The detection of post-therapy residual minimal disease in leukemias characterized by specific chromosomal anomalies.

Chromosomal and Southern Blot analyses have been used to diagnose Leukemias characterized by non-random chromosomal rearrangements. They have also been used to monitor disease progression during and after chemotherapy. These methodologies are often not adequate to detect RMD after ablative therapy and Bone Marrow Transplantation (BMT). Molecular quantitative Polymerase Chain Reaction (PCR) techniques have been developed to detect low levels of leukemic cells in patients with diseases characterised by fusion transcripts. 95% of Chronic Myelocytic (CML) and 15-25% of Acute Lymphoblastic Leukemia (ALL) patients are Ph1 producing a fusion transcript between the abl proto-oncogene and the bcr gene. Acute Promyelocytic Leukemia (APL) with break points in the (RAR) gene and the zyl gene also produces a fusion transcript. The significance of PCR for 1) detecting RMD after therapy, 2) correlating low levels of leukemic cells over time with therapeutic response and long term remission and 3) assessing the effect of RMD during remission by sequential analyses is discussed.

Cytogenetics and cell surface marker analysis in chronic myelocytic leukemia. II. Implications for patient management.

Chronic myelocytic leukemia (CML) is a model system for the study of many aspects of malignant disease. One aspect that correlates with decreasing therapeutic response is tumor progression. This progression is often accompanied by clonal evolution. In those cases where aggressive therapy does not prevent this evolution, the clinical response to therapy usually proves to be poor and of short duration. Investigators are concentrating their efforts in three primary, but not mutually exclusive, areas with respect to the clinical management of CML. These include: an attempt to distinguish patients at risk for early transformation from those who will have a prolonged chronic phase; the cryopreservation of autologous bone marrow or buffy coat early in chronic phase for subsequent use in the accelerated phase and; endeavors to identify early markers for disease progression allowing intervention before an irreversible blast crisis occurs. This report deals with two types of potential prognostic markers of transformation: chromosomal and cell surface characteristics. The appearance of nonrandom abnormal chromosomal patterns has been correlated with myeloblastic transformation by many investigators. However, there has always been a subset of CML patients who do not undergo clonal evolution. Additionally, the type(s) of transformation in CML may vary depending on the cell lineages involved. Unlike myeloblastic transformants, many of our patients who do not exhibit clonal evolution as a concomitance of disease progression develop a lymphoblastic transformation. Cytofluorometric analysis can distinguish small populations of abnormal cells with lymphoblastic characteristics (HLA DR+). Initial data suggests that patients expressing the HLA DR+ in their "normal" peripheral blood cells are at risk of undergoing lymphoblastic transformation. The combined use of clinical, cytogenetic, and cytofluorometric data to predict an impending transformation and to discriminate between myeloblastic and lymphoblastic populations allows clinicians to manage their patients more effectively.

Cytogenetics and flow cytometry may predict phenotype of CML blast crisis.

Twenty-eight patients with chronic myelocytic leukemia (CML) and the Philadelphia chromosome (Ph1) were monitored using cytofluorometry and cytogenetics. During chronic phase, abnormal populations could be detected using commercially available monoclonal antibodies. These abnormal populations fell into two categories based on the presence or absence of HLA.DR. Patients with HLA.DR+ abnormal cells showed no clonal evolution and progressed to lymphoid blast crisis. Patients with HLA.DR- abnormal cells exhibited chromosomal abnormalities in addition to the Ph1 and progressed to a myeloblastic acute phase.

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.

Correlation of a specific chromosomal marker, 21q-, and retroviral indicators in patients with thrombocythemia.

A chromosomal anomaly, 21q-, has been found in association with retroviral indicators in patients with myeloproliferative disorders (MPD) including polycythemia vera (PV), essential thrombocythemia (ET), chronic myelocytic leukemia (CML) and acute non-lymphocytic leukemia (ANLL). The viral indicators are found in platelet homogenates of thrombocythemic patients. Evidence is presented from 2 laboratories (Philadelphia, USA and Bologna, Italy) for the 21q- deletion in MPD patients. Thirty patients evaluated for the presence of both viral and chromosomal markers in Philadelphia showed positive correlations.

Chronic myeloid leukemia: predictive value of sequential chromosomal surveys and their effect on survival.

A program has been initiated to evaluate the efficacy of intensive therapy based on sequential cytogenetic studies in patients diagnosed as having Ph1 positive chronic myelocytic leukemia (CML). Eighteen patients have been induced into hematological remission with busulfan, splenectomized and treated with cycle active drugs. Maintenance therapy is continued during the benign chronic phase of the disease. Intervention with cycles of aggressive therapy is predicated on the results of chromosomal surveys of bone marrow aspirates. The results of this limited study suggest that survival can be improved by such a program.

Effect of busulfan on oncornavirus-like activity in platelets and chromosomes in polycythemia vera and essential thrombocythemia.

The effect of busulfan therapy on the activity of oncornavirus-like particles and chromosome patterns in patients with polycythemia vera and essential thrombocythemia was studied. Three patients had pretreatment platelet counts greater than 1 million/microliter, abnormal bone marrow karyotypes, and electron microscopic and biochemical evidence of oncornavirus. The results demonstrated that in all 3 patients virus-like particles and reverse transcriptase-like activity could no longer be found in the platelets within 2-4 weeks after the initiation of busulfan treatment. The platelet count was still elevated at this point for each patient, although the count returned to normal levels within 2-3 weeks after virus-like activity was no longer detectable. The chromosome patterns, characterized by aneuploidy (30-50%) before treatment, improved after therapy.

Analysis of platelets from patients with thrombocythemia for reverse transcriptase and virus-like particles.

A preliminary analysis of an RNA-directed DNA polymerase was made and a C-type virus-like particle was identified in platelets from 2 patients with the myeloproliferative disorder thrombocythemia (primary, essential, hemorrhagic, or idiopathic thrombocythemia). Platelet homogenates were centrifuged through a sucrose equilibrium density gradient. Both endogenous and exogenous DNA polymerase activity was found at a density of 1.19 g/ml. No activity was seen at comparable densities in control gradients. Electron micrographs of thin sections of these platelets revealed a particle with the morphologic characteristics of a C-type virus; however, the diameter of this particle was about 80 nm, slightly lower than that commonly found for C-type particles. Critical-point dried specimens, from the fractions of the sucrose gradient at which DNA polymerase activity was found, contained particles of the same size and morphology as those in the thin sections.

Effect of anti-B antiserum on the phagocytosis of Escherichia coli.

An increase in phagocytosis of Escherichia coli O86, an organism containing blood group B substance, was seen in the presence of anti-B antibodies.

Genetic analysis of lysine auxotrophs of Staphylococcus aureus.

The genetics of lysine biosynthesis in Staphylococcus aureus was examined by a transductional analysis of lysine auxotrophs. These mutants had previously been grouped according to their biochemical characteristics. The mutant sites appeared to be closely linked. Complementation was observed between different groups but not between mutant strains belonging to the same group. A strain was detected which seemed to have a mutant control region. Evidence is presented to support the hypothesis that the lysine biosynthetic region functions as an operon.