Based on the representative articles in recent years, the different mechanisms of decitabine on immune regulation in patients with acute myeloid leukemia (AML) after allogeneic hematopoietic stem cell transplantation (HSCT) are summarized. Decitabine improves the expression of WT1 gene to stimulate specific cytotoxic T cells which can enhance graft versus leukemia effect (GVL) and improve the expression of FOXP3 gene to stimulate regulatory T cells so as to inhibit the acute graft versus host disease (GVHD). Through the above-mentimed mechanisms, decitabine can improve both therapeutic effect and quality of life in the patients with AML after allogeneic HSCT.
Antimetabolites, Antineoplastic ; pharmacology ; Azacitidine ; analogs & derivatives ; pharmacology ; Graft vs Leukemia Effect ; Hematopoietic Stem Cell Transplantation ; Humans ; Leukemia, Myeloid, Acute ; immunology ; therapy ; Quality of Life ; T-Lymphocytes, Cytotoxic ; T-Lymphocytes, Regulatory ; Transplantation, Homologous

PURPOSE: The repopulating lymphocytes after allogeneic hematopoietic stem cell transplantation have an important role not only on the prevention of serious infections in the early transplantation period, but also on the killing of residual leukemic cells by graft-versus-leukemia effect. The aim of this study was to analyze the impact of lymphocyte recovery after allogeneic stem cell transplantation in children with hematologic malignancies. MATERIALS AND METHODS: We evaluated 69 children transplanted for acute lymphoblastic leukemia (ALL) (n=34), acute myeloid leukemia (AML) (n=26), chronic leukemia (n=7) and juvenile myelomonocytic leukemia (n=2) between 1996 and 2008 at the Chonnam National University Hospital, Korea. The patients were grouped based on absolute lymphocyte counts (ALC) <500/microL or > or =500/microL at D+21 and D+30 after transplant. RESULTS: Patients with a High ALC at D+21 and D+30 had a faster neutrophil and platelet engraftment. The High at D+30 group had a better 5 year overall survival (71% vs. 53%, p=0.043) and event-free survival (72% vs. 53%, p=0.065) than the Low at D+30 group. The incidence of grade II-IV acute and chronic graft-versus-host disease (GVHD), and relapse rate did not differ by the ALC counts. However, the Low at D+30 group had a significantly increased risk for transplant-related mortality (p=0.019). The univariate analysis showed that the factors associated with decreased survival were a Low ALC at D+30, patients with high risk ALL, and grade II-IV aGVHD in patients with ALL and AML. CONCLUSION: Early posttransplant serial lymphocyte measurement would be a simple but useful method for predicting transplant outcomes.
Adolescent ; Blood Platelets/metabolism ; Child ; Child, Preschool ; Female ; Graft vs Leukemia Effect ; *Hematopoietic Stem Cell Transplantation ; Humans ; Infant ; Killer Cells, Natural/cytology ; Leukemia/*therapy ; Lymphocyte Count ; Lymphocytes/*cytology ; Male ; Neutrophils/cytology ; Prognosis ; Recurrence ; Remission Induction ; Republic of Korea ; Retrospective Studies ; Stem Cells/cytology ; Transplantation Conditioning ; Transplantation, Homologous ; Treatment Outcome

OBJECTIVETo investigate the effect of immature dendritic cells (inDC) genetically modified to express sTNFR I on acute graft-versus-host disease (aGVHD) and the graft-versus-leukemia (GVL) effect ofter allogeneic bone marrow transplantation (allo-BMT) in leukemic mice and its mechanism.

METHODSAn EL4 leukemia allo-BMT model was established with the BALB/c (H-2d) donor mice (DM)and C57BL/6 (H-2b) recipient mice (RM). The RM received DM bone marrow (BM) cells at a 1:1 ratio with spleen cells intravenously via tail vein at 4 h after TBI. Fifty DM were separated randomly into five groups: (1) Group A: total body irradiation (TBI) group, (2) Group B: lymphoma cell leukemia group, (3) Group C: allo-BMT group, (4) Group D: pXZ9-DC group, (5) Group E: sTNFR I-DC group. Acute GVHD scores, incidence of leukemic cell infiltration, histopathological analysis, survival rate, and survival rate of the recipients were estimated after allo-BMT. Enzyme-linked immunosorbent assay (ELISA) method was used to detect cytokines (INF-gamma and IL-4 ) production. Flow cytometry (FCM) analysis was used to detect allogeneic chimerism.

RESULTS(1) The mice in group A and group B all died of the BM failure and lymphoma cell leukemia, respectively. The mice in group C developed typical clinical signs of a GVHD after BMT with an average survival time(AST) of (11.50 +/- 3.50) d. The signs of aGVHD were less evident in the group D and E, and their AST (21.70 +/- 5.80 and 25.80 +/- 5.20 days, respectively) were all longer than that in group C (P < 0.05). AST of group E was the longest (P < 0.05). The mice in group B all died of leukemia within 18 days after engraftment of EL4 cells. There was was no significant difference in groups C, D and E in the incidence of leukemia (P > 0.05). (2) Serum IFN-gamma level reached peak value. At + 12 d, then decreased gradually in group C, D, and E, and then reached the nadir at +18 d post-BMT, with the lowest in group E (P < 0.05), and the level was significantly lower in group D than in group C (P < 0.05). After BMT, serum IL-4 level slightly decreased in group C, but gradually elevated in group D and E and reached their peak at +12 d, and even more significantly increased in group E (P < 0.05). There was no statistical significance in the pair wise comparison among three group (P < 0.05). (3) The average proportion of H-2d positive cells in RM was 95%-100% on day 30 post-BMT, with complete donor-type implantation.

CONCLUSIONImmature DC can induce immuno tolerance. Immature DC genetically modified to express sTNFR I has been shown to prevent acute GVHD in lethally irradiated mice reconstituted with allogeneic bone marrow grafts while maintaining the GVL response.

Animals ; Bone Marrow Transplantation ; adverse effects ; methods ; Dendritic Cells ; immunology ; Female ; Graft vs Host Disease ; prevention & control ; Graft vs Leukemia Effect ; Immune Tolerance ; Male ; Mice ; Mice, Inbred BALB C ; Mice, Inbred C57BL ; Receptors, Tumor Necrosis Factor, Type I ; genetics ; Transplantation, Homologous

Aim of this study was to compare the outcomes of transplantation by donor source and to help select the best alternative donor in children with leukemia. Donor sources included matched related donor (MRD, n = 35), allele-matched unrelated donor (M-UD, n = 10) or -mismatched (MM)-UD (n = 13) or unrelated umbilical cord blood (UCB, n = 11). UCB group had a significantly higher incidence of grade II-IV acute graft versus host disease (MRD, 11.8%; M-UD, 30.0%; MM-UD, 15.4%, UCB, 54.4%, P = 0.004) but there was no difference in incidence of chronic graft versus host disease between 4 groups. The 5-yr leukemia-free survival (LFS) was 76.7%, 60.0%, 69.2%, and 45.5%, respectively (P = 0.128). MRD group showed higher LFS rate than UCB group (P = 0.022). However, LFS of M-UD and MM-UD together (65.2%) was not different from that of MRD group (76.7%, P = 0.325), or from that of UCB (45.5%, P = 0.190). The relapse incidence at 5 yr was 17.1%, 20.0%, 15.4%, and 0%, respectively (P = 0.460). The 100-day treatment-related mortality was 2.9%, 20.0%, 7.7%, and 36.4%, respectively (P = 0.011). Despite the limitations of small number of patients, unrelated donor transplants including even allele-mismatched ones, seem to be as effective in children with leukemia lacking suitable relative donors. Also, UCB transplant may serve as another possible option in urgent transplants.
Adolescent ; Child ; Child, Preschool ; *Cord Blood Stem Cell Transplantation/adverse effects/methods ; Disease-Free Survival ; Female ; Fetal Blood/transplantation ; Graft vs Leukemia Effect ; *Hematopoietic Stem Cell Transplantation/adverse effects/methods/mortality ; Histocompatibility Testing ; Humans ; Infant ; Leukemia/mortality/*therapy ; Male ; Transplantation, Homologous ; Treatment Outcome ; Unrelated Donors

Graft vs Host Disease ; prevention & control ; Graft vs Leukemia Effect ; Hematopoietic Stem Cell Transplantation ; methods ; Humans ; Transplantation, Homologous ; methods

OBJECTIVETo explore the relationship between WT1-induced T-cell subsets and graft-versus-host disease (GVHD) after nonmyeloablative allogeneic hematopoietic stem cell transplantation (NST).

METHODSPeripheral blood mononucleated cells (PBMCs) from 19 patients who expressed WT1 and developed GVHD after NST were simulated by WT1126-134 peptide in vitro, and proportions of WT1-induced-T-cell subsets (Tc1, Tc2, Th1, Th2 cells) before and after transplant were detected by intracellular cytokine staining (ICCS) assay. WT1-specific CD8(+) CTLs of 14 patients with HLA-A*0201 were detected by HLA-A*0201/WT1 pentamer.

RESULTS(1) 17 of 19 patients developed GVHD, among whom proportions of Tc1 and Th1 cells, achieved peak value in 16 patients at occurrence of GVHD (P = 0.039); (2) The peak proportions of Tc1 and Th1 cells in patients with aGVHD above grade II were higher than those with grade I, but being no statistical difference (P = 0.900 and P = 0.140, respectively); (3) The peak proportion of Th1 cells (P = 0.004), but not Tc1 cells (P = 0.060) in patients with extensive cGVHD was significantly higher than that in patients with limited one; (4) Proportions of Tc1, Th1 and WT1(+)CD8(+)CTL in patients without GVHD were similar to those in patients with Grade I aGVHD, but lower than those in aGVHD above grade II.

CONCLUSIONGVHD promotes the generation of WT1-induced GVL effect, and the intensity of the latter maybe correlated with the intensity of GVHD, especially cGVHD. Th1 cells play a more important role in the enhancement of WT1-induced GVL effect in extensive cGVHD patient than in limited cGVHD patients.

Adolescent ; Adult ; Female ; Graft vs Host Disease ; etiology ; Graft vs Leukemia Effect ; Hematopoietic Stem Cell Transplantation ; adverse effects ; Humans ; Male ; Middle Aged ; T-Lymphocyte Subsets ; immunology ; Transplantation, Homologous ; WT1 Proteins ; metabolism ; Young Adult

In order to explore the influence of purified donor regulatory T cells (Treg) infused after allogeneic bone marrow transplantation (allo-BMT) on GVHD and GVL effect in mice, an EL4 leukemia allo-BMT model of BALB/c-->C57BL/6 mice was established. The CD4(+)CD25(+)T cells were purified by positive selection using MACS. The recipients were injected with CD4(+)CD25(+)T cells or CD4(+)CD25(-)T cells within 4 hours respectively along with allo-BMT. Survival time, clinical GVHD score or histopathological features were observed after allo-BMT. The results showed that the mean survival time in leukemia control group was (17.9 +/- 0.7) days and all mice died of leukemia. The mean survival times in transplantation control group and CD4(+)CD25(-)T group were (23.2 +/- 1.6) and (22.3 +/- 1.9) days. Histopathological analysis in several target organs (skin, liver and small intestine) confirmed the presence of severe GVHD. The mean survival time in Treg group was (47.3 +/- 6.5) days. 70% of recipients were alive until day 60 without features of GVHD or tumor progression. Clinical GVHD scores in Treg group significantly decreased as compared to transplantation control group and CD4(+)CD25(-)T group (p < 0.05). It is concluded that allo-BMT combined with injection of donor CD4(+)CD25(+)Treg cells can efficiently prevent recipients from lethal GVHD with preserving GVL effect during allo-BMT.
Animals ; Bone Marrow Transplantation ; methods ; Female ; Graft vs Host Disease ; prevention & control ; Graft vs Leukemia Effect ; Male ; Mice ; Mice, Inbred BALB C ; Mice, Inbred C57BL ; T-Lymphocytes, Regulatory ; transplantation ; Tissue Donors

OBJECTIVETo explore the dissociation of graft-versus-leukemia (GVL) effects from graft-versus-host disease (GVHD) in the patients who experienced GVHD during leukemia relapse after allogeneic hematopoietic stem cell transplantation (allo-HSCT).

METHODSThe primary disease, disease status, GVHD, response to donor lymphocyte infusion (DLI) and prognosis were analysed in 11 leukemia patients who relapsed with GVHD after allo-HSCT.

RESULTSOf the 11 relapsed, 5 were acute lymphoblastic leukemia and 6 acute myeloid leukemia. Five received DLI before relapse and all developed post-DLI GVHD, including 2 grade II acute GVHD (aGVHD), 1 limited chronic GVHD (cGVHD) plus grade II aGVHD, and 2 extensive cGVHD. After relapse of the 5 patients, 2 received Chemo-DLI, one achieved CR with extensive cGVHD and then relapsed again, the other didn't achieved CR. The other 6 patients didn't received DLI before relapse and also developed post-HSCT GVHD while relapsing, including 3 extensive cGVHD, 1 grade I aGVHD and 2 grade II-IV aGVHD. After relapse, these 6 patients received Chemo-DLI, 2 achieved CR and then relapsed again, 4 didn't achieved CR.

CONCLUSIONThe elicited GVHD after allo-HSCT may not accompany effective GVL effects inhibiting leukemic relapse.

Graft vs Host Disease ; Graft vs Leukemia Effect ; Hematopoietic Stem Cell Transplantation ; Humans ; Leukemia, Myeloid, Acute ; Precursor Cell Lymphoblastic Leukemia-Lymphoma

Despite significant recent advances in the applicability and outcome following unrelated cord blood transplantation (UCBT), infections remain a major cause of mortality associated with poor immune recovery in the first 6 months after UCBT. Enhanced immune reconstitution not only could improve survival by reduced transplant related mortality, but may also favorably impact on relapse incidence by improved graft-versus-leukemia effects. This review will summarize our current understanding of the biology of immune recovery post-UCBT with an emphasis on adaptive T cell dependent immunity. New efforts to boost immunity will be also highlighted including our own laboratory, where ex vivo T cell expansion is pursued towards adoptive immunotherapy.
Biology ; Cord Blood Stem Cell Transplantation ; Fetal Blood ; Graft vs Leukemia Effect ; Immunotherapy, Adoptive ; Incidence ; Opportunistic Infections ; Recurrence ; Transplants

OBJECTIVETo study the role of donor-derived NK cells in haploidentical bone marrow transplantation (BMT) in leukemic mice.

METHODSCB6F1(H-2b/d) mice model of EL9611 (H-2d) erythroleukemia was established by injection of EL9611 (H-2d) cells via tail vein. CB6F1(H-2b/d) mice were used as recipient, and C57BL/6(H-2b) mice as donor. Five days later, 70 CB6F1(H-2b/d) mice were randomly divided into 7 groups (10 mice per group) as follows: group 1: without treatment; group 2: simple-irradiated group; group 3: treated with cytarabine (Ara-C) at 50 mg/kg x6 d; group 4: simple BMT; group 5: haploidentical BMT with graft-versus-host disease (GVHD) that injected with bone marrow cells and spleen cells of C57BL/6(H-2b) mice 4 hours after irradiation; group 6: after irradiated with 9 Gy, mice were injected with C57BL/6(H-2b) NK cells (1 x 10(6)) and 4 hours later with BM cells, group 7: after irradiation of 9 Gy, mice were injected with C57BL/6(H-2b) NK cells (1 x 10(6)) and 4 hours later with BM cells and spleen cells. The blood routine test, survival time, body weight, and histopathology in the recipients were observed and compared among these group.

RESULTSThe survival time was (10.1 +/- 0.9), (9.8 +/- 0.9), (22.7 +/- 3.2) and (20.1 +/- 1.7) days in groups 1, 2, 3, and 5 respectively; was (30.1 +/- 16.0) days in group 4, out of which 2 mice survived for more than 30 days. The survival time was (39.1 +/- 18.1) and (49.3 +/- 17.2) days in groups 6 and 7 respectively, out of which 4 mice in group 6 and 7 mice in group 7 survived for more than 30 days. The survival time in group 6 was much longer than that in group 1, 2, 3 and 5 (P < 0.01). The survival time in group 7 was much longer than that in other groups (P < 0.05). The liver and spleen enlargement, organ destruction and infiltration with leukemic cells were observed in mice died from leukemia. The chimerism of Y chromosome appeared (80%-90%) in long-term survival mice in groups 6 and 7.

CONCLUSIONDonor-derived NK cells have the antileukemia ability and reduce GVHD in haploidentical BMT in erythroleukemia mice (EL9611, H-2d).

Animals ; Bone Marrow Transplantation ; immunology ; Disease Models, Animal ; Female ; Graft vs Host Disease ; prevention & control ; Graft vs Leukemia Effect ; Killer Cells, Natural ; immunology ; Leukemia, Erythroblastic, Acute ; surgery ; Lymphocyte Transfusion ; Male ; Mice ; Mice, Inbred BALB C ; Mice, Inbred C57BL