Philadelphia chromosome positive blood B lymphocytes in chronic myelocytic leukemia

Cytogenomics of cancers: from chromosome to sequence

The role of acquired chromosomal rearrangements in oncogenesis (cytogenomics) and tumor progression is now well established. These alterations are multiple and diverse and the products of these rearranged genes play an essential role in the transformation and growth of cancer cells. The validity of this assumption is demonstrated by the development of specific inhibitors or antibodies that eliminate tumoral cells by targeting some of these changes. Imatinib, an inhibitor of the tyrosine kinase ABL, the prototype of these targeting drugs, is yielding complete remissions in most CML patients. Knowledge of chromosomal abnormalities is becoming an essential contribution to the diagnosis and prognosis of cancers but also for monitoring minimal residual disease or relapse. The concept of the "cytogenetic uniqueness" of each cancer has resulted in personalized treatment. This investigation will expound upon, besides the recurrent genomic alterations, the numerous products of perverted Darwinian selection at the cellular level.

[Transfusion in haematology]

In the field of oncohematology, the rationale for the use of blood transfusion relies both on the proliferative advantage of the transformed clone over the others and on hematologic toxicity of chemotherapy. In France, transfusion thresholds are established by a consensus conference organized by the Agence française de sécurité sanitaire des produits de santé (Afssaps), the French health products safety agency: 80g/l for PRC and 10G/l for platelets concentrates in patients without additional hemorragic risk factors. For FFP especially in TTP, thresholds are more patient-related. Transfusion for sickle cell patients remains a scientific challenge.

The challenges of targeting chronic myeloid leukemia stem cells

Chronic myeloid leukemia (CML) is sustained by a clonally amplified population of Bcr Abl-positive pluripotent stem cells. Persistence of a large, functionally intact yet suppressed residual normal hematopoietic stem cell population in most patients with CML has made it possible to aim at the development of curative therapies. However, achieving this goal requires the identification of agents that will eradicate the leukemic stem cell population. Several potent Bcr-Abl-targeted drugs have now been introduced into clinical practice with remarkable effects. Nevertheless, accumulating data indicate that the leukemic CML stem cells in patients with chronic phase CML are less responsive to these agents than the bulk of the neoplastic cells. In this article, we review emerging evidence that CML stem cells have a number of unusual properties that underlie their relative insensitivity to treatment, including those that specifically target the Bcr-Abl oncoprotein. The biology of the neoplastic stem cells in patients with CML is clearly important to the future attainment of cures and might also prove a paradigm relevant to other types of malignancies that are sustained by transformed stem cell populations.

Philadelphia-chromosome-positive T-lymphoblastic leukemia: acute leukemia or chronic myelogenous leukemia blastic crisis

The Ph1 chromosome has rarely been reported in T-lineage acute lymphoblastic leukemia (T-ALL), and the clinical relevance of this translocation in T-ALL is currently unknown. In chronic myelogenous leukemia (CML) some data indicate derivation of T-cells from the leukemic clone and only a few cases of T-derived blastic crisis have been reported and quite often disputed. Particularly in cases identified initially in blastic crisis it may be difficult to distinguish those from Ph1-positive T-ALL. We herein report 2 patients who presented with a clinical picture of Ph1-positive T-ALL and who raised a differential diagnosis from T-cell blastic crisis of CML. We review the literature and suggest clinical and laboratory features that can help in the diagnosis. According to our literature review, 23 cases of Ph1-positive T-ALL and 44 cases of T-cell blastic crisis of CML, including ours, were reported. Some major differences between the two entities could help in establishing a diagnosis of Ph1-positive T-cell blastic crisis of CML vs. Ph1-positive T-ALL: Male sex and younger age was more predominant in T-ALL. While in most cases of CML blastic crisis there was a history of CML there was no such history in the T-ALL cases. Medullary involvement with lymphoblastic leukemia was present in all cases of T-ALL but only in about half of the cases of CML blastic crisis. None of the CML-blastic crisis cases tested by RT-PCR showed the minor breakpoint transcript, while 2 cases with T-ALL had the minor breakpoint transcript and 1 had both transcripts. Combined morphologic and FISH analysis can help to distinguish between the two entities and was applied in one of our cases. Although both entities carry a severe prognosis, differentiating between them might have clinical relevance, especially in the imatinib era.

Elucidating critical mechanisms of deregulated stem cell turnover in the chronic phase of chronic myeloid leukemia

Chronic myeloid leukemia (CML) has been studied intensively for many years; yet its treatment remains problematic and its biology remains elusive. In chronic phase, the leukemic clone appears to be maintained by a small number of BCR-ABL-positive hematopoietic stem cells that differentiate normally and amplify slowly. In contrast, as these cells enter the intermediate stages of lineage restriction, their progeny are selectively expanded and generate an enlarged pool of neoplastic progenitors. Recent analyses of purified subsets of primitive CML cells have provided a coherent explanation for this dichotomous behavior of BCR-ABL-positive stem and progenitor cells based on the discovery of an unusual autocrine IL-3/G-CSF mechanism activated in them. This only partially counteracts in vivosignals that maintain normal stem cells in a quiescent state but, when active in CML stem cells, promotes their differentiation in favor of their self-renewal. In more differentiated CML progenitors, the same mechanism has a more potent mitogenic effect which is then extinguished when the cells enter the terminal stages of differentiation. Thus, further expansion of the clone is limited until inevitably additional mutations are acquired that further distort or override the regulatory mechanisms still operative in the chronic phase.

Cytogenetic clonality analysis in monosomy 7 associated with juvenile myelomonocytic leukemia: clonality in B and NK cells, but not in T cells

It remains unclear which lymphoid lineages are involved in juvenile myelomonocytic leukemia (JMML). We report a JMML patient who acquired monosomy 7 after intensive chemotherapy. In this case, the expression of monosomy 7 was analyzed in T, B and natural killer (NK) cells highly purified from peripheral blood mononuclear cells of the patient. The fluorescence in situ hybridization method revealed the expression of monosomy 7 in B cells, but not T cells. Half of the NK cells expressed monosomy 7; when NK cells were divided into CD2- and CD2+ populations, this abnormality was positive in 91.1% of CD2- NK cells but in only 14.7% of CD2+ NK cells. These results suggest that, in this JMML patient who acquired monosomy 7 after intensive chemotherapy, B cells and half of NK cells, but not T cells, have monosomy 7.

The majority of T lymphocytes are polyclonal during the chronic phase of chronic myelogenous leukemia

To clarify the extent of cell lineage involvement in chronic myelogenous leukemia (CML), we investigated the bcr gene rearrangement and clonality using the X-chromosome-linked restriction fragment length polymorphism (RFLP) methylation method in T lymphocytes and granulocytes. We examined the granulocyte and T-cell fractions from the peripheral blood of seven female patients with CML during the chronic phase; patients were heterozygous for RFLPs at the phosphoglycerate kinase (PGK) or the hypoxanthine phosphoribosyltransferase (HPRT) gene. RFLP-methylation analysis of granulocytes demonstrated a monoclonal pattern in six of the seven patients and a rearranged bcr gene in all seven patients. In contrast, T lymphocytes exhibited a polyclonal pattern in six cases; in one case, a faint band was observed following methyl-sensitive enzyme cleavage. The bcr gene analysis in T lymphocytes showed the germline in every case. Our results indicate that the majority of T lymphocytes are polyclonal during the chronic phase of CML and confirm previous reports based on glucose-6-phosphate dehydrogenase, cytogenetic, and bcr rearrangement analyses.

Fluorescent in situ hybridization studies of lymphocytes and neutrophils in chronic granulocytic leukemia

Using immunomagnetic cell separation and fluorescent in situ hybridization (FISH), we studied nine patients who had chronic granulocytic leukemia (CGL) for the proportion of interphase nuclei with Mbcr/abl fusion in a direct preparation of the bone marrow and also in the mononuclear cell (MNC), neutrophil, and B- and T-cell fractions of the peripheral blood. In five untreated patients, conventional cytogenetics revealed 97% to 100% Philadelphia chromosome (Ph)+ metaphases. In three of these five patients, FISH studies on bone marrow direct preparations and peripheral blood MNCs indicated that an Mbcr/abl fusion occurred in 62% to 69% of the cells. We observed 69% to 88% of nuclei with Mbcr/abl fusion within the neutrophil fractions. In contrast, the values were 12% to 39% within the T-cell fractions in the four patients we studied. B-cell fractions were studied in three patients, and only one had an abnormal value (58%). In the four patients receiving alpha-interferon therapy, the degree of conventional cytogenetic remission correlated best with the degree of FISH remission observed in the peripheral blood neutrophil fraction. Our results are in agreement with earlier studies in that both B and T lymphocytes may be involved with the clonal process in CGL. The FISH-based detection of Mbcr/abl fusion in the peripheral blood neutrophil compartment provided the best estimate for the proportion of Ph metaphases determined by conventional cytogenetics.

Cell lineage involvement of recurrent chromosomal abnormalities in hematologic neoplasms

Analysis of most hematologic neoplasms indicates the involvement of one or more cell lineages in the bone marrow and/or the blood but rules out the involvement of all lineages in any one neoplasm. It is important to detect lineage involvement in order to clarify which stem cells are involved in leukemia, to predict prognosis, and to select appropriate treatment. Our aim was to study the cell lineage involvement of some of the recurrent chromosomal abnormalities seen in hematological neoplasms. The direct morphology-antibody-chromosomes (MAC) method was used. The deletion 20q in myeloproliferative diseases (MPD), the deletion of 5q and t(1;7) in myelodysplastic syndromes (MDS), and t(3;3) in acute myeloid leukemia subtype M7 (AML-M7) were seen in all or at least in two myeloid lineages. These were interpreted as stem cell abnormalities. Deletion 13q in MPD, t(8;21) in AML-M2 and t(15;17) in AML-M3 were seen in granulocytic lineages only; t(14;18) in non-Hodgkin's lymphoma and trisomy 12 as the sole abnormality in chronic lymphocytic leukemia (B-CLL) were seen only in immunoglobulin light chain clonal B cells; inversion 14 in T-CLL was seen only in T cells, whereas t(15;14) in acute lymphocytic leukemia with eosinophilia (ALL-EO) was seen in lymphoid stem cells but not in mature granulocytes or lymphocytes. Additional abnormalities (in addition to the Philadelphia chromosome) in chronic myeloid leukemia (CML) were seen in all myeloid cell lineages and also in mature granulocytes, B cells, and large granular lymphocytes. Abnormalities in Hodgkin's disease were restricted to CD30-positive Reed-Sternberg cells. Trisomy 8 and monosomy 7 are abnormalities that may be present in either stem cells or any of the single cell lineages.

Immunomodulation by bacterial fractions

The cells of Nocardia opaca are a source of potent immunostimulating substances, differing in solubility and in the presence or absence of peptidoglycan. Three classes of N. opaca fractions have been investigated: (1) NDCM (Nocardia delipidated cell mitogen), the starting fraction; (2) PG (peptidoglycan)-containing fractions: CW (cell walls), PG, and fractions containing soluble PG derivatives such as NWSM (Nocardia water soluble mitogen) and NSPD (Nocardia soluble peptidoglycan derivative); and (3) soluble fractions devoid of PG, such as NWSMP (NWSP-pellet) and CyI (cytoplasmic membrane). This report summarizes our results on the relationship between the structure of N. opaca fractions and their stimulatory activities on mouse, rabbit, germ-free piglet and human lymphocytes and monocytes/macrophages. The studies of biological properties of these compounds are the result of an extensive collaborative effort of several teams.

Analysis of genotype and phenotype on the same interphase or mitotic cell. A manual of MAC (morphology antibody chromosomes) methodology

The purpose of this paper is to serve as a MAC (Morphology Antibody Chromosome) manual describing combined methodologies that allow simultaneous and/or sequential analysis of cell morphology, immunophenotype, and banded chromosomes and/or in situ hybridization signals. The MAC techniques used at the Department of Medical Genetics of the University of Helsinki, Finland, are described and modifications or related techniques reported by other authors are discussed. A list of references concerning applications is also given.

Lack of involvement of T-lymphocytes in the leukaemic population during prolonged chronic phase of Philadelphia chromosome positive chronic myeloid leukaemia

Nine patients with prolonged (> 2 years) chronic phase chronic myeloid leukaemia (CML) were investigated for the presence of T-cell involvement in the leukemic clone. Pure populations of peripheral blood T-cell populations were obtained by culturing separated mononuclear cells in the presence of pokeweed mitogen and IL2, until cultures showed > 99% pure T-cells. Purified T-cells and bone marrow and peripheral blood hematopoietic precursors were analysed for the presence of bcr-abl mRNA transcripts following RNA extraction and message amplification using polymerase chain reaction. In none of the 9 patients was bcr-abl mRNA found in T-lymphocytes while in all cases such transcripts were found in bone marrow and peripheral blood hematopoietic cells. Failure to detect T-cell involvement in patients with prolonged chronic phase CML using techniques designed to enhance even low level involvement of these cell populations supports the view that acquisition of the Ph chromosome abnormality does not occur in the totipotent stem cells but in more committed precursor cell/s with multilineage capacity but which only rarely retain the capacity for T-cell differentiation.

Simultaneous chronic lymphocytic leukemia and chronic myelogenous leukemia. Evidence of a separate stem cell origin

The authors studied a patient with the simultaneous occurrence of chronic lymphocytic leukemia (CLL) and chronic myelogenous leukemia (CML). The coexistence of these two hematologic malignancies leads to questions about their cell of origin. Through analysis of this patient's DNA, the authors studied the derivation of the two malignancies. They separated the blood into a myeloid-rich fraction and a fraction containing the malignant lymphocytes. JH and bcr probes were used to study these loci in the myeloid and lymphoid fractions and in unfractionated white blood cells. The authors found that the unfractionated leukocytes contained the bcr and JH rearrangements. Conversely, the lymphoid fraction contained only the JH rearrangement, and the myeloid fraction contained only the bcr rearrangement, suggesting that these malignancies arose from separate stem cells. This is the first reported patient with simultaneously occurring CML and CLL definitively shown to arise from distinct progenitors, and this report raises questions about the origin of these two cell lines.

The biology of normal and neoplastic stem cells in CML

Chronic myeloid leukemia (CML) has long served as a prototype malignancy for basic as well as clinical studies aimed at developing curative cancer treatment protocols. Well established features of chronic phase CML are its origin in a pluripotent stem cell, a now well defined molecular genetic basis involving the creation of a BCR-ABL fusion gene and evidence of resultant abnormalities in the mechanisms that normally control primitive hemopoietic cell proliferation. We have recently shown how the long-term marrow culture system can be adapted to quantitate and characterize a very primitive cell type in normal blood and marrow samples, as well as their normal and leukemic counterparts in patients with CML. This system has also been used to dissect mechanisms of normal progenitor regulation and to identify specific anomalies affecting leukemic (CML) progenitors. Our studies show that cells detected by their ability to initiate long-term cultures (LTC) of leukemic cells (i.e., CML LTC-initiating cells or LTC-IC) are differently distributed between marrow and blood by comparison to LTC-IC in normal individuals and, although functionally similar in terms of the number and differentiation types of clonogenic cells they produce, CML LTC-IC exhibit defective self-maintenance. Phenotypically these primitive leukemic cells are heterogeneous; the majority display features of activated/proliferating cells but a significant proportion do not. We have also documented heterogeneity in primitive CML cell responses to two factors that specifically and reversibly arrest the cycling of primitive normal hemopoietic cells; i.e., TGF-beta and MIP-1 alpha, to which CML cells are normally responsive and abnormally unresponsive, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Chronic Myelogenous Leukemia Associated with Extranodal B-Cell Lymphoma

A 75-year-old man is reported with a 10 year-history of villous adenoma of the colon and carcinoma in situ treated by hemicolectomy. Seven years later, he developed chronic myelogenous leukemia (CML). After a 3-month course of busulfan he was kept off chemotherapy for a one year period. Two years after the diagnosis of CML, an extranodal B-cell lymphoma developed in the left ankle region. A clonal pericentric inversion of chromosome 20 was shown in the lymphoma cells, but without Philadelphia (Ph') chromosome. The possible relation between the two malignant disorders is discussed in the light of current knowledge on the clonal origin of CML.

Prevalence of monoclonal Ig with lambda light chains in chronic myelocytic leukaemia

Light chains from seven of eight monoclonal Ig detected in the serum of patients with chronic myelocytic leukaemia (CML) were of the lambda isotype. Although the presence of monoclonal Ig in CML is distinctly unusual, this prevalence of lambda chains is unlikely to be a mere coincidence. All patients had otherwise typical clinical, chromosomal and molecular (bcr rearrangements) features of classical CML. The lambda locus appeared unaltered. Only two patients had an excess of dystrophic plasma cells suggestive of multiple myeloma.

Clonal B lymphocytes lack bcr rearrangement in Ph-positive chronic myelogenous leukaemia

Philadelphia (Ph) chromosome-positive chronic myelogenous leukaemia (CML) was studied in a subject heterozygous for the X chromosome-linked alloenzyme system of glucose-6-phosphate dehydrogenase (G6PD). Determination of G6PD mosaicism showed homogeneous expression in granulocytes, erythrocytes and platelets. Cytogenetic studies showed the typical Ph translocation in all metaphases from bone marrow and peripheral blood myeloid cells, bcr rearrangement was detected in bone marrow and in granulocytes. B cells were stimulated with Epstein-Barr virus (EBV) in order to evaluate involvement of lymphocytes, EBV-transformed lymphoblastoid cells expressed a single G6PD phenotype and therefore probably derived from the leukaemic stem cell. However they had a normal karyotype and a constitutional bcr restriction pattern. Molecular analysis in this case of CML clarifies the differentiative potential of cells belonging to the leukaemic clone, by demonstrating that clonal Ph-negative B cells maintain normal differentiative capacity and have a bcr gene sequence which is not rearranged.

Immunophenotyping of aneuploid cells

This review article describes the MAC and MACISH (morphology, antibody, chromosomes, in situ hybridization) methods, which allow the examination of numerical chromosome abnormalities of morphologically and immunologically classified interphase or mitotic cells. Results of studies using these methods indicate that the proportion of mitotic B cells is the same in phytohemagglutinin- and pokeweed mitogen-stimulated lymphocyte cultures, that the proportions of different cell lineages vary greatly after short-term culture of bone marrow cells, that only B cells have a clonal chromosome abnormality in B-cell type chronic lymphatic leukemia and lymphoma, that a clonal chromosome abnormality of patients with T-cell lymphoma may occur in a different T cell subpopulation or at a different maturation stage in certain lineages while B cells show a normal karyotype, that only Reed-Sternberg cells have a clonal chromosome abnormality in Hodgkin's disease, and that in a proportion of patients with acute myeloid leukemia not only a granulocytic-monocytic lineage but also erythrocytic and megakaryocytic lineages show a clonal chromosome abnormality.

Chronic leukemias of childhood

Chronic leukemias account for fewer than 5 per cent of childhood hematologic malignancies. The various subtypes are chronic mylocytic leukemia (adult, juvenile, and familial), chronic myelomonocytic leukemia chronic monocytic leukemia, and chronic lymphocytic leukemia. The most common of these, adult-type chronic myelocytic leukemia, is characterized by specific cytogenetic alterations; recent advances in molecular biology are linking these genetic events to the pathophysiology and course of this fascinating neoplasm.

Diffuse small intestinal lymphoid infiltration in nonimmunodeficient adults from Western Europe

In two white adults born, raised, and living in central France and presenting with long-lasting malabsorption, massive and diffuse lymphoid infiltrate of the lamina propria associated with crypt scarcity was found along the whole small bowel. It was mostly composed of mature lymphocytes, focally mixed with plasma cells and reactive germinal centers. There was no evidence of celiac disease, systemic or intestinal immune deficiency or alpha-chain disease, overt lymphoid malignancy, or stagnant-loop syndrome. By immunofluorescence the infiltrate was constituted in 1 case of polyclonal B cells and, in the other, of a large majority of T11, T8, T10, and class II-positive T cells associated with a population of monotypic B cells. A gluten-free diet and parenteral nutrition proved ineffective. A dramatic and protracted clinical response was observed in both patients after the onset of oral tetracycline therapy, and still persists after 8 and 5.5 yr, respectively, together with morphologically unchanged small bowel infiltrate. These cases may be the equivalents, in people from Western developed countries, of the predominantly lymphocytic variety of the immunoproliferative small intestinal disease described in people from developing countries.

[Occurrence of non-Hodgkin's lymphoma in chronic myeloid leukemia]

The authors report the case of a 42-year old woman who developed chronic myelocytic leukemia with Philadelphia chromosome followed, 21 months later, by malignant follicular lymphoma with small cleaved cells and giant cells. This case is comparable to the other associations of acute or chronic myelocytic and lymphocytic blood diseases previously published. Several pathogenic theories are reviewed. They involve chemotherapy with alkylating drugs (but the diagnosis is sometimes simultaneous), cellular oncogens or, more probably, a clonal abnormality of the stem cell sequentially or concomitantly expressed in the cells of both lineages; unfortunately, in the absence of Philadelphia chromosome this theory has not yet been demonstrated on lymphoma cells.

Cytogenetic study of myeloid and erythroid colonies in chronic myeloid leukaemia with stable Ph1 mosaicism

We have investigated two chronic myeloid leukaemic (CML) patients with a stable Ph1 mosaicism to see whether the Ph1 positive cells belonged to more than one lineage. Individual erythroid and granulocytic colonies were cytogenetically examined. Ph1-positive and Ph1-negative colonies were found both in the erythroid and granulocytic lineage supporting the contention that CML with a stable Ph1 mosaicism as well as classical CML involves a pluripotent stem cell.

Immunoenzymatic staining methods for simultaneous demonstration of chromosomes and cell surface markers

We have developed immunocytochemical staining methods for the simultaneous phenotypic and karyotypic characterization of individual cells. Following a mild hypotonic pretreatment, isolated cells are cytocentrifuged on poly-L-lysine coated slides, fixed in formol buffered acetone, and subsequently labeled with monoclonal antibodies utilizing indirect immunoenzymatic staining procedures with horseradish peroxidase (HRP) or alkaline phosphatase monoclonal anti-alkaline phosphatase (APAAP) as second antibodies. Preparations are refixed consecutively in methanol and 45% acetic acid and counterstained with either "Stains-all" (HRP labeled preparations) or Giemsa (APAAP labeled preparations). C-banding or weak G-banding, which allows the identification of individual chromosomes, can be induced in labeled as well as unlabeled mitotic cells by Ba(OH)2 and/or 2 X SSC treatment after refixation, respectively. Our method has been successfully tested with a variety of monoclonal antibodies against lymphoid, myeloid, erythropoietic, and thrombopoietic cell surface antigens. It is fast, allows the adjustment of the intensity of cell surface staining, and results in permanent preparations suitable for light microscopic analysis.

T-cell involvement in benign phase chronic myelogenous leukemia

T cells from the peripheral blood of patients with chronic myeloid leukemia (CML) were cultured with phytohemagglutinin and T-cell growth factor (TCGF) in agar culture. These T-cell colonies were pooled and expanded further in liquid culture with TCGF and then simultaneously analysed for the E-rosette receptor with the monoclonal antibody OKT11 and for the presence of the Philadelphia (Ph1) chromosome. OKT11 analysis showed these populations to be composed 99.5% or more of T cells. In four of the seven patients the T-cell suspension showed 7/50 (14%), 3/36 (8%), 2/34 (6%), and 4/44 (9%) Ph1 metaphases. Furthermore, Ph1 metaphases were demonstrated in T-cell cultures in two patients when bone marrow metaphases simultaneously showed 90 and 100% Ph1 negative metaphases secondary to human leukocyte interferon therapy or combination chemotherapy. A minority of T cells in benign phase CML have the Ph1 abnormality despite reduced number of Ph1 metaphases in bone marrow from therapy.

Early T-cell features in blast crisis of Ph1-positive chronic myeloid leukaemia

A patient with Ph1-positive chronic myeloid leukaemia (CML) presented in extramedullary blast crisis. Whereas the peripheral blood and bone marrow features were consistent with the chronic phase of CML, study of the enlarged lymph nodes demonstrated massive replacement by Ph1-positive blast cells of lymphoblastic morphology. Such blast cells showed diffuse acid phosphatase positivity, were positive for TdT, and had an enzyme pattern (adenosin-deaminase, purine-nucleosidephosphorilase and lactate-dehydrogenase) typical of immature T-cells. To further characterize the phenotype of the blast cells, they were analyzed for surface markers using a panel of monoclonal antibodies selected to identify differentiation antigens of T cells, B cells and myeloid cells. The results of the latter analysis were consistent with an early T-cell origin of the blast cells, since they were positive for TdT, CRIS1 (T1), E rosettes and OKT10, and were negative for OKT3, Leu3 and OKT8. These features demonstrate that T-cell markers may also be expressed in blast crisis of CML and provide evidence that T-cells may share a common stem cell with myeloid and B-cells in CML.

Evidence for the involvement of B lymphoid cells in polycythemia vera and essential thrombocythemia

Previous studies with the X-chromosome-linked glucose-6-phosphate dehydrogenase (G6PD) as a marker of cellular mosaicism demonstrated that polycythemia vera (PV) and essential thrombocythemia (ET) are clonal disorders of hematopoietic stem cells that can differentiate to erythrocytes, granulocytes, and platelets. To determine if the involved stem cells could also differentiate along the B-lymphoid pathway, we studied one woman with PV and one woman with ET. Of 117 Epstein-Barr virus-transformed B-lymphoblastoid lines expressing a single G6PD derived from the patient with PV, 108 expressed G6PD type A, the type characteristic of the abnormal clone. The ratio of 108:9 was significantly different from the one to one ratio predicted for this patient, which suggested that at least some circulating progenitors for B-lymphoid cell lines differentiate from the stem cell involved by the disease. Results obtained from the patient with ET were similar--104 of the 109 lymphoblastoid lines monotypic for G6PD expression displayed the enzyme type found in the abnormal clone of marrow cells. Therefore, in these patients, PV and ET, like chronic myelogenous leukemia, involve a stem cell pluripotent for the lymphoid as well as the myeloid series.

Cytogenetics and cell surface marker analysis in CML--1. Prediction of phenotype of acute phase transformation

Thirty-nine patients with Philadelphia chromosome-positive (Ph1) chronic myelocytic leukemia (CML) were monitored using cytofluorometry and cytogenetics. During chronic phase, abnormal populations could be detected using commercially available monoclonal antibodies. Most of these abnormal populations had either an HLA.DR+ or an OKM1+ HLA.DR- phenotype. Thirteen patients progressed to acute phase disease. Five patients with HLA-DR+ abnormal cells during chronic phase showed no clonal evolution detectable using standard cytogenetic techniques and underwent lymphoid transformation. Seven patients with OKM1+-HLA.DR- abnormal cells exhibited chromosomal abnormalities in addition to the Ph1 and progressed to a myeloblastic acute phase. One patient with HLA.DR+ OKM1+ 63D3+ abnormal cells in chronic phase showed clonal evolution and progressed to a myelomonocytic acute phase. These results suggest that cell surface markers on chronic phase cells can be used in conjunction with cytogenetic monitoring to predict the phenotype of cells involved in the acute transformation of CML. B cells (6, 13), but not T cells (18), bearing the Ph1 have been isolated from chronic phase CML patients. Thus cells other than those of myeloid lineage may be involved. Periodic cytogenetic monitoring has been shown to detect clonal evolution (i.e. genetic changes in addition to the PH1) in as many as 75% of patients prior to the acute phase (14, 37). However, neither cytogenetic changes nor morphologic analysis appear to predict the lymphoblastic type of transformation (14). Since fluorescence analysis of cell surface markers has shown reduced numbers of normal cells (28), the identity of the 'abnormal' cells was probed with antibodies recognizing a variety of markers on immature and mature lymphoid and myeloid cells. Not only were significant numbers of abnormal cells detected in the peripheral blood of chronic phase patients, but the phenotype of the abnormal population, in combination with cytogenetic analyses, predicted the type of blasts involved in acute phase disease.

Mixed megakaryocytic-granulocytic differentiation during diffusion chamber culture of peripheral blast cells from the blast crisis of chronic myelocytic leukemia

Morphologically and cytochemically undifferentiated peripheral blast cells from three patients in blast crisis of Ph'-positive chronic myelocytic leukemia were analysed morphologically, immunologically and cytogenetically prior to and during in-vivo diffusion chamber culture (DC) to investigate their differentiation capacity. In two patients immunological markers characteristic of the megakaryocytic lineage were found on the original cells, but lineage-specific differentiation markers were absent on the blast cells of the third patient. During DC culture multilineage differentiation capacity could be demonstrated immunologically and morphologically in all three patients with expression of megakaryocytic and granulocytic markers as well as terminal differentiation along these lineages. Cytogenetic analysis prior to and during DC culture provided evidence that the cells differentiating in culture were derived from the blast crisis clones and that the event leading to blast crisis might have occurred in a pluripotent precursor cell which retained its differentiation capacity along several lineages.

Promyelocytic blast crisis of chronic myelocytic leukemia with both t(9;22) and t(15;17) in M3 cells

A blast crisis with the features of promyelocytic leukemia (M3) occurred during the evolution of chronic myelocytic leukemia (CML) with the t(9;22) translocation. This rare form of transformation was confirmed by means of cytologic and electron microscopic examination. Cytogenetic studies showed two simultaneous translocations t(15;17) and t(9;22) in the promyelocytes. After intensive chemotherapy, a complete remission was obtained and only karyotypes with t(9;22) translocation were present. These data confirm the specificity of the t(15;17) translocation in malignant promyelocytic proliferation and provide evidence for a second genetic event in the genesis of blast crisis occurring in a committed cell belonging to the abnormal population defined by the Ph1 chromosome.

Simultaneous occurrence of a T-cell lymphoma and a chronic myelogenous leukemia with an unusual karyotype

The simultaneous occurrence of malignant T-cell lymphoma and chronic myelogenous leukemia is reported. The lymph nodes contained E rosette forming cells. Blood and bone marrow cell morphology were consistent with the diagnosis of chronic myelogenous leukemia. Lymph nodes, bone marrow and blood mitosis showed a t(6;8) (6pter----6q27 ::8p12----8pter;6qter----6q27 ::8p12----8qter) translocation. So far a number of recent reports have shown simultaneous B lymphoid and myeloid proliferations in some malignancies, this is apparently the first reported case of simultaneous T lymphoid and myeloid proliferations.

Patient with B-cell neoplasia (immunoblastic sarcoma) and the Philadelphia chromosome

Philadelphia chromosome-positive cells with a standard translocation (9;22) were found in bone marrow and peripheral blood samples from a patient with non-Hodgkin's lymphoma (immunoblastic sarcoma) in the final leukemic phase. The neoplastic clone was of monoclonal B-cell character with surface Ig (mu, kappa) and mouse red blood cell receptors. This is the first case with surface Ig and t(9;22) cells reported without evidence of chronic myeloid leukemia. Also, additional consistent chromosome aberrations were found.

The origin of human B and T cells from multipotent stem cells: a study of the Tn syndrome

The Tn (or polyagglutinability) syndrome corresponds to a human nonmalignant acquired condition which results from a somatic mutation occurring at the level of bone marrow stem cells. This model offers therefore a unique opportunity to study the contribution of multipotential stem cells to the maintenance of cells from the lymphoid lineage. We found that the Tn mutation is expressed by both myeloid and lymphoid mature blood cells. Whereas a large proportion of surface IgM-bearing B cells carry the Tn mutation, only a small percentage of T cells and IgA- or IgG-bearing B cells are defective, showing that under physiological conditions the penetration of stem cells into the various myeloid and lymphoid compartments is variable.

Polycythaemia rubra vera and hairy cell leukaemia in the same patient: studies on the spleen

The first association of polycythaemia rubra vera (PRV) and hairy cell leukaemia (HCL) is reported. The secretion by spleen cells in short term culture of IfGlambda to the exclusion kappa demonstrated that despite aberrant surface marker studies the HCL was a monoclonal tumour of B cells. Chromosomal studies on splenic cells were not able to demonstrate the common clonal origin of the two tumours.