA for the p40 and p35 subunits of interleukin‐12 (IL‐12). Injection of transfected cells producing 5 × 103 U IL‐12/106 cells/ml/day in nude mice with an established fibrosarcoma at a contralateral site efficiently eliminated tumor growth in the early phase (injection on day 0 or 4) but not later (day 8). This effect could be abrogated by simultaneous i.v. injection of antibodies against NK1.1 or ASGM1 (asialoGM1 = ganglio‐N‐tetraosyl‐ceramide), which indicates that natural killer (NK) cells play a major role in tumor eradication or suppression when stimulated by IL‐12. In wild‐type mice, application of IL‐12‐secreting CMS5j cells abrogated growth of tumors established 8 days before but not earlier. Based on our experiments with antibody blocking in vivo, all CD4+, CD8+ and ASGM1+ cells are involved in tumor rejection. However, in our system, CD4+ cells or CD8+ cells alone, but not ASGM1+ cells alone, also could lead to tumor rejection. IL‐12‐engineered fibrosarcoma cells may constitute an efficient and safe system for immunotherapy of cancer. Int. J. Cancer 72:505–511, 1997.

Biphasic expression of CD4 in acute myelocytic leukemia (AML) cells: AML of monocyte origin and hematopoietic precursor cell origin

In 227 of 495 (45.9%) Japanese adult patients with acute myelocytic leukemia (AML), leukemic cells expressed CD4. Incidence of CD4 expression in each FAB subtype was as follows: M1 37.4%, M2 33.7%, M3 35.4%, M4 65.0%, and M5 78.3%. The typical expression pattern of myelomonocytic differentiation antigens and cytokine receptors in CD4+ AML was CD34lowCD33high CD11bhighGM-CSFRhigh. AML cases with 11q23 abnormalities and with inv(16) were frequently CD4-positive. These data collectively indicate that CD4 expression in AML cells is associated with monocytic characteristics. However, CD4+CD34high AML cases appear to have unique immature characteristics including low expression of myelomonocytic differentiation antigens (ie CD33 and CD11b), and accumulation of chromosome abnormalities (ie t(8;21) in CD4lowCD34high AML and chromosome 7 abnormalities in CD4highCD34high AML). We speculate that these leukemia subsets originate from CD4+ hematopoietic precursor cells, therefore then should be considered separately from most of the CD4+ AML as represented by CD34lowCD33high CD11bhighGM-CSFRhigh. Overall survival of patients with CD4+ AML in our series was worse than that of those with CD4− AML (P = 0.0202).

Granulocyte colony-stimulating factor and its receptor in acute promyelocytic leukemia

Expression of granulocyte colony‐stimulating factor (G‐CSF) receptor (G‐CSFR) and in vitro proliferative response to G‐CSF were investigated by quantitative immunofluorescence and [3H] thymidine uptake, respectively, in a series of acute myeloid leukemias (AML). The results indicated that G‐CSFR was detected at high levels in acute promyelocytic leukemia (APL) cells, in comparison with other types of AML. Moreover, APL cells were also seen to predominantly proliferate in response to G‐CSF. Based on these observations, we administered recombinant human G‐CSF to a patient with APL in the third relapse that was resistant to both cytotoxic agents and all trans retinoic acid, in an attempt to sensitize the leukemic cells to cell‐cycle‐dependent agents. Complete remission was achieved. The finding that APL cells are exquisitely responsive to G‐CSF supports the view that G‐CSF is useful for augmentation of their vulnerability to cell‐cycle specific agents. Am. J. Hematol. 58:31–35, 1998.

Complex Gangliosides are Essential in Spermatogenesis of Mice: Possible Roles in the Transport of Testosterone

Mice, homozygous for disrupted ganglioside GM2/GD2 synthase (EC 2.4. 1.94) gene and lacking all complex gangliosides, do not display any major neurologic abnormalities. Further examination of these mutant mice, however, revealed that the males were sterile and aspermatogenic. In the seminiferous tubules of the mutant mice, a number of multinuclear giant cells and vacuolated Sertoli cells were observed. The levels of testosterone in the serum of these mice were very low, although testosterone production equaled that produced in wild-type mice. Testosterone was found to be accumulated in interstitial Leydig cells, and intratesticularly injected testosterone was poorly drained in seminiferous fluid in the mutant mice. These results suggested that complex gangliosides are essential in the transport of testosterone to the seminiferous tubules and bloodstream from Leydig cells. Our results provide insights into roles of gangliosides in vivo.