Emi An

CD20-positive T cell leukemia/lymphoma: case report and review of the literature

Abstract. We report on a case of CD20-positive peripheral T cell lymphoma. The lymphoma cell was positive for CD20 and T cell lineage markers such as cytoplasmic CD3, CD4, and CD5 and had a monoclonal rearrangement of the T cell receptor (TCR) γ chain gene. The clinical characteristics resembled angioimmunoblastic lymphadenopathy: spontaneous regression of lymphadenopathy and immunological abnormalities such as polyclonal hypergammaglobulinemia, positive results of direct and indirect antiglobulin tests, and a high antinuclear antibody titer. We reviewed seven cases of CD20-positive T cell malignancies including the present case. Three were immature T cell malignancies (acute lymphoblastic leukemia) and four were peripheral T cell malignancies (non-Hodgkins lymphoma and chronic lymphocytic leukemia). Hepatomegaly and/or splenomegaly were common features. Further cases must be evaluated to understand the clinical significance of the CD20 expression on the surface of T cell malignancies.

Megakaryocyte, Erythroid and Granulocyte-Macrophage Colony Formation in Myelodysplastic Syndromes

Bone marrow progenitor cell assays of three cell lineages, i.e., colony-forming unit megakaryocytes (CFU-Meg), burst-forming unit erythrocytes (BFU-E) and colony-forming unit granulocyte-macrophages (CFU-GM), were performed for 21 patients with myelodysplastic syndromes (MDS). Markedly reduced or absent colony formation was found in 67% of the patients for CFU-Meg and all patients except 2 with refractory anemia (RA) for BFU-E. Abnormal CFU-GM colony formation was found in only 5 of 12 patients with RA and RA with ring sideroblasts, in contrast to all of the RA patients with excess of blasts and excess of blasts in transformation. Defective colony formation of all three cell lineages was seen in 63% of the MDS patients. The colony number of CFU-Meg correlated significantly with the numbers of both BFU-E and CFU-GM. These findings indicate that hematopoiesis in MDS patients is disturbed due to a qualitative or quantitative defect at the multipotent stem cell level.

Flow cytometric assessment of CD15+CD117+ cells for the detection of minimal residual disease in adult acute myeloid leukaemia

There is little information available regarding immunophenotypic monitoring of minimal residual disease (MRD) in acute myeloid leukaemia (AML). We investigated leukaemic cells co‐expressing CD15 and CD117 (CD15+CD117+) in 72 adult AML cases at diagnosis. In 22 cases (31%) with various AML subtypes, more than 5% of leukaemic cells showed the CD15+CD117+ phenotype (range 5.22–55.48%). These 22 cases were younger and had a higher complete remission (CR) rate than the other AML cases, but the CD15+CD117+ cell percentage at diagnosis showed no correlation with the CR duration among the 72 cases. The CD15+CD117+ cell percentage showed a range of 0.00–0.08% in bone marrow cells from 10 haematologically normal subjects. We also investigated CD15+CD117+ cells in sequential bone marrow samples from 17 AML patients who achieved CR and who had had more than 5% CD15+CD117+ leukaemic cells at diagnosis. Because the CD15+CD117+ cell percentage varied among these AML cases, we calculated the percentage of MRD {MRD% = [CD15+CD117+ cells (%) in each sequential marrow sample] ÷ [CD15+CD117+ cells (%) at diagnosis of the corresponding case] × 100}. A high MRD% after 10 months of CR was significantly associated with a short CR duration (P = 0.0004), whereas continuation of a well‐reduced MRD% was associated with a long CR duration. The leukaemic cells conserved the CD15+CD117+ phenotype in all of the eight cases who relapsed. Flow cytometric monitoring of CD15+CD117+ cells is simple and can be applied to a substantial fraction of AML cases. This monitoring may be useful for predicting relapse of adult AML.

Chemotherapy for minimally differentiated acute myeloid leukemia (AML-M0) : a report on five cases and review of the literature

SummaryWith the objective of establishing the optimal therapy for minimally differentiated acute myeloid leukemia (AML-M0), we examined the therapeutic results of five AML-M0 cases and reviewed the literature. In a series of 63 patients with newly diagnosed acute leukemia who were admitted to the Main Hospital of Nippon Medical School, five patients fit the criteria for AML-M0: negative myeloperoxidase (MPO) and Sudan black B reaction by light microscopy, negative for B- and T-lineage markers, and positive for myeloid markers. They were treated by means of AdVP [adriamycin, vincristine, and prednisolone (PSL)] therapy and/or BHAC-DMP [behenoylcytosine arabinoside (BHAC), daunorubicin (DNR), 6-mercaptopurine (6-MP), and PSL] therapy. The AdVP therapy was unsuccessful in the two patients who received it, while a complete remission (CR) was achieved with the BHAC-DMP therapy in three of four patients. Although one patient treated with BHAC-DMP did not achieve CR, his blasts were apparently sensitive to the therapy. In assessable cases in the literature where leukemic blasts were MPO-negative, myeloid marker-positive and B- and T-lineage marker-negative, CR was achieved in 54.5% and 44.4% with anti-acute myeloid leukemia therapy and anti-acute lymphocytic leukemia therapy, respectively. Five cases in the literature were treated with a chemotherapeutic regimen containing BHAC [or cytosine arabinoside (Ara-C)], DNR, and 6-MP, and all achieved CR. The regimen containing BHAC (or Ara-C), DNR, and 6-MP may be useful as induction chemotherapy for AML-MO.

Cell-mediated cyclic thrombocytopenia treated with azathioprine.

We studied a male patient with cyclic thrombocytopenia whose bone marrow megakaryocyte count showed cyclic fluctuations in synchrony with cyclic changes of platelet count. He failed to respond to either prednisolone or bolus methylprednisolone therapy, but subsequently he was successfully treated with azathioprine. To investigate the underlying pathogenesis of the cyclic fluctuations in the platelet count. we studied the kinetics of megakaryocyte progenitor cells (CFU‐Meg) and the effects of the patients peripheral blood mononuclear cells on CFU‐Meg. In one cycle of the platelet fluctuation, the increase in the CFU‐Meg number preceded an increase in the bone marrow megakaryocyte count and then the platelet count. In the latter half of the cycle, CFU‐Meg, bone marrow megakaryocytes and platelets began to decrease in that order. Peripheral blood mononuclear cells obtained from the patient in the thrombo‐cytopenic phase suppressed megakaryocyte colony formation from normal bone marrow cells in a dose‐dependent manner. In contrast, these cells obtained in the phase of a normal platelet count did not suppress megakaryocyte colony formation at all. These findings indicate that the cause of platelet fluctuation is periodic failure of megakaryocytopoiesis at the stage of CFU‐Meg and that the patients peripheral mononuclear cells are responsible for periodically suppressing the CFU‐Meg.

Effects of interleukin‐12 on natural killer cell cytotoxicity and the production of interferon‐7 and tumour necrosis factor‐a in patients with myelodysplastic syndromes

The effects of Interleukin 12 (IL‐12) on natural killer (NK) cell cytotoxicity and on the production of interferon‐7 (IFN‐7) and tumour necrosis factor‐a (TNF‐a) were examined in 15 patients with myelodysplastic syndromes (MDS), which are well known to have immunologic defects, and in 11 normal subjects. The NK cell cytotoxicity of all of the normal subjects was augmented by incubation with IL‐12 alone, and co‐incubation with interleukin 2 (IL‐2) further augmented it (type A response). The MDS patients showed varied responses to IL‐12/IL‐2. Seven patients showed the type A response, resulting in augmented NK cell cytotoxicity which was similar to that in the normal subjects. In five other patients the cytotoxicity was not increased by IL‐12 alone, but the combination of IL‐12 and IL‐2 did augment the cytotoxicity (type B response). The augmented cytotoxicity in these type B patients was lower than that in the normal subjects. In the final three MDS patients the cytotoxicity was low and not affected by IL‐ 12 and/or IL‐2 (type C response). AH patients with refractory anaemia with excess blasts (RAEB) and patients with RAEB in transformation showed a type B or C response. Conversely, six of eight refractory anaemia patients showed a type A response. In MDS patients there was a positive correlation between the percentage of CD3CD56+ cells in pre‐incubated cells and the cytotoxicity of cells incubated with IL‐12/IL‐2. The combination of IL‐12 and IL‐2 augmented IFN‐7 and TNF‐Q production by nonadherent mononuclear cells in a synergistic or cumulative manner, respectively, in most patients. These results suggest that IL‐12, alone or with IL‐2, may modulate these important immunologic functions in most MDS patients.

Plasma soluble interleukin‐2 receptor level in patients with primary myelodysplastic syndromes: a relationship with disease subtype and clinical outcome

To assess the hypothesis that the plasma soluble interleukin‐2 receptor (sIL‐2R) level may have predictive value for morbidity/mortality in patients with myelodysplastic syndromes (MDS), we determined the plasma sIL‐2R level of 80 MDS patients and examined their subsequent clinical course. Compared with low‐risk MDS (refractory anaemia (RA) and RA with ringed sideroblasts) patients and normal subjects, the plasma sIL‐2R level was significantly elevated in high‐risk MDS (three other MDS subtypes and acute leukaemia following MDS) patients (high‐risk MDS versus low‐risk MDS, P < 0.01; high‐risk MDS versus normal subjects, P < 0.01). 14/40 low‐risk MDS patients developed at least one of the following during the follow‐up period: erythrocyte transfusion dependence, infections requiring hospitalization, disease progression or MDS‐related death. The plasma sIL‐2R level was higher in these eventful subjects than in event‐free low‐risk subjects (P < 0.0001), and all of 10 low‐risk subjects with a plasma sIL‐2R level > 540 U/ml experienced at least one event. By logistic regression analysis of various parameters in these 40 low‐risk subjects, the plasma sIL‐2R level was identified as the strongest independent parameter for predicting eventful subjects (P < 0.0047). The plasma sIL‐2R level did not show a predictive value in high‐risk MDS. This study revealed that the plasma sIL‐2R level is significantly elevated in high‐risk MDS and suggested that the plasma sIL‐2R level is a valuable predictive factor for the clinical outcome in low‐risk MDS.

Elevated plasma soluble interleukin 2 receptor level correlates with defective natural killer and CD8+ T-cells in myelodysplastic syndromes

The plasma soluble interleukin 2 receptor (sIL-2R) level and its relationships with haematologic and immunologic data were examined in 40 patients with myelodysplastic syndromes (MDS). The plasma sIL-2R level was significantly higher in the high-risk MDS group (refractory anaemia with excess blasts (RAEB), RAEB in transformation and chronic myelomonocytic leukaemia) than in the low-risk MDS group (refractory anaemia (RA) and RA with ringed sideroblasts) or in normal subjects, although there was considerable variation in the plasma sIL-2R level within each MDS group. The plasma sIL-2R level correlated positively with the bone marrow cellularity and bone marrow blast mass, but not with the absolute number of CD25+ lymphocytes. This may support the idea that plasma sIL-2R is derived from malignant MDS cells in the bone marrow. The plasma sIL-2R level correlated negatively with the absolute numbers of the CD8+, CD3-CD16+, and CD3-CD56+ cell populations in freshly isolated lymphocytes, the percentage of CD3-CD56+ cells in lymphokine (interleukin 2)-activated killer (LAK) cells, and the cytotoxicity of LAK cells. We conclude that MDS patients having a high plasma sIL-2R level often have a defect in natural killer and CD8+ T-cells.

Assessment of therapeutic potential of interleukin 2 for myelodysplastic syndromes

Summary. The therapeutic potential of interleukin 2 (IL‐2) for myelodsplastic syndromes (MDS) was evaluated in vitro, IL‐2‐induced lymphokine‐activated killer (LAK) cells were prepared from 38 MDS patients and 20 normal subjects. The cytotoxicity of LAK cells against K562 and Raji cell lines and MDS blasts was significantly reduced in high‐risk MDS (refractory anaemia with excess blasts (RAEB). RAEB in transformation, and leukaemic transformation of MDS), but was relatively well‐preserved in low‐risk MDS (refractory anaemia (RA) and RA with ringed sideroblasts). Examination of the immunophenotypes of freshly‐isolated lymphocytes showed that the percentage of CD4+ cells in low‐risk MDS and the percentage of CD3+, CD4+ and CD8+ cell populations in high‐risk MDS was significantly reduced compared with these populations in normal subjects. After cultivation with IL‐2, these three cell populations were still reduced in the corresponding MDS groups and the percentage of CD3‐CD56+ cells were significantly reduced in high‐risk MDS. There was a positive correlation between the percentage of K562 cells lysed by MDS LAK cells and the percentage of CD3‐CD56+ lymphocytes in MDS LAK cells. These aberrant lymphocyte subpopulations appeared to explain, at least in part, the reduced LAK cell cytotoxicity in MDS. These results present a possibility that IL‐2 and LAK therapies are ineffective for most high‐risk MDS patients, whereas they have potential value for low‐risk MDS patients whose lymphocyte cytotoxicity is usually preserved.

Defective natural killer (NK) cell-mediated cytotoxicity does not imply clonal involvement of NK cells in myelodysplastic syndromes

SUMMARY. The clonality of purified cells was examined in 10 myelodysplastic syndromes (MDS) patients by analysing the restriction fragment length polymorphism and methylation pattern of the phosphoglycerate‐kinase gene. Natural killer (NK) cell‐mediated cytotoxicity was also examined. The granulocytes and monocytes were monoclonal or oligoclonal in all cases, except for the monocytes in one case. Conversely, the NK and T cells had a polyclonal pattern in most cases, including all cases who had defective NK cellmediated cytotoxicty. The hypothesis that reduced NK cellmediated cytotoxicity in MDS is caused by a clonal involvement of NK cells was not supported by the present study.