No abstract

We provide novel prognostic factors for CBF AML and show that patients with t(8;21) who experience relapse have an inferior survival duration.

This study evaluated azacitidine as treatment of minimal residual disease (MRD) determined by a sensitive donor chimerism analysis of CD34+ blood cells to pre-empt relapse in patients with CD34+ myelodysplastic syndromes (MDS) or acute myeloid leukemia (AML) after allogeneic hematopoietic stem cell transplantation (HSCT). At a median of 169 days after HSCT, 20/59 prospectively screened patients experienced a decrease of CD34+ donor chimerism to <80% and received four azacitidine cycles (75 mg/m2/day for 7 days) while in complete hematologic remission. A total of 16 patients (80%) responded with either increasing CD34+ donor chimerism to ⩾80% (n=10; 50%) or stabilization (n=6; 30%) in the absence of relapse. Stabilized patients and those with a later drop of CD34+ donor chimerism to <80% after initial response were eligible for subsequent azacitidine cycles. A total of 11 patients (55%) received a median of 4 (range, 1–11) additional cycles. Eventually, hematologic relapse occurred in 13 patients (65%), but was delayed until a median of 231 days (range, 56–558) after initial decrease of CD34+ donor chimerism to <80%. In conclusion, pre-emptive azacitidine treatment has an acceptable safety profile and can substantially prevent or delay hematologic relapse in patients with MDS or AML and MRD after allogeneic HSCT.

In younger patients with AML, the ELN classification seems to be the best available framework for prognostic estimations to date. Caution is advised concerning its use for prospective treatment allocation before it has been prospectively validated. In elderly patients, alternative prognostic factors are desirable for further risk stratification of IR.

Summary:Monitoring the engraftment of donor cells after allogeneic blood stem cell transplantation (BSCT) may be important for the early diagnosis of graft failure or relapse of disease. Several techniques have been reported for this purpose. PCR-based assays analyzing polymorphic short tandem repeat (STR) markers are attractive because they are sensitive and can be performed rapidly. The intent of the present study was to test a novel approach for the quantification of mixed chimerism using a commercial multiplex STR assay with fluorescence-based detection for forensic purposes. The feasibility of this assay and the accuracy of quantitative results was tested using serial cell mixtures of unrelated individuals. Sample preparation was optimized to obtain information from minute amounts of starting material, eg from patients with aplasia or from sorted cell populations. Using the STR-PCR, discrimination between donor and recipient was possible in all patients analyzed (n = 25). Cell dilution experiments showed a linear correlation between the cell numbers added and the proportions found, with the limit of detection for a minor cell population being 5%. Comparison of values obtained with standard FISH analysis in patients transplanted from sex-mismatched donors showed an excellent correlation with the STR-PCR results. Taken together, this procedure allows the rapid, versatile and accurate quantification of mixed chimerism, even with minuscule numbers of cells. Keywords: chimerism; short-tandem repeats (STR); quantification; PCR; fluorescence detection Allogeneic blood stem cell transplantation is frequently performed in patients with nonmalignant and malignant hematological diseases such as severe aplastic anemia (SAA), severe combined immunodeficiency (SCID), acute and chronic leukemia and lymphoma. Detection of the degree of chimerism after transplantation is an important method for monitoring the engraftment of donor cells and allows early detection of graft failure. This seems to be especially important in patients at risk for graft failure, ie patients Correspondence: C Thiede, Medizinische Klinik und Poliklinik I, Universitätsklinikum Carl Gustav Carus der Technischen Universität, Fetscherstrasse 74, 01307 Dresden, Germany Received 12 September 1998; accepted 4 January 1999 receiving T cell-depleted stem cell grafts from unrelated donors.1 In addition, novel therapeutic approaches like nonmyeloablative stem cell transplantation 2,3 are dependent on rapid information on the degree of mixed chimerism to schedule therapeutic interventions, eg donor lymphocyte infusion (DLI).Several approaches have been published for the detection of chimerism. In sex-mismatched transplantation settings, information on the ratio between donor and recipient can be obtained efficiently and rapidly by using fluorescent in situ hybridization (FISH) with probes specific for X-and Y-chromosome.4,5 PCR-based amplification of a single variable number of tandem repeat (VNTR) or short tandem repeat (STR) markers is another frequently perf...

Sequential analysis of chimerism after allogeneic blood stem cell transplantation (BSCT) has been shown to be predictive for graft failure and relapse. We have explored the impact of a novel approach for the quantitative determination of chimerism using a commercial PCR assay with multiplex amplification of nine STR-loci and fluorescence detection. The feasibility was studied in 121 patients transplanted from related or unrelated donors. Follow-up investigation was performed in 88 patients. Twenty-eight of these patients had received a transplantation after dose-reduced conditioning therapy. Results were compared to data obtained by FISH analysis in a subgroup of patients receiving grafts from sex-mismatched donors. The analysis was possible in all patients, the median number of informative alleles was 4 (range 1-8) compared to 7 (range 1-9) in the related and unrelated situation, respectively. A good correlation was seen in 84 samples from 14 patients analyzed in parallel with STR-PCR and FISH. Decreasing values of donor chimerism were detected prior to or concomitantly with the occurrence of graft failure and relapse of disease in all patients investigated prospectively. Using FACS-sorted material, eg peripheral blood CD34 + cells, the assay permitted the detection of residual recipient cells with high sensitivity (down to one CD34 + Kasumi cell in 40 000 normal WBC). Evaluation of the inter-laboratory reproducibility revealed that in 20 samples analyzed in three different centers, the median coefficient of variation was 2.1% (range 0.7-9.6%). Taken together, the results support the use of the test as a valuable tool in the follow-up of patients undergoing allogeneic BSCT. In cases lacking PCRdetectable disease-specific gene products, this assay may represent an alternative to recently established real-time PCR methods. Leukemia (2001) 15, 293-302.

Loss of p53Fa tumor suppressor gene located on the short arm of chromosome 17 (band 17p13.1)Fwas detected in 105 out of 2272 (5%) adult acute myeloid leukemia (AML) patients who took part in the Study Alliance Leukemia AML96 and AML2003 multi center trials. There were 85 patients with 17p (p53) deletion with multiple aberrations and 20 patients with a 17p (p53) deletion as single aberration or with only one additional chromosomal abnormality. None of the p53-deleted patients displayed additional low-risk aberrations, like t(8;21) or inv(16). Significant positive association between p53 deletion and other high-risk factors was identified for del(5q) (Po0.001), À5 (Po0.001) and À7 (Po0.05). The molecular risk factors FLT3-ITD and NPM1 mutation showed an inverse correlation to the p53 deletion in complex aberrant patients (Po0.001). The multivariate analysis revealed p53 deletion without multiple aberrations as an independent negative prognostic factor for disease-free survival (Po0.001), relapse risk (P ¼ 0.028) and overall survival (Po0.001). Thus, the single p53 deletion should be considered as a high-risk aberration for future risk-adapted treatment strategies in AML.

We present an analysis of prognostic factors derived from a trial in patients with acute myeloid leukemia older than 60 years. The AML96 trial included 909 patients with a median age of 67 years (range, 61-87 years). Treatment included cytarabine-based induction therapy followed by 1 consolidation.