Characterization of blast cells in chronic granulocytic leukaemia in transformation, acute myelofibrosis and undifferentiated leukaemia. II. Studies with monoclonal antibodies and terminal transferase

Morphologic, Immunologic, and Cytogenetic Characteristics of Secondary Acute Unclassifiable Leukemia in Hodgkin's Disease

Blast cells from five cases of secondary unclassifiable leukemia following therapy for Hodgkin's disease were studied by cytochemical, immunological and cytogenetic analyses. Cytochemical and immunological reactivity were in accordance with poorly differentiated, myeloid blasts. The four cases in which karyotype analysis was performed showed specific chromosomal abnormalities. No evidence of multiple lineage involvement was found. Problems in classifying these cases of secondary ANLL were due to the high grade of undifferentiation of the blast cells. Their low cytochemical reactivity with markers of myeloid differentiation was similar to what may be observed in patients with acute undifferentiated leukemia or with chronic myeloid leukemia in blast crisis.

Myeloperoxidase cytochemical negativity: an unexpected but intrinsic property of blasts of all phases of chronic myeloid leukemia

Myeloperoxidase (MPO) cytochemical activity, recognized as a very important hallmark of myeloblasts, is generally negative in chronic myeloid leukemia (CML) blast crisis (BC). Because this finding is unexpected, being not in keeping with the myeloproliferative nature of CML, we tried to ascertain if MPO cytochemical negativity could be an intrinsic property of blasts of CML and hence present in the preblastic phases as well. Myeloperoxidase cytochemistry of peripheral blood blasts in 161 cases of CML, including 103 in chronic phase (CP) and 29 each in accelerated phase (AP) and BC, was assessed and compared with that of 30 cases of acute myeloid leukemia, AML-M2. Blasts of 97 (94.2%) of 103 cases of CP, 28 (96.6%) of 29 cases of AP, and 22 (75.9%) of 29 cases of BC were negative for MPO (<3% MPO-positive blasts). Compared with the strong MPO positivity, both in terms of intensity and proportion, in the AML-M2 cases, the positivity in the CML cases was generally weak and was seen in a small number of blasts (5-15%), except in one case of BC with 20% positive blasts. Absence or, at times, weak MPO cytochemical activity is an intrinsic property of blasts of all phases of CML, and use of the term myeloblast in CML should be understood to refer to a cell with this property. This also explains why MPO cytochemistry, despite its high reputation as a myeloid-lineage marker, generally does not help in CML BC. CML BC should therefore be considered as a possible diagnosis along with acute lymphoblastic leukemia, AML-M0, AML-M7, etc., in the setting of MPO-negative blasts. Similarity between MPO expression pattern in CML, i.e., negative in blasts and positive in the more mature cells, and that during maturation of normal myeloid series of cells shows the deranged myelopoiesis of CML to be undisturbed at least with respect to MPO expression. There is need for a more comprehensive study of blasts of preblastic phases.

Diagnosis of acute basophilic leukemia

De novo acute basophilic leukemia (ABL) is a rare form of acute leukemia. Most frequently, the blast cells are morphologically undifferentiated, and the recognition of the presence of coarse basophilic granules may be the first step in diagnosis of this rare disorder. These granules are metachromatic and MPO negative. Immunophenotyping shows myeloid markers and some more specifically associated antigens such as CD9 or CD25 which are strongly expressed. Lymphoid, erythroid or megakaryocytic markers are not significantly expressed. In the absence of basophilic granules, some cases are classified as AML M0 if they express myeloid markers, or undifferentiated leukemia if no markers are present. If specific immature basophilic or theta granules are present, only an electron microscopic study will enable the diagnosis of a basophilic lineage assignment. Some cases may be misdiagnosed if all these steps are not followed. After all these investigations, two types of ABL may be defined: 1-A pure ABL, monophenotypic with basophilic lineage involvement alone, which should be classified as AML M8 . Genetic studies in these cases are very important for understanding the leukemic process and in a few cases, we can suspect c-MYB oncogene involvement but further investigations are still necessary. 2- More frequently, acute leukemia can be a mixture of blasts from different lineages with an important but variable participation of mature or immature basophilic cells. These cases must be classified as AML/Baso or multiphenotypic acute leukemias and often present Phl -chromosomal abnormality.

The myeloproliferative disorders. An historical appraisal and personal experiences

According to strict morphological, biochemical and cytogenetic criteria Philadelphia chromosome positive essential thrombocythemia and chronic granulocytic leukemia constitute a separate malignant and individual disease entity, whereas Philadelphia chromosome negative essential thrombocythemia, polycythemia vera and agnogenic or megakaryocytic myeloid metaplasia form a chronic proliferation of three hematopoietic cell lines. Histopathology from bone marrow biopsies permits the characterization and diagnostic differention of the various myeloproliferative disorders and appears to be a main and specific diagostic criterion for polycythemia vera and essential thrombocythemia. Hemorrhagic thrombocythemia is a clinical syndrome of recurrent spontaneous mucocutaneous and secondary hemorrhages often preceded by thromboses, extremely high platelet counts, pseudohyperkalemia, increased bone marrow cellularity and frequently splenomegaly. The diagnostic criteria of essential thrombocythemia with paradoxical occurrence of thrombotic events and hemorrhagic manifestations are a platelet count in excess of 1000 x 10(9)/L and increased bone marrow cellularity in the majority of the cases. Erythromelalgia and other microcirculatory ischemic or thrombotic events or accidents in essential thrombocythemia and polycythemia vera already occur at platelet counts in excess of the upper limit of normal. First line treatment options in essential thrombocythemia and polycythemia vera are control of platelet function with low-dose aspirin and reductive control of platelet count and erythrocytes by bloodletting, interferon and busulfan or hydroxyurea monochemotherapy.

Immunophenotype and ultrastructural studies in blast crisis of chronic myeloid leukemia

Thirty-four patients with chronic myeloid leukemia in blast crisis (CML-BC) were evaluated for lineage differentiation with immunological markers and the presence of ultrastructural peroxidase. Eighteen (52.9%) were found to have myeloid blast crisis. Cytochemically, myeloperoxidase (MPO) could be detected only in six patients on light microscopy while in the remaining 12 patients, myeloid differentiation was confirmed only by demonstration of MPO either at ultrastructural level or by the reactivity with anti myeloperoxidase (anti MPO) antibody. Six (17.6%) had lymphoid blast crisis as identified by lymphoid specific markers (CD19; CD10; CD7; CD4) along with the absence of myeloid markers. Heterogenous blast cell populations with mixed lineage differentiation were seen in 4 (11.7%) patients. These cases showed both lymphoid (CD19, CD10) and myeloid (anti MPO and ultrastructural MPO) characteristics. A single case of megakaryoblastic blast crisis was identified with positivity for CD41 and CD42 along with the presence of platelet peroxidase at the ultrastructural level. Five cases (14%) of CML blast crisis remained unclassifiable. These results suggest that blast crisis in CML show an arrest of differentiation at an early stage when compared to de novo acute leukemias. This is particularly evident from the fact that MPO could only be demonstrated ultrastructurally or with anti MPO antibody in the majority of patients with myeloid differentiation. It is expected that utilisation of molecular studies including immunoglobulin and T-cell receptor gene rearrangement and m-RNA expression for myeloperoxidase will provide a better insight into the level of differentiation for the presently unclassifiable cases of CML-blast crisis.

Platelet derived growth factor expression, myelofibrosis and chronic myelogenous leukemia

CML is often associated with myelofibrosis, and fibrosis in the accelerated phase is one of the diagnostic criteria for this accelerated phase. In this review, the mechanism of myelofibrosis associated with CML is discussed with emphasis on the cell origin of the production and release of platelet derived growth factor (PDGF) and its interaction with marrow fibroblasts. In the initial stage of myelofibrosis in chronic phase CML, atypical small megakaryocytes might leak PDGF, possibly PDGF-AB, together with other growth factors. As the clinical phase of the disease progresses to accelerated or blastic phase, a larger quantity of PDGF-AB or PDGF-BB might be secreted from blastic cells with myeloid phenotype. In addition some fibroblasts may be attracted by the PDGF and proliferate, and deposit collagen as well as fibronectin in the bone marrow stroma.

Occurrence of acute megakaryoblastic leukemia in a patient with idiopathic growth hormone deficiency

We describe a case of a 15 year old boy who developed acute megakaryoblastic leukemia (AMKL) while receiving treatment with human growth hormone (hGH) for idiopathic growth hormone deficiency (GHD). He was diagnosed as having idiopathic GHD and given hGH from December 1991. The examination of his peripheral blood showed mild pancytopenia 2 months before the start of the hGH therapy. Since January 1992, paleness of the skin, general fatigue and fervescence progressed gradually. In February 1992, because of the occurrence of acute leukemia, administration of hGH was discontinued. Judging from the results of surface marker analysis of the blast cells, the patient was diagnosed as having AMKL. He was treated with chemotherapy for acute non-lymphoblastic leukemia from March 1992. A complete remission was obtained after 4 weeks of treatment. The chemotherapy was completed in July 1993. He remains in complete remission 26 months after diagnosis. This case suggests the importance of hematological examination and, when there is any abnormality which is not caused by GHD, such as pancytopenia, more detailed medical examinations (for example bone marrow examination) are necessary.

Acute lymphoid leukemias following either a previous chronic myelogenous leukemia or myelodysplastic syndrome: phenotypic and genomic differences

We have analyzed the immunological and genomic characteristics of the lymphoid blast cells present in secondary lymphoid leukemias following either a previous chronic myelogenous leukemia (CML) or myelodysplastic syndrome (MDS). Twenty-one of 107 secondary leukemias analyzed displayed a lymphoid phenotype (15 after a CML and 6 after a MDS). Most of the lymphoid blast crises of CML (73%) correspond to pure lymphoid transformation, all of them having a common acute lymphoblastic leukemia (ALL) phenotype (CD10+). By contrast, in all MDS cases, lymphoid blast cells coexisted with another myeloid component (hybrid leukemias) and showed an early B phenotype. IgH and TCR-gamma gene rearrangements were detected in the CML-lymphoid blast crisis (86% of cases) more frequently than in the MDS transformations (33%). The TCR-beta gene was in germ line configuration in all cases while TCR-delta gene rearrangements were detected in four cases, all of them corresponding to a previous diagnosis of CML. These results show the existence of both immunophenotypic and genomic differences between the lymphoid transformations of either CML or MDS, which could reflect differences at the stage of maturation of the target cell in these transformations.

Immunophenotypic characterisation of acute leukaemia after polycythemia vera

AIMS

To analyze the immunophenotype of blast cells in patients with acute leukaemia after polycythemia vera, together with the most relevant clinical and haematological disease characteristics.

METHODS

The immunophenotype was analysed in nine patients by immunofluorescence flow cytometry using a panel of 15 monoclonal antibodies. The DNA content of blast cells was determined using Vindelov's technique.

RESULTS

The most relevant clinical and haematological disease characteristics included: the presence of enlarged spleen and liver by 56% and 67%, respectively; a moderate degree of leucocytosis with thrombocytopenia while haemoglobin was normal in 50% of patients. All patients received alkylating agents or hydroxyurea, or both. Interestingly, the chronic phase in patients receiving this latter drug was shorter. All cases showed a myeloid phenotype, four of them reactive only to early myeloid antigens (CD13/33); in the remaining cases the blast cells displayed granulomonocytic (CD14+, CD15+), erythroid (CD71 ), or megakaryocytic (CD61+, CD41+) markers. Coexpression of lymphoid related antigens (CD7, TdT, or CD19) was also detected. The morphological assessment of blast cells agreed with the immunophenotyping in five out of the nine cases. Blast cells from all six patients analysed displayed a diploid DNA content and the proportion of S-phase cells ranged from 0.4% to 4%.

CONCLUSIONS

These findings suggest a pluripotential stem cell with myeloid commitment as the target cell of acute leukaemia after polycythemia vera.

Ultrastructural and ultracytochemical differences between megakaryoblastic leukemia in children and adults. Analysis of 49 patients

BACKGROUND

Acute megakaryoblastic leukemia (AMKL) has two peaks in distribution of incidence (in adults and children 1 to 2 years of age) and is frequently seen in children with Down syndrome. The current study was undertaken to disclose whether there were any differences between these groups.

METHODS

Electron microscopic and ultrastructural cytochemical features of 49 children and adults with a AMKL or chronic myelogenous leukemia (CML) in megakaryoblastic crisis were compared.

RESULTS

Blast cells from children with AMKL, including those with and without Down syndrome, had immature features lacking typical alpha granules and a demarcation membrane system (DMS). However, blast cells from patients with AMKL with Down syndrome had more theta, electron-lucent, and basophil-like granules, suggesting that the blast cells had more potential to differentiate into other cell lines than megakaryocytes. The AMKL blast cells of adult patients showed a higher percentage of platelet peroxidase (PPO) positivity than other subgroups, and they occasionally contained typical alpha granules and DMS. This indicated that the blast cells of adults with AMKL were more mature than those of children and CML in megakaryoblastic crisis.

CONCLUSIONS

By electron microscopic analysis, leukemic megakaryoblasts differed between children with AMKL with and without Down syndrome, adults with AMKL, and patients with CML in megakaryoblastic crisis.

Development of acute leukaemia after idiopathic myelofibrosis

AIMS

To determine the characteristics of blastic transformation of idiopathic myelofibrosis.

METHODS

The clinical and haematological features, as well as the morphological characteristics of blast cells, were analysed in nine adults with blast transformation.

RESULTS

Most of the patients were male and had enlarged spleens and livers. Five of the patients had normal platelet counts, while all had pronounced anaemia and a moderate degree of leucocytosis. The duration of the acute phase was usually short: 16 (SD 8) weeks. Most myeloid cell lineages--granulocytic, monocytic, and megakaryocytic--were similarly distributed. One patient also had a hybrid (lymphoid-myeloid) phenotype. The morphological assessment of blast cells agreed with immunophenotyping in five out of the nine cases. The onset of the blastic phase was not related to previous treatment.

CONCLUSIONS

A pluripotential stem cell with preferential myeloid commitment would be the target cell of blast transformation in idiopathic myelofibrosis. Our immunophenotypic data do not support the concept of a preferential association between megakaryocytic lineage and the acute transformation of idiopathic myelofibrosis. The absence of previous treatment in some cases suggests that this kind of evolution is part of the natural history of idiopathic myelofibrosis.

Erythromelalgia in thrombocythemia of various myeloproliferative disorders

Erythromelalgia is caused by platelet-mediated acral inflammation and arteriolar thrombosis in thrombocythemia in its primary form or associated with polycythemia vera. The prompt and lasting relief of burning pain by low-dose aspirin is a prerequisite for the diagnosis of thrombocythemic erythromelalgia. Here we extend observations on the occurrence of erythromelalgia in thrombocythemia associated with primary myelofibrosis, Philadelphia-chromosome positive micromegakaryocytic myelofibrosis, and myelodysplastic syndrome type II. It is concluded that erythromelalgia may occur in thrombocythemia of all variants of chronic myeloproliferative disease as well as myelodysplastic syndrome if platelet counts are sufficiently high.

Immunophenotypic, genomic and clinical characteristics of blast crisis of chronic myelogenous leukaemia

We have studied phenotypic and clinical features in a consecutive series of 45 patients with chronic myelogenous leukaemia (CML) in blast crisis (BC). In addition, in 22 of these patients we have analysed the genotypic characteristics including immunoglobulin, T-cell receptor (TCR) and major breakpoint cluster region (M-bcr) gene organization. The granulomonocytic and megakaryoblastic lineages are the most commonly involved in these BC of CML (33% and 33% of cases, respectively); only 18% of our cases displayed a lymphoid phenotype. Moreover, both morphological and immunophenotypic studies revealed the frequent coexistence of two or three cell populations, especially when the megakaryoblast component is involved. The lymphoid BC displayed the highest incidence of complete remissions although this was not associated with a longer survival. Only minor differences between the different myeloid subgroups were observed. Immunoglobulin heavy chain (IgH) gene rearrangement was found in five of the six lymphoid BC and in one myeloid BC. Only one case showed k light chain gene rearrangement. In all but one myeloid BC the TCR-beta gene was in germline configuration. The TCR-gamma gene was rearranged in all lymphoid and one myeloid BC, while TCR-delta gene rearrangement was detected in 67% and 16% of the lymphoid and myeloid BC, respectively. Most of the lymphoid BC (4/5) had the M-bcr breakpoint in subregion 3, while the myeloid BC had the breakpoint either in subregion 2 or 3. No differences between the different myeloid phenotypic subgroups were observed in relation to breakpoint.

A method for identifying megakaryocytic and erythroid cells by a combined immunocytochemical and cytochemical stain

The effectiveness of immunoperoxidase staining for platelet glycoprotein IIb/IIIa coupled with cytochemical staining for hemoglobin has been evaluated as a dual staining technique for identifying lineage-specific characteristics of the megakaryocytic and erythroid series in cells of the same hemopoietic tissue preparation. A sequence of staining was established which produced a circumferential brown stain around cells of the megakaryocytic series, and a diffuse yellow to orange stain in the cytoplasm of cells of the erythroid series. Each staining reaction possessed a high degree of specificity and sensitivity which enabled the combined stain to provide a convenient means for establishing the megakaryocytic and erythroid nature of individual cells in hematological specimens where classification cannot be achieved with certainty on morphological grounds.

Morphological and immunological pattern of blastic transformation in chronic myeloid leukemia in Saudi Arabia: Study of 90 transformations among 248 patients

We examined the pattern of blastic transformation in 90 of 248 patients (36%) with chronic myeloid leukemia who were seen at the King Faisal Specialist Hospital and Research Centre between 1975 and 1988. The mean and median ages of all patients were 38.2 and 36.0 years, respectively. Four of the 90 transformants (4.4%) presented in blastic transformation, and 86 cases (95.5%) evolved from a well-defined chronic phase. Twenty-nine (32.2%) of the patients underwent lymphoid blastic transformation, while 28 (31.1%) were myeloid, seven (7.8%) were myelomonocytic, four (4.4%) were monocytic or erythroblastic, six (6.7%) were megakaryoblastic, ten (11.1%) were of mixed lineage, and two (2.2%) were unclassifiable. The lymphoid blast cells were uniformly common acute lymphocytic leukemia (i.e., Ia and CD10 positive), whereas the myeloid transformations were predominantly Ia negative. Mixed phenotype blasts were also predominantly Ia positive (i.e., 8 of 10), with varying positively for CD10 and myeloid/monocyctic markers. We conclude that blast crisis in chronic myeloid leukemia occurs in Saudi patients in a pattern similar to that seen in patients elsewhere, and that surface Ia antigen positivity in lymphoblast cells is a reliable marker for differentiating lymphoid from nonlymphoid crisis, in which the Ia antigen is not usually demonstrable.

Chronic myeloid leukaemia lymphoid blast crisis. Relevance of molecular analysis at the bcr and immunoglobulin heavy chain gene level in monitoring response to therapy and residual disease

Southern blot analyses were performed in sequential DNA samples from 4 patients with Ph' + chronic myeloid leukaemia (CML) who underwent lymphoid or mixed blast crisis (BC). Genomic rearrangements at the breakpoint cluster region (bcr) and immunoglobulin heavy chain (IgH) gene level provided, in these cases, a sensitive and specific evaluation of response to therapy both in terms of blasts and Ph' + cell suppression. Recurrent BC was molecularly characterized in the 4 patients, showing each time identical individual specific DNA rearrangement patterns. Residual blasts were detected in 2 cases during intervening chronic phases by IgH rearrangements. Such findings highlight the specificity of these molecular markers, clearly indicating the failure of ablative therapy in eradicating the neoplastic clone. Finally, molecular and phenotypic identity in individual recurrent BC also suggested, in our cases, a lack of clonal evolution during disease progression.

A study of prognostic factors in blast crisis of Philadelphia chromosome-positive chronic myelogenous leukaemia

In 80 patients with Ph-positive chronic myelogenous leukaemia the main clinical, haematological and cytogenetical data were recorded at diagnosis of blast crisis and evaluated for prognostic significance. At the time of the analysis 73 patients had died, with a median survival of 4-8 months from diagnosis of blast crisis for the whole series. When analysed as a time-dependent variable, the achievement of a favourable response to chemotherapy resulted in a longer patient's survival. On the other hand, the univariate analysis identified six pretreatment characteristics associated with a poorer prognosis: a longer chronic phase, presence of extramedullary blastic involvement, a platelet count below 200 x 10(9)/l, a less marked leucocytosis, a blood blast cell percentage higher than 10%, and presence of trisomy 8. The latter parameters were included in a multiple regression model together with the blast cell phenotype (lymphoid versus non-lymphoid), and only four of them (trisomy 8, duration of chronic phase, platelet count, and leucocyte count) retained their prognostic influence. When the therapeutical response was also included in the regression model, it proved to be the most important prognostic variable, followed by trisomy 8, length of chronic phase, extramedullary disease, and platelet count, whereas the leukocyte count lost its predictive value. Thus, in spite of the short overall survival of blast crisis patients, the identification of prognostic factors in such a haematological condition may be of interest, especially in the interpretation of new therapeutical approaches.

Target cell of leukemic transformation in acute megakaryoblastic leukemia

Acute megakaryoblastic leukemia (AMkL) is a newly defined acute leukemia in which the differentiation of proliferating blasts is arrested at the megakaryocytic precursor stage. In order to clarify whether a target cell of leukemic transformation in AMkL is a cell committed to megakaryocytic lineage, or a multipotential stem cell, we examined AMkL patients with regard to: a) the presence of myelodyplastic features in residual erythroid and granulocytic cells, b) coexistence of myeloperoxidase (MPO)-positive blasts with megakaryoblasts, and c) the presence of the same chromosomal abnormality in erythroid and granuloid colony-forming cells as seen in megakaryoblasts. Regarding the former two items, results were compared with those from megakaryoblastic crisis of chronic myelocytic leukemia (CML-MkBC) and transient myeloproliferative disorder in Down syndrome (DS-TMD), which are thought to be multipotential stem cell disorders. Among 18 patients with AMkL, three, all complicating myelofibrosis, had marked myelodysplastic changes of erythroid series and/or granulocytic series. In 4 out of 7 patients with CML-MkBC, 5 out of 8 patients with DS-TMD, and 7 out of 18 patients with AMkL, MPO-positive blasts, even though rare, were observed in addition to PPO-positive blasts. All except one of these patients with AMkL also showed complicating myelofibrosis. In one case of AMkL with myelofibrosis, chromosomal analysis of cultured cells of individual colonies revealed that all the analysable metaphases from both CFU-GM and BFU-E had the same chromosomal abnormality as megakaryoblasts. This study has clarified that a considerable proportion of AMkL cases, particularly those with complicating myelofibrosis or showing acute myelofibrosis, arise against the background of a multipotential stem cell disorder, even if blasts are exclusively megakaryocytic in phenotype.

bcr rearrangements in Philadelphia chromosome-positive acute lymphoblastic leukemia. A study of five Chinese patients in Taiwan

Cytogenetic studies were successfully conducted on 73 Chinese patients with acute lymphoblastic leukemia (ALL). A Philadelphia chromosome (Ph) was identified in four (9%) of the 46 children and in four (15%) of the 27 adults. None of these patients had any clinical features suggestive of chronic myelogenous leukemia (CML). Leukemic cells from five of the eight Ph-positive (Ph+) ALL patients were analyzed for bcr rearrangement by Southern blot analysis with three restriction enzymes and two bcr probes. One of the three children and both adult patients studied showed bcr rearrangement. Based on the data from the literature and the present study, 58% of adult and 14% of childhood Ph+ ALL patients demonstrated bcr rearrangement. There were no significant differences in clinical or laboratory findings between the two groups of patients with or without bcr rearrangement. Patients who had Ph+ ALL but no bcr rearrangement appear to have been victims of de novo acute leukemia, but it was still difficult to determine whether patients with bcr rearrangement had acute lymphoid transformation of subclinical CML. More studies and longer follow-ups are needed for clarification.

Aggressive polychemotherapy for acute myelofibrosis

Acute myelofibrosis is a rare and still ill-defined disease. Based on morphological observation, immunophenotyping and ultrastructural analysis, we support the assumption that acute myelofibrosis is a malignant disorder mainly of the megakaryocytic lineage and is closely related to acute megakaryocytic/blastic leukaemia. Consequently, the 11 patients reported here were treated with aggressive polychemotherapy with combinations including daunorubicin and cytosine arabinoside and 6-thioguanin or VP16-213. 4 complete remissions, 2 partial remissions and 1 minor response were observed. Duration of aplasia was not significantly prolonged. These findings indicate that the use of aggressive polychemotherapy is feasible in acute myelofibrosis and results in a significant number of remissions.

Cytogenetic findings in adult acute leukemia and myeloproliferative disorders with an involvement of megakaryocyte lineage

Cytogenetic analyses were performed on 12 adult patients with abnormal megakaryoblastic proliferation which was detected by ultrastructural cytochemical study (platelet peroxidase) and platelet-megakaryocytes-specific monoclonal antibodies (TP-80, Plt1, AN51, and KOR-77). The patients consisted of two patients with myelodysplastic syndromes (MDS), three with acute megakaryoblastic leukemia (AMKL), six with megakaryoblastic transformation in Philadelphia-positive chronic myelogenous leukemia (CML-meg-BC), and one case of chronic myeloproliferative disorder (CMPD). Among them, an inversion of the long arm of chromosome 3 [inv(3)(q21q26)] was found in one AMKL patient with a normal platelet count. Chromosome change at band 3q26 was also found in one MDS patient without thrombocythemia. Furthermore, the long arm of chromosome 13, where rearrangements in myelofibrosis are clustered (13q12----q22) was seen in one MDS patient. Trisomoy of chromosome 19 was found in one AMKL patient and three CML-meg-BC patients. These findings indicate that cytogenetic abnormalities involving 3q26, 13q, and trisomy 19 are associated with hematologic neoplasia with megakaryocytic lineage in adult patients, although these abnormalities were not related to the survival of the patients. During the period of this study, two acute myelogenous leukemia patients (AML-M2 and AML-M5b) with chromosome rearrangements at band 3q21 and thrombocythemia were found, indicating that chromosome abnormality at band 3q21 is related to quantitative platelet dysfunction, whereas that at 3q26 is related to hematologic malignancies with a proliferation of megakaryocytic lineage.

Myelofibrosis: a review of clinical and pathologic features and treatment

The purpose of this review is to discuss and clarify the current understanding of the pathogenesis, clinical manifestations, and treatment of MF. MF may be either a primary or secondary disorder. It is characterized by an increased deposition of bone marrow collagen, fibronectin, and laminin. Present evidence indicates that MF may be mediated by platelet or megakaryocyte growth factors, decreased prostaglandin mediated stem cell inhibition, immune complex deposition, and both fibroblast and endothelial cell proliferation. Recently acute MF has been recognized to be identical to acute megakaryocytic leukemia. Secondary MF usually responds to appropriate treatment of the underlying disease. Primary MF is usually treated by blood product support, but may be responsive to androgens, splenectomy, splenic irradiation, chemotherapy, or bone marrow ablation with marrow reconstitution.

Chromosomal characteristics of Ph-positive chronic myelogenous leukemia in transformation. A study of 23 Chinese patients in Taiwan

Cytogenetic study was performed in the past 3 years on 23 Chinese patients with Philadelphia chromosome (Ph) positive chronic myelogenous leukemia (CML) in transformation; seven were in accelerated phase and 16 in acute blast crisis. Chromosomal abnormalities in addition to Ph were found in three (43%) of the patients at accelerated phase and 14 (88%) of the patients at blast crisis. The common nonrandom chromosomal aberrations were double Ph, trisomy 8, trisomy 19, and trisomy 21, which occurred in 47%, 41%, 35%, and 29%, respectively, of the total patients with extra chromosomal abnormalities. Isochromosome for the long arm of chromosome 17 was found in only one patient. In patients with blast crisis, the type of blast cell was characterized through morphologic, cytochemical, and immunocytochemical studies. Eleven cases were classified as myeloid and five as lymphoid transformation. Trisomy 8, 19, and 21 were detected only in patients with myeloid blast crisis. This study also revealed a high incidence of trisomy 21 and a low incidence of i(17q) in Chinese patients with transformation of CML.

The role of ultrastructural cytochemistry and monoclonal antibodies in clarifying the nature of undifferentiated cells in acute leukaemia

The nature of the cells in 21 cases of acute leukaemia with blasts which were undifferentiated by light microscopy criteria was investigated by immunophenotyping, ultrastructural cytochemistry and DNA analysis. Two groups of cases were recognized. Fourteen cases were negative with B and T lymphoid markers and expressed one or two myeloid antigens detected by the monoclonal antibodies (McAb) MCS2 (CD13) and MY9 (CD33). Peroxidase activity was demonstrated at ultrastructural level by the method of Roels on unfixed cells in eight out of 10 cases; rearrangement of the immunoglobulin (Ig) genes was demonstrated in one of the three cases investigated. These cases are proliferations of early, MO, myeloblasts which can only be recognized by immunological and ultrastructural cytochemical methods. The remaining seven cases revealed a complex phenotype with expression of myeloid and lymphoid antigens. Peroxidase activity was detected in blasts from two cases with rearrangement of the Ig-heavy chain gene; in one of them the T cell receptor beta and gamma chain genes were also found in rearranged configuration. This group comprises cases of biphenotypic and mixed acute leukaemia which probably involve multipotent stem cells. This study demonstrates that the expression of myeloid antigens on blast cells parallels closely the presence of peroxidase activity and that lymphoid markers correlate with gene rearrangements at DNA level. Our findings are reassuring with respect to the specificity of the antimyeloid McAb for the diagnosis of cases which are unclassifiable by conventional methods.

Possible cytogenetic distinction between lymphoid and myeloid blast crisis in chronic granulocytic leukemia

This study consists of 25 patients with chronic granulocytic leukemia in blast crisis (BC) or with acute leukemia who had a Ph1 chromosome and one or more other chromosome abnormalities and who were investigated by cytochemistry and immunocytochemistry techniques to determine whether the predominant blasts were myeloid or lymphoid. The disorder was myeloid in 15 patients, lymphoid in 8, and mixed in 2. Among the 15 patients with myeloid disorders, 13 (86.6%) had an additional Ph1 chromosome, i(17q), +8, +19, or some combination of these abnormalities. None of the eight patients with a lymphoid disorder had +8, +19, or i(17q), but one had an additional Ph1 chromosome. Among the eight patients with lymphoid disorders, two had structural abnormalities of chromosome 7 and two were monosomy 7. None of the patients with myeloid disease had a structurally abnormal chromosome 7, but one was monosomy 7. Our findings suggest that the number of chromosomes in an abnormal clone may be unreliable for distinguishing between lymphoid and myeloid BC. Most patients with myeloid disease had only abnormal metaphases, whereas many patients with lymphoid disorders had both normal and abnormal metaphases. This finding may partially explain why many patients with lymphoid BC respond better to treatment than do those with myeloid BC.

Immunophenotype of blast cells in chronic myeloid leukemia

The immunophenotype of peripheral blood blast cells from 14 patients in the chronic phase of chronic myeloid leukemia (CML) was studied using a panel of monoclonal antibodies (McAb) directed against megakaryocytic, granulomonocytic, erythroid and lymphoid antigenic determinants. The blast cells were enriched by a simple bovine serum albumin (BSA) density-cut separation and cooled in liquid nitrogen. The study was done using the alkaline phosphatase-anti-alkaline phosphatase (APAAP) technique on the thawed blast cells. A consistent pattern of reactivity with McAb was found in all patients, showing that blast cells were heterogeneous. A minor component of the blast cells react with platelet antibodies, most of them being labelled with anti-GPIIb-IIIa McAb. Anti-GPIb and Von Willebrand factor McAb detected 4 times fewer megakaryocytic blast cells, suggesting that these cells are located very early in the differentiation scheme. Two major blast cell compartments were labelled with early myelomonocytic (anti-CD13: MY7) and early erythroid (anti-CD36: FA6-152) McAb. The CD34 (My10) and DR antigens which are expressed by immature blast cells and myeloid progenitors of human bone marrow (BM) were present on more than 50% of the CML blast cells. Thus, the blast cells of chronic phase CML patients, showed the same cellular diversity as the increased progenitor cell compartment observed in this disease, and their differentiation stages seemed to be very closely related.

Chronic myelogenous leukemia in blast crisis. Analysis of 242 patients

Two hundred forty-two patients with Philadelphia chromosome-positive chronic myelogenous leukemia in blast crisis were reviewed to identify significant biologic and prognostic associations. Twenty percent of patients had lymphoid blast crisis. Clonal evolution was present in 60 percent of patients at blast crisis and involved most frequently the development of a double Philadelphia chromosome, trisomy 8, or isochromosome 17. The overall median survival from blast crisis was 18 weeks. Patient characteristics demonstrated to have significant association with short survival were: anemia; thrombocytopenia; myeloid or undifferentiated blast cell morphology; clonal evolution involving the presence of a double Philadelphia chromosome, trisomy 8, or isochromosome 17; and low marrow blast percentage. Of 195 patients who received therapy for blast crisis, complete remission was achieved in 44 (23 percent) patients, and 24 (13 percent) patients had a partial remission or hematologic improvement. Lower complete remission rates were associated with old age, thrombocytopenia, myeloid or undifferentiated blast cell morphology, clonal evolution--especially isochromosome 17 and trisomy 8--and long interval from diagnosis to onset of blast crisis. A multivariate analysis identified two characteristics to have independent prognostic importance for both survival and remission: platelet counts and blast cell morphology. In addition, clonal evolution had additive prognostic value for survival (double Philadelphia chromosome) and for response (isochromosome 17). The beneficial association of therapy with survival was demonstrated by the significantly longer median survival of patients treated since 1981 compared with those treated earlier, even after accounting for the pretreatment prognostic factors, and by the significant improvement in survival of patients achieving remission using the "landmark" analysis technique.

Megakaryoblastic transformation of chronic granulocytic leukemia

Three cases of megakaryoblastic transformation of chronic granulocytic leukemia (CGL) are reported. In each case, the leukemic transformation had morphologic features suggesting megakaryocytic differentiation. This was confirmed by positive immunostaining with a monoclonal antibody (HP1-1D) specific for platelet and megakaryocyte glycoprotein IIb/IIIa antigen, which was expressed by the majority of the leukemic blasts in all three cases. Cases with evidence of multilineage differentiation of the leukemic transformation were excluded. A striking feature in two patients was the manifestation of lytic bone lesions and soft tissue masses at presentation. A biopsy of a lytic bone lesion and soft tissue mass in one patient revealed a megakaryoblastic leukemic infiltrate, which by immunocytochemical staining was positive for the megakaryocytic markers, glycoprotein IIb/IIIa antigen, and Factor VIII (von Willebrand factor) antigen. In contrast to granulocytic sarcomas, the megakaryoblastic sarcoma did not stain cytochemically for chloroacetate esterase. The mean survival after acute transformation was 5.3 months. The three cases of megakaryoblastic transformation represented a significant proportion of all CGL blastic transformation cases (ten cases) evaluated by bone marrow examination in our institution during a 13-month period. Megakaryoblastic transformation of CGL may occur more frequently than has been appreciated, and can present as lytic bone lesions or as soft tissue megakaryoblastic sarcomas.

Phenotypic and genotypic analysis of chronic myelogenous leukaemia with T lymphoblastic and megakaryoblastic mixed crisis

A case of blast crisis in chronic myelogeneous leukaemia (CML) in which two distinct cell lineages were involved is presented. The phenotype of blasts in lymph nodes was T11 (CD2)+, Ia+, TdT+, suggesting T cell lineage. On the other hand, blasts in bone marrow and peripheral blood expressed platelet glycoprotein IIb/IIIa complex on their surface, suggesting megakaryocyte lineage. Cytogenetic analysis of lymph node and bone marrow cells revealed the abnormalities, inv(7) (p15q34) and t(1;3) (q23;q21), respectively, as well as the presence of the Ph1 chromosome in both cell types. Rearrangement of the T cell receptor beta-chain gene was detected in lymph node blasts, although blast cells in peripheral blood showed a germ line configuration. The involvement of T cell and megakaryocyte lineages in the blast crisis phase of CML was confirmed in our phenotypic and genotypic analysis, and the pathogenic association between blast crisis lineages and the additional chromosome abnormalities present is discussed.

Cytochemical profile of megakaryoblastic leukaemia: a study with cytochemical methods, monoclonal antibodies, and ultrastructural cytochemistry

A cytochemical study using: Sudan black B; alpha-naphthyl acetate (ANAE) staining; estimation of alpha-naphthyl butyrate (ANBE) esterase activity; acid phosphatase activity; and 5' nucleotidase activity was carried out in 15 cases of megakaryoblastic leukaemia. These included cases of M7 acute myeloid leukaemia and blast crises of chronic granulocytic leukaemia. The megakaryoblastic nature of the blasts was first established using two monoclonal antibodies against platelet glycoproteins, and by estimating the platelet/peroxidase reaction at ultrastructural level. Our findings suggest that megakaryoblasts have a typical cytochemical profile comprising positive ANAE staining and acid phosphatase activity with a predominant localisation in the Golgi zone and negative or weak ANBE activity. A similar positive cytochemical pattern was also found in five cases of erythroleukaemia (M6). The specificity of the 5'nucleotidase activity for megakaryoblasts was not confirmed. In most cases of megakaryoblastic leukaemia there was no 5'nucleotidase activity only two cases showed positive reactions--reactions were positive in several cases of myeloblastic and lymphoblastic leukaemia. We suggest that cytochemical methods may be useful in diagnosing M6 and M7 acute leukaemia because less than 40% of leukaemic cells react with specific monoclonal antibodies.

'Pseudo-lymphoid' leukaemia with unusual features: ultrastructural, immunological, cytogenetic and molecular studies

An unusual case of 'pseudo-lymphoid' leukaemia is described. The leukaemic cells resembled small, mature lymphocytes but lacked B- and T-cell membrane markers as well as immunoglobulin (Ig) and T-cell receptor gene rearrangements. They showed, instead, features of early myeloid cells since they expressed 2 myeloid antigens, CDW13 and My9, and displayed peroxidase activity demonstrable by electron microscopy (EM) on unfixed cells. Cytogenetic studies showed monosomy 5, t(4;17) (p12;p11), t(2;3)(p23;q14) and an abnormal chromosome 12. Abnormalities of chromosomes 4 and 5 have been previously associated with 'pseudo-lymphoid' leukaemias. This case illustrates the value of sensitive methods for the characterization of blast cells and for the precise diagnosis of leukaemias with apparent 'lymphoid' morphology.

Chronic myeloid leukemia: manifesting as spontaneous splenic rupture and terminating in megakaryoblastic transformation

We report a case of chronic myeloid leukemia with spontaneous splenic rupture as the initial presenting feature; there was a successful surgical outcome, but this case terminated in megakaryoblastic transformation. Results are reported based on morphological, immunological, cytochemical, ultrastructural, immunocytochemical studies, and in vitro liquid culture studies. The megakaryocytic nature of the blast cells was identified through the demonstration of platelet peroxidase activity by ultrastructural cytochemistry and the presence of platelet and megakaryocyte-specific antigen using monoclonal antibody, as well as the anti-factor VIII antibody by immunocytochemical technique.

Detection of cells of megakaryocyte lineage in haematological malignancies by immuno-alkaline phosphatase labelling cell smears with a panel of monoclonal antibodies

Immuno-alkaline phosphatase staining (by the APAAP technique) has been used to identify promegakaryoblasts in cell smears from 10 cases of leukaemia (three acute leukaemia, seven blast transformations). In all cases promegakaryoblasts were labelled by at least two anti-platelet glycoprotein (gp) antibodies, the highest percentages being obtained with anti-gp IIIa (antibody C17). HLA-DR was expressed by a variable percentage of neoplastic cells in all cases, the T11 (CD2) antigen (sheep red cell receptor) in four of seven cases tested and the p150,95 antigen in three of the six cases tested. In some cases of acute myeloid leukaemia APAAP staining of blood smears revealed circulating promegakaryoblasts and micromegakaryocytes (which superficially resemble small lymphoid cells). It is concluded that immuno-alkaline phosphatase staining of cell smears offers a convenient means of diagnosing acute megakaryoblastic leukaemia in the routine laboratory.

Surface marker analysis in acute myeloid leukaemia and correlation with FAB classification

The immunological phenotype of blast cells in 102 patients with acute myeloid leukaemia (AML) was analysed with a panel of 20 monoclonal antibodies and the enzyme terminal transferase, and correlated with the FAB classification. Although a partial correlation between these two approaches could be observed, almost every morphological group contained patients from more than one immunological phenotype. The M1 and M5a leukaemias showed the most undifferentiated phenotype, often lacking in specific myelomonocytic antigens. The M3 formed a uniform group defined as My7+, Ia-, FMC8+, a phenotype which was also observed in two cases of the microgranular variant. The granulocytic (CDw15) and monocytic (CDw14) antibodies crossreacted with some M5b and M2 leukaemias, respectively. Compared with M5a, the M5b leukaemias showed a large increase in the expression of CDw14 antigen, confirming the validity of the morphological differentiation. Glycophorin-A was present in four out of five M6 leukaemias. TdT activity was demonstrated in 10% of AML cases, with a higher incidence among the monocytic variants: M4 and M5-. Eleven AML were considered as unclassifiable according to the FAB criteria and in seven of them a megakaryoblastic cell population (GP IIb/IIIa+, GPIb+) was demonstrated; this confirms the need to include the subgroup of megakaryoblastic leukaemias within the AML. Finally, a possible immunological classification for AML is proposed.

TdT activity in acute myeloid leukemias defined by monoclonal antibodies

Blast cells from eight out of 71 patients diagnosed with acute myeloid leukemia (AML) by morphological, cytochemical, and immunological criteria showed TdT activity. Their distribution according to the FAB classification was one M1, one M2, one M4, two M5a, one M5b, one M6, and one undifferentiated case. The TdT+ AML cases did not show major clinical and hematological differences when compared with the classical TdT- AML patients. Other phenotypical aberrations in the expression of membrane antigens, apart from the presence of nuclear TdT, were not observed in these TdT+ cases after study with a large panel of monoclonal antibodies. A higher incidence of TdT+ cases was found among the monocytic variants of AML (M4 and M5)--four cases--than in the granulocytic variants (M1, M2, and M3)--2 cases. These TdT+ cases should be distinguished from mixed leukemias by double labeling techniques, assessing in the TdT+ AML the coexpression of TdT and myeloid markers in individual cells as shown in four of our cases.

The nature of blast cells in myelodysplastic syndromes evolving to acute leukaemia

The blast cells from nine patients with an overt acute leukaemia following a previous myelodysplastic syndrome (MDS) are analyzed with a panel of monoclonal antibodies as well as by morphological and cytochemical criteria. By integrating the results obtained with these three approaches the leukaemia in 6 patients was assessed as myeloid-granulocytic and/or monocytic-, in two as mixed- megakaryoblastic/myeloid- and in one as lymphoid. A good correlation between morphology, cytochemistry and immunological markers was observed in 7 out of the 9 cases. In three cases a noteworthy percentage of J5+ cells was detected. The exceptional finding of lymphoid as well as megakaryocytic and myeloid transformations suggests that the target cell for these leukaemias could be a pluripotent stem cell.

Correlation between chromosomal abnormalities and blast phenotype in the blast crisis of Ph-positive CGL

We carried out cytogenetic analysis in 23 patients with Ph-positive chronic granulocytic leukemia in blast crisis. In all cases the type of blast cell was characterized by cytochemistry, immunologic markers, and ultrastructural studies. Twelve cases were classified as myeloid transformation, six as lymphoid, two as mixed (lymphoid and myeloid), and two were unclassifiable. Duplication of Ph was the most frequent abnormality in the whole series. Trisomy 8, i(17q) and trisomy 19 were seen only in patients with myeloid blast crisis (53%, 30%, and 23%, respectively). Our findings suggest that the nature of additional chromosome abnormalities arising in blasts with features of myeloid differentiation are different from those in blasts showing lymphoid differentiation.

Characterization of myeloid leukemias with monoclonal antibodies 3C5 and MY9

The expression of two membrane antigens identified by the monoclonal antibodies (McAb) My9 and 3C5 has been investigated in cells from 80 acute leukemias. My9 was positive in the blasts of 33 out of the 38 (87 per cent) cases of acute myeloid leukemia (AML) tested, regardless of FAB subtype, and in 13 of 18 (72 per cent) cases of chronic granulocytic leukemia (CGL) in myeloid blast crisis. The reactivity of 3C5 was confined to myeloblastic (M1) AML, 85 per cent of cases, and to lymphoblastic leukemia (ALL) of B-lineage, 70 per cent of cases, including CGL in lymphoid transformation. My9 was negative in ALL except for an unusual case. The phenotype My9+, 3C5+ was seen exclusively in M1 (69 per cent) and M2 (14 per cent) AML. Ultrastructural analysis with the immunogold method in combination with the myeloperoxidase (MPO) reaction showed that expression of My9 increased in parallel with MPO activity whereas 3C5 was expressed mainly in myeloblasts with little MPO content. We conclude that the use of these two McAb will contribute to the diagnosis and classification of AML and may throw some light to the pathogenesis of biphenotypic acute leukemias, including TdT + AML.