Hermann Kreyenberg

Prognostic Value of Minimal Residual Disease Quantification Before Allogeneic Stem-Cell Transplantation in Relapsed Childhood Acute Lymphoblastic Leukemia: The ALL-REZ BFM Study Group

PURPOSE Minimal residual disease (MRD) before allogeneic stem-cell transplantation was shown to predict outcome in children with relapsed acute lymphoblastic leukemia (ALL) in retrospective analysis. To verify this, the Acute Lymphoblastic Leukemia Relapse Berlin-Frankfurt-Münster (ALL-REZ BFM) Study Group conducted a prospective trial. PATIENTS AND METHODS Between March 1999 and July 2005, 91 children with relapsed ALL treated according to the ALL-REZ BFM 96 or 2002 protocols and receiving stem-cell transplantation in >or= second remission were enrolled. MRD quantification was performed by real-time polymerase chain reaction using T-cell receptor and immunoglobulin gene rearrangements. RESULTS Probability of event-free survival (pEFS) and cumulative incidence of relapse (CIR) in 45 patients with MRD >or= 10(-4) leukemic cells was 0.27 and 0.57 compared with 0.60 and 0.13 in 46 patients with MRD less than 10(-4) leukemic cells (EFS, P = .004; CIR, P < .001). Intermediate-risk patients (strategic group S1) with MRD >or= 10(-4) leukemic cells (n = 14) had a pEFS of 0.20 and CIR of 0.73, whereas patients with MRD less than 10(-4) leukemic cells (n = 21) had a pEFS of 0.68 and CIR of 0.09 (EFS, P = .020; CIR, P < .001). High-risk patients (S3/4, third complete remission) who received transplantation with an MRD load of less than 10(-4) leukemic cells (n = 25) showed a pEFS and CRI of 0.53 and 0.18, respectively. In contrast, pEFS and CRI were 0.30 and 0.50 in patients who received transplantation with an MRD load of >or= 10(-4) leukemic cells. Multivariate Cox regression analysis revealed MRD as the only independent parameter predictive for EFS (P = .006). CONCLUSION MRD is an important predictor for post-transplantation outcome. As a result, new strategies with modified stem-cell transplantation procedures will be evaluated in ALL-BFM trials.

Increasing Mixed Chimerism Is an Important Prognostic Factor for Unfavorable Outcome in Children With Acute Lymphoblastic Leukemia After Allogeneic Stem-Cell Transplantation: Possible Role For Pre-Emptive Immunotherapy?

PURPOSE We recently reported that children with acute leukemias who show increasing mixed chimerism (MC) after allogeneic stem-cell transplantation have a significantly enhanced risk of relapse. Here we present the results of a prospective multicenter study to investigate (1) whether relapse of acute lymphoblastic leukemia (ALL) can be determined in advance by serial analysis of chimerism, and (2) if outcome can be influenced by withdrawal of immunosuppression and/or by low-dose donor lymphocyte infusion when increasing MC is detected. PATIENTS AND METHODS Serial and quantitative analysis of chimerism was performed using a fluorescent-based short-tandem-repeat-polymerase chain reaction in 163 children with ALL. RESULTS One hundred one patients revealed complete chimerism (CC) or low-level MC (CC/low-level MC); increasing MC was found in 46 patients; and decreasing MC, in 16 patients. Relapse was significantly more frequent in patients with increasing MC (26 of 46) than in patients with CC/low-level MC (eight of 101) or in patients with decreasing MC (0 of 16; P <.0001). The probability of 3-year event-free survival (EFS) was 54% for all patients, 66% for patients with CC/low-level MC (n = 101), 66% for patients with decreasing MC (n = 16), and 23% for patients with increasing MC (n = 46; P <.0001). Of the 46 patients with increasing MC, 31 received immunotherapy. This group had a significantly higher 3-year EFS estimate (37%) than the 15 patients who did not receive immunotherapy (0%; P <.001). CONCLUSION Serial analysis of chimerism reliably identifies patients at highest risk to relapse. The 3-year EFS of patients with increasing MC without immunotherapy was 0%, by which overt relapse could be prevented in a considerable group of patients.

Minimal residual disease (MRD) status prior to allogeneic stem cell transplantation is a powerful predictor for post-transplant outcome in children with ALL

We have retrospectively investigated the relationship between the level of minimal residual disease (MRD) detected in bone marrow taken prior to conditioning therapy and outcome following stem cell transplantation for high risk childhood ALL. Forty-one patients, in whom both a molecular marker of MRD and sufficient archival material was available, were included in the study. All were in remission at BMT: eight in CR1, 32 in CR2 and five in greater than CR2. MRD was measured by PCR amplification of antigen receptor gene rearrangements and clone-specific oligoprobing, the median sensitivity of detection being one leukaemic cell in 10000 normals. Results were classified as high-level positive (if a clonal band was evident after electrophoresis), low-level positive (if MRD was detected only after oligoprobing) and negative. MRD was detected at high levels in 17 patients, at low levels in 10 patients and 14 patients were MRD negative at the time of transplant. The 5-year event-free survival for these groups was 23%, 48% and 78%, respectively (P = 0.022). Limited multivariate analysis confirmed the significance of MRD (P = 0.0095) vs CR status, donor type, sex, immunophenotype and acute GvHD. This study confirms the strong relationship between MRD level and outcome following allogeneic transplantation. In contrast to a previous study we observed that a minority of children with high-level pre-BMT MRD can enter long lasting remission. The possible role for acute GVHD coupled with a graft-versus-leukaemia effect in the clearance of high level MRD in patients with ALL is discussed.

Complete remission after blinatumomab-induced donor T-cell activation in three pediatric patients with post-transplant relapsed acute lymphoblastic leukemia

Complete remission after blinatumomab-induced donor T-cell activation in three pediatric patients with post-transplant relapsed acute lymphoblastic leukemia

Quantitative analysis of chimerism after allogeneic stem cell transplantation by PCR amplification of microsatellite markers and capillary electrophoresis with fluorescence detection: the Tuebingen experience

Quantitative analysis of chimerism after allogeneic stem cell transplantation by PCR amplification of microsatellite markers and capillary electrophoresis with fluorescence detection: the Tuebingen experience

CD271 antigen defines a subset of multipotent stromal cells with immunosuppressive and lymphohematopoietic engraftment-promoting properties

Background In vitro proliferative and differentiation potential of mesenchymal stromal cells generated from CD271+ bone marrow mononuclear cells (CD271-mesenchymal stromal cells) has been demonstrated in several earlier and recent reports. In the present study we focused, in addition to proliferative and differentiation potential, on in vitro and in vivo immunosuppressive and lymphohematopoietic engraftment-promoting potential of these mesenchymal stromal cells compared to bone marrow-derived mesenchymal stromal cells generated by plastic adherence (plastic adherence-mesenchymal stromal cells). Design and Methods We set up a series of experimental protocols in order to determine the phenotype of CD271-mesenchymal stromal cells, and their clonogenic, proliferative, differentiation and immunosuppressive potential. The potential of CD271-mesenchymal stromal cells to improve the engraftment of CD133+ hematopoietic stem cells at co-transplantation was evaluated in immunodeficient NOD/SCID-IL2Rγnull mice. Results In vitro studies demonstrated that CD271-mesenchymal stromal cells differentiate along adipogenic, osteogenic and chondrogenic lineages (trilineage potential), produce significantly higher levels of cytokines than plastic adherence-mesenchymal stromal cells, and significantly inhibit the proliferation of allogeneic T-lymphocytes in mixed lymphocyte reaction assays. Elevated levels of prostaglandin E2, but not nitric monoxide, mediated the majority of this immunosuppressive effect. In vivo studies showed that CD271-mesenchymal stromal cells promoted significantly greater lymphoid engraftment than did plastic adherence-mesenchymal stromal cells when co-transplanted with CD133+ hematopoietic stem cells at a ratio of 8:1 in immunodeficient NOD/SCID-IL2Rγnull mice. They induced a 10.4-fold increase in the number of T cells, a 2.5-fold increase in the number of NK cells, and a 3.6-fold increase in the number of B cells, indicating a major qualitative difference between these two mesenchymal stromal cell populations. Conclusions Our results indicate that CD271 antigen provides a versatile marker for prospective isolation and expansion of multipotent mesenchymal stromal cells with immunosuppressive and lymphohematopoietic engraftment-promoting properties. The co-transplantation of such cells together with hematopoietic stem cells in patients with hematologic malignancies may prove valuable in the prevention of impaired/delayed T-cell recovery and graft-versus-host disease.

Level of minimal residual disease prior to haematopoietic stem cell transplantation predicts prognosis in paediatric patients with acute lymphoblastic leukaemia: a report of the Pre-BMT MRD Study Group

Level of minimal residual disease prior to haematopoietic stem cell transplantation predicts prognosis in paediatric patients with acute lymphoblastic leukaemia: a report of the Pre-BMT MRD Study Group

Minimal residual disease prior to stem cell transplant for childhood acute lymphoblastic leukaemia

Summary. Allogeneic stem cell transplantation (SCT) is a highly effective therapy for childhood acute lymphoblastic leukaemia (ALL). Concerns about unnecessary toxicity and expense mean that SCT is currently largely reserved for children who cannot be cured with chemotherapy. Not surprisingly, many such children also fail SCT. Retrospective studies have shown that a single analysis of minimal residual disease (MRD) pre‐SCT identified those at highest risk of relapse. It is now appropriate to call for the universal incorporation of standardized MRD testing into SCT protocols as the next step to maximize the clinical impact of this technology in ALL.

Preemptive immunotherapy in childhood acute myeloid leukemia for patients showing evidence of mixed chimerism after allogeneic stem cell transplantation

Previous studies have shown that children with acute myeloid leukemia (AML) who developed mixed chimerism (MC) were at high risk for relapse after allogeneic stem-cell transplantation (allo-SCT). We investigated the feasibility of intensified preemptive immunotherapy in children receiving allo-SCT for AML. Eighty-four children were registered in our trial from May 2005 to April 2009; of these, 71 fulfilled the inclusion criteria and were treated according to the study protocol. Serial and semiquantitative analyses of posttransplantation chimerism were performed. Defined immunotherapy approaches were considered in MC patients. Continuous complete chimerism (CC) was observed in 51 of 71 patients. MC was detected in 20 patients and was followed by immunotherapy in 13. Six of 13 MC patients returned to CC without toxicity and remained in long-term remission. Overall, the probability of event-free survival (pEFS) was 66% (95% confidence interval [95% CI] = 53%-76%) for all patients and 46% (95% CI = 19%-70%) in MC patients with intervention; however, this number increased to 71% (95% CI = 26%-92%) in 7 of 13 MC patients on immunotherapy who were in remission at the time of transplantation. All MC patients without intervention relapsed. These results suggest that MC is a prognostic factor for impending relapse in childhood AML, and that preemptive immunotherapy may improve the outcome in defined high-risk patients after transplantation.

The EuroChimerism concept for a standardized approach to chimerism analysis after allogeneic stem cell transplantation

Hematopoietic stem cell transplantation is becoming an increasingly important approach to treatment of different malignant and non-malignant disorders. There is thus growing demand for diagnostic assays permitting the surveillance of donor/recipient chimerism posttransplant. Current techniques are heterogeneous, rendering uniform evaluation and comparison of diagnostic results between centers difficult. Leading laboratories from 10 European countries have therefore performed a collaborative study supported by a European grant, the EuroChimerism Concerted Action, with the aim to develop a standardized diagnostic methodology for the detection and monitoring of chimerism in patients undergoing allogeneic stem cell transplantation. Following extensive analysis of a large set of microsatellite/short tandem repeat (STR) loci, the EuroChimerism (EUC) panel comprising 13 STR markers was established with the aim to optimally meet the specific requirements of quantitative chimerism analysis. Based on highly stringent selection criteria, the EUC panel provides multiple informative markers in any transplant setting. The standardized STR-PCR tests permit detection of donor- or recipient-derived cells at a sensitivity ranging between 0.8 and 1.6%. Moreover, the EUC assay facilitates accurate and reproducible quantification of donor and recipient hematopoietic cells. Wide use of the European-harmonized protocol for chimerism analysis presented will provide a basis for optimal diagnostic support and timely treatment decisions.