Dual rearrangement of immunoglobulin and T-cell receptor genes in blast crisis of CML

Dual rearrangement of immunoglobulin and T-cell antigen receptor (beta, delta) genes was demonstrated in a case of Philadelphia chromosome-positive chronic myeloid leukemia (CML) in blast crisis. The blast cells, showing L2 morphology and high activity of TdT, expressed pre-B cell (CD19+, Ia+) and myeloid (CD13+, CD34+) surface antigens but lacket T-cell antigens (CD2-, CD7-). Cytogenetic studies on bone marrow and peripheral blood revealed the Phl chromosome in all metaphases analyzed, majority of which also had the additional chromosome changes, +8, +10, +21. Furthermore, molecular analysis of the breakpoint cluster region (bcr) on chromosome 22 showed a rearrangement, confirming the CML origin of the blast cells.     

Evidence for a multipotential stem cell disease in some childhood Philadelphia chromosome-positive acute lymphoblastic leukemia

Children with Philadelphia chromosome (Ph+) acute lymphoblastic leukemia (ALL) have a poorer prognosis than do most pediatric patients with ALL. Because of this poor prognosis and the presence of the Ph chromosome, we have asked whether or not Ph + ALL involves a multipotential stem cell. We cultured hematopoietic progenitors from two children with Ph+ ALL and examined individual BFU-E and CFU-GM colonies for the Ph chromosome. We studied cells from two patients after 18 to 34 months of first complete clinical remission; direct cytogenetic analyses showed 26% and 13% Ph+ metaphases in these patients' marrow cells. BFU-E colonies were obtained from light density marrow cells cultured in methylcellulose supplemented with erythropoietin and CFU-GM colonies from agar or methylcellulose cultures stimulated with leukocyte feeder layers. Fifty-seven G-banded metaphases were recovered from 33 colonies. Ten metaphases from seven colonies were Ph+. Ph+ metaphases were found in three of 12 and three of five BFU-E colonies from the two patients. One of 16 CFU-GM colonies from one patient had the Ph+ chromosome; analyzable metaphases were not obtained from CFU-GM of the other patient. No colonies contained both Ph+ and Ph- cells. These results indicate that Ph+ ALL with persistence of Ph+ cells in remission involves a multipotential stem cell for erythroid and granulocyte/macrophage as well as lymphoid lineages. Multipotential stem cell involvement in the pathogenesis of some childhood Ph+ ALL suggests similarities to Ph+ chronic myelocytic leukemia and may contribute to the poor prognosis of these patients.     

In vivo leukemic transformation: cytogenetic evidence of in vivo leukemic transformation of engrafted marrow cells.

A 4-year-old girl with acute myeloblastic leukemia was treated with 50 mg/kg cyclophosphamide daily for 4 days before being given 1.7 X 10(8) bone marrow cells/kg from her HL-A identical, MLC nonreactive, cytogenetically normal brother. The patient died 92 weeks after the marrow graft. Postmortem examination showed increased myeloblasts and promyelocytes. Cytogenetic studies before transplantation showed that all sex determination metaphases had an XX pattern, and 41% of the hyperdiploid metaphases had an additional 19-20(F) chromosome. At autopsy all hyperdiploid metaphases with XY pattern and 43% of the hyperdiploid metaphases with an XX pattern had an additional F chromosome. Occasional metaphases with 47, XX, + F or 47, XY, + F were seen during the follow-up studies. These findings indicated that an acute leukemia had developed in the XY cell line of this artifically induced sex chimeric child. This suggests that a leukemic stimulus other than that proposed to be induced by total-body irradiation existed in this patient and transformed the engrafted cells.     

Establishment and characterization of a novel CD34-positive human myeloid leukemia cell line: MHH225 growing in serum-free culture

A new human multilineage myeloid leukemia cell line, MHH225, has been established in our laboratory from the bone marrow of a 60-year-old patient suffering from acute megakaryoblastic leukemia (M7); it provides a unique model for studying the effect of biologic and chemical agents on the lineage specificity of a multipotent myeloid leukemia clone containing a mixed population of megakaryoblast, erythroblast, and myeloblast cells in a serum-free culture. Morphologically, all 225 cells are large blast cells with basophilic cytoplasm containing no granules, large round nucleus containing 2–3 prominent nucleoli, and fine chromatin structure and a large nuclear/cytoplasm ratio. The MHH225 cells are CD34⁺HLA-DR⁺CD33⁺CD13⁺ with 57.6%, 28.3%, and 7.8% of them being CD41⁺, glycophorin A⁺, and CD15⁺, respectively, and all lymphoid-specific antigens are negative. The karyotype analysis of MHH225 cells revealed a deletion of the short arm of chromosome 7: del(7)(p13)-, a whole-arm translocation between the long arms of chromosomes 9 and 21: t(9;21)(q10;q10), and a chromosome 11 with an elongated long arm due to duplication of chromosome 11 material as well as to translocation of part of chromosome 9 onto 11q+. Also, chromosome 21 was deleted in some metaphases or showed a ring formation in other metaphases. Utrastructurally, MHH25 cells display a strong platelet peroxidase activity in the nuclear envelope and the endoplasmic reticulum. The MHH25 cells have been grown exponentially without growth factors or conditioned media or serum only in RPMI1640 culture medium. None of the myelopoietic growth factors, i.e., interleukin-3, GM-CSF, G-CSF, erythropoietin, or interleukin-6, has any effect on the proliferation and differentiation of MHH25 cells. The two, hematopoietic inhibitory cytokines, interferon-alpha and tumor necrosis factor-alpha, have only minimal growth inhibitory effect. Stem cell factor showed only weak growth-stimulatory effect on MHH225 cells but significantly inhibited chemotherapy-induced apoptosis in these cells. The new cell line MHH225 should constitute a useful model for studying stem cell antigen (CD34)-positive human multilineage myeloid leukemia cells carrying a deletion in the short arm of chromosome 7 and an aberration in chromosome 11 and provide a unique tool for investigating human hematopoietic stem cell biology and its cytokine regulation in serum-free cultures. To our knowledge, the MHH225 cell line is the first human CD34-positive leukemia cell line growing in serum-free cultures to be established.     

Ph1-positive acute lymphocytic leukemia with chromosome 7 abnormalities.

A 56-yr-old woman with acute lymphocytic leukemia showed the presence of a Philadelphia chromosome in 90% of the bone marrow metaphases and in 10% of the peripheral blood metaphases. Part of the long arm of a G22 chromsome was translocated to the long arm of a C9 chromosome. A second cytogenetic abnormality was found in chromosome 7. Monosomy 7 was found in 60% of the marrow and in 20% of the peripheral blood metaphases. Chromosome 7q- was also found in a small percentage of the metaphases examined. Three months later, when the patient was in partial remission, only 10% of the marrow cells showed chromosome 7 monosomy and a Ph1 chromosome. During complete remission, no chromosomal abnormalities were found, except for a high breakage rate. The finding of a Ph1 chromosome in acute lymphocytic leukemia indicates that different precursors, both granulocytic and lymphocytic, may be involved in the Ph1 process.     

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.     

A case of T cell prolymphocytic leukemia involving blast transformation

We report a case of T cell prolymphocytic leukemia (T-PLL) involving blast transformation. At the initial diagnosis, most peripheral blood cells demonstrated proliferation of indolent T cell small cell variants, i.e., small to medium prolymphocytes with inconspicuous nucleoli and a normal karyotype. These cells were positive for surface CD4, CD5, and CD7, and cytoplasmic CD3, but negative for surface CD3 and CD8 and cytoplasmic terminal deoxynucleotidyl transferase (TdT). The T cell receptor (TCR) Cβ1 gene was rearranged in the cells. Large prolymphocytes with prominent nucleoli, irregular nuclei, and cytoplasmic vacuoles that exhibited chromosome 8 trisomy were observed about 1.5 years later. The CD4+CD8− single positive effector memory T cells transformed into surface CD4+CD8+ double positive precursor T cells. The clonal TCR gene rearrangement patterns of these cells were identical throughout the clinical course, suggesting clonal blast transformation. The CD4+CD8+ cells demonstrated increased chromosome 8 trisomy combined with complex chromosome abnormalities with t(14;14)(q11.2;q32) containing a 14q32 chromosome after transformation. T cell leukemia 1a (TCL1a) (14q32.1) may be implicated in this case. The TCL1a oncoprotein is expressed in approximately 70% of T-PLL cases. The disease gradually developed resistance to chemotherapy, and the patient died of the disease. It is known that indolent T-PLL can become aggressive. Therefore, similar transformations may occur in other aggressive T-PLL cases, particularly those involving trisomy 8 and TCL1a.     

The Philadelphia chromosome in human macrophages.

Three patients with chronic myelocytic leukemia in different phases of the natural history of the disease were studied. Their bone marrow cells were cultured under conditions favoring macrophage proliferation, and parallel cytogenetic and cytochemical studies were performed. All cell metaphases examined contained the Ph1 chromosome at a time when more than 80% of these metaphases were in identifiable macrophages. We conclude that the mononuclear phagocyte cell line contains the abnormal chromosome in Ph1-positive chronic myelocytic leukemia.     

Comparison of Chromosome Constitution in Chronic Myelocytic Leukemia and Other Myeloproliferative Disorders

The frequency of the Ph¹ chromosome in freshly aspirated marrow cells of14 patients with typical chronic myelocytic leukemia processed by a "directtechnic" without resort to culture or colchicine was significantly higher (>75 per cent) than that observed in the cultured blood cells (< 35 per cent)of the same subjects. The karyotypic abnormally of the abbreviated G-groupchromosome would appear not to be related to therapy, since the frequencywith which it occurred was not materially affected by treatment (including radiation). The Ph¹ chromosome was not observed in any of the metaphases ofblood or marrow of 12 subjects who had developed a leukemia-like picturecomplicating either myelofibrosis, polycythemia vera or myeloid metaplasia. Anew chromosome abnormality—a shortened D-group chromosome—was observed with about the same frequency in the blood and marrow metaphases ofa female patient with treated chronic myelocytic leukemia. This new karyotypicabnormality was associated with the highest frequency of the Ph¹ chromosomein cultured blood cells in the group studied. The Ph¹ chromosome was observed in the metaphases of a patient with the blastic phase of chronic myelocytic leukemia. The variations of the morphology of the Ph¹ chromosome arediscussed and illustrated, especially in relation to the Y-chromosome. In fourpatients with an atypical picture of CML, the Ph¹ chromosome was not observed either in the marrow or cultured blood.

Submitted on April 25, 1962 Accepted on June 7, 1962     

A novel leukemia cell line, MR-87, with positive Philadelphia chromosome and negative breakpoint cluster region rearrangement coexpressing myeloid and early B-cell markers

We developed a Philadelphia chromosome (Ph) positive cell line, designated MR-87, from a 4-year-old boy with Ph+-acute leukemia. MR-87 cells grew in single cell suspensions with a doubling time of 120 to 144 hours. Both MR-87 and original leukemia cells were positive for myeloperoxidase (MPO) and myeloid antigen CD13. These cells exhibited the early B-cell phenotype, ie, terminal deoxynucleotidyl transferase+, Ia+, CD19+, and CD10+. Rearrangement of the immunoglobulin heavy chain was confirmed in both. Approximately 80% of MR-87 cells coexpressed CD13 and lymphoid antigens CD10 or CD19, as confirmed by a two-color analysis. Simultaneous expression of MPO and CD19 on a single MR-87 cell was demonstrated at ultrastructural level. Thus, MR-87 is a Ph+ leukemia cell line exhibiting a hybrid phenotype. The breakpoint cluster region (bcr) was not rearranged in the MR-87 cells and subsequent analysis using antisera revealed that these cells expressed a novel protein, P190c-abl, which was immunoprecipitated with anti-abl and anti-phosphotyrosine antibodies. The MR-87 line will be most useful for investigating the biology and pathogenesis of Ph+ bcr- acute leukemia.     

Recurrence of acute lymphoblastic leukemia in donor cells after allogeneic marrow transplantation associated with a deletion of the long arm of chromosome 6

This report concerns a woman who experienced a relapse of acute lymphoblastic leukemia (ALL) associated with an interstitial deletion of the long arm of chromosome 6 in donor cells more than 4 years after allogeneic bone marrow transplantation (BMT). Direct bone marrow preparations revealed the presence of two leukemic clones 46,XY,del(6)(q23q25) and 45,X,-4,del(6)(q23q25),+8,-15,-21,+i(21q), +mar, the former clearly indicating that male donor cells were involved in the malignant process. Relapse as evidenced by these chromosome anomalies was confined to metaphases from directly prepared marrow cells and phytohemagglutinin (PHA)-stimulated peripheral blood cells. Cytogenetic analyses of T cell colonies gave predominantly normal donor karyotypes (65 of 69 mitoses) along with three host mitoses and a single donor metaphase carrying the 6q- anomaly. The marrow stroma, as represented by first-passage adherent layer cells from long-term marrow cultures, showed 17 of 19 host metaphases. One of two donor cells found within the stromal elements exhibited a 6q- chromosome. In the subsequent remission mitoses derived from myeloid and lymphoid cells were exclusively of donor origin, and chromosomal abnormalities could no longer be detected. Stromal elements remained host-derived (14 of 16 mitoses).     

Numerical chromosome aberrations are present within the CD30+ Hodgkin and Reed-Sternberg cells in 100% of analyzed cases of Hodgkin's disease [see comments]

In Hodgkin's disease, cytogenetically aberrant clones have been demonstrated in a minority of cases studied. In the remaining cases, only normal metaphases have been found, but it is questionable whether normal karyotypes actually correspond to the pathognomonic Hodgkin and Reed-Sternberg (HRS) cells. Numerical aberrations could be studied by fluorescence in situ hybridization (FISH). However, in Hodgkin's disease, the percentage of tumor cells is mostly below the detection limit of FISH, which is near 1%. With the technique of simultaneous fluorescence immunophenotyping and interphase cytogenetic analysis (FICTION), this problem can be overcome. By FICTION, hybridization signals can selectively be evaluated within the CD30a+ cell population. We have studied 30 cytogenetically analyzed cases of Hodgkin's disease by means of FICTION. In all cases, we found numerical chromosome aberrations within the majority of CD30+ HRS cells. In cases with complex and hyperdiploid karyotypes, the cytogenetic results agreed with the FICTION data. There was considerable variability in the chromosome numbers, demonstrating that karyotype instability is an in vivo phenomenon of HRS cells. Lymphocytes never displayed numerical chromosome changes. Our results indicate that HRS cells regularly exhibit numerical chromosome aberrations and that the chromosome numbers are always in the hyperploid range.     

Nephrotic syndrome associated with a clonal T-cell leukemia of large granular lymphocytes with cytotoxic function

A 51-year-old man presented with a T-cell leukemia of large granular lymphocytes and rapidly developed a nephrotic syndrome due to presumptive minimal-change glomerulopathy. The E-rosette+, Ia+ cells demonstrated cytotoxic activity similar to that of natural killer lymphocytes but lacked other T-subset markers, except that one third of them bore Fc(IgG) receptors. Cytogenetic analysis revealed loss of chromosome 10 and the translocation (1;10)(p11;q11) in all metaphases. Regression of the leukemia after chemotherapy was accompanied by a dramatic resolution of the nephrotic syndrome, suggesting that the activated granular lymphocytes induced the renal lesion. The close association of a clonal T-lymphoproliferative disorder with minimal-change nephrotic syndrome lends further support to current views implicating activated T cells or their products in the pathogenesis of this glomerulopathy.     

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

In an attempt to document possible T-cell involvement in chronic myeloid leukaemia, E rosette-positive colonies (ERPC) were grown in agar culture using a T-cell-conditioned medium. Colonies were grown from whole mononuclear cells (WMN), nonadherent E rosette-positive (NAT+) and nonadherent E rosette-negative (NAT-) cells. Cells collected from the colonies after 10 d in culture were 99-100% E rosette-positive. 8 metaphases were obtained from both NAT+ and NAT- ERPCs. In NAT- ERPCs, 5 out of 8 metaphases were positive for the Philadelphia (Ph1) chromosome as compared to 1 Ph1 positive out of 8 metaphases in the NAT+ ERPCs. These results suggest that, at least in this particular patient we studied, a subpopulation of E rosette-positive cells derived from the NAT- cell fraction express the Ph1 chromosome.     

Cytogenetic events after bone marrow transplantation for chronic myeloid leukemia in chronic phase

Forty-eight patients treated by allogeneic bone marrow transplantation (BMT) for Philadelphia (Ph) chromosome-positive chronic myeloid leukemia in chronic phase had serial cytogenetic studies of marrow performed at intervals after transplant. Twenty patients received marrow cells from donors of opposite sex. Ph+ marrow metaphases were identified in 24 of 48 (50%) of patients after BMT; they were first seen early (within 1 year) in 16 cases and late (greater than 1 year after BMT) in eight cases. Ph-positivity after BMT occurred more commonly in recipients of T-depleted than nondepleted marrow (19 of 28 v 5 of 20). In 4 cases the Ph+ metaphases were found only transiently after BMT; in 11 cases the Ph+ metaphases have persisted but hematologic relapse has not ensued; in 9 cases the finding of Ph+ metaphases coincided with or preceded hematologic relapse. Chromosomes in cells of donor origin had morphological abnormalities in two cases. No relapses were identified in cells of donor origin. Our data suggest that the relationship between cells of recipient and donor origin is complex: cure of leukemia may depend on factors that operate for some months or years after BMT.     

Clonal chromosome abnormalities in patients with Waldenstrom's and CLL- associated macroglobulinemia: significance of trisomy 12

We performed cytogenetic analyses by Q- and G-banding techniques of unstimulated or B-mitogen-stimulated spleen, bone marrow, and peripheral blood cells from six patients with malignant macroglobulinemia [two with Waldenstrom's macroglobulinemia (WM) and four with chronic lymphocytic leukemia associated macroglobulinemia (CLL-M)]. Normal karyotypes were obtained in two of the treated patients (one with WM in remission and the other with CLL-M in relapse). An extra chromosome 12 (trisomy 12) was observed in all four untreated patients. In patient no. 2 (K.R.) and no. 3 (F.G.) with CLL- M, an abnormal karyotype, with trisomy 12 as the only abnormality, was identified. In patient no. 1 (C.C.) with WM, there were two clonal chromosome changes, identified: 47, XX, -9, +12, plus marker chromosome and 48, XX, -9, +12, plus both marker and minute chromosomes. In patient no. 4 (R.M.) with CLL-M, a minute chromosome with or without loss of a G-group chromosome was seen in some metaphases without trisomy 12, in addition to metaphases with trisomy 12 alone. Each of the four untreated patients with WM or CLL-M had clonal chromosome abnormalities, suggesting that chromosome changes may be more frequently associated with WM or CLL-M than with typical CLL without macroglobulinemia. These observations also suggest that trisomy 12 may be the primary karyotypic change in malignant macroglobulinemia, whereas the appearance of the minute or marker chromosome as well as the loss of G-group chromosomes or chromosome no. 9 may be secondary karyotypic changes resulting from clonal evolution in these malignancies.     

The benzene metabolite, hydroquinone, selectively induces 5q31- and -7 in human CD34+CD19- bone marrow cells

OBJECTIVE: Chronic exposure to high concentrations of benzene is associated with an increased incidence of myelodysplastic syndrome and acute myelogenous leukemia. Acute myelogenous leukemia developing in patients treated with alkylating agents for other cancers or occupationally exposed to benzene exhibit a pattern of cytogenetic aberrations predominantly involving loss of all or part of chromosomes 5 and/or 7. In contrast, trisomy 8 is observed equally in both de novo and secondary acute myelogenous leukemia. Studies using peripheral lymphocytes or lymphoblastoid cell lines have observed dose-dependent loss of chromosomes 5, 7, and 8 following treatment with the benzene metabolite, hydroquinone. The purpose of this study was to determine the dose response and specificity of hydroquinone-induced aberrations on chromosomes 5, 7, and 8 using human CD34+CD19 bone marrow cells. MATERIALS AND METHODS: Fluorescence in situ hybridization analysis was performed on CD34+CD19- bone marrow cells using the locus-specific probes, 5q31, 5p15.2, and centromeric probes specific for human chromosomes 7 and 8 following hydroquinone exposure. RESULTS: Hydroquinone exposure results in -7, selective deletion of 5q31 but not chromosome 5 and no loss or gain of chromosome 8 in human CD34+CD19- cells. CONCLUSION: CD34+ bone marrow cells are more susceptible and show a different pattern of cytogenetic aberrations as a result of hydroquinone exposure compared to lymphocytes. CD34+ bone marrow cells exhibit unique susceptibility to the development of specific chromosome aberrations that have been identified as the earliest structural changes occurring in the development of secondary myelodysplastic syndrome and acute myelogenous leukemia.     

Molecular cytogenetics of stem cells: target cells of chromosome aberrations as revealed by the application of fluorescence in situ hybridization to fluorescence-activated cell sorting

The lineage involvement in stem cell disorders, such as chronic myeloid leukemia (CML) and myelodysplastic syndrome (MDS), remains unclear. To explore this issue, we used fluorescence in situ hybridization for cells sorted by fluorescence-activated cell sorting (FACS) from 12 patients with chronic-phase CML. Philadelphia chromosome (Ph) was found in pluripotent stem cells (CD34+Thy-1+), B cells (CD34+CD19+), and T/natural killer (NK) progenitor cells (CD34+CD7+) collected by FACS from bone marrow cells. B (CD19+), T (CD3+), and NK (CD3-CD56+) cells showed a marked decrease in Ph+ cells between progenitor cells and mature cells The Ph+ T and NK cells decreased to below background levels. These data suggest that Ph+ lymphocytes either do not differentiate or are eliminated during their maturation process Among 7 MDS patients associated with trisomy 8, sorted lymphocytes from peripheral blood did not have +8. CD34+ subpopulations from bone marrow including B,T/NK progenitors, and pluripotent progenitor cells also did not have +8.Trisomy 8 was identified from the level of multipotent colony-forming units (CD34+CD33+), and the lymphoid lineage was not involved. Thus, MDS with trisomy 8 conceivably arises from nonlymphoid progenitor cells, sparing T, B, or NK cells. Further studies using molecular cytogenetics may clarify the mechanism of leukemia happening at the level of stem cells.     

Quantification of the breakpoint cluster region rearrangement for clinical monitoring in Philadelphia chromosome-positive chronic myeloid leukemia

The purpose of this report was to evaluate scintigraphy analysis of Southern blot hybridization as a method to quantify the breakpoint cluster region (BCR) rearrangement of Philadelphia chromosome (Ph)+ chronic myelogenous leukemia (CML). Cytogenetic and molecular studies performed simultaneously on 474 bone marrow and/or blood samples from 300 patients treated with alpha-interferon-based therapy were compared. Molecular results were expressed as the percentage of rearranged BCR bands versus the total scintigraphic signal. The percentage of Ph+ metaphases was calculated on 25 metaphases. The results of molecular studies obtained on both peripheral blood and bone marrow samples were identical. The rank correlation between the BCR quantification and the percentage of Ph positivity in 465 samples was excellent (r = .78). However, of 99 samples with a normal karyotype, 24% had a BCR rearrangement. Of 86 samples with no BCR rearrangement, 13% showed a Ph chromosome. Of 49 samples with partial cytogenetic remission (Ph+ metaphases, 1% to 34%), 23% had no BCR rearrangement. In samples with a minor or no cytogenetic response (Ph+ metaphases, > 34%), BCR analysis overestimated the degree of response in 73 of 326 samples (22%). Nevertheless, survival analysis by BCR quantification level showed statistically better outcome for patients in complete or partial molecular response (P < .01). Molecular quantification of BCR was useful in monitoring the course of Ph+ CML. This method, which can be used on peripheral blood, detected residual disease not shown by cytogenetic analysis and was prognostically relevant as a measure of disease suppression.     

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

A patient presented with lymphoblastic lymphoma in lymph-nodes and chronic myeloge-nous leukemia (CML) in marrow 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. © 1993 Wiley-Liss, Inc.