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Paediatric Leukemia

Increasing mixed chimerism defines a high-risk group of childhood acute myelogenous leukemia patients after allogeneic stem cell transplantation where pre-emptive immunotherapy may be effective


Children with leukemias and increasing mixed chimerism (increasing MC) after allogeneic stem cell transplantation have the highest risk to relapse. Early immunological intervention was found to be effective in these cases. To substantiate this on a defined group of pediatric acute myelogenous leukemia (AML) patients, we performed serial analysis of post transplant chimerism and pre-emptive immunotherapy in patients with increasing MC. In total, 81 children were monitored, 62 patients revealed complete chimerism (CC), low-level MC or decreasing MC. Increasing MC was detected in 19 cases. Despite early immunological intervention relapse was still significantly more frequent in patients with increasing MC (9/19) than in patients with CC, low-level or decreasing MC (8/62, P<0.005). The probability of 3-year event-free survival (EFS) was 52% for all patients (n=81), 59% for patients with CC, low-level MC, 60% for patients with decreasing MC (n=62), and 28% for patients with increasing MC (n=19, P<0.005). Patients with increasing MC who received early immunological intervention showed a significantly enhanced probability for event-free survival (pEFS 36%, n=15) compared to patients with increasing MC without intervention (pEFS 0%, n=4, P<0.05). These results prove that pediatric AML patients with increasing MC are at highest risk for relapse and that early immunological intervention can prevent relapse in these patients.


Allogeneic stem cell transplantation (allo-SCT) has evolved to a convincing treatment modality for children with a high-risk acute myelogenous leukemia (AML), but the success is still mainly threatened by relapses.1 In case of relapse, an additional allo-SCT may provide a small curative chance, but success is limited by the high lethality.2,3,4,5 Therefore, a wide range of procedures has been tried in patients with relapses, all following the same principle to control malignant cells by engendering a graft-versus-leukemia (GVL) effect.2,3,4,6,7,8,9,10, 11,12,13 These treatment regimens were based on (1) cessation of cyclosporine A (CSA) or other immunosuppressive drugs,14,15 (2) administration of lymphocyte activating cytokines6,11,16 and (3) additional infusion of donor lymphocyte (DLI) eventually supported by cytokines.17,18 These attempts are convincing in patients with chronic myelogenous leukemias (CML)13,19,20,21,22 but still questionable in patients with relapsed acute leukemias.9,11,18,23 A major risk of this approach is the induction of severe graft-versus-host disease (GVHD), caused by the high cell numbers given, which are necessary in the treatment of an open relapse.

Vice versa, pre-emptive treatment of an impending relapse might allow DLI with low cell numbers, which in turn might prevent the occurrence of GVHD.18,24,25,26 In previous studies we found evidence that patients with different types of high-risk leukemias and myelodysplastic syndromes (MDS) who developed a dynamic increase of autologous hematopoietic cells (increasing mixed chimerism, increasing MC) in peripheral blood relapse significantly more often (P<0.0001) than patients with a stable complete chimerism (CC).27,28

In a small series of such increasing MC patients, the relapse rate could be reduced by termination of CSA or application of low-dose DLI. These findings supported the hypothesis that patients with low leukemic cell numbers might be more effectively controlled by immune modulatory treatment modalities than those patients with acute leukemia who had developed an open relapse post transplant.

To prove this hypothesis especially in AML pediatric patients after allo-SCT, we performed a prospective multicenter trial to investigate two important questions: (1) does increasing MC significantly predict outcome and (2) can outcome be improved by early immunological intervention?

Patients and methods


Between January 1996 and December 2001, post transplant samples of 81 children who had received allo-SCT for AML were referred from 13 pediatric transplant centers in Germany to the study center in Tübingen. The study protocol was approved by the Clinical Ethics Committee of the University of Tübingen, and the study was performed according to the principles of the Declaration of Helsinki. Informed consent was obtained from the patients and parents according to the institutional guidelines. Data were obtained for analysis until May 2002. Table 1 summarizes the patient characteristics, the types of stem cell donors, the sources of stem cells, and the conditioning regimens.

Table 1 Patient characteristics

Chimerism assays and immunotherapy

Hematopoietic chimerism of each patient was assayed in the peripheral blood at weekly intervals during the first 100 days and monthly thereafter. A previously described semiquantitative PCR approach based on the amplification of STR markers was used.29,30 Patients who showed increasing MC post transplant, as defined in detail below, were offered immunotherapy according to the study protocol.31 We decided against performing a randomized trial, which would have given the greatest evidence as we have discussed in detail elsewhere.32 This was because (i) we observed almost solely fatal outcome in children with increasing MC and (ii) we had experienced that relapse could be prevented by pre-emptive immunotherapy in some of these patients without serious side effects.28,31

Immunotherapy for patients receiving CSA consisted of immediate discontinuation of the immunosuppressive agent. Chimerism was further assayed weekly until CC status was restored. If MC showed an additional increase of more than 5% after cessation of CSA, a DLI was given.

Immunotherapy for patients not receiving CSA consisted of DLI as frontline treatment. The cell dose administered was based on the number and potential severity of HLA mismatches between the donor and recipient. The study design prescribed to administer 1 × 105 CD3-positive cells per kilogram of body weight in case of an MFD, 5 × 104 in case of a MUD and 2.5 × 104 in case of MMUD or MMFD. After DLI, chimerism status was assayed weekly until CC status was restored. Patients who would have shown a further increase in MC were scheduled to receive an additional DLI after at least 3 weeks had elapsed. However, this was not necessary in any of these patients, because they had either relapsed within this time span or responded.

Definition of chimerism status and response

The patients were differentiated exclusively on the basis of serial analysis by STR-PCR, within the limits of sensitivity (approximately 1%). Patients who showed no evidence of autologous cells at any time post transplant were considered to have CC. Patients who manifested weak autologous signals not exceeding 1% were defined as having low-level MC. Patients who showed autologous signals immediately post transplant that decreased spontaneously during follow-up were classified as having decreasing MC. Patients who showed a significant increase (5% or more) in the proportion of autologous cells between sequential assessments were defined as having increasing MC. Response was defined as a return to CC. GVHD was graded according to clinical criteria as previously described.33,34

Statistical methods

The probability of survival and of event- (EFS) and relapse-free survival was estimated by the Kaplan–Meier method.35 Univariate analyses of prognostic factors were performed by using the log-rank test and Fisher's exact test. Multivariate analyses have been performed using the Cox proportional hazards model to analyze different risk factors simultaneously.



In total, 81 patients were included in the analysis. These patients showed either CC (n=35), low-level MC (n=22), decreasing MC (n=5) or increasing MC (n=19). Early immunological intervention was recommended to all patients with increasing MC but was performed in only 15 of those cases. Although the study protocol assigned all patients with increasing MC to be treated as described above, each transplant center made its own final decision on whether to start immunotherapy. In four patients physicians decided against treatment for different reasons. In 3/4 patients a DLI from the donor was not available on time, and 1/4 patients suffered from severe infection and toxicity.


Relapses occurred significantly more often in the group of patients with increasing MC (7/19) than in patients with CC, low-level MC or decreasing MC (8/62, P<0.01). Further analysis of the increasing MC group revealed a striking difference between treated and untreated patients. In total, 6/15 patients with increasing MC who received early immunological intervention remained in complete remission, 2/15 died from transplant-related causes, and 7/15 relapsed. A total of 4/4 patients with increasing MC who did not receive prophylactic treatment either rejected their graft (n=2) or relapsed (n=2) and none of these patients survived. Survival rate in treated compared to untreated patients turned out to differ significantly (log rank: P<0.05; Table 2).

Table 2 Outcome according to chimerism status

Patients who responded to cessation of CSA as frontline therapy generally showed a decrease of autologous DNA in the peripheral blood approximately 1 week after cessation of CSA. Patients who responded to DLI did not show a decrease of autologous DNA until 2 to 3 weeks after treatment.

In seven patients, the hematological relapse could not be anticipated by the serial analysis of hematopoietic chimerism. In 2/7 patients, the relapse occurred beyond day +100 (day 208 and 543). In these patients, the monthly intervals between the respective analyses beyond day +100 might have been too long. Five out of seven patients developed relapse before day +100 post transplant. Serial analysis of chimerism in weekly intervals was not able to identify these high-risk patients. They all developed a fulminate relapse and died.


The probability of estimated 3-year EFS was 52% for all patients (n=81, Figure 1). Patients who showed CC, low-level MC (n=57) or decreasing MC (n=5) showed significantly higher 3-year EFS estimates (59 and 60%, resp.) than patients with increasing MC (n=19, 28%, Figure 2).

Figure 1

Kaplan–Meier analysis of EFS for all study patients (n=81).

Figure 2

Kaplan–Meier analysis of EFS according to chimerism status. Abbr.: CC, complete chimerism; LL-MC, low-level mixed chimerism; de-MC, decreasing mixed chimerism; in-MC, increasing mixed chimerism.

Patients with increasing MC who received additional immunotherapy (n=15) had an estimated 3-year EFS of 36% and patients with increasing MC who did not receive additional treatment (n=4) had an estimated 3-year EFS of 0% (P<0.05; Figure 3).

Figure 3

Kaplan–Meier analysis of EFS in patients with increasing MC. Comparison of patients with increasing MC who received early immunological intervention (n=15) and patients with increasing MC who did not receive early immunological intervention (n=4).

Univariate analyses revealed that outcome was also affected by the type of donor and state of remission. The 3-year EFS estimates were 73% for MFD (n=28), 51% for MUD (n=32), 15% for MMFD (n=13), 50% for MMUD (n=8) (Log rank: P<0.05), 69% for CR1 (n=34), 48% for CR2 (n=29), 40% for>CR2 (n=5), and 20% for patients where a remission could not be achieved prior to transplantation (n=13) (Log rank: P<0.05). Patients who received a busulfan containing regimen (n=71) had an estimated 3-year EFS of 56% compared to 27% in patients who were treated with total body irradiation (n=10). This difference was barely not significant (Log rank: P=0.07).

Toxicity and GVHD

After immunotherapy, 10 of the 15 patients developed acute GVHD with different severity. Of the 10 patients who developed GVHD, four survived in complete remission, five died of relapsed disease, one died of transplant-related causes and one developed chronic GVHD (Tables 3 and 4). Of the five children who did not develop acute GVHD after immunological intervention, two survived in complete remission, two died after relapse, and one died of transplant-related causes (Table 5).

Table 3 Characteristics of patients with increasing MC
Table 4 Univariate and analyses of different parameters with respect to EFS
Table 5 Acute GVHD and outcome of immunotherapy in patients with increasing mixed chimerism (increasing MC)

We found a relatively high TRM with respect to all patients included in this study (Table 2). Although there is a trend to a higher TRM rate in patients with CC and low level MC (14/57 patients; 25%), compared to 1/5 patients with decreasing MC (20%), or to 2/19 patients with increasing MC (11%) this difference was not significant (P=0.388). In a proportional hazards analysis, the five patients with MMUD were disregarded to avoid spurious results; neither the donor, nor the remission status, nor the conditioning regimen (TBI vs BUS) had influence on the TRM rate. However, no T-cell depletion decreased the risk for TRM by a factor 0.169 (95 CI: 0.05–0.579; P<0.005) compared to T-cell depletion of the graft.


The efficacy of immunotherapy after allo-SCT for acute leukemia is still a matter of debate.11,12,13,18,36 Compared to patients with chronic myelogenous leukemia (CML) where DLI has been demonstrated to be effective,13,20,21,22 experience with immunotherapy in patients with acute leukemias has shown that DLI initiated in a stage of frank hematological relapse only rarely induces complete remission (8% of patients with acute lymphoblastic leukemia (ALL) and 22% of patients with AML).14,37,38,39 If tumor burden is effectively reduced by chemotherapy prior to DLI, the rate of complete response can be significantly improved (33% in ALL and 37% in AML).40,41 This gives evidence that immunotherapy is more effective when the amount of malignant cells is still very small so that the limited number of lymphocytes to which clinicians are restricted to avoid severe GVHD efficiently overcomes relapse.18,25,26 Hence, it is desirable to identify those patients who represent the high-risk group for relapse at the very early stage of its development, so that additional immunotherapy might be more effective even with low doses of DLI. Patients with increasing MC represent such high-risk patients and can be identified with short-term monitoring of hematopoietic chimerism. These investigations can serve as a basis for additional immunotherapy.

Our prospective study on children who received allo-SCT for high-risk AML is based on 81 evaluable patients and therefore represents a relative large cohort for this rare entity in children. Seven out of 26 patients could not be identified in advance as high-risk patients for impending relapse. Two of them relapsed, beyond day +200 (days 208 and 543) when chimerism was monitored only at monthly intervals. Thus, the time span between last analysis of chimerism and relapse might have been too long in these cases, but 5/7 patients developed a relapse before day +100. Even weekly analysis of chimerism was not able to identify these patients in advance. We hypothesize whether the pre-transplant leukemia burden was so overwhelmingly high that the transplanted immune system was not able to control the residual disease. It must be accepted that some children with aggressive AML developed a fulminate relapse, which could neither be identified in advance nor influenced by a pre-emptive immunotherapy with any method presently available.

We also acknowledge that this study was not randomized for early immunological intervention due to the fact that prior results on patients after allo-SCT with heterogeneous entities of severe hematological malignancies already showed significant results.31 Early immunotherapy was recommended for all patients with increasing MC as has been argued in detail elsewhere.32 Therefore, comparison can only be made between treated patients and patients who were not treated for different reasons. Consequently, a selection bias as a factor in our results cannot be ruled out. Nonetheless, the data were gained in a prospective study and substantiate recent findings.

Furthermore, our previous study revealed that MC first developed within various subgroups of peripheral hematopoietic cells. Within the first year of observation, the reappearance of leukemia relapse is regularly preceded by a dynamic increase of recipient cells of different hematopoietic cell subpopulations.

We recently showed that the type of normal autologous hematopoietic cells that initially dominate in increase greatly differ individually and more often represent just normal autologous granulocytes or monocytes.42 However, this increase of normal autologous cells very reliably predicts relapse and can therefore be taken as a decisive signal that development of relapse has commenced without a chance for self-limitation.

These results are in line with reports from solid organ transplants where mixed hematopoietic chimerism seems to be associated with the development of graft tolerance.43 We therefore hypothesize that this immune tolerance might be accompanied with a loss of the GVL effect, thus giving low numbers of residual leukemia cells a novel chance to expand. An immunological intervention just enough to overcome this fatal immune tolerance might then be effective in suppressing an imminent relapse at this very early stage. These findings and the underlying hypothesis can be supported by recent experimental findings in animals. Mice sublethally irradiated and coinjected with allogeneic bone marrow and leukemic blast cells develop MC followed by leukemia. In contrast, mice supra-lethally irradiated and subsequently treated identically maintain a CC and remain free from leukemic blasts.44 These interesting results substantiate a model that the phenotype of increasing MC is based on an increase of autologous cells and suggests that immune tolerance is a crucial factor for the expansion of leukemic blasts.

In conclusion, this study confirms that semiquantitative and serial analysis of hematopoietic chimerism in peripheral blood can detect at a high rate the critical increasing MC phenotype, which indicates AML patients after allo-SCT with highest risk for relapse. Furthermore, early immunological intervention might improve their outcome. However, future trials are necessary to optimize treatment modalities.


  1. 1

    Amadori S, Testi AM, Arico M et al. Prospective comparative study of bone marrow transplantation and postremission chemotherapy for childhood acute myelogenous leukemia. The Associazione Italiana Ematologia ed Oncologia Pediatrica Cooperative Group. J Clin Oncol 1993; 11: 1046–1054.

    CAS  Article  Google Scholar 

  2. 2

    Bosi A, Laszlo D, Labopin M et al. Second allogeneic bone marrow transplantation in acute leukemia: results of a survey by the European Cooperative Group for Blood and Marrow Transplantation. J Clin Oncol 2001; 19: 3675–3684.

    CAS  Article  Google Scholar 

  3. 3

    Munoz A, Badell I, Olive T et al. Second allogeneic hematopoietic stem cell transplantation in hematologic malignancies in children: long-term results of a multicenter study of the Spanish Working Party for Bone Marrow Transplantation in Children (GETMON). Haematologica 2002; 87: 331–332.

    Google Scholar 

  4. 4

    Barrett AJ, Locatelli F, Treleaven JG et al. Second transplants for leukaemic relapse after bone marrow transplantation: high early mortality but favourable effect of chronic GVHD on continued remission. A report by the EBMT Leukaemia Working Party. Br J Haematol 1991; 79: 567–574.

    CAS  Article  Google Scholar 

  5. 5

    Chessells JM . Treatment of childhood acute lymphoblastic leukaemia: present issues and future prospects. Blood Rev 1992; 6: 193–203.

    CAS  Article  Google Scholar 

  6. 6

    Sosman JA, Sondel PM . The graft-vs-leukemia effect. Implications for post-marrow transplant antileukemia treatment. Am J Pediatr Hematol Oncol 1993; 15: 185–195.

    CAS  Article  Google Scholar 

  7. 7

    Verdonck LF, Lokhorst HM, Dekker AW et al. Graft-versus-myeloma effect in two cases. Lancet 1996; 347: 800–801.

    CAS  Article  Google Scholar 

  8. 8

    Bertz H, Burger JA, Kunzmann R et al. Adoptive immunotherapy for relapsed multiple myeloma after allogeneic bone marrow transplantation (BMT): evidence for a graft-versus-myeloma effect. Leukemia 1997; 11: 281–283.

    CAS  Article  Google Scholar 

  9. 9

    Porter DL, Connors JM, Van Deerlin VM et al. Graft-versus-tumor induction with donor leukocyte infusions as primary therapy for patients with malignancies. J Clin Oncol 1999; 17: 1234.

    CAS  Article  Google Scholar 

  10. 10

    Porter DL, Roth MS, Lee SJ et al. Adoptive immunotherapy with donor mononuclear cell infusions to treat relapse of acute leukemia or myelodysplasia after allogeneic bone marrow transplantation. Bone Marrow Transplant 1996; 18: 975–980.

    CAS  PubMed  Google Scholar 

  11. 11

    Mehta J, Powles R, Kulkarni S et al. Induction of graft-versus-host disease as immunotherapy of leukemia relapsing after allogeneic transplantation: single-center experience of 32 adult patients. Bone Marrow Transplant 1997; 20: 129–135.

    CAS  Article  Google Scholar 

  12. 12

    Imamura M, Hashino S, Tanaka J . Graft-versus-leukemia effect and its clinical implications. Leuk Lymphoma 1996; 23: 477–492.

    CAS  Article  Google Scholar 

  13. 13

    Kolb HJ, Schattenberg A, Goldman JM et al. Graft-versus-leukemia effect of donor lymphocyte transfusions in marrow grafted patients. European Group for Blood and Marrow Transplantation Working Party Chronic Leukemia. Blood 1995; 86: 2041–2050.

    CAS  PubMed  PubMed Central  Google Scholar 

  14. 14

    Collins R-HJ, Rogers ZR, Bennett M et al. Hematologic relapse of chronic myelogenous leukemia following allogeneic bone marrow transplantation: apparent graft-versus-leukemia effect following abrupt discontinuation of immunosuppression. Bone Marrow Transplant 1992; 10: 391–395.

    Google Scholar 

  15. 15

    Abraham R, Szer J, Bardy P, Grigg A . Early cyclosporine taper in high-risk sibling allogeneic bone marrow transplants. Bone Marrow Transplant 1997; 20: 773–777.

    CAS  Article  Google Scholar 

  16. 16

    Mehta J, Powles R, Singhal S et al. Cytokine-mediated immunotherapy with or without donor leukocytes for poor-risk acute myeloid leukemia relapsing after allogeneic bone marrow transplantation. Bone Marrow Transplant 1995; 16: 133–137.

    CAS  PubMed  Google Scholar 

  17. 17

    Mehta J, Powles R, Treleaven J et al. Outcome of acute leukemia relapsing after bone marrow transplantation: utility of second transplants and adoptive immunotherapy. Bone Marrow Transplant 1997; 19: 709–719.

    CAS  Article  Google Scholar 

  18. 18

    Slavin S, Naparstek E, Nagler A et al. Allogeneic cell therapy: the treatment of choice for all hematologic malignancies relapsing post BMT. Blood 1996; 87: 4011–4013.

    CAS  PubMed  Google Scholar 

  19. 19

    Bacigalupo A, Soracco M, Vassallo F et al. Donor lymphocyte infusions (DLI) in patients with chronic myeloid leukemia following allogeneic bone marrow transplantation. Bone Marrow Transplant 1997; 19: 927–932.

    CAS  Article  Google Scholar 

  20. 20

    Mackinnon S, Papadopoulos EB, Carabasi MH et al. Adoptive immunotherapy evaluating escalating doses of donor leukocytes for relapse of chronic myeloid leukemia after bone marrow transplantation: separation of graft-versus-leukemia responses from graft-versus-host disease. Blood 1995; 86: 1261–1268.

    CAS  PubMed  PubMed Central  Google Scholar 

  21. 21

    Mackinnon S, Papadopoulos EB, Carabasi MH et al. Adoptive immunotherapy using donor leukocytes following bone marrow transplantation for chronic myeloid leukemia: is T cell dose important in determining biological response? Bone Marrow Transplant 1995; 15: 591–594.

    CAS  PubMed  Google Scholar 

  22. 22

    Gardiner N, Lawler M, O'Riordan JM et al. Monitoring of lineage-specific chimaerism allows early prediction of response following donor lymphocyte infusions for relapsed chronic myeloid leukaemia. Bone Marrow Transplant 1998; 21: 711–719.

    CAS  Article  Google Scholar 

  23. 23

    Pati AR, Godder K, Lamb L et al. Immunotherapy with donor leukocyte infusions for patients with relapsed acute myeloid leukemia following partially mismatched related donor bone marrow transplantation. Bone Marrow Transplant 1995; 15: 979–981.

    CAS  PubMed  Google Scholar 

  24. 24

    van Rhee F, Lin F, Cullis JO et al. Relapse of chronic myeloid leukemia after allogeneic bone marrow transplant: the case for giving donor leukocyte transfusions before the onset of hematologic relapse. Blood 1994; 83: 3377–3383.

    CAS  Google Scholar 

  25. 25

    Johnson BD, Truitt RL . Delayed infusion of immunocompetent donor cells after bone marrow transplantation breaks graft-host tolerance allows for persistent antileukemic reactivity without severe graft-versus-host disease. Blood 1995; 85: 3302–3312.

    CAS  Google Scholar 

  26. 26

    Or R, Ackerstein A, Nagler A et al. Allogeneic cell-mediated and cytokine-activated immunotherapy for malignant lymphoma at the stage of minimal residual disease after autologous stem cell transplantation. J Immunother 1998; 21: 447–453.

    CAS  Article  Google Scholar 

  27. 27

    Bader P, Beck J, Frey A et al. Serial and quantitative analysis of mixed hematopoietic chimerism by PCR in patients with acute leukemias allows the prediction of relapse after allogeneic BMT. Bone Marrow Transplant 1998; 21: 487–495.

    CAS  Article  Google Scholar 

  28. 28

    Bader P, Holle W, Klingebiel T et al. Mixed hematopoietic chimerism after allogeneic bone marrow transplantation: the impact of quantitative PCR analysis for prediction of relapse and graft rejection in children. Bone Marrow Transplant 1997; 19: 697–702.

    CAS  Article  Google Scholar 

  29. 29

    Kreyenberg H, Holle W, Mohrle S et al. Quantitative analysis of chimerism after allogeneic stem cell transplantation by PCR amplification of microsatellite markers and capillary electrophoresis with fluorescence detection: the Tuebingen experience. Leukemia 2003; 17: 237–240.

    CAS  Article  Google Scholar 

  30. 30

    Bader P, Holle W, Klingebiel T et al. Quantitative assessment of mixed hematopoietic chimerism by polymerase chain reaction after allogeneic BMT. Anticancer Res 1996; 16: 1759–1763.

    CAS  Google Scholar 

  31. 31

    Bader P, Klingebiel T, Schaudt A et al. Prevention of relapse in pediatric patients with acute leukemias and MDS after allogeneic SCT by early immunotherapy initiated on the basis of increasing mixed chimerism: a single center experience of 12 children. Leukemia 1999; 13: 2079–2086.

    CAS  Article  Google Scholar 

  32. 32

    Klingebiel T, Niethammer D, Dietz K, Bader P . Progress in chimerism analysis in childhood malignancies – the dilemma of biostatistical considerations and ethical implications. Leukemia 2001; 15: 1989–1991.

    CAS  Article  Google Scholar 

  33. 33

    Klingebiel T, Schlegel PG . GVHD. Overview on pathophysiology, incidence, clinical and biological features. Bone Marrow Transplant 1998; 21 (Suppl. 2): S45–S49.

    Google Scholar 

  34. 34

    Glucksberg H, Storb R, Fefer A et al. Clinical manifestations of graft-versus-host disease in human recipients of marrow from HL-A-matched sibling donors. Transplantation 1974; 18: 295–304.

    CAS  Article  Google Scholar 

  35. 35

    Kaplan E, Meier P . Nonparametric estimation from incomplete observations. J Am Stat Assoc 1958; 58: 457–481.

    Article  Google Scholar 

  36. 36

    Shlomchik WD, Emerson SG . The immunobiology of T cell therapies for leukemias. Acta Haematol 1996; 96: 189–213.

    CAS  Article  Google Scholar 

  37. 37

    Collins R-HJ, Shpilberg O, Drobyski WR et al. Donor leukocyte infusions in 140 patients with relapsed malignancy after allogeneic bone marrow transplantation. J Clin Oncol 1997; 15: 433–444.

    Article  Google Scholar 

  38. 38

    Kolb HJ . Donor leukocyte transfusions for treatment of leukemic relapse after bone marrow transplantation. EBMT Immunology and Chronic Leukemia Working Parties. Vox Sang 1998; 74 (Suppl. 2): 321–329.

    CAS  Article  Google Scholar 

  39. 39

    Kolb HJ, Holler E . Adoptive immunotherapy with donor lymphocyte transfusions. Curr Opin Oncol 1997; 9: 139–145.

    CAS  Article  Google Scholar 

  40. 40

    Riddell SR, Murata M, Bryant S, Warren EH . T-cell therapy of leukemia. Cancer Control 2002; 9: 114–122.

    Article  Google Scholar 

  41. 41

    Luznik L, Fuchs EJ . Donor lymphocyte infusions to treat hematologic malignancies in relapse after allogeneic blood or marrow transplantation. Cancer Control 2002; 9: 123–137.

    Article  Google Scholar 

  42. 42

    Bader P, Stoll K, Huber S et al. Characterization of lineage-specific chimaerism in patients with acute leukaemia and myelodysplastic syndrome after allogeneic stem cell transplantation before and after relapse. Br J Haematol 2000; 108: 761–768.

    CAS  Article  Google Scholar 

  43. 43

    Jankowski RA, Ildstad ST . Chimerism and tolerance: from freemartin cattle and neonatal mice to humans. Hum Immunol 1997; 52: 155–161.

    CAS  Article  Google Scholar 

  44. 44

    Truitt RL, Atasoylu AA . Impact of pretransplant conditioning and donor T cells on chimerism, graft-versus-host disease, graft-versus-leukemia reactivity, and tolerance after bone marrow transplantation. Blood 1991; 77: 2515–2523.

    CAS  Google Scholar 

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We thank all participating centers and all colleagues who included less than four patients in the study: Prof Dr W Holter, University Children's Hospital Erlangen; Prof Dr S Müller-Weihrich, University Children's Hospital München-Schwabing; Dr I Schmidt, München v Haunersches Kinderspital; Prof Dr C Bender-Götze, München-Poliklinik. This work was supported by the ‘Deutsche Krebshilfe’ (70-2178-Kl I)’, Bonn, Germany, the ‘Fortüne-Programm’ of the University of Tuebingen (925-0-0) and by the ‘Förderverein für Krebskranke Kinder Tübingen e.V.’, Tübingen, Germany. We are indebted to Nicole Ata for the critical reading of the manuscript and helpful suggestions.

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Bader, P., Kreyenberg, H., Hoelle, W. et al. Increasing mixed chimerism defines a high-risk group of childhood acute myelogenous leukemia patients after allogeneic stem cell transplantation where pre-emptive immunotherapy may be effective. Bone Marrow Transplant 33, 815–821 (2004).

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  • allogeneic stem cell transplantation
  • AML
  • childhood
  • chimerism
  • adjuvant immunotherapy

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