Engraftment of chronic myeloid leukemia in SCID mice.

Chronic myeloid leukemia (CML) is a clonal disorder of primitive hematopoietic stem cells characterized by a reciprocal translocation between chromosomes 9 and 22. Animal models of CML would be useful to study the biology and potential therapies in this disease. Mice with severe combined immunodeficiency (SCID) which will accept human xenografts have been useful in the study of a variety of human malignancies. CML has been difficult to establish in SCID mice possibly due to the lack of a functioning human stroma and relevant cytokines. To facilitate engraftment we injected cells in matrigel which is a soluble extract of basement membranes; is liquid below 22 degrees C and gels at 37 degrees C. CD34+ myeloid blast crisis cells (2 x 10(6)) were mixed in matrigel and injected subcutaneously into 10 SCID mice. All mice developed large tumours which spread to the mouse BM and spleen. However the percentage of human cells in the mouse BM and spleen was variable and ranged from 1 to 50 per cent. In contrast chronic phase (CP) CML cells mixed in matrigel did not form subcutaneous tumours and spread to the BM and spleen was detectable by PCR and not macroscopically. Groups of mice were injected with matrigel containing 1-20 x 10(7) MNC (2-20 x 10(5) CD34+ cells) from five patients with CP CMP. Bcr-abl sequences were detected by RT-PCR in the peripheral blood (PB) of 38/84 (45 per cent) mice at 3-10 weeks following injection of the CML cells but rarely at later time points. In addition, 33/75 (44 per cent) of mice sacrificed between 7 and 35 weeks following injection of CML cells were bcr/abl positive in the bone marrow and 17/70 (24 per cent) were positive in the spleen. Bcr-abl positive human CFU-GM colonies were also cultured from the murine bone marrow of several mice indicating that hematopoietic progenitor cells were able to migrate from the matrigel and engraft in murine hematopoietic organs. Engraftment of CP-CML was more successful in mice given higher numbers of CD34+ cells. Histological examination revealed that myeloid cells grow locally in the matrigel for several weeks, during which time the matrigel is infiltrated by blood vessels which may allow for the migration of CML progenitors to the murine bone marrow. This model system may be useful for studying the role of immunotherapy after allogeneic and autologous bone marrow transplantation.

Multiple cycles of high dose chemotherapy supported by hematopoietic progenitor cells as treatment for patients with advanced malignancies.

BACKGROUND: Retrospective studies suggest that dose intensity is an important determinant of outcome in the treatment of patients with a variety of malignant diseases such as breast cancer, ovarian cancer, and lymphoma. Unfortunately, these results have not been clearly substantiated in prospective randomized trials. One problem with these studies may be that the degree of dose escalation is not sufficient to result in an improved outcome because the chemotherapy doses are limited by hematopoietic toxicity. In an attempt to deliver more dose-intensive therapy, the feasibility of the administration of multiple cycles of high dose chemotherapy with hematopoietic progenitor cell and growth factor support was investigated in patients with advanced malignancies. METHODS: Nineteen patients with metastatic breast cancer and six patients with refractory non-Hodgkin's lymphoma were initially treated with etoposide (VP-16) (2 gm/m2) and granulocyte-colony stimulating factor (G-CSF). Peripheral blood hematopoietic progenitor cells were collected by leukapheresis and cryopreserved as the patients' leukocyte counts recovered from the nadir induced by VP-16. Patients were then treated with four cycles of mitoxantrone (18 mg/m2), thiotepa (150-200 mg/m2) and cyclophosphamide (4500-5000 mg/m2) as a 48-72 hour continuous infusion followed by infusion of one-quarter of their progenitor cells 48 hours later. All patients also received G-CSF (5 micrograms/kg/day) until engraftment. RESULTS: A total of 88 of a planned 100 cycles of therapy were administered to these 25 patients. The median time to recovery of an absolute neutrophil count of 500/microliters or greater was 13-14 days (range, 7-18 days) and time to recovery of a platelet count of 20,000/microliters or greater was 13-14 days (range, 7-16 days) after the initiation of each cycle of chemotherapy. The median number of platelet transfusions required after each cycle was 2-3 (range, 0-18 transfusions) and the number of erythrocyte transfusions was 4 (range, 0-10). The most common toxicity was diarrhea. Prophylactic intravenous antibiotics were administered to avoid fever with neutropenia. Two patients developed interstitial pneumonitis and one patient died. One heavily pretreated patient failed to engraft after the first cycle. Reversible veno-occlusive disease of the liver developed in one patient after the fourth cycle of therapy. Four patients progressed while on therapy. Eight patients were disease free and 13 patients had a partial response or had a positive bone scan as the only evidence of disease at the completion of therapy. Seven patients, two with lymphoma and five with breast cancer (28%), remain progression free with a median follow-up of 24.7 months (range, 17-28 months). CONCLUSIONS: Support with hematopoietic progenitor cells and growth factors allows the timely administration of repetitive cycles of high dose chemotherapy, resulting in a significant increase in dose intensity with acceptable toxicity.

Prognostic importance of Sudan Black positivity: a study of bone marrow slides from 1,386 patients with de novo acute myeloid leukaemia.

Analysis of bone marrow slides from 1,386 patients entered into the Medical Research Council's 8th and 9th trials in Acute Myeloid Leukaemia confirmed that features associated with differentiation in blast cells, in particular increasing Sudan Black (SB) positivity, were the most important morphological features for predicting remission achievement (P = 0.002) and hence survival (P less than 0.0001). SB positivity was also weakly predictive of remission duration (P = 0.05). A low complement of maturing granulocytes was associated with early induction death and a high percentage of blasts with shorter remissions. The few patients with acute promyelocytic leukaemia (FAB M3) had a high haemorrhagic death rate during induction and a low relapse rate. Apart from this, lineage involvement was not predictive of outcome. Multiple lineage leukaemias, in particular those with megakaryocytic and/or erythroid involvement, which had been reported previously to have a poor prognosis, did not have any worse remission rates in this series. When more than one cell line was involved, no combination with particularly good or poor prognosis could be identified. Multivariate analysis suggested that percentage SB positivity was adequate on its own to divide granulocytic leukaemias into poorly differentiated (less than 50% SB +ve) and well-differentiated groups (50% or more SB +ve) without the need for further measurements. This simple and reproducible test was strongly predictive of resistant disease but not of induction deaths. It was of considerably greater prognostic value--and was less open to inter-observer disagreement--than the FAB criteria which are usually used to classify granulocytic lineage leukaemias into the M1 and M2 subgroups. It is proposed that greater than or equal to 50% of blasts with SB positivity should replace blasts greater than 10% of maturing myeloid cells for this sub-categorization between M1 and M2.

T-Cell Receptor and Immunoglobulin Gene Rearrangements in Acute Myeloid and Undifferentiated Leukemias of Adults: Correlation with Weak Surface Expression of CD45 and CDw52 Antigens.

We examined 150 cases of acute myeloid leukemia (AML) and 8 cases of acute undifferentiated leukemi (AUL) of adults for both phenotypic and genotypic evidence of commitment to the lymphoid lineages. There was no correlation between expression of lymphoid differentiation antigens and rearrangement of T-cell receptor (TCR) and immunoglobulin (Ig) DNA sequences. In particular 8 cases of CD7(+) AML were germline for all TCR α, ß,µ, and δ Also none of the 11 cases with IgJH rearrangement expressed CD19 either on the cell surface or within the cytoplasm. Ten out of 13 cases with TCR/Ig gene rearrangement were either cytologically undifferentiated AML of FAB type M1 or AUL. None had clear immunophenotypic evidence for commitment to lymphoid lineages but 9 expressed only very small amounts of CD45 'framework' antigens and 7 expressed small amounts of CDw52 (CAMPATH-1). This phenotypic combination is otherwise seen only in precursor B cell ALL. TCR/Ig gene rearrangement in AML and AUL of adults appears to have become dissociated from the rest of the lymphoid differentiation 'program'. Recognition of these cases may be facilitated by the weak expression of both CD45 and CDw52 antigens.

Basophils in acute myeloid leukaemia.

Thirty four out of 750 patients entered into the Medical Research Council's (MRC) 9th Acute Myeloid Leukaemia Trial had more than 1% basophils (range 1-27%) often with bizarre granulation and primitive forms, a rare finding in this disease. Both normal and abnormal karyotypes were present including abnormalities of 6p, 12p, and the Philadelphia chromosome. Basophilia was found in both "monolineage" and "multilineage" leukaemias and the commonest French-American-British (FAB) classification group was M2, followed by M4. Basophilia did not seem to be associated with a worse prognosis, although cases with abnormalities of 6p died of disease that was resistant to first line conventional chemotherapy.

AML associated with previous cytotoxic therapy, MDS or myeloproliferative disorders: results from the MRC's 9th AML trial.

The outcome of treatment with standard first line therapy of 66 patients with acute myeloid leukaemia (AML) secondary to preceding chemotherapy (Group 1), a myelodysplastic state (Group 2) or a myeloproliferative disorder (Group 3) was analysed in relation to the preceding disorder, the cytogenetic pattern where available, and the cytology and cytochemistry of blood and bone marrow. The complete remission (CR) rate for the secondary AMLs was 36% (24/66), with 24% (16/66) dying in the induction period and 39% (26/66) having resistant disease. The CR rate was 25% (5/20) for Group 1, 42% (15/36) for Group 2, and 40% (4/10) for Group 3. Even after allowance for the generally older age of the secondary AML patients, they still had a significantly poorer CR rate than the de novo AMLs (P = 0.0004). The lower CR rate was chiefly due to resistant disease. Despite this, overall survival was not significantly worse for the secondary AML patients (P = 0.15). For the 36% that achieved remission, remission duration appeared similar to that of de novo cases. Of 62 cases with adequate cytology, 38 (61%) had evidence of erythroid and/or megakaryocytic dysplasia with a CR rate of 32% (12/38). The CR rate of these multineage leukaemias was not significantly different from that of the 24 (39%) who showed granulocyte/monocyte precursor involvement only, 42% (10) of whom achieved CR. The presence of features of differentiation within blast cells such as Auer rods or sudanophilia (greater than 50% positive blasts) was associated with a higher remission rate 47% (18/38) than that of poorly differentiated cases 17% (3/18) (P = 0.04) and thus appeared to be a more important determinant of CR achievement than was lineage involvement. Cases with a normal karyotype had a 33% (7/21) CR rate, while those with chromosomal abnormalities had a 37% (9/24) CR rate. Only 12 of the 45 cases with adequate cytogenetic analysis showed deletions or monosomies involving chromosomes 5 or 7, and seven of these were in Group 1.

Two further cases of acute myeloid leukemia with trisomy 4.

Two cases of acute myeloid leukemia (FAB M1 and M2) with trisomy 4 are described. Morphologic abnormalities were confined to the granulocytic monocytic lineage with no evidence of erythroid or megakaryocytic involvement. One of the cases, who also had trisomy 13, presented initially with skin infiltration without bone marrow involvement.

Beneficial effect of heparin in the management of patients with APL.

115 patients with acute promyelocytic leukaemia (APL) were studied retrospectively to evaluate prognostic factors and assess therapeutic approaches, particularly the use of heparin in the management of disseminated intravascular coagulation (DIC). The remission rate was 86% (30/35 patients) in those who received heparin and 49% (39/80 patients) in those who received no heparin (P = 0.0002). This difference in remission rates was accounted for by a marked decrease in the number of haemorrhagic deaths, especially those due to intracranial haemorrhage (ICH), in the heparin treated group. Other factors associated with a poor remission rate were prothrombin ratio (PTR) greater than 1.3 (P = 0.008), fibrinogen less than 1.5 g/l (P = 0.02) and WCC greater than 2.0 x 10(9)/l (P = 0.03).

Translocation (3;6)(q21;p21) in acute myeloid leukemia with abnormal thrombopoiesis and basophilia.

A case of acute myeloid leukemia (AML) with increased numbers of basophils and abnormal megakaryocytes was shown to have a t(3;6)(q21;p21) in the bone marrow cells. The morphology is described in detail and the case is discussed with reference to t(6;9)(p23;q34) and inv/ins(3)(q21q26) in AML. It is possible that increased numbers of basophils in AML may be associated with a translocation involving 6p21-6p23.