E rosette-positive agar colonies containing the Philadelphia chromosome in chronic myeloid leukaemia

Simultaneous demonstration of the Philadelphia chromosome in T, B, and myeloid cells

A patient presented with lymphoblastic lymphoma in lymph-nodes and chronic myelogenous leukemia (CML) in narrow and peripheral blood. All marrow and unstimulated peripheral blood cells contained the Philadelphia chromosome[t(9:22)]. Lymphoma cells were analyzed by flow cytometry and were identified as T cells (CD2+CD5+CD7+CD34+). All fresh lymphoma cells contained the t(9:22) translocation. Cultures of purified peripheral blood T and B cells and specifically stimulated NK cells revealed that 59% of the B cells, 10% of the NK cells, and none of the normal T cells contained the translocation. The lack of translocation in normal peripheral T cells is attributed to their long lifespan. No rearrangement of immunoglobulin or T cell receptor beta or gamma genes was found in either the leukemia or lymphoma cells. Analysis of the DNA from cryopreserved lymphoma biopsy showed clonal rearrangement within the common breakpoint cluster region of the bcr gene identical to the bcr rearrangement in DNA from leukemia blood cells. The data support the concept that T and B cells originate in the patient's totipotent stem cell from which the CML is also derived.

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.

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.