Kuniaki Meguro

Altered expression of retinoblastoma protein‐interacting zinc finger gene, RIZ, in human leukaemia

Summary. The retinoblastoma protein‐interacting zinc finger gene (RIZ), a member of the nuclear protein methyltransferase superfamily, is characterized by the presence of the N‐terminal PR domain. The RIZ gene encodes for two proteins, RIZ1 and RIZ2. While RIZ1 contains the PR (PRDI‐BF1 and RIZ homologous) domain, RIZ2 lacks it. RIZ gene expression is altered in a variety of human cancers and RIZ1 is now considered to be a candidate tumour suppressor. To investigate the role of RIZ in leukaemogenesis, we analysed the differential expression of RIZ1 and RIZ2 by quantitative real‐time reverse‐transcription polymerase chain reaction assay. Our results showed that the expression of RIZ1 was significantly decreased in leukaemia cell lines (14 out of 17, 82%) and in patients with acute myeloblastic leukaemia (eight out of 14, 57%). In contrast, RIZ2 expression was increased in patients with acute lymphoblastic leukaemia (eight out of 11, 73%), compared with normal bone marrow cells. These findings indicate that suppression of RIZ1 expression or enhancement of RIZ2 expression may have an important role in leukaemogenesis.

T-Cell Variant of Classical Hodgkin's Lymphoma with Nodal and Cutaneous Manifestations Demonstrated by Single-Cell Polymerase Chain Reaction

The atypical cells of CD30+ cutaneous lymphoproliferative disorders (CD30CLD) are commonly of T-cell origin and frequently have a similar morphology as Hodgkin or Reed-Sternberg cells of Hodgkins lymphoma (HL). HL is one of the tumors associated with CD30CLD. Although most studies support a B-cell derivation of the tumor cells in HL, recently a few cases of classical HL with T-cell genotype have been reported. We report a patient who presented with CD30CLD whose lymph nodes showed classical HL of mixed cellularity subtype at presentation. By single-cell PCR, the same clonal gene rearrangements of the T cell receptor-β gene locus could be assigned to the CD30+ and CD15+ cells of both skin and lymph node. In a lymph node biopsy specimen taken in relapse after several courses of chemotherapy, the CD30+ tumor cells were abundant. The T cell–derived tumor cells displayed aberrant expression of the Pax-5 gene in all specimens. A common clonal origin of both CD30CLD and HL of the lymph node in the patient presented here suggests that HL with T-cell genotype exists in association with CD30CLD as well as in sporadic cases and may share clonal origin with the skin tumor.

Two chronic myelogenous leultaemia cell lines which represent different stages of erythroid differentiation

Summary We established two cell lines, YN‐1 and Y‐1K. from the peripheral blood of two chronic myelogenous leukaemia patients in blastic crisis. Characterization of the YN‐1 and Y‐1K cells revealed that these cells expressed erythroid lineage markers. However, there was a marked difference in the level of γ‐globin mRNA and haenioglobin in YN‐1 and Y‐1K cells. YN‐1 contained approximately 1–5% benzidine‐positive staining cells, whereas no benzidine‐positive cells were observed in Y‐1K cells. Haemoglobin production in YN‐1 cells was markedly increased with various chemical inducers of erythroid differentiation, but was not in Y‐1K cells. In contrast, Y‐1K cells expressed CD34 stem cell antigen and CD41 megakaryocyte‐specific antigen. These observations suggested that, although both cell lines were committed to the erythroid lineage. each cell line represented a distinct differentiation stage in the erythroid differentiation programme. Y‐1K seemed to correspond to an early stage of cells in erythroid lineage, whereas YN‐1 represented a more advanced stage in human erythropoiesis.

Overexpression of AML1 renders a T hybridoma resistant to T cell receptor-mediated apoptosis

The AML1 gene, which encodes the DNA binding subunit of the heterodimeric transcription factor, PEBP2/CBF, is involved in several types of chromosomal translocations associated with human acute myeloid leukemia, and has been shown by gene targeting to be essential for the development of definitive hematopoiesis in the murine fetal liver. In addition, the gene is expressed abundantly in T lymphocytes and has been implicated in T cell specific gene expression. In the present study we examined the function of AML1 in T cell receptor (TCR)-mediated, Fas/Fas-ligand dependent apoptosis of a T hybridoma line, DO11.10. Several independent cell clones overexpressing the AML1 protein were isolated by transfecting AML1 cDNA into these cells. These clones possessed an increased level of PEBP2/CBF DNA binding activity and were found to be resistant to apoptosis induced by anti-CD3 antibody treatment. Northern blot analysis revealed that induction of the Fas-ligand transcript was markedly suppressed in the anti-CD3 treated clones. Instead, expression of IL-2 receptor α subunit (IL-2Rα), which is a manifestation of proliferative TCR signaling, was induced. This was in contrast to the parental, anti-CD3 treated DO11.10 cells where induction of Fas-ligand but not of IL-2Rα was observed. Resistance of the AML1 overexpressing cell clones to TCR-mediated apoptosis is most likely attributable to the lack of Fas-ligand induction, since simultaneous treatment with anti-CD3 and anti-Fas antibodies caused apoptosis of the clones. The overall results suggest that the AML1 protein may play a pivotal role in switching TCR signaling between apoptosis and cell proliferation in T lymphocytes.

T cell-mediated inhibition of erythropoiesis in aplastic anaemia: the possible role of IFN-γ and TNF-α

Summary. The inhibitory activity of T cells on autologous erythroid colony‐forming units (CFU‐E) (T cell inhibitory activity) in patients with aplastic anaemia (AA) was investigated. In 11 (32·4%) out of 34 AA cases, T cell inhibition on autologous CFU‐E growth was greater than that in normal individuals. In order to evaluate the mechanism of this inhibitory activity, T cell surface markers, interferon (IFN) production in peripheral blood mononuclear cell (PBMNC) liquid culture, and cytokine levels such as IFN and tumour necrosis factor‐α (TNF‐α) in CFU‐E clot cocultured with T cells, were measured in a portion of the patients. In five patients investigated for IFN production in PBMNC liquid culture, all produced statistically more IFN activity than normal individuals under phytohaemagglutinin (PHA‐P) stimulation (P<0·01) with no relation to T cell inhibitory activity. In only one patient whose T cells displayed increased CD8 and HLA‐DR antigen (CD8+HLA‐DR+) and inhibitory activity, a significant amount of IFN‐γ was observed in CFU‐E clot cocultured with T cells, and the addition of anti‐IFN‐γ antibody to the coculture resulted in recovered CFU‐E colony growth. These results suggest that IFN‐γ production by T cells may explain, at least in part, the pathogenesis of haematopoietic defects in AA. In other patients however, T cell inhibitory activity neither correlated to the T cell subpopulations (CD4+/CD8+, CD8+HLA‐DR+), IFN production in PBMNC liquid culture, nor to IFN and TNF‐α levels in CFU‐E clot culture. The roles played by cytokines other than IFN and TNF‐α on haematopoietic precursor cells require further evaluation in a larger sample of patients with AA.

Autoimmune neutropenia in pregnant women causing neonatal neutropenia

Autoimmune neutropenia (AIN) can occur during pregnancy. However, neonatal neutropenia occurring in an infant born to a mother with AIN has only rarely been documented. Recently, we have experienced two cases of AIN during pregnancy, both of which caused severe yet transient neonatal neutropenia (< 0·3 × 109/l), probably as a result of transplacental maternal anti‐neutrophil autoantibodies. The anti‐neutrophil antibodies seemed to be against antigens other than NA1/NA2 because the autoantibodies did not bind to neutrophils of specific NA types selectively in the granulocyte indirect immunofluorescence test. Although AIN is a relatively uncommon disease, neonatal neutropenia caused by maternal AIN may not be quite as rare.

Clonal evolution from trisomy into tetrasomy of chromosome 8 associated with the development of acute myeloid leukemia from myelodysplastic syndrome

Tetrasomy 8, though rare, is usually associated with trisomy 8, a far more common chromosomal abnormality in acute myeloid leukemia (AML). Yet the clonal relationship between trisomy 8 and tetrasomy 8 in the cases with these chromosomal abnormalities has been unclear. Here, we report a case of a 17-year-old male, diagnosed as having a myelodysplastic syndrome (MDS). Chromosome analysis showed the presence of trisomy 8. Five years later, he developed overt AML exhibiting tetrasomy 8 only. After chemotherapy, the blast cells in the bone marrow decreased to 3.4%, and the karyotype showed trisomy 8 alone. Fluorescence in situ hybridization using a probe specific for chromosome 8 showed that the percentages of cells exhibiting 2/ 3 /4 signals were 7.8/89.2/2.0 at the MDS stage, 20.5/36.1/41.0 when overt AML developed and 24.0/72.1/2.4 after chemotherapy. These results suggested that tetrasomy 8 is derived from the AML clone, possibly evolved from the MDS clone with trisomy 8. To our knowledge, this is the first detailed case report of clonal evolution from trisomy 8 into tetrasomy 8 associated with the development of AML from MDS.

Primary marginal zone lymphoma of the thymus accompanied by chromosomal anomaly 46, X, dup(X)(p11p22)

We report a case of primary marginal zone lymphoma in the thymus of a 34-year-old woman. She was initially suspected of having a mediastinal plasmacytoma because of the presence of dominantly proliferating plasmacytic cells in a small fragment obtained by thoracoscopic biopsy, and an elevated level of serum monoclonal IgA. However, histology of the tissue obtained by a subsequent open surgical biopsy revealed diffuse proliferation of atypical monocytoid B-lymphocyte-like cells, which showed prominent plasmacytic differentiation and a close association with thymic epithelial cells consistent with the histology of a marginal zone lymphoma of the thymus. These lymphoma cells were positive for CD19, CD20, IgA, and kappa, and negative for CD5, CD10, and other T/NK-cell and myelomonocyte antigens. Both G-banded and spectral karyotyping analyses revealed the lymphoma cells carried a chromosomal anomaly, 46,X,dup(X)(p11p22). Although large cell type B-cell lymphoma in the thymus (mediastinal diffuse large B-cell lymphoma), which is categorized as a definite subtype in revised European-American classification of lymphoid neoplasms and the new World Health Organization classification, is not infrequent, primary marginal zone lymphoma of the thymus is extremely rare. To our knowledge, this is the first case report of primary marginal zone lymphoma of the thymus with a detailed chromosomal analysis.

Switching to nilotinib in patients with chronic myeloid leukemia in chronic phase with molecular suboptimal response to frontline imatinib: SENSOR final results and BIM polymorphism substudy.

Optimal management of patients with chronic myeloid leukemia in chronic phase with suboptimal molecular response (MR) to frontline imatinib is undefined. We report final results from SENSOR, which evaluated efficacy/safety of nilotinib in this setting. A substudy assessed whether BIM polymorphisms impacted response to nilotinib. In this single-arm, multicenter study, Japanese patients with suboptimal MR per European LeukemiaNet 2009 criteria (complete cytogenetic response, but not major MR [MMR]) after ≥18 months of frontline imatinib received nilotinib 400mg twice daily for 24 months. MR, BCR-ABL1 mutations/variants, and BIM polymorphisms were evaluated in a central laboratory. Primary endpoint was the MMR rate at 12 months (null hypothesis of 40%). Of 45 patients (median exposure, 22.08 months), 39 completed the study and six discontinued. At 12 and 24 months, 51.1% (95% CI, 35.8%-66.3%) and 66.7% (95% CI, 51.0%-80.0%) achieved MMR, respectively. Cumulative MMR incidence by 24 months was 75.6%. Of 40 patients analyzed, 10 of 12 (83.3%) with and 17 of 28 (60.7%) without BIM polymorphisms achieved MMR at 24 months. The safety profile was manageable with dose reductions and interruptions. Nilotinib provided clinical benefit for patients with suboptimal response to imatinib, and BIM polymorphisms did not influence MMR achievement. ClinicalTrials.gov: NCT01043874.

Cardiac surgery in a patient with multiple myeloma combined with renal amyloidosis

We present a case of a 62-year-old woman who underwent mitral valve and aortic valve replacement owing to infective endocarditis. Previously, the patient had been diagnosed with renal amyloidosis and multiple myeloma. She underwent chemotherapy and autologous peripheral blood stem cell transplantation and has achieved nearly complete remission. The patient’s postoperative course was almost uneventful, and she was discharged on the 22nd postoperative day. This is the first case report about cardiac surgery for the patient with multiple myeloma combined with renal amyloidosis.