Minimal residual disease-directed immunotherapy for high-risk myelodysplastic syndrome after allogeneic hematopoietic stem cell transplantation

Abstract

The efficacy of minimal residual disease (MRD)-directed immunotherapy, including interferon-α (IFN-α) treatment and chemotherapy plus granulocyte colony-stimulating factor-primed donor leukocyte infusion (chemo-DLI), was investigated in patients with high-risk myelodysplastic syndrome (MDS) who were MRD-positive after allogeneic hematopoietic stem cell transplantation (allo-HSCT). High-risk MDS patients who received non-T-cell-depleted allo-HSCT at the Peking University Institute of Hematology and were MRD-positive after allo-HSCT were studied (n=47). The MRD-positive status was considered if leukemia-associated aberrant immune phenotypes or Wilms’ tumor gene 1 expression is present in a single bone marrow sample. The cumulative incidence of the relapse and non-relapse mortality 2 years after immunotherapy were 14.5% and 21.4% (P=0.377) and 9.1% and 0.0% (P=0.985) for patients in the IFN-α and chemo-DLI groups, respectively. The probability of disease-free and overall survival 2 years after immunotherapy were 76.4% and 78.6% (P=0.891) and 84.3% and 84.6% (P=0.972) for patients in the IFN-α and chemo-DLI groups, respectively. Persistent MRD after immunotherapy was associated with poor survival. Thus, the MRD-directed immunotherapy was effective for patients with high-risk MDS who were MRD-positive after allo-HSCT, and the efficacy was comparable between chemo-DLI and IFN-α treatment.

Keywords

donor leukocyte infusion / hematopoietic stem cell transplantation / interferon-α / minimal residual disease / myelodysplastic syndrome

Introduction

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is one of the most effective treatments for high-risk myelodysplastic syndrome (MDS); however, post-transplant relapse remains a major cause of transplant failure [¹]. The impending relapse of high-risk MDS may be indicated through minimal residual disease (MRD) monitoring after allo-HSCT [²], which makes MRD-directed intervention a reasonable option for relapse prophylaxis. Hypomethylating agents (HMAs) may delay the hematologic relapse of patients with MDS or acute myeloid leukemia after allo-HSCT; however, long-term outcomes have not been satisfactory [³]. In addition, HMAs may be too expensive for patients in developing countries such as China.

MRD-directed immunotherapy is important for relapse prophylaxis after allo-HSCT [⁴]; moreover, chemotherapy plus granulocyte colony-stimulating factor-primed donor leukocyte infusion (chemo-DLI) is the most important immunotherapy that can significantly improve the condition of MRD-positive patients after allo-HSCT [⁵,⁶]. However, only a small (<10) number of MDS patients with MRD have been studied [²,⁵,⁶], and the efficacy of MRD-directed chemo-DLI in patients with high-risk MDS remains unclear.

Some patients do not receive chemo-DLI because of provider or patient refusal. These patients require further studies to identify reasonable alternative pre-emptive interventions. Interferon-a (IFN-a) may be a feasible maintenance therapy for patients with acute myeloid leukemia [⁷]. In addition, IFN-a can kill leukemia cells by regulating T-cell and natural killer cell functions [⁸,⁹], induce the graft-versus-leukemia (GVL) effect, and eliminate leukemia cells in allo-HSCT recipients [¹⁰,¹¹]. In our pilot study, MRD-directed IFN-a treatment was safe and effective for allo-HSCT recipients [¹²]. Thus, IFN-a may be an alternative treatment for high-risk MDS with MRD after allo-HSCT. However, small number (n=4) of high-risk MDS was considered.

Thus, the efficacy of MRD-directed immunotherapy was further investigated in patients with high-risk MDS after allo-HSCT. Moreover, we wanted to compare the efficacy between MRD-directed chemo-DLI and IFN-a treatment.

Materials and methods

Patients

Consecutive patients receiving non-T-cell-depleted allo-HSCT at the Peking University Institute of Hematology were studied based on the following criteria: (1) those with high-risk or very high-risk MDS; and (2) who were positive for MRD after allo-HSCT. A total of 47 patients were enrolled from February 1, 2013 to July 31, 2016 (Fig.1), and the characteristics were comparable between the enrolled and excluded patients (data not shown). Final follow-up visits were conducted on December 20, 2017. Informed consent was obtained from all patients or their guardians. The study was conducted in accordance with the Declaration of Helsinki, and the protocol was approved by the Ethics Committee of Peking University People’s Hospital.

Transplant regimens

Preconditioning consisted of cytarabine (Ara-C), busulfan, cyclophosphamide, and simustine. Rabbit anti-thymocyte globulin was administered to human leukocyte antigen (HLA)-haploidentical-related donor and HLA-unrelated donor groups, as detailed in the Supplementary methods [¹³,¹⁴]. Granulocyte colony-stimulating factor-mobilized, fresh, and unmanipulated bone marrow (BM) and peripheral blood harvests were administered to the recipients on the same day of collection. Patients received graft-versus-host disease (GVHD) prophylactic agents, including cyclosporine A, mycophenolate mofetil, and short-term methotrexate [¹⁵,¹⁶].

MRD monitoring

Patients were monitored for MRD post-transplantation according to leukemia-associated aberrant immune phenotypes (LAIPs) and Wilms’ tumor gene 1 (WT1) expression. LAIPs were detected through multicolor flow cytometry. LAIP positivity was considered when>0.01% of cells have a LAIP in post-transplantation BM samples [¹⁷]. The expression of WT1 was determined using TaqMan-based reverse transcription-polymerase chain reaction of diagnostic specimens. The WT1 transcript level above 0.60% was considered positive [¹⁸]. Routine MRD monitoring was performed after 1, 2, 3, 4.5, 6, 9, and 12 months post-transplantation and at 6-month intervals thereafter. A patient was considered MRD-positive when a single BM sample was positive for LAIPs or WT1 expression [¹⁹]. High-level MRD was considered for WT1 transcript levels≥1.0% and/or LAIP positivity of≥0.1% in post-transplantation BM samples; low-level MRD was considered for the remaining patients.

MRD-directed immunotherapy protocol

Patients who tested positive for LAIPs or WT1 expression in a single BM sample were defined as MRD_sin+. Patients who tested positive for LAIPs or WT1 expression in two consecutive BM samples within a 2-week interval or those who tested positive for both LAIPs and WT1 expression in a single BM sample were defined as MRD_co+. Chemo-DLI is efficient [6], but the role of IFN-a treatment has remained undefined in MRD_co+ patients. Hence, MRD-directed chemo-DLI was the first choice for patients in the MRD_co+ group, and those who could not receive DLI received IFN-a treatment.

A total of 18 MRD_sin+ patients received IFN-a treatment. The tests for patients who did not agree to receive any intervention were repeated 2 weeks after the first positive results for WT1 or LAIPs (n=19). If two consecutive BM samples tested positive for LAIPs or WT1 expression within a 2-week interval, patients received MRD-directed immunotherapy, and those who did not receive DLI due to patient (n=10) or provider (n=2) refusal received IFN-a treatment. Patients who tested positive for both WT1 expression and LAIPs in a single BM sample received IFN-a treatment if they did not receive DLI because of patient refusal (n=3). Thus, a total of 18, 15, and 14 patients were categorized as MRD_sin+, MRD_co+ receiving IFN-a treatment, and MRD_co+ receiving chemo-DLI groups, respectively (Fig.1). Furthermore, MRD status was monitored 1, 2, 3, 4.5, 6, 9, and 12 months after MRD-directed immunotherapy and at a 6-month interval thereafter.

Patients with active GVHD, active infections, severe myelosuppression, organ failure, or relapse were excluded from MRD-directed IFN-a treatment. Recombinant human IFN-a-2b injections (Anferon; Tianjin Hualida Biotechnology Co., Ltd., Tianjin, China) were subcutaneously administered for 6 cycles (twice or thrice weekly every 4 weeks) at 3 million units (MU) for patients over 16 years and at 3 MU/m² for those under 16 years (capped by 3 MU). Prolonged treatment with IFN-a was permitted per patient request. IFN-a was suspended in all patients with severe GVHD, severe infection, grade≥3 toxicity, relapse, or non-relapse mortality (NRM).

Patients with active GVHD, active infections, organ failure, or relapse were excluded from MRD-directed chemo-DLI treatment, with a detailed protocol in the Supplementary methods [⁵,⁶,²⁰,²¹].

Diagnosis and treatment of GVHD after MRD-directed IFN-a treatment

GVHD after MRD-directed immunotherapy was diagnosed [²²,²³] and treated [²⁴,²⁵] according to international criteria (Supplementary methods).

Definitions and assessments

MDS patients were categorized according to the WHO Prognostic Scoring System (WPSS) [²⁶] which can predict the post-HSCT outcomes [²⁷]. Therapeutic toxicities, rated according to the WHO criteria, were monitored every 1–2 weeks after IFN-a treatment, and GVHD was excluded as an adverse event. Relapse was defined as morphologic evidence of disease in peripheral blood, bone marrow, or extramedullary samples or by the recurrence and sustained presence of pre-transplantation chromosomal abnormalities. MRD patients were not classified as showing relapse. NRM was defined as death without disease progression or relapse. Disease-free survival (DFS) was defined as the survival period with continuous CR. Overall survival (OS) events were defined as death from any cause.

Statistical analysis

Mann–Whitney U-test was used to compare continuous variables, and c² and Fisher’s exact tests were used for categorical variables. The Kaplan–Meier method was used to estimate the probability of survival. Competing risk analyses were performed to calculate the cumulative incidence of GVHD, relapse, and NRM [²⁸]. Landmark analysis was performed to assess the effects of MRD-directed immunotherapy on each outcome by using the post-HSCT day as the landmark day.

Potential prognostic factors for clinical outcomes after MRD-directed immunotherapy were evaluated by multivariate analysis by using Cox proportional hazards regression with a forward-stepwise model selection approach. The regression model considered the risk level according to the WPSS, MRD type (MRD_sin+ vs. MRD_co+) and level (high- vs. low-level MRD) before immunotherapy, type of immunotherapy (IFN-a vs. chemo-DLI), and MRD status after immunotherapy (positive vs. negative). The level of significance was set at P<0.05. Data analyses were primarily conducted using the SPSS software (SPSS Inc., Chicago, IL, USA), while the R software package (version 2.6.1; http://www.r-project.org) was used for competing risk analysis.

Results

Patient characteristics

Table 1 summarizes the characteristics of the 47 patients, which all had full donor chimerism. Fourteen patients received MRD-directed chemo-DLI. The median doses of mononuclear, CD3⁺, and CD34⁺ cells were 1.0 (0.8–1.8)×10⁸, 3.7 (2.6–7.6)×10⁷, and 0.3 (0.1–0.6)×10⁶/kg, respectively. Thirty-three patients received MRD-directed IFN-a treatment, the median cycles of IFN-a treatment was 3 (range, 1–13 cycles), and the reasons for discontinuing IFN-a treatment included complete treatment (n=11), occurrence of severe GVHD (n=15), relapse (n=4), or grade≥3 toxicity (hematologic: n=1; infectious: n=2).

GVHD after MRD-directed immunotherapy

Thirteen patients developed aGVHD after IFN-a treatment, and grades I, II, and III aGVHD were observed in 1, 8, and 4 patients, respectively. The median duration from immunotherapy to the occurrence of aGVHD was 14 (5–91) days. A patient developed grade II aGVHD 18 days after chemo-DLI. The cumulative incidence of grade I–II aGVHD and grade III aGVHD 2 years after immunotherapy was 27.3% versus 7.1% (P=0.129) and 12.1% versus 0.0% (P=0.179) in the IFN-a and chemo-DLI groups, respectively.

Fourteen patients experienced cGVHD after IFN-a treatment; mild, moderate, and severe cGVHD were observed in 3, 5, and 6 patients, respectively. Six patients experienced cGVHD after chemo-DLI; moderate and severe cGVHD were observed in 4 and 2 patients, respectively. The median duration from immunotherapy to the occurrence of cGVHD was 59 (7–519) and 95 (72–117) days in the IFN-a and chemo-DLI groups, respectively (P=0.274). The cumulative incidence of mild to moderate cGVHD and severe cGVHD 2 years after immunotherapy was 30.6% versus 36.4% (P=0.401) and 18.2% versus 18.2% (P=0.799) in the IFN-a and chemo-DLI groups, respectively.

MRD status and relapse after MRD-directed immunotherapy

Four and three patients showed relapse after IFN-a treatment and chemo-DLI, respectively, with the median duration from the beginning of IFN-a treatment and chemo-DLI to the relapse of 333 (200–468) and 56 (37–64) days, respectively. The cumulative incidence of relapse (CIR) 2 years after immunotherapy was 16.4% among all patients, which was comparable in patients with MRD_sin+, MRD_co+ receiving IFN-a treatment, and MRD_co+ receiving chemo-DLI (Fig.2A).

A total of 16 (48.5%), 5 (15.2%), 3 (9.0%), and 5 (15.2%) patients were MRD-negative 1, 2, 3, or>3 months after MRD-directed IFN-a treatment, respectively, while 6 (42.9%) and 1 (7.1%) patients were MRD-negative 1 or>3 months after chemo-DLI, respectively. The cumulative incidence of turning MRD negative 3 months and 2 years after immunotherapy was showed in Fig.3A and Fig.3B. The CIR 2 years after immunotherapy of patients who turned MRD-negative and those with persistent MRD was 12.9% and 27.3%, respectively (P=0.137, Fig. 2B).

In the multivariate analysis, no variable was significantly associated with increased relapse, but the persistent MRD after immunotherapy seemed to increase the risk of relapse (Table 2).

Toxicities after MRD-directed immunotherapy

Grade≥3 hematologic toxicity was experienced by a patient in the IFN-a group for 14 days, and 14 in the chemo-DLI group for a median duration of 11 (3–40) days. Two (6.1%) and five (35.7%) patients suffered grade≥3 non-hematologic toxicities in the IFN-a and chemo-DLI groups, respectively.

NRM after MRD-directed immunotherapy

Three patients died from NRM (infection: n=2; GVHD: n=1) after IFN-a treatment, with a median time from the beginning of IFN-a treatment to NRM of 130 (range, 77–164) days. A patient died because of severe pneumonia 750 days after chemo-DLI. The cumulative incidence of NRM 2 years after immunotherapy was 6.4% among all patients, which was comparable among those who were MRD_sin+, MRD_co+ receiving IFN-a treatment, and MRD_co+ receiving chemo-DLI (Fig.4A). The cumulative incidence of NRM 2 years after immunotherapy in patients who turned MRD-negative and with persistent MRD was 2.8% and 18.2%, respectively (P=0.067, Fig.4B). In the multivariate analysis, the elimination of MRD after immunotherapy significantly decreased the risk of NRM (Table 2).

DFS and OS after MRD-directed immunotherapy

The probability of DFS 2 years after immunotherapy was 77.3% among all patients, which was comparable among those who were MRD_sin+, MRD_co+ receiving IFN-a treatment, and MRD_co+ receiving chemo-DLI (Fig. 5A), while that in patients who turned MRD-negative and with persistent MRD was 84.3% and 54.5%, respectively (P=0.006, Fig.5B).

The probability of OS 2 years after immunotherapy was 84.5% among all patients, which was comparable among those who were MRD_sin+, MRD_co+ receiving IFN-a treatment, and MRD_co+ receiving chemo-DLI (Fig. 6A), while that in patients who turned MRD-negative and with persistent MRD was 91.2% and 60.6%, respectively (P=0.006, Fig. 6B).

In the multivariate analysis, the MRD negativity after immunotherapy was significantly associated with increased survival (Table 2).

Discussion

MDS patients who received MRD-directed immunotherapy had a 2-year CIR of 16.4%, and the 2-year probability of DFS and OS after immunotherapy was 77.3% and 84.5%, respectively. To our knowledge, this study provides an opportunity to explore the currently undefined role of MRD-directed immunotherapy in patients with high-risk MDS after allo-HSCT. In addition, this is the first study that compares chemo-DLI with IFN-a treatment in a disease-specific population of patients with high-risk MDS.

The relapse and DFS rates 2 years after MRD-directed immunotherapy were 16.4% and 77.3%, respectively. In MRD_sin+ patients who received MRD-directed IFN-a treatment, the relapse and DFS rates were 5.9% and 83.0%, respectively. These results are similar to those of MDS patients who were MRD-negative after allo-HSCT in our previous studies (relapse: 8.3%; DFS: 82.9%) [²]. The GVL effect was the major mechanism involved in clearing MRD in both IFN-a treatment and DLI. In addition, IFN-a could inhibit blast cell growth in patients with acute leukemia [²⁹,³⁰]. Thus, MRD-directed immunotherapy was effective for patients with high-risk MDS after allo-HSCT.

cGVHD is closely related to the GVL effect [³¹,³²], and the cGVHD after MRD-directed immunotherapy is critical for clearing MRD in patients with acute leukemia [⁵,¹²]. Its occurrence was comparable between the IFN-a and chemo-DLI groups, which suggests their similar ability for inducing GVL effect in patients with MDS. By contrast, among the patients who received IFN-a treatment, the relapse and DFS rates of MRD_co+ patients were 24.4% and 68.9%, respectively, which are lower than those of MRD_sin+ patients. Thus, MRD-directed IFN-a treatment may be more appropriate for MRD_sin+ patients.

Several studies reported the efficacy of MRD-directed IFN-a treatment in patients with acute leukemia [⁴]. The CIR and DFS rates in patients with acute leukemia receiving IFN-a treatment after allo-HSCT were 11.5%–27.3% and 68.2%–82.4%, respectively [¹²,³³]. In the present study, the CIR and DFS rates were 14.5% and 76.4% in the IFN-a group. Thus, the efficacy of MRD-directed IFN-a treatment was comparable between patients with acute leukemia and high-risk MDS.

The 2-year NRM rate after MRD-directed immunotherapy was only 6.4% in the present study, which was similar to that of patients with MRD-negative MDS after allo-HSCT (8.8%) [²], MRD-directed chemo-DLI and IFN-a treatment ranged from 4.4%–14.4% [⁵,⁶,¹²,³⁴] and 4.3%–4.5% [12,33], respectively. Severe aGVHD can cause NRM after post-HSCT immunotherapy. In this study, the incidence of severe aGVHD was 0.0% and 12.1% in the chemo-DLI and IFN-a groups, respectively (P=0.179), which is similar to that of the MRD-directed chemo-DLI (4.0%–8.2%) [⁵,⁶,¹²] and IFN-a treatment (4.5%–5.7%) [¹²,³³] in our previous studies. Thus, MRD-directed chemo-DLI and IFN-a treatment after allo-HSCT were safe for patients with high-risk MDS.

HMAs are safe in allo-HSCT recipients [³⁵,³⁶] and may be an effective treatment option for MDS patients with relapse after allo-HSCT, particularly in patients with low disease burden [³⁷,³⁸]. However, MRD-directed HMA treatment may only delay the hematologic relapse [³,³⁹]. In the RELAZA trial, although 16 out of 20 patients (80%) responded to pre-emptive azacitidine treatment, 65% experienced hematologic relapse [³]. In the present study, the 2-year CIR after MRD-directed immunotherapy was only 16.4%. However, patients with persistent MRD after immunotherapy had poor clinical outcomes, and other methods that destroy leukemia cells through different mechanisms could be considered. Thus, the efficacy of HMA in the patients who did not respond to MRD-directed immunotherapy remains to be explored.

The first limitation of this retrospective study is the use of a relatively small number of patients, which could only explain the problem to some extent. Second, the observation period was relatively short, and our extension study could further evaluate the long-term clinical outcomes after MRD-directed immunotherapy in patients with high-risk MDS after receiving allo-HSCT. Lastly, patients with active GVHD and infections, severe myelosuppression, or organ failure were not administered with MRD-directed immunotherapy, and pre-emptive intervention methods should be further studied.

In summary, MRD-directed immunotherapy is effective for patients with high-risk MDS after allo-HSCT. Additionally, the efficacy was comparable between the chemo-DLI and IFN-a treatment. In the future, large-scale, randomized trials should be conducted to further compare the efficacy among IFN-a, chemo-DLI, and HMA treatments in MRD-positive patients after allo-HSCT and to identify the most effective intervention strategy.

References

[1] Wang Y, Wang HX, Lai YR, Sun ZM, Wu DP, Jiang M, Liu DH, Xu KL, Liu QF, Liu L, Wang JB, Gao F, Ou-Yang J, Gao SJ, Xu LP, Huang XJ. Haploidentical transplant for myelodysplastic syndrome: registry-based comparison with identical sibling transplant. Leukemia 2016; 30(10): 2055–2063

[2] Mo XD, Qin YZ, Zhang XH, Xu LP, Wang Y, Yan CH, Chen H, Chen YH, Han W, Wang FR, Wang JZ, Liu KY, Huang XJ. Minimal residual disease monitoring and preemptive immunotherapy in myelodysplastic syndrome after allogeneic hematopoietic stem cell transplantation. Ann Hematol 2016; 95(8): 1233–1240

[3] Platzbecker U, Wermke M, Radke J, Oelschlaegel U, Seltmann F, Kiani A, Klut IM, Knoth H, Röllig C, Schetelig J, Mohr B, Graehlert X, Ehninger G, Bornhäuser M, Thiede C. Azacitidine for treatment of imminent relapse in MDS or AML patients after allogeneic HSCT: results of the RELAZA trial. Leukemia 2012; 26(3): 381–389

[4] Mo XD, Lv M, Huang XJ. Preventing relapse after haematopoietic stem cell transplantation for acute leukaemia: the role of post-transplantation minimal residual disease (MRD) monitoring and MRD-directed intervention. Br J Haematol 2017; 179(2): 184–197

[5] Mo XD, Zhang XH, Xu LP, Wang Y, Yan CH, Chen H, Chen YH, Han W, Wang FR, Wang JZ, Liu KY, Huang XJ. Salvage chemotherapy followed by granulocyte colony-stimulating factor-primed donor leukocyte infusion with graft-vs.-host disease control for minimal residual disease in acute leukemia/myelodysplastic syndrome after allogeneic hematopoietic stem cell transplantation: prognostic factors and clinical outcomes. Eur J Haematol 2016; 96(3): 297–308

[6] Yan CH, Liu DH, Liu KY, Xu LP, Liu YR, Chen H, Han W, Wang Y, Qin YZ, Huang XJ. Risk stratification-directed donor lymphocyte infusion could reduce relapse of standard-risk acute leukemia patients after allogeneic hematopoietic stem cell transplantation. Blood 2012; 119(14): 3256–3262

[7] McSweeney EN, Worman CP, Tsakona CP, Jewel AP, Hoffbrand AV, Milligan DW, Burnett AK, Lewis ML, Goldstone AH. Low-dose recombinant α-2a-interferon: a feasible maintenance therapy in acute myeloid leukaemia in the older patient. Acta Haematol 1993; 89(1): 1–5

[8] Smits EL, Anguille S, Berneman ZN. Interferon a may be back on track to treat acute myeloid leukemia. OncoImmunology 2013; 2(4): e23619

[9] Anguille S, Lion E, Willemen Y, Van Tendeloo VF, Berneman ZN, Smits EL. Interferon-a in acute myeloid leukemia: an old drug revisited. Leukemia 2011; 25(5): 739–748

[10] Gesundheit B, Shapira MY, Resnick IB, Amar A, Kristt D, Dray L, Budowski E, Or R. Successful cell-mediated cytokine-activated immunotherapy for relapsed acute myeloid leukemia after hematopoietic stem cell transplantation. Am J Hematol 2009; 84(3): 188–190

[11] Tang X, Song YH, Sun A, Zhu X, Ruan C, Wu D. Successful treatment of relapsed acute myeloid leukemia without chemotherapy. J Clin Oncol 2016; 34(13): e117–e119

[12] Mo XD, Zhang XH, Xu LP, Wang Y, Yan CH, Chen H, Chen YH, Han W, Wang FR, Wang JZ, Liu KY, Huang XJ. Interferon-a: a potentially effective treatment for minimal residual disease in acute leukemia/myelodysplastic syndrome after allogeneic hematopoietic stem cell transplantation. Biol Blood Marrow Transplant 2015; 21(11): 1939–1947

[13] Huang XJ, Xu LP, Liu KY, Liu DH, Wang Y, Chen H, Chen YH, Han W, Wang JZ, Chen Y, Zhang XH, Shi HX, Wang FR, Tang FF. Partially matched related donor transplantation can achieve outcomes comparable with unrelated donor transplantation for patients with hematologic malignancies. Clin Cancer Res 2009; 15(14): 4777–4783

[14] Wang Y, Liu QF, Xu LP, Liu KY, Zhang XH, Ma X, Fan ZP, Wu DP, Huang XJ. Haploidentical vs identical-sibling transplant for AML in remission: a multicenter, prospective study. Blood 2015; 125(25): 3956–3962

[15] Huang XJ, Liu DH, Liu KY, Xu LP, Chen H, Han W, Chen YH, Wang JZ, Gao ZY, Zhang YC, Jiang Q, Shi HX, Lu DP. Haploidentical hematopoietic stem cell transplantation without in vitro T-cell depletion for the treatment of hematological malignancies. Bone Marrow Transplant 2006; 38(4): 291–297

[16] Huang XJ, Liu DH, Liu KY, Xu LP, Chen H, Han W, Chen YH, Zhang XH, Lu DP. Treatment of acute leukemia with unmanipulated HLA-mismatched/haploidentical blood and bone marrow transplantation. Biol Blood Marrow Transplant 2009; 15(2): 257–265

[17] Zhao XS, Liu YR, Zhu HH, Xu LP, Liu DH, Liu KY, Huang XJ. Monitoring MRD with flow cytometry: an effective method to predict relapse for ALL patients after allogeneic hematopoietic stem cell transplantation. Ann Hematol 2012; 91(2): 183–192

[18] Zhao XS, Jin S, Zhu HH, Xu LP, Liu DH, Chen H, Liu KY, Huang XJ. Wilms’ tumor gene 1 expression: an independent acute leukemia prognostic indicator following allogeneic hematopoietic SCT. Bone Marrow Transplant 2012; 47(4): 499–507

[19] Zhao XS, Yan CH, Liu DH, Xu LP, Liu YR, Liu KY, Qin YZ, Wang Y, Huang XJ. Combined use of WT1 and flow cytometry monitoring can promote sensitivity of predicting relapse after allogeneic HSCT without affecting specificity. Ann Hematol 2013; 92(8): 1111–1119

[20] Huang XJ, Liu DH, Liu KY, Xu LP, Chen H, Han W. Donor lymphocyte infusion for the treatment of leukemia relapse after HLA-mismatched/haploidentical T-cell-replete hematopoietic stem cell transplantation. Haematologica 2007; 92(3): 414–417

[21] Huang XJ, Wang Y, Liu DH, Xu LP, Liu KY, Chen H, Chen YH, Han W, Shi HX. Administration of short-term immunosuppressive agents after DLI reduces the incidence of DLI-associated acute GVHD without influencing the GVL effect. Bone Marrow Transplant 2009; 44(5): 309–316

[22] Przepiorka D, Weisdorf D, Martin P, Klingemann HG, Beatty P, Hows J, Thomas ED. 1994 Consensus Conference on Acute GVHD Grading. Bone Marrow Transplant 1995; 15(6): 825–828

[23] Filipovich AH, Weisdorf D, Pavletic S, Socie G, Wingard JR, Lee SJ, Martin P, Chien J, Przepiorka D, Couriel D, Cowen EW, Dinndorf P, Farrell A, Hartzman R, Henslee-Downey J, Jacobsohn D, McDonald G, Mittleman B, Rizzo JD, Robinson M, Schubert M, Schultz K, Shulman H, Turner M, Vogelsang G, Flowers ME. National Institutes of Health consensus development project on criteria for clinical trials in chronic graft-versus-host disease: I. Diagnosis and staging working group report. Biol Blood Marrow Transplant 2005; 11(12): 945–956

[24] Dignan FL, Clark A, Amrolia P, Cornish J, Jackson G, Mahendra P, Scarisbrick JJ, Taylor PC, Hadzic N, Shaw BE, Potter MN; Haemato-oncology Task Force of British Committee for Standards in Haematology; British Society for Blood and Marrow Transplantation. Diagnosis and management of acute graft-versus-host disease. Br J Haematol 2012; 158(1): 30–45

[25] Dignan FL, Amrolia P, Clark A, Cornish J, Jackson G, Mahendra P, Scarisbrick JJ, Taylor PC, Shaw BE, Potter MN; Haemato-oncology Task Force of British Committee for Standards in Haematology; British Society for Blood and Marrow Transplantation. Diagnosis and management of chronic graft-versus-host disease. Br J Haematol 2012; 158(1): 46–61

[26] Malcovati L, Germing U, Kuendgen A, Della Porta MG, Pascutto C, Invernizzi R, Giagounidis A, Hildebrandt B, Bernasconi P, Knipp S, Strupp C, Lazzarino M, Aul C, Cazzola M. Time-dependent prognostic scoring system for predicting survival and leukemic evolution in myelodysplastic syndromes. J Clin Oncol 2007; 25(23): 3503–3510

[27] Alessandrino EP, Della Porta MG, Bacigalupo A, Van Lint MT, Falda M, Onida F, Bernardi M, Iori AP, Rambaldi A, Cerretti R, Marenco P, Pioltelli P, Malcovati L, Pascutto C, Oneto R, Fanin R, Bosi A; Gruppo Italiano Trapianto di Midollo Osseo (GITMO). WHO classification and WPSS predict posttransplantation outcome in patients with myelodysplastic syndrome: a study from the Gruppo Italiano Trapianto di Midollo Osseo (GITMO). Blood 2008; 112(3): 895–902

[28] Gooley TA, Leisenring W, Crowley J, Storer BE. Estimation of failure probabilities in the presence of competing risks: new representations of old estimators. Stat Med 1999; 18(6): 695–706

[29] Zhang C, Cui G, Chen Y, Fan K. Antitumor effect of interferon-α on U937 human acute leukemia cells in vitro and its molecular mechanism. J Huazhong Univ Sci Technolog Med Sci 2007; 27(5): 513–515

[30] Rohatiner AZ. Growth inhibitory effects of interferon on blast cells from patients with acute myelogenous leukaemia. Br J Cancer 1984; 49(6): 805–807

[31] Baron F, Labopin M, Niederwieser D, Vigouroux S, Cornelissen JJ, Malm C, Vindelov LL, Blaise D, Janssen JJ, Petersen E, Socié G, Nagler A, Rocha V, Mohty M. Impact of graft-versus-host disease after reduced-intensity conditioning allogeneic stem cell transplantation for acute myeloid leukemia: a report from the Acute Leukemia Working Party of the European group for blood and marrow transplantation. Leukemia 2012; 26(12): 2462–2468

[32] Mo XD, Xu LP, Zhang XH, Liu DH, Wang Y, Chen H, Yan CH, Chen YH, Han W, Wang FR, Wang JZ, Liu KY, Huang XJ. Chronic GVHD induced GVL effect after unmanipulated haploidentical hematopoietic SCT for AML and myelodysplastic syndrome. Bone Marrow Transplant 2015; 50(1): 127–133

[33] Mo XD, Zhang XH, Xu LP, Wang Y, Yan CH, Chen H, Chen YH, Han W, Wang FR, Wang JZ, Liu KY, Huang XJ. IFN-a is effective for treatment of minimal residual disease in patients with acute leukemia after allogeneic hematopoietic stem cell transplantation: results of a registry study. Biol Blood Marrow Transplant 2017; 23(8): 1303–1310

[34] Mo XD, Zhang XH, Xu LP, Wang Y, Yan CH, Chen H, Chen YH, Han W, Wang FR, Wang JZ, Liu KY, Huang XJ. Comparison of outcomes after donor lymphocyte infusion with or without prior chemotherapy for minimal residual disease in acute leukemia/myelodysplastic syndrome after allogeneic hematopoietic stem cell transplantation. Ann Hematol 2017; 96(5): 829–838

[35] Pusic I, Choi J, Fiala MA, Gao F, Holt M, Cashen AF, Vij R, Abboud CN, Stockerl-Goldstein KE, Jacoby MA, Uy GL, Westervelt P, DiPersio JF. Maintenance therapy with decitabine after allogeneic stem cell transplantation for acute myelogenous leukemia and myelodysplastic syndrome. Biol Blood Marrow Transplant 2015; 21(10): 1761–1769

[36] Schroeder T, Rautenberg C, Haas R, Kobbe G. Hypomethylating agents after allogeneic blood stem cell transplantation. Stem Cell Investig 2016; 3: 84

[37] Schroeder T, Czibere A, Platzbecker U, Bug G, Uharek L, Luft T, Giagounidis A, Zohren F, Bruns I, Wolschke C, Rieger K, Fenk R, Germing U, Haas R, Kröger N, Kobbe G. Azacitidine and donor lymphocyte infusions as first salvage therapy for relapse of AML or MDS after allogeneic stem cell transplantation. Leukemia 2013; 27(6): 1229–1235

[38] Schroeder T, Rachlis E, Bug G, Stelljes M, Klein S, Steckel NK, Wolf D, Ringhoffer M, Czibere A, Nachtkamp K, Dienst A, Kondakci M, Stadler M, Platzbecker U, Uharek L, Luft T, Fenk R, Germing U, Bornhäuser M, Kröger N, Beelen DW, Haas R, Kobbe G. Treatment of acute myeloid leukemia or myelodysplastic syndrome relapse after allogeneic stem cell transplantation with azacitidine and donor lymphocyte infusions—a retrospective multicenter analysis from the German Cooperative Transplant Study Group. Biol Blood Marrow Transplant 2015; 21(4): 653–660

[39] Sockel K, Wermke M, Radke J, Kiani A, Schaich M, Bornhäuser M, Ehninger G, Thiede C, Platzbecker U. Minimal residual disease-directed preemptive treatment with azacitidine in patients with NPM1-mutant acute myeloid leukemia and molecular relapse. Haematologica 2011; 96(10): 1568–1570

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