Imatinib mesylate-induced molecular remission of Philadelphia chromosome-positive myelodysplastic syndrome.
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Aged↗
Biomedical subjects
J Kaeda
Publications and source records attributed to J Kaeda.
Early detection of BCR-ABL transcripts by quantitative reverse transcriptase-polymerase chain reaction predicts outcome after allogeneic stem cell transplantation for chronic myeloid leukemia.
The reverse transcriptase-polymerase chain reaction (RT-PCR) has become widely used for monitoring minimal residual disease after allogeneic stem cell transplantation (SCT) for chronic myeloid leukemia (CML). However, most of these studies were performed using qualitative RT-PCR, and the interpretation of the results obtained has been conflicting. The correlation of a quantitative RT-PCR test performed early after SCT (at 3 to 5 months) and long-term outcome of CML patients surviving for more than 6 months was studied. Between January 1991 and June 1999, data from 138 CML patients who received allografts were evaluated. Early RT-PCR results were classified as (1) negative if there were no BCR-ABL transcripts detected (n = 61), (2) positive at low level if the total number of BCR-ABL transcripts was less than 100 per microg RNA and/or the BCR-ABL/ABL ratio was less than 0.02% (n = 14), or (3) positive at high level if transcript levels exceeded the thresholds defined above (n = 63). Three years after SCT the cumulative incidence of relapse was 16.7%, 42.9%, and 86.4%, respectively (P =.0001). The relationship between BCR-ABL transcript level and probability of relapse was apparent whether patients had received sibling or unrelated donor SCT and also whether or not the transplantation was T cell depleted. The results suggest that quantitative RT-PCR performed early after SCT is useful for predicting outcome and may help to define the need for further treatment.
Actuarial Analysis↗
Immune haemolytic anaemia following T cell-depleted allogeneic bone marrow transplantation for chronic myeloid leukaemia: association with leukaemic relapse and treatment with donor lymphocyte infusions.
Immune haemolytic anaemia (IHA) is a recognised complication after allogeneic stem cell transplantation (SCT) and occurs more frequently if marrow cells have been subjected to T cell depletion (TCD). Among 58 consecutive patients who underwent TCD-allogeneic SCT from volunteer unrelated donors for the treatment of CML at the Hammersmith Hospital during a 3-year period (1 March 1996 to 28 February 1999) we identified nine cases of IHA. All patients had a strongly positive direct and indirect antiglobulin test and in eight patients the serological findings were typical of warm-type haemolysis often with antibody specificities within the Rh system. All nine cases had clinically significant haemolysis and were treated initially with prednisolone and immunoglobulin. The onset of IHA coincided with the occurrence of leukaemic relapse in six cases, and the presence of host haemopoiesis confirmed by lineage-specific chimerism in all four cases studied. Five patients received donor lymphocyte infusions (DLI); in three molecular remission and the restoration of full donor chimerism coincided with resolution of haemolysis. We conclude that in the context of leukaemic relapse, DLI is an effective therapy for IHA following allografts involving TCD.
Adolescent↗
Analysis of chimaerism in thalassaemic children undergoing stem cell transplantation.
We have prospectively assessed the relative contribution of host and donor to haemopoiesis following stem cell transplantation (SCT) in children with beta-thalassaemia major (n = 35), using karyotype analysis or Southern blot/polymerase chain reaction analysis of variable number tandem repeats on genomic DNA from peripheral blood. Early haemopoiesis was fully donor in origin in 24 out of 35 cases and remained so throughout the post-transplant course in all but one patient, who evolved to stable mixed chimaerism. The remaining 11 cases (31%) initially showed mixed chimaerism: four of these rejected, one eventually eradicated host haemopoiesis to become fully donor haemopoietic, and the remaining six had persistent mixed chimaerism, with 5--38% host haemopoiesis. The risk of graft rejection was high when > 15% host haemopoiesis was present at 3 months post transplant: four out of six such patients rejected their grafts; conversely, zero out of 29 patients with < 15% host haemopoiesis at 3 months rejected (P < 0.0001). There was a higher incidence of significant acute and chronic graft-versus-host disease in patients with full donor chimaerism. These studies confirm that the mixed chimaeric state is common following SCT for thalassaemia, often persists (with up to 4 years follow-up) and is compatible with long-term cure. Analysis of chimaerism in patients undergoing SCT for beta-thalassaemia enables monitoring of engraftment in the early post-transplant period, provides insight into the biology of engraftment and may be useful in identifying patients at high risk of rejection.
ABO Blood-Group System↗
Molecular studies in patients with chronic myeloid leukaemia in remission 5 years after allogeneic stem cell transplant define the risk of subsequent relapse.
We identified 103 consecutive patients who, 5 years after allogeneic transplantation for chronic myeloid leukaemia (CML), were in molecular remission (MR). The 103 patients were divided into three groups on the basis of reverse transcription-polymerase chain reaction (RT-PCR) studies for BCR-ABL transcripts in the first 5 years post transplant: Group A comprised 63 patients who had been continuously PCR negative; Group B comprised 20 patients with one or more positive PCR result but only at a low level; and Group C comprised 20 patients who had fulfilled the criteria for molecular relapse, been treated with donor lymphocyte infusions (DLI) and had thereafter regained complete MR within the 5-year post-transplant period. The median follow-up for all 103 patients was 8.4 years from transplant (range 5-17.6 years). In group A only one patient relapsed at 9.2 years. In group B eight patients (40%) relapsed: six at molecular, one at cytogenetic and one haematological levels. The actuarial probabilities of survival at 10 years for patients in Groups A, B and C were 97.4%, 92.9% and 100% respectively; the probabilities of relapse were 3%, 54% and 0% respectively. We conclude that molecular studies during the first 5 years post transplant can help to predict long-term leukaemia-free survival and, possibly, cure of CML.
Adolescent↗
Durability of responses following donor lymphocyte infusions for patients who relapse after allogeneic stem cell transplantation for chronic myeloid leukemia.
An analysis was performed of the response to treatment with donor lymphocyte infusions (DLI) and the survival in 66 consecutive patients who relapsed after primary treatment by allogeneic stem cell transplantation for BCR-ABL-positive chronic myeloid leukemia. The transplant donor was an HLA-identical sibling (n = 35) or a "matched" unrelated volunteer (n = 31). Fifty-seven patients were transplanted in chronic phase, eight in accelerated phase, and one in second chronic phase. The recognition of relapse was based on precise molecular, cytogenetic, or hematologic criteria. The median interval from transplant to relapse was 12 months (range 3-85). The median interval from relapse to initiation of DLI was 9.4 months (range 1-70). Patients received DLI from their original transplant donors on a bulk-dose (n = 34) or on an escalating-dose (n = 32) regimen. Patients were monitored serially by hematologic, cytogenetic, and molecular criteria. Molecular remission was defined by the finding of negative results by nested primer reverse transcriptase polymerase chain reaction (RT-PCR) for BCR-ABL transcripts on two consecutive occasions, subject to satisfactory controls. Forty-four patients (67%) achieved molecular remission. Patients who had relapsed to advanced phase disease and patients with short intervals between transplant and relapse had significantly lower probabilities of achieving molecular remission. Of the 44 patients who achieved molecular remission, 4 reverted to a PCR-positive status at 15, 18, 37, and 87 weeks after remission. The probability of survival for patients who achieved molecular remission was significantly better than for those who failed to do so (95% versus 53% at 3 years post-DLI, P = .0001). We conclude that the majority of molecular remissions after DLI are durable, and thus the majority of responding patients may prove to have been cured. (Blood. 2000;96:2712-2716)
Adult↗
Absence of host-derived cells in the blood of patients in remission after allografting for chronic myeloid leukemia.
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Blood Cells↗
Fusion of H4/D10S170 to the platelet-derived growth factor receptor beta in BCR-ABL-negative myeloproliferative disorders with a t(5;10)(q33;q21).
We have studied a patient who presented with clinical features suggestive of chronic myeloid leukemia in accelerated phase. BCR-ABL transcripts were undetectable by reverse transcription-PCR, but a novel reciprocal translocation, t(5;10)(q33;q21.2), was seen by standard cytogenetic analysis. Chromosome band 5q33 contains the gene encoding the platelet-derived growth factor beta receptor (PDGFbetaR), the receptor tyrosine kinase that is disrupted by the t(5;7), t(5;12), and t(5;14) in myeloid disorders, resulting in the fusion of PDGFbetaR to HIP1, TEL/ETV6, and CEV14, respectively. Southern analysis with PDGFbetaR cDNA revealed novel bands in patient but not control DNA after digestion with several restriction enzymes, indicating that this gene is also targeted by the t(5;10). Fluorescence in situ hybridization analysis of chromosome 5 indicated that a small inversion at 5q33 had taken place in addition to the interchromosomal translocation. The site of the chromosome 10 breakpoint fell within YAC 940e4. Because all PDGFbetaR fusions described thus far result in splicing to a common exon of this gene, we performed 5'-rapid amplification of cDNA ends PCR on patient RNA. Several clones were isolated in which PDGFbetaR fused in frame to H4/D10S170, a previously described ubiquitously expressed gene that is fused to the ret protein tyrosine kinase to form the PTC-1 oncogene in approximately 20% of papillary thyroid carcinomas. The presence of H4-PDGFbetaR chimeric mRNA in the patient was confirmed by reverse transcription-PCR; reciprocal PDGFbeta1R-H4 transcripts were not detected. We conclude that t(5;10)(q33;q21.2) is a novel translocation in BCR-ABL-negative chronic myeloid leukemia and that this abnormality results in an H4-PDGFbetaR fusion gene. This finding further strengthens the association between myeloproliferative disorders and deregulated tyrosine kinases.
Amino Acid Sequence↗
Molecular heterogeneity in complete cytogenetic responders after interferon-alpha therapy for chronic myelogenous leukemia: low levels of minimal residual disease are associated with continuing remission. German CML Study Group and the UK MRC CML Study Group.
A substantial minority of patients with chronic myelogenous leukemia (CML) achieve a complete response (CR) to treatment with interferon-alpha (IFN), defined as the disappearance of Philadelphia chromosome-positive metaphases. Currently it is unclear how long IFN treatment should be continued for such patients. We used a competitive reverse transcriptase-polymerase chain reaction (RT-PCR) to quantify levels of BCR-ABL transcripts in 297 peripheral blood specimens collected from 54 patients who had achieved CR with IFN. The median duration of observation was 1.9 years (range, 0.3-11.0 years). Total ABL transcripts were quantified as internal control and results were expressed as the ratio BCR-ABL/ABL. All 54 patients had molecular evidence of residual disease, although 3 patients were intermittently PCR negative. The median BCR-ABL/ABL ratio at the time of maximal response for each patient was 0.045% (range, 0%-3. 6%). During the period of observation 14 patients relapsed, 11 cytogenetically to chronic phase disease and 3 directly to blastic phase. The median ratio of BCR-ABL/ABL at maximal response was significantly higher in patients who relapsed than in those who remained in CR (0.49% versus 0.021%, P < 0.0001). Our findings show that the level of residual disease falls with time in complete responders to IFN, but molecular evidence of disease is rarely if ever eliminated. The actual level of minimal residual disease correlates with the probability of relapse. We suggest that for patients who reach CR, IFN should be continued at least until relatively low levels of residual leukemia are achieved. (Blood. 2000;95:62-66)
Adolescent↗
Comparison of single-dose and escalating-dose regimens of donor lymphocyte infusion for relapse after allografting for chronic myeloid leukemia.
Donor lymphocyte infusion (DLI) was originally administered as a single, relatively large dose of lymphocytes called a bulk dose regimen (BDR). It has since been suggested that the use of an escalating dose regimen (EDR) may be equally effective against leukemia while it induces less graft-versus-host disease (GVHD). We therefore compared the efficacy and incidence of complications in a nonrandomized sequential study of the 2 regimens in 48 consecutive patients who had relapses with cytogenetic or hematologic evidence of chronic myeloid leukemia after allogeneic stem cell transplantation. Twenty-eight patients were treated on a BDR (August 1990 to November 1995) and 20 were treated on an EDR (December 1995 to January 1998). Although the probability of achieving cytogenetic remission within 2 years of starting DLI did not differ significantly between the 2 groups (EDR, 91% [CI, 63%-98%] vs. BDR, 67% [CI,49%-83%], P =.70), the incidence of GVHD was much lower using EDR (10% vs. 44%, P =.011). When we considered only subsets of patients treated by BDR or EDR who had received comparable total lymphoid cell doses, the incidence and severity of acute and chronic GVHD were both significantly lower for recipients treated by EDR than for recipients treated by BDR (P =.005 and P =.031, respectively). These findings suggest that the incidence of GVHD associated with the EDR is low, not because the final cell dose is small, but because lymphocytes are administered over a considerable number of months. (Blood. 2000;95:67-71)
Disease-Free Survival↗
Clonal instability preceding lymphoid blastic transformation of chronic myeloid leukemia.
We have sought the presence of rearrangements of the immunoglobulin heavy chain gene locus in 13 patients with chronic myeloid leukemia (CML) in lymphoid blastic transformation (L-BT) using the polymerase chain reaction (PCR). The lymphoid nature of the transformation was confirmed by immunophenotyping and/or Southern blot hybridization with a J(H) probe. Clonal rearrangements were detected in 85% of cases and two or more rearrangements were visible in 64% of informative cases. The pattern of V(H) gene family utilization revealed an apparent reduction in V(H)4 family gene usage but otherwise reflected the known proportion of each gene family in the germline repertoire. In six cases the third complementary determining regions (CDR3) of the predominant blast crisis clone/s were sequenced revealing minimal evidence of somatic mutation. No clonal changes were detected in the chronic phase leukemia cells collected more than 6 months before the onset of L-BT in three of these patients. Of the other three patients studied in chronic phase from 1 to 6 months before L-BT, two showed clonal rearrangements which differed in size from those present at L-BT. In one patient a V(H)3 to V(H)5-D(H)-J(H) substitution had occurred at least 3 months prior to L-BT. In the other patient, however, the sequence of the rearrangement present 5 months prior to L-BT was unrelated to the rearrangements at the time of L-BT indicating a pattern of clonal succession. We conclude that: (1) IgH gene rearrangements are detectable in the majority of patients with L-BT using PCR and the lymphoid lineage of blastic CML is most readily confirmed using consensus primers to the framework 3 region; (2) somatic mutation is uncommon; and (3) B lymphoid clones distinct from those identified later may be detected before overt lymphoid BT. The identification of such 'abortive' clones is evidence for clonal instability before the onset of transformation and might have prognostic value.
Adolescent↗
DNA haplotypes in Africans and West Indians with sickle cell anaemia or SC disease.
Considering that genetic variation linked to the beta S mutation may influence the clinical manifestations of sickle cell disease, we have analyzed the beta globin cluster haplotypes in 47 patients with this condition (33 SS homozygotes, one S/beta thal (0), and 13 SC) living in London (30 West Indian, 17 West African). Of the 80 chromosomes tested, 82.5% had the Benin haplotype and of the 13 C chromosomes tested, 85% had the Bantu-A4 haplotype. A minority of patients had Bantu or Senegal haplotypes, and in 5 patients we found new haplotypes called E, H and O which may have arisen through mutation or recombination. Because of the predominance of a single haplotype (Benin) nearly all our homozygous S patients were either homozygous or heterozygous for this haplotype. We concluded that the beta globin haplotype is unlikely to be an important determinant of the clinical severity in this patient population.
Africa, Western↗
Beta-thalassemia mutations in the Portuguese; high frequencies of two alleles in restricted populations.
We report the characterization of seven different beta-thalassemia mutations in 131 newly diagnosed Portuguese beta-thalassemia heterozygotes. Methodology included the detection of abnormal fragments by agar gel electrophoresis of PCR-amplified DNA fragments after digestion with specific restriction endonucleases, as well as hybridization with synthetic nucleotide probes and sequencing of amplified DNA. Four mutations, including the newly discovered TGG-->TGA change at codon 15, occurred in excess of 10% and accounted for some 90% of the beta-thalassemia alleles in this population. The geographical distribution is uneven; the TGG-->TGA mutation at codon 15 was primarily observed in the coastal region north of Lisbon, while the IVS-I-6 (T-->C) mutation was confined to the central part of the country.
Alleles↗
A distinct large granular lymphocyte (LGL)/NK-associated (NKa) abnormality characterized by membrane CD4 and CD8 coexpression. The Yorkshire Leukaemia Group.
In a study of 870 individual patients with either lymphocytosis (excluding known lymphoproliferative disease), increased proportions of blood lymphocytes with granular morphology (LGL), or neutropenia, 14 cases were found with abnormally increased CD3+CD4+CD8+ components. Eleven of these were further investigated and 10 shown in follow-up studies to be persistent in nature. Morphological assessments revealed increased LGL in 9/11 cases, and in seven of these > 50% lymphocytes had discernable cytoplasmic granulation. Immunophenotypic studies indicated that CD8 expression by CD4+ lymphocytes in these patients was of low density (CD8dim+), and that both the CD4+CD8- and CD4+CD8dim+ fractions in each patient was characterized by a CD11b+CD16-CD56+CD57+ composite NK-associated (NKa) phenotype (in contrast to normal CD4+CD8- blood lymphocytes and CD4+CD8+ thymocytes which were consistently CD11b-CD16-CD56-CD57-). TCR genotypic studies revealed rearranged components (beta plus gamma, or beta alone) in 5/11 cases, but there were no obvious relationships between TCR configuration (including rearranged band densities) and immunophenotypes, absolute lymphocyte or neutrophil numbers, the proportions of blood LGL, or the proportions of CD4+ cells coexpressing CD8. The occurrence of identical NKa phenotypic profiles in both germline and rearranged TCR cases does, however, suggest the possibility of an evolutionary process from a non-clonal expansion to a clonal state. Serum studies, including soluble CD4, CD8 and IL2-R concentrations and autoantibody investigations, of representative germline and rearranged TCR cases failed to indicate any consistent abnormalities, but there was some suggestion for the existence of a chronic reactive process in some of the patients with germline TCR. These findings suggest that expanded LGL/NKa+ components with phenotypic evidence of CD4/CD8 coexpression should be regarded as a distinct diagnostic category and that persistent CD4+CD8+ abnormalities with germline TCR should be monitored for possible clonal transition.
Antigens, CD↗
Acquired beta thalassaemia trait in MDS.
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Adult↗
A third instance of the high oxygen affinity variant, Hb Heathrow [beta 103(G5)Phe- greater than Leu]: identification of the mutation by mass spectrometry and by DNA analysis.
Hb. Heathrow [beta 103(G5)Phe- greater than Leu] was identified in an Englishman with a life-long history of polycythemia, his father had been similarly affected. A hemoglobin variant was suspected from the high oxygen affinity of the patient's blood. The Hb Heathrow abnormal beta chain was resolved from the normal beta chain by high performance liquid chromatography, and the abnormal peptide and the amino acid replacement were identified by mass spectrometry. The corresponding base change (C- greater than G at codon 103) was demonstrated by sequence analysis of the polymerase chain reaction amplified exon 2 of the genomic beta-globin gene. This is only the third known instance of Hb Heathrow.
Aged↗
High-level, erythroid-specific expression of the human alpha-globin gene in transgenic mice and the production of human hemoglobin in murine erythrocytes.
Using the dominant control region (DCR) sequences that flank the beta-globin gene locus, we have been able to achieve high-level expression of the human alpha-globin gene in transgenic mice. Expression in fetal liver and blood is copy number dependent and at levels comparable to that of the endogenous mouse alpha-globin genes. Transgenic fetuses with high-copy numbers of the transgene suffer severe anemia and die before birth. Using a construct with both the human alpha- and beta-globin genes and the beta-globin DCR, live mice with low-copy numbers were obtained. Both human globin genes are expressed at high levels in adult red cells to give human hemoglobin HbA in amounts equal to or greater than endogenous mouse hemoglobin. Expression of HbA in murine red cells is not accompanied by any increase in mean corpuscular volume (MCV) or mean corpuscular hemoglobin concentration (MCHC). However, these transgenic mice tend to have an increased number of reticulocytes in peripheral blood; consistent with some degree of hemolysis. Metabolic labeling experiments showed balanced mouse globin synthesis, but imbalanced human globin synthesis, with an alpha/beta biosynthetic ratio of approximately 0.6. Thus, these mice have mild anemia. These results are discussed with relation to the coordinate regulation of alpha- and beta-globin synthesis in erythroid tissues.
Animals↗
Molecular characterization of erythrocyte glucose-6-phosphate dehydrogenase deficiency in Al-Ain District, United Arab Emirates.
In a cross-sectional study, the activity, electrophoretic mobility and genotypes of glucose-6-phosphate dehydrogenase (G6PD) were determined among healthy, UAE national school boys from Al-Ain District in the United Arab Emirates, The prevalence of G6PD deficiency in this population sample was 11%. The majority of G6PD-deficient subjects were descendants of Omani, Baluchi or Yemeni migrants. Of 18 deficient subjects, 16 had an enzyme activity of < 10% of normal while 2 had an activity of just above 10%. Electrophoresis was performed on 166 samples and showed that, apart from deficient samples, all had the normal mobility of G6PD type B. Of the 18 deficient subjects, 14 had the B type mobility of G6PD Mediterranean and 4 had the A type mobility of G6PD A-. Genotyping demonstrated that 10 had the Mediterranean mutation while 3 had the A- mutation, consistent with their electrophoretic mobility. Another 3 had the G6PD Aures mutation, recently described as polymorphic in Algeria and Spain. The mutations in the remaining 2 subjects have not yet been identified.
Adolescent↗