Expression of p15INK4B in normal hematopoiesis

The cyclin-dependent kinase inhibitor (CDKI) p15INK4B (p15) induces cell cycle arrest in G0/G1 phase. Several studies report deletion or transcriptional loss of the p15 gene in myeloid and lymphoid hematological malignancies, and a possible role as a tumor suppressor gene has been proposed for this CDKI. In this study we evaluated the expression of p15 by cytofluorometric, immunohistochemical, and reverse transcriptase-polymerase chain reaction (RT-PCR) methods in CD34+ progenitors (both during steady state and after chemotherapy and/or granulocyte-colony stimulating factor [G-CSF] administration) and in cells belonging to different hematopoietic differentiative lineages. We found that p15 is not expressed in normal G0/G1-arrested peripheral blood (PB)- or bone marrow (BM)-CD34+ cells. Moreover, p15 is expressed in G0/G1-blocked CD34+ cells mobilized by chemotherapy and G-CSF but not in CD34+ cells mobilized by G-CSF alone. To clarify the role of p15 in normal hematopoiesis, we used flow cytometry to investigate its expression in normal differentiating BM and PB cells. We found that p15 was expressed in cells belonging to the granulocyte-monocyte lineage and in B and T lymphocytes, whereas erythroid and megakaryocytic cells were p15 negative. These findings, which were confirmed both by immunohistochemical and RT-PCR analysis, definitely establish a linkage between p15 expression and granulocyte-monocyte differentiation.

Spontaneous erythroid colony formation as the clue to an underlying myeloproliferative disorder in patients with Budd-Chiari syndrome or portal vein thrombosis

Budd-Chiari syndrome is a severe disease characterized by occlusion of large hepatic veins leading to death if untreated. Using the classical criteria for the diagnosis of polycythemia vera (PV), essential thrombocythemia (ET), and idiopathic myelofibrosis (IMF), overt PV was the underlying cause in about 10% of the cases and ET or IMF in only a very few. Using spontaneous endogenous erythroid colony (EEC) formation in vitro and/or bone marrow biopsies, a primary myeloproliferative disorder (PMD) was present in 78% of the patients with apparently idiopathic Budd-Chiari syndrome and in about half of the patients with portal, splenic, and/or mesenteric vein thrombosis. The diagnoses in 40 reported cases with hepatic vein thrombosis and spontaneous EEC were overt PV in 25 and latent unclassified PMD in 15 patients. The diagnoses of 40 reported cases with splanchnic vein thrombosis and spontaneous EEC were overt PV in 12, ET in 2, IMF in 2, and latent unclassified PMD with the presence of EEC in 24 patients. Thrombocytosis as a manifestation of myeloproliferative disease was recorded in 34 of 80 (42.5%) patients with spontaneous EEC and Budd-Chiari syndrome or portal vein thrombosis. Thrombocythemia was present in 15 of 41 patients with a proven and in 19 of 39 patients with a latent myeloproliferative disorder. Patients with hepatic vein or splanchnic vein thrombosis associated with a PMD are predominantly females younger than 45. It is concluded that both spontaneous EEC and histopathology from bone marrow biopsy provide specific information as sensitive clues to the diagnosis of all variants of overt and latent myeloproliferative disorders. The association of hepatic and splanchnic vein thrombosis and PMD is not fully understood. Therapeutic options of Budd-Chiari syndrome include anticoagulation with heparin, fibrinolysis followed by oral anticoagulation, and appropriate treatment of the underlying PMD. In case of failure, invasive options include local procedures such as angioplasty or stenting, venous decompression by portal-systemic shunts, or liver transplantation.

Differential sensitivity of leukemic and normal hematopoietic progenitors to the killing effect of hyperthermia and quercetin used in combination: role of heat-shock protein-70

Autologous bone-marrow transplantation (ABMT) is widely used in the treatment of acute leukemias where a matched sibling donor is not available for allogeneic transplantation. However, a major problem in ABMT is relapse, and ex vivo purging may be very important in preventing it. We show here that quercetin enhances the growth-inhibitory effect of hyperthermia (HT) in AML (19 cases) and ALL (6 cases) leukemic blasts. Furthermore, the inhibitory effect of this combined treatment resulted in leukemic-cell apoptosis. On the contrary, normal hematopoietic progenitors were neither growth-inhibited nor induced to apoptosis by HT-plus-quercetin treatment. To explain this difference in sensitivity of leukemic and normal hematopoietic progenitors, we analyzed the effect of quercetin on heat-induced expression of heat-shock protein-70 (HSP-70), which has been shown to be important in regulating thermosensitivity. We found that quercetin inhibits heat-induced HSP-70 expression both at protein and at mRNA levels in AML and ALL blasts. In normal CD34+ progenitors, the combined treatment with HT and quercetin did not reduce HSP-70 expression and did not induce cell apoptosis. Considering the difference in heat sensitivity of normal CD34+ and leukemic progenitors in the presence of quercetin, the combined use of HT and quercetin could constitute a purging protocol for ABMT.

Inhibition of lymphocyte blastogenic response in healthy donors treated with recombinant human granulocyte colony-stimulating factor (rhG-CSF): possible role of lactoferrin and interleukin-1 receptor antagonist

The effects of rhG-CSF on lymphocyte blastogenesis were evaluated in six healthy donors, submitted to progenitor cell mobilization for allogeneic transplantation. Neutrophil, monocyte and lymphocyte count increased 6.7-fold, 5.3-fold and 2.0-fold on day +4 of rhG-CSF as compared with baseline. The DNA stimulation index (DNA SI) of 72 h phytohemagglutinin (PHA)-treated cultures decreased from 20% (15-35.5) prior to rhG-CSF to 6.7% (1.5-11.9; P = 0.0026), 8% (4-12; P = 0.0091) and 15% (9-22; P = 0.0091) on days +2, +4 and +6; similarly, reactivity to concanavalin A decreased from 18% (12-20) to 1.8% (0.5-7; P < 0.01), 3% (2-8; P < 0.01) and 5% (2-11; P = 0.009). No changes of lymphocyte response to pokeweed mitogen were observed. DNA SI of PHA-treated cultures inversely correlated with neutrophil and monocyte count. IL-1 receptor antagonist (IL-1ra) and lactoferrin (Lf) plasma levels sharply increased and correlated with neutrophil and monocyte count. IL-10 increased five-fold on day +2, returned to pretreatment values thereafter and did not show any correlation with DNA SI, suggesting that it was not responsible for the observed phenomena. Interestingly, DNA SI of PHA-treated cultures inversely correlated with IL-1ra and Lf levels. CD3+ and CD19+ lymphocyte activation status, ie CD23, CD25, CD30 and HLA-DR coexpression, was not affected by rhG-CSF administration. Pharmacological doses of rhG-CSF in healthy donors inhibit lymphocyte blastogenesis via an increased production and/or release of immunoregulatory soluble mediators, ie IL-1ra and Lf, by primed neutrophils and monocytes.

RhG-CSF-mobilized CD34+ peripheral blood progenitors are myeloperoxidase-negative and noncycling irrespective of CD33 or CD13 coexpression

Cycling status, myeloperoxidase expression, informative surface markers, and proliferative potential of peripheral blood hemopoietic progenitors (PBHP) were evaluated by flow cytometry in 10 patients affected by resistant lymphoma, and submitted to stem cell mobilization with combination chemotherapy (MiCMA) followed by recombinant human granulocyte colony-stimulating factor (rhG-CSF, 5 micrograms/kg/day). CD34+ PBHP coexpressed myeloid-associated and activation antigens, i.e., CD33 (96%, range 85-99), CD13 (99.5%, range 99.4-99.8), HLA-DR (99%, range 96.5-99.8), and CD38 (98%, range 90-100), lacked intracytoplasmic myeloperoxidase (MPO, < 3%), and resided in the Gzero/G1 phase of the cell cycle (96.5%, range 81-99.5, compared with 70%, range 49-78 bone marrow HP; p = 0.0007), independently of surface membrane phenotype; S-phase percentages of sorted CD34+ CD33(+)/-, CD34+CD38(+)/-, CD34+HLA-DR(+)/-, CD34+CD45RA(+)/-, CD34+CD45RO(+)/-, and CD34+CD41a(+)/- subpopulations were always negligible. In colony assays, 5-week-old long-term cultures seeded with CD34+CD33- cells yielded as many colonies as did CD34+CD33+ cells. In conclusion, rhG-CSF-mobilized CD34+ PBHPs contain noncycling, highly immature progenitors in which the expression of myeloid-associated antigens, i.e., CD33 or CD13, might not be indicative of myeloid commitment.

Quercetin and the growth of leukemic progenitors

The bioflavonoid quercetin (3, 3', 4', 5-7-pentahydroxyflavone) inhibits in a dose-dependent manner the in vitro growth of acute leukemias and enhances the anti-proliferative activity of cytosine arabinoside. Quercetin exerts a blocking action of cell transition from the G0/G1 to the S phase of the cell cycle. Acute myeloid leukemias (AML)-M3,-M4 and -M5, and acute lymphoid leukemias (ALL) were more sensitive to quercetin than AML-M1 and -M2 subtypes. The sensitivity of leukemic progenitors to the growth inhibitory effect of quercetin significantly correlated with their clonogenic efficiency. We postulate that quercetin exerts its growth inhibitory action by interaction with type II estrogen binding sites and subsequent induction of Transforming Growth Factor-beta 1 expression and secretion. Finally quercetin is synergistic with hyperthermia in inducing apoptosis of leukemic cells sparing normal stem cell progenitors. Taken together these results stress the potential role of quercetin in the treatment of acute leukemias and its in vitro use in purging procedures for autologous bone marrow transplantation.

Separation of chemotherapy plus G-CSF-mobilized peripheral blood mononuclear cells by counterflow centrifugal elutriation: in vitro characterization of two different CD34+ cell populations

Counterflow centrifugal elutriation (CCE) has been extensively employed in T cell depletion of bone marrow cells for allografting. Nevertheless very little is known about CCE properties of mobilized hematopoietic progenitors. In this study five leukapheresis products collected after chemotherapy and G-CSF from patients with non-Hodgkin's lymphoma were elutriated. Two mononuclear cell fractions were obtained containing smaller and less dense cells (lymphocyte fraction) and larger and denser cells (monocyte fraction), respectively. The presence of immature CD34+ progenitor cells, not co-expressing CD33, CD38 and HLA-DR antigens, was demonstrated in both cell fractions. CD34+ cells were isolated from each fraction and grown in various culture conditions (CFU-GM and BFU-E assay, blast cell colony assay, cytokine supplemented liquid culture). CD34+ cells isolated from the monocyte fraction showed a longer lasting expansion in liquid culture and a higher number of blast cell colonies than CD34+ cells selected from the lymphocyte fraction. Moreover a significant reduction of T cell number was obtained in the monocyte fraction. These data suggest that chemotherapy plus G-CSF-mobilized progenitor cells show a characteristic behavior when subjected to CCE, allowing an efficient T cell depletion without losing more immature progenitors.

Effect of all-trans retinoic acid on procoagulant and fibrinolytic activities of cultured blast cells from patients with acute promyelocytic leukemia

The mechanisms underlying acute promyelocytic leukemia (APL) coagulopathy and its reversal by administration of all-trans retinoic acid (ATRA) have been investigated. Bone marrow promyelocytic blasts from nine patients with APL were cultured with or without ATRA 1 mumol/L. Cultured blasts (days 0, 3, 6, and 9) were washed, resuspended in phosphate buffer, lysed by freezing and thawing, and then assayed for procoagulant activity (PCA), elastase activity, tissue factor (TF) antigen, tissue-type plasminogen activator (t-PA) antigen and urokinase-type plasminogen activator (u-PA) antigen. PCA was determined by a recalcification assay. Elastase was measured by an amidolytic assay (S-2484). TF, t-PA, and u-PA antigens were measured by an enzyme-linked immunosorbent assay (ELISA). Malignant promyelocytes isolated from the patients had increased levels of PCA and TF as compared with the control polymorphonucleates, and low levels of elastase, t-PA, and u-PA; the patient blast PCA level was significantly related to the degree of hypofibrinogenemia. In this system, blast PCA depended on the tissue factor and was significantly correlated to the TF antigen values. In the cultures without ATRA, PCA, TF, and u-PA progressively increased, whereas elastase and t-PA levels remained essentially unchanged. In the presence of ATRA, all parameters (except u-PA) decreased during the culture time. Thus, a major role of the promyelocytic blast cell PCA in the pathogenesis of M3-related coagulopathy is suggested; the ATRA effect on coagulopathy seems mainly mediated by a downregulation of the PCA.

Quercetin inhibits the growth of leukemic progenitors and induces the expression of transforming growth factor-beta 1 in these cells

We previously showed that quercetin (3,3',4',5,7 pentahydroxyflavone) inhibits in a dose-dependent manner the growth of acute leukemias and is able to enhance the antiproliferative activity of cytosine arabinoside. We show here that quercetin inhibits the clonogenic activity of 20 of 22 acute leukemias (AL; 4 M1-AML, 3 M2-AML, 2 M3-AML, 3 M4-AML, 3 M5-AML, and 7 ALL). In the present report, we show that the induction of transforming growth factor-beta 1 (TGF-beta 1) in leukemic blasts is one of the growth-inhibitory mechanisms of quercetin in these cells. This observation was supported by the following data. (1) Quercetin-sensitive leukemic blasts, when treated with quercetin, secrete large amounts of TGF-beta 1 in the medium and show positivity for TGF-beta 1-immunoreactive material in the cytoplasm. (2) At a concentration of 8 mumol/L, antisense TGF-beta 1 oligonucleotides prevent the growth-inhibitory action of quercetin. (3) Anti-TGF-beta 1 neutralizing monoclonal antibodies can prevent almost completely the growth-inhibitory activity of quercetin. The analysis of quercetin-resistant cases confirmed as well the central role of TGF-beta 1 in the growth-inhibitory activity of quercetin. In conclusion, quercetin can act as a cytostatic agent for leukemic cells by modulating the production of TGF-beta 1.

Characterization of peripheral blood CD34+ progenitor cells mobilized with chemotherapy and granulocyte colony-stimulating factor

Peripheral blood (PB) mononuclear cells mobilized with chemotherapy and granulocyte colony-stimulating factor (G-CSF) were enriched in CD34+ cells; aliquots were seeded in long-term cultures (LTC) on bone marrow (BM)-derived stromal layers and in liquid cultures containing various growth factors. The final recovery of PB CD34+ cells was similar to normal BM controls, and no difference was found in the expression of CD33 and CD13 antigens; a lower number of CD34+/HLA-DR- cells was found in PB with respect to BM samples (p < 0.001). PB cells sustained hematopoiesis in LTC at least as long as BM cells. At week 3 and 4, PB total mononuclear cell (MC) and CD34(+)-selected cell cultures showed a higher nonadherent cell recovery compared to the respective BM controls (p = 0.05 and p < 0.01). The liquid culture of PB CD34+ cells in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), and stem cell factor (SCF) resulted in a marked and long-lasting increase of colony-forming units-granulocyte/macrophage (CFU-GM). Taken together, our data suggest that chemotherapy and G-CSF-primed cells contain a considerable number of both committed and early precursors, accounting for the rapid hematopoietic recovery observed after their reinfusion following myeloablative chemotherapy.

In vitro and in vivo effects of recombinant human erythropoietin plus recombinant human G-CSF on human haemopoietic progenitor cells

We tested in vitro the effect of recombinant human erythropoietin (rhEPO) plus recombinant human G-CSF (rhG-CSF) on purified human CD34+ haemopoietic progenitors (HP) and in vivo in patients who had undergone anti-cancer chemotherapy for advanced ovarian cancer. In this preliminary experience we found that, in vitro, rhEPO potentiates the effect of rhG-CSF on HP growth and differentiation toward the granulocyte-macrophage lineage. rhEPO plus rhG-CSF produced in vitro a proliferative stimulus of HP which represents 26% of the maximum stimulation obtained using IL-1, IL-3, IL-6, G-CSF, GM-CSF and stem cell factor in combination. In the patients treated with rhEPO plus rhG-CSF after chemotherapy, we observed a favourable trend for platelet and neutrophil recoveries compared with a control group treated with rhG-CSF alone and a significantly higher haematocrit nadir was observed in the rhEPO plus rhG-CSF series. In the patients treated with rhEPO plus rhG-CSF we observed a significant increase of circulating colony-forming unit granulocyte-macrophage (CFU-GM) and burst forming unit-erythroid (BFU-e) compared with the rhG-CSF series. Our results, in vitro and in vivo, encourage the in vivo use of rhEPO plus rhG-CSF to improve blood cell recoveries of patients who have undergone conventional or high-dose chemotherapy. Moreover, rhEPO plus rhG-CSF was demonstrated to be a good HP mobilising treatment for blood stem cell collection after chemotherapy.

Sequential peripheral blood progenitor cell transplantation after mobilization with salvage chemotherapy and G-CSF in patients with resistant lymphoma

We enrolled 18 patients affected by refractory or relapsed lymphoma (HD, NHL) in a two-step protocol that included salvage chemotherapy with mitoxantrone, carboplatinum, methylprednisolone, and cytosine arabinoside (MiCMA) plus G-CSF (5 micrograms/kg/day), peripheral blood progenitor cell (PBPC) collection, and subsequent transplantation after BUCY2 regimen. After MiCMA chemotherapy, four patients (22%) achieved complete response, eight patients (44%) obtained a partial response, and six showed progression of disease (PD). Fourteen out of 18 patients (78%) were considered eligible for PBPC transplantation. Three patients with complete response refused PBPCT; they are currently in continuous complete remission (CCR) at 15, 13, and 15 months, respectively. One patient has been recently transplanted but is too early to be evaluated. Ten patients so far completed the study, eight of whom are currently alive in CR, with a median follow-up of 7.5 months (range 2-13). Hematologic reconstitution was very rapid with a median time to achieve WBC > 1 x 10(9)/L, PMN > 0.5 x 10(9)/L, platelets > 50 x 10(9)/L and > 100 x 10(9)/L of 13 (range 9-15), 12 (range 9-14), 10 (range 0-22), and 14 (range 5-49) days, respectively. Our protocol is highly effective as a salvage treatment, while permitting PBPC collection after G-CSF administration. Hemopoietic reconstitution after transplantation of PBPCs collected with this procedure is complete, rapid, and sustained.

In vitro expansion of CD34+ cells mobilized with chemotherapy and G-CSF

Hemopoietic CD34+ progenitors were isolated by immunomagnetic method from normal bone marrow (BM) or from peripheral blood (PB) of patients with non-Hodgkin's lymphoma treated with chemotherapy and granulocyte colony-stimulating factor (GCSF). Aliquots were seeded in long-term cultures (LTC) on bone marrow-derived stromal layers; non-adherent and adherent clonogenic content of the cultures was assayed weekly. The final recovery and the clonogenic efficiency of the CD34+ cells were slightly higher in PB samples than in BM controls. In long term cultures PB cells sustained hemopoiesis as much as BM cells; at week 3 and 4 PB total mononuclear cells and CD34+ cells showed a non-adherent cell recovery higher than the respective BM controls. Furthermore, PB CD34+ cells were expanded in liquid culture in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF) or G-CSF alone or combined with interleukin 3 (IL3), stem cell factor (SCF), interleukin 1 (IL1), interleukin 6 (IL6). The combination of GM-CSF, IL3, SCF, IL1 and IL6 produced the maximum increase of both mononuclear cells (30-fold) and granulocyte-macrophage colony forming units (CFU-GM) (4.6-fold) after 7 days of cultures; yet after 14 days a strong decrease of the CFU-GM occurred. These data suggest that G-CSF following chemotherapy mobilizes both early and committed hemopoietic progenitors.

Haemopoietic CD34+ progenitor cells are not infected by HIV-1 in vivo but show impaired clonogenesis

We evaluated the role of CD34+ bone marrow progenitor cells in vivo, in the pathogenesis of AIDS-related haematological abnormalities. The clonogenic activity of CD34+ cells from seven patients with HIV-1 infection, without bone marrow involving opportunistic infections or neoplasms, was assessed in semisolid cultures. The number of CFU-GM was significantly reduced as compared to the controls (P = 0.017), independently from myelotoxic therapy, while the number of BFU-E was not. The presence of retroviral sequences in CFU-GM colonies from four patients and in the total population of CD34+ cells from six patients with advanced stage HIV infection was investigated using the polymerase chain reaction. The presence of HIV-1 sequences was also searched for in a purified suspension of CD34+ cells after 3 weeks liquid culture. All these cells were always HIV-1 negative, while viral sequences were always detected in bone marrow mononuclear cells from these and other patients. The number of HIV-1 DNA copies decreased with increasing enrichment. At most 1:10,000 CD34+ cells are infected in vivo. Other mechanisms than direct viral infection of progenitor cells must account for the defective haemopoiesis in HIV-1 infected patients.

Further investigations on the expression of HLA-DR, CD33 and CD13 surface antigens in purified bone marrow and peripheral blood CD34+ haematopoietic progenitor cells

We evaluated the HLA-DR, CD33 and CD13 antigen expression on CD34+ haematopoietic progenitor cells (HPC) isolated from the bone marrow (BM) and peripheral blood (PB) of normal donors. The majority of both BM and PB CD34+ HPC expressed CD13 and HLA-DR. The coexpression of CD34 and CD33 was found in a minor CD34+ subset. After 7 d of culture in the presence of interleukin-3 and granulocyte-macrophage colony-stimulating factor, CD33 expression was detected in about 50% of HPC. At this point CD34 antigen expression was lost and CD13 and HLA-DR expression was partially lost. After 14 d of culture, the majority of HPC were CD33+. HPC maintained the capacity to generate colony forming unit granulocyte-macrophage but they lost the capacity to generate burst forming unit-erythroid. A correlation was found between the percentage of CD34+/HLA-DR+ cells and the total number of colony forming cells in unfractionated samples from BM and PB of patients with malignancies. These studies demonstrate that, in normal conditions, only a minor subset of CD34+ cells coexpress CD33 antigen either in BM or in PB and CD33 antigen is a lineage marker which is coexpressed with HLA-DR and CD13 on a progenitor committed to the granulocytic-macrophagic lineage.

In Vitro Expansion of CD34+ Cells Mobilized with Chemotherapy and G-CSF

Hemopoietic CD34+ progenitors were isolated by immunomagnetic method from normal bone marrow (BM) or from peripheral blood (PB) of patients with non-Hodgkin's lymphoma treated with chemotherapy and granulocyte colony-stimulating factor (GCSF). Aliquots were seeded in longterm cultures (LTC) on bone marrow-derived stromal layers; non-adherent and adherent clonogenic content of the cultures was assayed weekly. The final recovery and the clonogenic efficiency of the CD34+ cells were sligthly higher in PB samples than in BM controls. In long term cultures PB cells sustained hemopoiesis as much as BM cells; at week 3 and 4 PB total mononuclear cells and CD34+ cells showed a non-adherent cell recovery higher than the respective BM controls. Furthermore, PB CD34+ cells were expanded in liquid culture in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF) or G-CSF alone or combined with interleukin 3 (IL3), stem cell factor (SCF), interleukin 1 (IL 1), interleukin 6 (IL6). The combination of GM-CSF, IL3, SCF, IL 1 and IL6 produced the maximum increase of both mononuclear cells (30-fold) and granulocyte-macrophage colony forming units (CFU-GM) (4.6-fold) after 7 days of cultures; yet after 14 days a strong decrease of the CFU-GM occurred. These data suggest that G-CSF following chemotherapy mobilizes both early and committed hemopoietic progenitors.

Lymph node blast crisis in chronic myeloid leukemia mimicking T-immunoblastic lymphoma

BACKGROUND

Chronic myeloid leukemia arises from a somatic mutation in a pluripotent stem cell. It generally terminates with a blastic crisis (BC). One third of BC are lymphoid, and most have a pre-B phenotype. Few cases of T-lymphoid BC have been reported. Here we describe a lymph node blast crisis mimicking T-immunoblastic lymphoma.

METHODS

Bone marrow and lymph nodes were histologically examined by standard methods and by an immunoperoxidase technique. Cytogenetic studies were also performed on lymph node and blood cells. Analysis of T-cell receptor genes and BCR rearrangements were performed on DNA extracted from both frozen bone marrow and lymph-node cells.

RESULTS

Lymph-node histology showed an infiltration by large lymphoid blasts, consistent with a diagnosis of immunoblastic lymphoma. Blast cells were CD2, CD7, TDT positive, and negative for myeloid and mature lymphoid antigens. The Ph1 chromosome was found in both bone marrow and lymph-node cells. BCR rearrangement was found in the DNA from both bone marrow and lymph-node cells. TCR genes were not rearranged.

DISCUSSION

The present study provides strong evidence that the lymph-node blast crisis of CML can assume the morphological appearance of immunoblastic lymphoma and may retain the immunological phenotype and genetic features of early T cells with BCR rearrangements.