Treatment of relapse after allogeneic bone marrow ... - Nature

Bone Marrow Transplantation, (1998) 22, 579–583  1998 Stockton Press All rights reserved 0268–3369/98 $12.00 http://www.stockton-press.co.uk/bmt

Treatment of relapse after allogeneic bone marrow transplantation with unmanipulated G-CSF-mobilized peripheral blood stem cell preparation W Siegert, J Beyer, D Kingreen, R Blasczyk, H Baurmann, N Schwella, J Schleicher, A Kirsch and D Huhn Abteilung fu¨r Innere Medizin und Poliklinik mS Ha¨matologie und Onkologie, Virchow Klinikum, Humboldt Universta¨t, Berlin, Germany

Summary: Donor lymphocyte infusions (DLI) are an effective treatment of leukemia relapse after allogeneic bone marrow transplantation. Undesired side-effects are the development of graft-versus-host disease (GVHD) and the occurrence of pancytopenia in some patients. In a pilot study, we investigated if unmanipulated G-CSF-mobilized peripheral blood stem cells which naturally contain large numbers of T lymphocytes (D-PBSC/LI) would be equally effective or even superior than DLI in generating a graft-versus-leukemia reaction (GVL) but could mitigate or prevent the development of pancytopenia. We treated 12 patients with CML chronic phase (n = 5), CML blast crisis (n = 2), AML (n = 2), ALL (n = 1), CLL (n = 1) and multiple myeloma (n = 1). In five patients with acute leukemia or CML blast crisis DPBSC/LI followed intensive chemotherapy (group A), in seven patients D-PBSC/LI were given without any prior chemotherapy (group B). In group A two patients were evaluable for hematologic toxicity. Leukopenia ⬍1000/ ␮l lasted for 10 and 19 days, and thrombocytopenia ⬍20 000/␮l for 11 and 13 days, respectively. In group B leukopenia ⬍1000/␮l and thrombocytopenia ⬍20 000/␮l was observed in only one patient. Moderate cytopenia developed in four of five evaluable patients. A complete remission could be achieved in all seven patients with CML who all developed acute and/or chronic GVHD. None of the remaining five patients achieved a complete remission despite acute and/or chronic GVHD in two of them. Four patients died from disease progression, one patient from a secondary lymphoma, and one patient as a result of uncontrolled GVHD. In conclusion, D-PBSC/LI is effective in inducing GVL reaction but it does not prevent pancytopenia in each case. It remains unclear if it mitigates the incidence and severity of pancytopenia. Keywords: relapse after BMT; PBSC; donor lymphocyte infusion

Correspondence: Prof Dr W Siegert, Abt Innere Medizin und Poliklinik mS Ha¨matologie und Onkologie, Virchow Klinikum, Augustenburgerplatz 1, 13353 Berlin, Germany Received 18 February 1998; accepted 13 May 1998

Leukemia relapse after allogeneic bone marrow transplantation can be successfully treated by infusion of lymphocytes (DLI) from the original marrow donor. Complete remissions have been achieved by this procedure in 50– 70% of patients with CML in chronic phase, and in 10– 20% of patients with acute myelogenous (AML) or lymphoblastic leukemia (ALL).1–4 In the majority of patients with chronic phase CML these remissions were durable, leading to an actuarial overall survival of 67% at 2 years.2 The long-term benefit in patients with relapsed acute leukemia was substantially less with a median survival of 8 months in AML and 4 months in ALL.5 Complications of DLI are the induction of acute and chronic GVHD as well as of profound and sometimes life-threatening pancytopenias that occur in 20–35% of patients.2,3 Due to the fact that standard peripheral blood stem and progenitor cell harvests mobilized with G-CSF contain a large number of lymphocytes, replacement of DLI by the infusion of donor PBSC ‘contaminated’ with T lymphocytes (D-PBSC/LI) appears to be an interesting approach.6 Advantages could be manifold. Firstly, D-PBSC/LI might contribute to avoid pancytopenia. Secondly, in patients with aggressive diseases such as acute leukemia or CML blast crisis, D-PBSC/LI could be transfused after administration of chemotherapy for remission induction and guarantee a calculable short regeneration period. The reduction or elimination of blast cells by cytostatic treatment would bridge time until an effective immune response was mounted to exert GVL reaction. Thirdly, it is conceivable that together with D-PBSC/LI further effector cells (cytokine producing cells, antigen presenting cells) are transferred in addition to T lymphocytes, thus possibly making the antileukemic reaction more effective.

Patients and methods Patient characteristics and prior treatment Twelve patients with relapse after T cell non-depleted HLA-identical sibling bone marrow transplantation were studied. Their characteristics are summarized in Table 1. Conditioning regimens were VP16 (60 mg/kg)/total body irradiation 12 Gy (TBI) (n = 2); busulfan 16 mg/kg/ cyclophosphamide 120 mg/kg (little Bu/Cy) (n = 2); busul-

G-CSF-mobilized PBSC for relapse after allogeneic BMT W Siegert et al

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Table 1

Patient characteristics

UPN

Group A 266 450 468 522 562 Group B 113 196 311 338 384 514 519

Age/ Sex

Diagnosis at BMT

Diagnosis at relapse

Interval BMT–relapse (months)

Chimerism

52/F 36/M 39/M 50/F 28/M

CLL CML CP CML CP AML, refractory ALL, refractory

CLL CML BC CML BC AML ALL

43 18 17 15 8

ND VNTR VNTR blood group sex

43/F 54/M 22/M 23/M 21/F 52/M 40/F

CML CP CML CP CML CP CML CP CML CP MDS/AML multiple myeloma

CML CP CML CP CML CP CML CP CML CP AML multiple myeloma

65 31 48 30 16 11 11

blood group VNTR blood group, VNTR blood group, VNTR ND VNTR ND

VNTR = variable number of tandem repeats; ND = no differences detected.

fan 16 mg/kg/cyclophosphamide 200 mg/kg (Bu/Cy) (n = 2); cyclophosphamide 200 mg/kg/TBI (n = 2); busulfan 10 mg/kg/thiotepa 750 mg/m2/cyclophosphamide (120 mg/kg) (n = 4). GVHD prophylaxis after BMT consisted of cyclosporin A and a short course of methotrexate.7 Chimerism Prior D-PBSC/LI chimerism could be documented in nine of 12 patients (Table 1). Methods included the demonstration of differences in blood groups, sex chromosomes, and in variable numbers of tandem repeat sequences (VNTR) by PCR and high-resolution gel electrophoresis.8 Treatment prior to D-PBSC/L infusion Treatment group A comprised five patients who received cytostatic treatment before D-PBSC/LI in an attempt to reduce the large tumor burden. One patient with CLL was treated with 30 mg/m2 fludarabin on 5 consecutive days. Two patients relapsing with CML blast crisis and one patient with AML received idarubicin 12 mg/m2 for 2 days and Ara-C 200 mg/m2 as continuous infusion for 5 days. One patient with relapsed ALL was treated with combination chemotherapy consisting of dexamethasone 20 mg/m2 p.o. daily for 5 days, vincristin 1.5 mg/m2, methotrexate 1000 mg/m2 as a 36 h continuous infusion, Ara-C 2 × 2000 mg/m2 as 3 h infusion, and asparaginase (E. coli) 10 000 U/m2 as 24 h continuous infusion. Treatment group B consisted of seven patients who relapsed with chronic phase CML (n = 5), multiple myeloma (n = 1) or MDS/AML (n = 1) and received D-PBSC/LI without any prior chemotherapy. Patient characteristics of the two treatment groups are summarized in Tables 1 to 3. After DPBSC/LI no G-CSF was given and no GVHD prophylaxis was performed. However, if clinically relevant acute GVHD (⭓grade II) or symptomatic chronic GVHD occurred patients were treated with prednisone or a combination of prednisone and cyclosporin A as required. In patients with incomplete response who did not develop GVHD interferon-alpha 2 × 106 IU/m2 s.c. daily for 4

weeks with or without 6 × 106 U interleukin-2 s.c. for 3 days was administered to induce a GVHD/GVL reaction. D-PBSC/L mobilization and collection PBSC were mobilized from the original bone marrow donor with 10 ␮g/kg filgrastim s.c. on 4 consecutive days.9 Aphereses were performed on the fifth day and depending on the harvested cell number also on day 6. We planned to harvest ⭓2 × 106 CD34+ cells/kg of the recipient, however, with two aphereses this aim was not reached in all cases. The cellular composition of the harvest product was determined and quantified by flow cytometry. In group A, patients were allowed an interval of 1 day between the end of chemotherapy and D-PBSC/LI. In patients of group B, D-PBSC/LI were performed immediately after PBPC collection without further processing of apheresis products. The numbers of transfused CD34+ cells and CD3+ lymphocytes are given in Tables 2 and 3.

Results D-PBSC/L infusion Between 1994 and 1997 12 patients were treated for relapse after BMT by D-PBSC/LI. Relapses occurred at a median time of 17.5 months (range 6–65 months) after BMT and D-PBSC/LI were given after a median time of 1.5 months (range 0.5–7 months) after relapse. Infusions were well tolerated. Patients received a median dose of 2.4 × 106 (range 1.1–18.2) CD34-positive cells per kg body weight. Within the PBSC preparation the numbers of CD3-, CD4- and CD8-positive lymphocytes were 12.7 × 107/kg median (range 6.5–28.4), 6.4 × 107/kg median (range 3.3–15.2) and 5.8 × 107/kg median (range 2.7–13.7), respectively. There was no quantitative correlation between the number of CD34+ cells and the number of either CD3-, CD4-, or CD8positive lymphocytes collected.


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Table 2

D-PBSC/L infusion with prior chemotherapy (group A)

UPN

Interval relapse– D-PBSC/LI (months)

CD34 ×106/kg

CD3 ×107/kg

IFN/IL-2

GVHD (day of onset)

Response

268 450 468 522 562

3 0.5 0.5 4 0.5

4.7 5.8 1.6 2.3 2.7

28.4 13.2 7.5 10.0 9.4

IFN/IL-2 — IFN IFN —

— a/- (11) a/c (54) a/- (42) —

PD hem CR mol CR PD PD

Survival after Days WBC D-PBSC/LI ⬍1000/␮l (months)

7 7 11+ 2 3

Days PLT ⬍20 000/␮l

Days with neutropenic fever

0 11 13 NA 15

0 2 10 6 4

0 10 19 NA 16

D-PBSC/L infusions = donor-peripheral blood stem cell/lymphocyte infusion; IFN = interferon-alpha; IL-2 = interleukin-2; GVHD = graft-versus-host disease; a = acute; c = chronic; WBC = white blood cells; PLT = platelets; NA = not applicable; mol CR = molecular complete remission; hem CR = hematologic complete remission; PD = progressive disease.

Table 3

D-PBSC/L infusion without prior chemotherapy (group B)

UPN Interval CD34 CD3 IFN/IL-2 GVHD (day of relapse– ×106/kg ×107/kg D-PBSC/LI onset) (months) 113 196 311 338 384 514 519

1 3 2 7 1 1 4

2.3 18.2 1.1 2.4 2.4 3.6 2.0

20.0 16.0 16.7 18.3 12.2 6.5 12.0

— — — — — — IFN

Response

a/c (86) mol CR a/c (66) mol CR -/c (44) mol CR a/c (79) mol CR a/c (48) mol CR NA PD a/c (68) transient mR

Survival Min Min WBC Days Min Min PLT Days PLT Days with after D- WBC/␮l day after WBC PLT/␮l day after ⬍20000/␮l neutropenic D-PBSC/LI fever PBSC/LI D-PBSC/LI ⬍1000/␮l (months) 13 37+ 3+ 15+ 27+ 1 8+

3100 1400 3600 3200 670 NA NA

76 67 44 58 56 NA NA

0 0 0 0 10 NA NA

NA 27000 NA NA 8000 NA NA

NA 67 NA NA 56 NA NA

0 0 0 0 10 NA NA

0 0 0 0 3 NA 0

D-PBSC/L infusions = donor-peripheral blood stem cell/lymphocyte infusion; IFN = interferon-alpha; IL-2 = interleukin-2; GVHD = graft-versus-host disease; a = acute; c = chronic; min = minimum; WBC = white blood cells; PLT = platelets; NA = not applicable; mol CR = molecular complete remission; hem CR = hematologic complete remission; mR = minor response; PD = progressive disease.

Pancytopenia In group A, five patients received chemotherapy for remission induction prior to D-PBSC/LI. Three of these patients (UPN 266, 522, 562) never went into remission and were not evaluable for hematologic regeneration because of progression of the underlying leukemia (Table 2). The two remaining patients with CML blast crisis (UPN 450, 468) achieved a complete remission after chemotherapy plus DPBSC/LI. The time from D-PBSC/LI to recovery of leukocytes ⬎1000/␮l lasted 10 and 19 days, and the recovery of platelets ⬎20 000/␮l occurred 11 and 13 days after DPBSC/LI. Both patients only had a short period of neutropenic fever for 2 and 10 days, but no other treatmentrelated complication. In group B, seven patients received D-PBSC/LI without prior chemotherapy (Table 3). Two of these patients (UPN 514, 519) could also not be evaluated for the development of pancytopenia because of non-response to D-PBSC/LI. The remaining five patients, all of whom suffered from CML in chronic phase, achieved a complete molecular remission. Their nadir leukocyte counts were a median of 3100/␮l (range 670–3600/␮l), and only one patient developed leukopenia ⬍1000/␮l lasting for 10 days. Leukocyte nadirs were reached on days 44, 56, 58, 67 and 76 after D-PBSC/LI. One patient (UPN 384) developed neutropenic fever lasting for 3 days. Two evaluable patients in group B showed nadir platelet counts of 8000 and

27 000/␮l on days 56 and 67. The period with platelet counts ⬍20 000/␮l lasted 10 days in one patient. The three remaining evaluable patients had normal platelet values throughout the post D-PBSC/LI period. GVL effect In group A, two patients who relapsed with CML blast crisis responded to chemotherapy and subsequent DPBSC/LI. One patient (UPN 450) achieved a hematologic complete remission lasting until his death from a rapidly progressing secondary high-grade T cell non-Hodgkin’s lymphoma 7 months after D-PBSC/LI. The second patient (UPN 468) is in continuous complete molecular remission 11 months after D-PBSC/LI. However, he suffers from extensive chronic GVHD and a moderate obstructive bronchiolitis. Chemotherapy and subsequent D-PBSC/LI were not effective in any of the patients with relapsed CLL, AML and ALL (UPN 266, 522, 562) despite clinical evidence of acute GVHD in one patient (UPN 522). Additional efforts to induce a GVL reaction with administration of alpha-interferon and interleukin-2 after D-PBSC/LI were equally ineffective (Tables 2 and 3). In group B, all five patients with chronic phase CML achieved complete molecular remissions. One patient (UPN 519) with multiple myeloma developed grade 1 acute GVHD and showed a transient minor response only after the additional adminis-


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tration of interferon-alpha. One patient with nonresponding AML (UPN 514) died from sepsis 1 month after D-PBSC/LI and is therefore not evaluable for GVL reaction (Table 3). GVHD and complications Acute GVHD developed in 8/11 evaluable patients (73%) after D-PBSC/LI. One patient with an early septic death is not evaluable for GVHD. Grade 1 and grade 2 acute GVHD was observed in four patients each. One patient developed limited chronic GVHD, six developed extensive disease. GVHD was first observed after a median period of 67 days (range 11–86 days) after D-PBSC/LI. Symptoms of acute GVHD (maculopapular skin rash) and chronic GVHD (the most troublesome symptom being lichenoid and ulcerative changes of oral mucosa), occurred in close temporal correlation with the development of pancytopenia in six patients. One patient (UPN 113) developed rapidly progressing bronchiolitis obliterans in the course of chronic GVHD and died in molecular remission from respiratory failure 13 months after D-PBSC/LI. Another patient (UPN 468) with chronic GVHD acquired obstructive bronchitis responding to prednisone. GVHD treatment with prednisone was required in two patients, combinations of prednisone and cyclosporin A were given to three patients. Survival and causes of death At the time of last evaluation in October 1997 six patients were alive 3+, 8+, 11+, 15+, 27+ and 37+ months after DPBSC/LI. Among those survivors five CML patients remain in complete remission. Six patients have died 1, 2, 3, 7, 7 and 13 months after D-PBSC/LI. Four patients died from infections during progressive leukemia (UPN 266, 514, 522, 562), one patient (UPN 113) died from bronchiolitis obliterans being in molecular complete remission of CML, one patient (UPN 450) died from progressive high grade T-NHL being in hematologic CR of CML.

Discussion Donor lymphocyte infusions for therapy of relapse of hematologic malignancies after allogeneic BMT have become an accepted treatment modality. Thereby, second BMTs which are associated with a very high rate of complications can be avoided.10 However, despite the ease with which some patients are brought to remission and probably cured by DLI, there is still a need to improve this procedure. For example, it is not understood why acute leukemias only respond in about 20% of cases in contrast to chronic phase CML in which response rates between 50% and 70% are observed. These results are curtailed by the induction of severe GVHD and its consequences. Efforts are being made to determine the minimum lymphocyte number required to exert a GVL without inducing life-threatening GVHD. Another problem arising after DLI in some patients is the development of pancytopenia. In reports from various centers and in several surveys these are reported to occur in

about 20–35% of patients, again contributing to death in some.2,3,11–17 With the development of peripheral blood stem cell transplantation and the finding that standard PBSC preparations contain T lymphocyte numbers equivalent to those infused during DLI, we wondered if application of donor PBSC (D-PBSC/LI) from the initial marrow donor would be as efficient as DLI to exert GVL reaction and, in addition, would reduce the incidence and the severity of pancytopenia. Futhermore, we hoped that D-PBSC/LI given to patients with relapsed acute leukemia after chemotherapy for remission induction would not only be helpful in shortening the duration of cytopenia but also potentially enhance the GVL reaction by the infusion of accessory cells. Our observations clearly show that D-PBSC/LI infusions can induce remissions in the majority of patients with chronic phase CML and even blast crisis, although cytoreductive treatment prior to D-PBSC/LI might be required in the latter. D-PBSC/LI was not effective in four patients with ALL, AML, CLL and multiple myeloma. The principle of reducing leukemia cell load by chemotherapy followed by D-PBSC/LI to shorten pancytopenia and to mount a GVL reaction proved to be effective in two of five patients. Concerning the duration of cytopenia after chemotherapy and D-PBSC/LI (group A) only two of five patients were evaluable (UPN 450, 468). However, both patients required only relatively short regeneration periods of 10 and 19 days to achieve ⬎1000 WBC/␮l and of 11 and 13 days to exceed 20 000 platelets/␮l. Leukopenic fever was present for 2 and 10 days, respectively (Table 2). Short regeneration periods were also described in four recent case reports and a smaller trial including 11 patients who were treated according to a similar strategy with chemotherapy followed by DPBSC/LI.18–22 Thus, our data together with observations reported in the literature argue in favor of a sequential treatment with cytostatic drugs followed by D-PBSC/LI. If a complete or partial remission of leukemia can be achieved this sequence guarantees with high probability a short regeneration period and initiates the desired GVL effect. In group B, all five patients with chronic phase CML responded to D-PBSC/LI with molecular complete remissions. Only one patient had critically low WBC ⬍1000/␮l persisting for 10 days, and only two of these five patients developed significant thrombocytopenia. In these patients, leukocyte and platelet nadirs occurred between 44 and 76 days after D-PBSC/LI, and interestingly, this period coincided with the first clinical manifestations of GVHD between 48 and 86 days after D-PBSC/LI. A definitive interpretation of our observations is difficult due to the low number of patients treated. However, our finding of short regeneration periods after intensive remission induction chemotherapy and D-PBSC/LI on the one hand, and of only one of five patients with chronic phase CML developing an only short lasting pancytopenia after D-PBSC/LI on the other hand, supports the notion that D-PBSC/LI may be superior to DLI. D-PBSC/LI is effective in GVL induction and, in addition, may avoid or ameliorate cytopenia. A similar strategy to the one described in this article was reported by Flowers et al.23 They treated 11 patients with leukemia relapse after BMT with G-CSF-mobilized D-


PBSC/LI and observed aplasia in two of nine cases. Their conclusion was that D-PBSC/LI cannot prevent aplasia in all cases. However, due to the limitations of the abstract, details on nadir values or the duration of cytopenia are not given. Thus, potential benefits of this treatment approach cannot be deduced. In summary, the data of this small pilot study show that D-PBSC/LI can induce an effective GVL reaction leading to molecular remission in the majority of patients with relapsed CML, and that after D-PBSC/LI cytopenia appears to be rare and of short duration. This trial points to a potentially advantageous treatment strategy. It is clear that to obtain a definite answer larger patient numbers need to be studied, preferentially in a randomized study comparing DLI and D-PBSC/LI. References 1 Kolb H-J, Mittermu¨ller J, Clemm C et al. Donor leukocyte transfusions for treatment of recurrent chronic myelogenous leukemia in marrow transplant patients. Blood 1990; 76: 2462–2465. 2 Kolb H-J, Schattenberg A, Goldman JM et al. Graft-versusleukemia effect of donor lymphocyte transfusions in marrow grafted patients. Blood 1995; 86: 2041–2050. 3 Collins RH, 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. 4 Slavin S, Naparstek E, Nagler A et al. Allogeneic cell therapy with donor peripheral blood cells and recombinant human interleukin-2 to treat leukemia relapse after allogeneic bone marrow transplantation. Blood 1996; 87: 2195–2204. 5 Dermime S, Mavroudis D, Jiang Y-Z et al. Immune escape from a graft-versus-leukemia effect may play a role in the relapse of myeloid leukemias following allogeneic marrow transplantation. Bone Marrow Transplant 1997; 19: 989–999. 6 Ko¨rbling M, Huh YO, Durett N et al. Allogeneic blood stem cell transplantation: peripheralization and yield of donorderived primitive hematopoietic progenitor cells (CD34+Thy1dim) and lymphoid subsets, and possible predictors of engraftment and graft-versus-host disease. Blood 1995; 86: 2842–2848. 7 Storb R, Deeg J, Pepe M et al. Methotrexate and cyclosporine versus cyclosporine alone for prophylaxis of graft versus host disease in patients given HLA-identical marrow grafts for leukemia: long-term follow-up of a controlled trial. Blood 1989; 73: 1729–1734. 8 Tully G, Sullivan KM, Gill P. Analysis of 6 VNTR loci by ‘multiplex’ PCR and automated fluorescent detection. Hum Genet 1993; 92: 554–562. 9 Bensinger WI, Clift R, Martin P et al. Allogeneic peripheral blood stem cell transplantation in patients with advanced hematologic malignancies: a retrospective comparison with marrow transplantation. Blood 1996; 88: 2794–2800.

10 Barrett AJ, Locatelli F, Treleaven JG et al. Second transplants for leukemic relapse after bone marrow transplantation: high early mortality but favorable effect of chronic GVHD on continued remission. Br J Haematol 1991; 79: 567–574. 11 Russell LA, Jacobsen N, Heilmenn C et al. Treatment of relapse after allogeneic BMT with donor leukocyte infusions in 16 patients. Bone Marrow Transplant 1996; 18: 411–414. 12 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. 13 Hertenstein B, Wiesneth M, Novotny J et al. Interferon alpha and donor buffy coat transfusions for treatment of relapsed chronic myeloid leukemia after allogeneic marrow transplantation. Transplantation 1993; 56: 1114–1118. 14 Giralt S, Hester J, Huh Y et al. CD8-depleted donor lymphocyte infusion as treatment for relapsed chronic myeloid leukemia after allogeneic bone marrow transplantation. Blood 1995; 86: 4337–4343. 15 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. 16 Ba¨r BMAM, Schattenberg A, Mensink EJBM et al. Donor leukocyte infusions for chronic myeloid leukemia relapsed after allogeneic bone marrow transplantation. J Clin Oncol 1993; 11: 513–519. 17 Drobyski WR, Keever CA, Roth MS et al. Salvage immunotherapy using donor leukocyte infusions as treatment for relapsed chronic myelogenous leukemia after allogeneic bone marrow transplantation: efficacy and toxicity of a defined Tcell dose. Blood 1993; 82: 2310–2318. 18 Sica S, Di Mario A, Salutari P et al. Chemotherapy and recombinant human granulocyte colony-stimulating factor primed donor leukocyte infusion for treatment of relapse after allogeneic bone marrow transplantation. Bone Marrow Transplant 1995; 16: 483–485. 19 Bernasconi P, Alessandrino EP, Caldera D et al. Intensive chemotherapy followed by donor PBSC in ANLL relapsed after allogeneic BMT. Bone Marrow Transplant 1995; 15: 643–645. 20 Trenschel R, Bernier M, Stryckmans P et al. Complete remission following donor PBSC after low-dose cytarabine chemotherapy for early relapse of acute myelogenous leukemia after allogeneic stem cell transplantation. Bone Marrow Transplant 1997; 19: 381–383. 21 Nachbaur D, Duba H-C, Feichtinger H et al. Polychemotherapy combined with G-CSF-mobilized donor buffy coat transfusion for granulocytic sarcoma after allogeneic BMT for AML. Bone Marrow Transplant 1997; 19: 947–949. 22 Glass B, Majolino I, Dreger P et al. Allogeneic peripheral blood progenitor cells for treatment of relapse after bone marrow transplantation. Bone Marrow Transplant 1997; 20: 533–541. 23 Flowers MED, Sullivan KM, Martin P et al. G-CSF stimulated donor peripheral blood infusion(s) as immunotherapy in patients with hematologic malignancies relapsing after allogeneic transplantation (abstract). Blood 1995; 86: 564.

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