Cytogenetics in patients with chronic myelogenous leukemia treated with bone marrow transplantation

Cytogenetic evolution patterns in CML post-SCT

The cytogenetic evolution patterns in chronic myeloid leukemia (CML) after allogeneic (allo) stem cell transplantation (SCT) are different from the ones observed in non-transplanted patients, a phenomenon suggested to be caused by the conditioning regime. We reviewed 131 CMLs displaying karyotypic evolution after SCT (122 allo, nine autologous (auto)), treated at Lund University Hospital or reported in the literature. Major route abnormalities (i.e., +8, +Ph, i(17q), +19, +21, +17 and -7) were seen in 14%, balanced aberrations in 61%, hyperdiploidy in 19%, pseudodiploidy in 79%, divergent clones in 14%, and Ph-negative clones in 21%. The breakpoints involved in secondary structural rearrangements clustered at 1q21, 1q32, 7q22, 9q34, 11q13, 11q23, 12q24, 13q14, 17q10 and 22q11. Cytogenetic abnormalities common in AML after genotoxic exposure, that is, der(1;7)(q10;p10), del(3p), -5, del(5q), -7, -17, der(17p), -18, and -21, were only rarely seen post-SCT. Comparing the cytogenetic features in relation to type of SCT revealed that balanced aberrations were significantly more common after allo than after auto SCT (64 and 22%, respectively, P=0.03). In addition, there was a trend as regards hyperdiploidy being more common after auto (P=0.07) and pseudodiploidy being more frequent after allo SCT (P=0.09). Possible reasons for these differences are discussed.

Cytogenetic clonal evolution alone in CML relapse post-transplantation does not adversely affect response to imatinib mesylate treatment

Good prognosis after imatinib mesylate treatment has been reported if cytogenetic clonal evolution (CE) is the only criterion of accelerated phase (AP) chronic myelogenous leukemia (CML). To evaluate the impact of CE upon imatinib treatment in post-transplant settings, responses and toxicities in the relapsed AP-CE were analyzed in comparison with those in the relapsed chronic phase (CP). Both CP (n=7) and AP-CE patients (n=6) received imatinib mesylate in an oral dose of 400 mg/day. Complete cytogenetic responses were obtained in six patients of each group, CP (86%) and AC-CE (100%), while molecular remission was seen in 43 and 50%, respectively. Granulocytopenia or thrombocytopenia of grade III or more occurred in four (57%) and two (33%) patients with CP and AP-CE, respectively. Nonhematological adverse events were mild and tolerable in both groups and only one (7%) of the 13 patients experienced recurrent graft-versus-host disease after imatinib treatment. Although this is a relatively small group of patients, we suggest that imatinib mesylate should be considered as a front-line treatment for relapsed CML as it showed the high response rate and low toxicity. We also suggest that CE alone is not an important factor in the induction of cytogenetic and molecular remissions in post-transplant relapse.

Spectral karyotyping (SKY) refinement of a complex karyotype with t(20;21) in a Ph-positive CML patient submitted to peripheral blood stem cell transplantation

A patient with a Ph-positive chronic myeloid leukaemia (CML) was submitted to allogeneic peripheral blood stem cell transplantation from an HLA-haploidentical related donor 7 years after the diagnosis. Six months later, he showed a disease relapse while cytogenetic analysis displayed a complex karyotype. To characterise the chromosomal rearrangements spectral karyotype (SKY) analysis was used. This redefined all chromosome rearrangements and revealed a t(20;21)(q11;q22). FISH analysis with a specific probe for the AML1 gene disclosed disruption of this gene which was partially translocated on to the long arm of chromosome 20. It is likely that this rearrangement, unusual for CML, was implicated in the disease evolution towards blastic crisis (BC).

Comparative Study of FISH, PCR and Cytogenetics on 25 Patients Submitted to Bone Marrow Transplantation (BMT) for Chronic Myelogenous Leukemia (CML); Which Tests can we Use in Routine Analysis Post BMT?

Chronic Myeloid Leukaemia (CML) shows an excellent response to allogeneic bone marrow transplantation (BMT) with a 60-80% long term disease free survival in recipients of unmanipulate marrow. The most frequent cause of treatment failure is leukaemic relapse, due to the re-emergence of malignant recipient clones. Clinical and haematological relapse is usually preceded by molecular evidence of relapse. Early detection of molecular relapse may allow intervention with immunotherapy such as donor lymphocyte infusions (DLI). This study was undertaken to compare results from two centres who employ either Fluorescent In Situ Hybridisation (FISH) or polymerase chain reaction (PCR) analysis of DNA polymorphisms as their routine method of detecting residual host cells following BMT for CML in order to establish (1) if these methods are equivalent for routine laboratory use in reporting of chimaerism results to the referring clinician, and (2) if these methods are beneficial for indicating new and early therapeutic strategies. FISH analyses for the X and Y chromosomes (in sex mismatched patients) and/or FISH for BCR and ABL loci were compared with short tandem repeat PCR (STR-PCR) and conventional karyotyping in serial analyses in 25 patients submitted to BMT for Philadelphia positive (Ph) CML. Comparison of all results on samples assessed between 1 and 13 years post BMT indicated that FISH and PCR, performed on the same bone marrow samples displayed similar results in more than 90% of patients in first 3 years after BMT which increased to a concordance rate of 100% in long term survivors. In contrast, comparison of FISH or PCR versus cytogenetic analysis indicated a low concordance rate, with less than 50% of samples showing similar results during all the follow-up period. Eighty percent of recipients (22 patients) had evidence of mixed chimaerism following BMT (initial level of positivity 1-6% recipient cells) during the follow-up period. This low percentage of recipient cells remained stable in 7 patients, while 9 patients reverted to a donor profile. All 16 patients are in haematological remission. In addition the 3 patients with complete donor chimaerism remain in remission. In the remaining 6 patients, a progressive increase in recipient cells occurred (progressive mixed chimaerism, PMC), and was followed by haematological relapse. We conclude that FISH and PCR can be used to monitor CML patients post BMT and transient or stable low level mixed chimaerism is not associated with leukaemia relapse, but PMC is predictive of imminent relapse and its detection may help to illucidate the timing of early intervention with donor lymphocyte infusion.

Retrospective investigation of hematopoietic chimerism after BMT by PCR amplification of hypervariable DNA regions

We report on nine patients submitted to BMT with sex-matched donors and investigated by means of PCR amplification of the VNTRs ApoB, D1S80, DXS52, and D17S5. In all cases it was possible to detect a polymorphism able to distinguish between donor and patient cells, thus allowing us to recognize the presence of complete or mixed chimerism. In eight patients PCR analysis showed a complete chimerism during the entire follow-up. Only one of these patients relapsed, while the others are alive and without any sign of relapse 56.2 months (mean) after BMT. Mixed chimerism was detected in only one patient, who relapsed 3 months after this finding. These results confirm the usefulness of the study of PCR-amplified VNTRs in the assessment of marrow engraftment after BMT, mostly in sex-matched transplants where, in the absence of specific chromosome rearrangements, cytogenetic or FISH analysis cannot be used.

Case report of spontaneous remission of cytogenetic relapse of chronic myelogenous leukemia suggestive of progression to blast crisis after allogeneic bone marrow transplantation

Detection of the chronic myelogenous leukemia (CML)-related marker, the bcr/abl m-RNA transcript, in blood or bone marrow of patients with CML in hematologic remission after allogeneic bone marrow transplantation (allo-BMT) may be associated with the presence of minimal residual disease but does not uniformly predict hematologic relapse. In contrast, when there is cytogenetic reappearance of the Philadelphia (Ph1) translocation [t(9;22)(q34;q11)] along with additional cytogenetic abnormalities, especially more than 2 years after BMT, progression to hematologic relapse and acceleration of CML usually occur. An exception to this rule may be our patient, who was a 29-year old white woman diagnosed with Ph1-positive CML by cytogenetics. She was initially treated with hydroxyurea. An allo-BMT was performed 4 months after the diagnosis, while the patient was still in the first chronic phase of her disease, her HLA-identical brother serving as bone marrow (BM) donor. The conditioning regimen for BMT consisted of cytosine arabinoside, cyclophosphamide, total body irradiation, splenic irradiation, and intrathecal methotrexate. Graft-versus-host disease (GVHD) prophylaxis consisted of cyclosporin A and methotrexate. Her hospital course was unremarkable and without evidence of acute GVHD. Six months after transplantation, the patient had mild chronic GVHD and was treated with azathioprine and prednisone for 6 months. A year later, she recurred with mild chronic GVHD. She was treated with azathioprine alone for 5 months. Subsequently, she received cyclosporin A and prednisone for 8 months, with resolution of her symptoms. Serial BM cytogenetic studies showed normal male donor karyotypes 12 and 24 months after BMT. At 36, 42, and 50 months after BMT, reappearance of the Ph1 was noted along with some cells with additional cytogenetic abnormalities, including t(6;14)(p21;q32). The breakpoint involvement of 14q32, the heavy chain Ig locus, in the new clone may be indicative of B-lymphoid lineage-based evolution. The abnormal clones disappeared 56 months from BMT and remained absent through 69 months after BMT. The patient has remained in hematologic remission during her entire post-BMT course. Clinically, she continues to do well without immunosuppressants at presently 69 months after BMT. The reappearance of the Ph1 chromosome could be associated with the immunosuppressive therapy given for chronic GVHD. This case supports the concept that immunologic mechanisms may be important in the eradication of CML after allo-BMT, and even cytogenetic evidence of blast crisis CML may spontaneously remit after allo-BMT.

Sequential cytogenetic study of patients after bone marrow transplantation

Thirty-one patients (19 males and 12 females; mean age 23.9 years, range 4-41 years) were treated with bone marrow transplantation (BMT) after intensive chemoradiotherapy. Their diagnoses were as follows: chronic myeloid leukemia (CML) in 13, acute myeloid leukemia (AML) in seven, acute lymphocytic leukemia (ALL) in six, myelodysplastic syndrome (MDS) in two, aplastic anemia (AA) in two, and Fanconi anemia (FA) in one. Allogeneic BMT was performed in 28 cases (17 donors were of like sex, 11 were of unlike sex), one patient received syngenic transplant, and one received transplant of cells obtained from an unrelated donor through a computerized international registry in London. Autologous BMT was performed in three patients. BM cells were analyzed cytogenetically at diagnosis, before and serially after BMT (three to nine times). Follow-up ranged from 2 to 55.5 months. Cytogenetic examination was a very useful method for monitoring posttransplantation course in patients with CML or in those who received BM cells of unlike sex. Results of concomitant cytogenetic examinations are reported in detail.

Detection of minimal residual disease by polymerase chain reaction in patients with different hematologic diseases treated by bone marrow transplantation

Thirteen male patients affected by different hematologic diseases who underwent bone marrow transplantation (BMT) with female donors were investigated by cytogenetic analysis and polymerase chain reaction (PCR) amplification of a DNA sequence specific for the Y chromosome. In six of these patients, PCR showed the presence of the Y chromosome-related sequence; in only three of these did cytogenetic analysis confirm the presence of mixed chimerism. In the remaining three patients, the results of the PCR were confirmed by in situ hybridization on cell nuclei with a probe for the alpha-satellite of the Y chromosome. We compare results obtained with the two methods and discuss the meaning of the minimal residual disease detected by PCR in patients submitted to BMT.

Graft-versus-leukemia effects after allogeneic bone marrow transplantation are active also in the presence of clones with chromosomal anomalies in addition to the Ph chromosome

Two male patients with Philadelphia-chromosome (Ph+) chronic myelogenous leukemia (CML) underwent allogeneic bone marrow transplantation (ABMT) in the first chronic phase after busulfan treatment. In both cases, the donor was a sister, and engrafting was demonstrated by chromosome analyses which showed only donor cells in the BM. Cytogenetic relapse occurred 29 and 30 months after ABMT, respectively, when host cells reappeared: in both cases, the Ph and additional anomalies typical of the blastic phase of CML were evident. We then monitored the chromosome picture for 52 and 39 months, respectively: no striking evolution occurred, and cells with the Ph and additional anomalies persisted together with donor cells, which were a minority in the first patient and a great majority in the second throughout the observation period. A clinical relapse was observed in the first patient, but the disease never progressed to a blastic phase, whereas the second patient has not relapsed 7 years after ABMT. We reviewed data from the literature on cytogenetic relapse after ABMT in CML without clinical relapse, especially the 12 patients in whom cytogenetic relapse included chromosome anomalies in addition to the Ph, as in our patients. We suggest that graft-versus-leukemia (GVL) reactions in such patients are able to arrest progression of the leukemic blastic clone and prevent a possible relapse in blastic phase.

Lymphohaematopoietic chimaerism after bone marrow transplantation for chronic myeloid leukaemia: results of simultaneous cytogenetic analyses on T-cell colonies, myeloid, and erythroid progenitor cells

Various lymphohaematopoietic compartments represented by cells from T-cell colonies, myeloid progenitor cells (CFU-GM), erythroid progenitor cells (BFU-E), and bone marrow after short-term culture (BM) have simultaneously been analysed in 15 patients receiving 17 bone marrow transplants for Philadelphia chromosome (Ph) positive chronic myeloid leukaemia (CML) or acute lymphoblastic leukaemia (ALL). The marrow grafts were not T-cell depleted. Ten patients without relapse did not show any myeloid cells of host origin until their last follow-up or until death. However, in four of these patients single lymphoid host cells not carrying the Ph chromosome were found after BMT without clinical consequences. In patients with cytogenetic or haematological relapse Ph positive metaphases were first detected in any of the progenitor cell compartments along with residual donor cells in two of three patients. BM became Ph positive after various time intervals. Another patient with CML became Ph positive in all compartments investigated at the same time. The only patient with Ph positive ALL remained completely Ph negative also when haematological and clinical relapse was evident. All patients with relapse exhibited complex clonal and non-clonal chromosomal aberrations at the time of recurrence of the Ph chromosome. Such abnormalities not identical to those usually found with evolution of the disease and preferentially occurring in progenitor cells preceded the reappearance of Ph positive metaphases in one of our patients.

Cytogenetic survey of 31 patients treated with bone marrow transplantation for acute nonlymphocytic and acute lymphoblastic leukemias

The authors report on a sequential cytogenetic study carried out on 31 patients with acute leukemia (20 with acute lymphoblastic leukemia and 11 with acute non-lymphocytic leukemia) who underwent bone marrow transplantation (BMT). Engraftment was documented in all patients with sex-mismatched donors and with donor constitutional aberrations. During the follow-up, ranging from 6 to 110 months, clinical and hematologic relapse was observed in 11 patients (35.5%). Five of these cases showed a normal karyotype, 3 were of undefined relapse origin, 2 were aneuploid karyotypes, and one was donor (male) metaphases. Cytogenetic and immunologic data in the latter patient were suggestive of relapse in donor cells.