T-Cell-Replete Haploidentical Hematopoietic Stem Cell Transplantation for a Patient With Tcf3-Hlf-Positive Acute Lymphoblastic Leukemia Extramedullary Relapse After Unrelated Bone Marrow Transplantation.

TCF3-HLF-positive B-cell precursor acute lymphoblastic leukemia (BCP-ALL) has an extremely poor prognosis. A 2-year-old boy with TCF3-HLF-positive BCP-ALL had an isolated extramedullary relapse in multiple bones after allogeneic hematopoietic stem cells transplantation (HSCT) from a human leukocyte antigen-matched unrelated donor. In this study, he received a T-cell-replete haploidentical HSCT (TCR-haplo-HSCT) from his father when in nonremission state, which resulted in a sustained complete remission for over 3 years. Immune therapies for patients with an extramedullary relapse of TCF3-HLF-positive BCP-ALL have been attempted; however, long-term efficacies of these therapies remain unknown. Our TCR-haplo-HSCT may be an effective therapeutic option for such patients.

Decline of serum albumin precedes severe acute GVHD after haploidentical HSCT.

BACKGROUND: Haploidentical hematopoietic stem cell transplantation (HSCT) is a useful therapy for relapsed/refractory acute leukemia or lymphoma because of the strong graft-vs-leukemia (GVL) effect. However, it is often accompanied by severe acute graft-versus-host disease (aGVHD), which is the most serious complication after haploidentical HSCT. Thus, it is important to control the severity of aGVHD while maintaining the GVL effect. In our experience of pediatric haploidentical HSCT, it takes several days for aGVHD to become severe after the appearance of initial symptoms, mostly skin rashes. In this study, we aimed to identify useful biomarkers at the onset of aGVHD that predict subsequent development of severe aGVHD. METHODS: Forty-five consecutive children with relapsed/refractory acute leukemia or lymphoma who developed aGVHD after haploidentical HSCT were enrolled. We analyzed possible biomarkers from samples collected at the onset of acute GVHD. RESULTS: Nineteen patients developed grade 1-2 aGVHD, and 26 patients developed grade 3-4 aGVHD. There was no significant difference in patient characteristics between the two groups. Transplant-related mortality occurred only in the grade 3-4 aGVHD group (34.5%). Multivariate analysis revealed that serum albumin was an independent biomarker for predicting the severity of aGVHD (P = 0.009). The area under the receiver operating characteristic curve of serum albumin was 0.864. CONCLUSIONS: The serum albumin level at the onset of aGvHD could be a useful biomarker for the development of subsequent severe aGVHD in pediatric patients after haploidentical HSCT.

Two Occurrences of Leukemia Relapse Due to Mismatched HLA Loss After Haploidentical Stem Cell Transplantation From Different Family Donors With KIR Ligand Mismatch.

Mismatched HLA loss is a cause of leukemia relapse after HLA-haploidentical stem cell transplantation (haplo-SCT). We report a patient with a history of 2 occurrences of leukemia relapse due to mismatched HLA loss after haplo-SCT. He received haplo-SCT from his father but showed leukemia relapse with loss of the maternal HLA haplotype. He then underwent haplo-SCT from his mother, and developed relapse with loss of the paternal HLA haplotype. Both donors had killer cell immunoglobulin-like receptor-ligand mismatch but alloreactive natural killer cells could not prevent relapse. Second haplo-SCT should be conducted carefully for patients with relapse due to mismatched HLA loss.

Optimal timing of apheresis for the efficient mobilization of peripheral blood progenitor cells recruited by high-dose granulocyte colony-stimulating factor in healthy donors.

Predictors of peripheral blood stem cell (PBSC) yield can potentially improve the comfort, safety, and efficacy of CD34+ cell collection from donors treated with recombinant human granulocyte colony-stimulating factor (G-CSF). We investigated 181 apheresis procedures on 109 healthy allogeneic donors to identify factors correlating with efficient PBSC collection. Apheresis started on Day 4 or 5 and continued up to Day 6 of G-CSF administration. CD34+ cell　yields on Days 4 and 5 were comparable, and significantly higher than on Day 6. This suggests that starting apheresis on Day 4 rather than Day 5 may be preferable, to reduce G-CSF exposure and optimize yield, even if multi-day collection is required. More CD34+ cells were collected from male and cytomegalovirus (CMV)-seronegative donors than from female and CMV-seropositive donors, respectively. The yields of CD34+ cells were similarly high in both male and female donors aged 20-29 years; yields decreased in female donors in their thirties, and were comparably low in both male and female donors in their forties and thereafter. These findings should guide decision-making about when to begin apheresis, and encourage careful consideration of donor factors such as gender, age, and CMV serostatus when collecting PBSCs.

Various checkpoint molecules, and tumor-infiltrating lymphocytes in common pediatric solid tumors: Possibilities for novel immunotherapy.

Long-term survival rates for pediatric patients with cancer have significantly improved, but novel approaches are desired for those with refractory/relapsed solid tumors. Recently, programed cell death-1/programed cell death-ligand-1 blockade has emerged as an effective option for many intractable cancers. However, not all patients show objective response to such therapy. On the other hand, several other checkpoint pathways, including Herpes virus entry mediator (HVEM)/B- and T-lymphocyte attenuator (BTLA), galectin-9 (GAL9)/T-cell immunoglobulin and mucin domain-3 (TIM3), and major histocompatibility complex class II (MHC-II)/lymphocyte activation gene-3 (LAG3), also regulate immune responses in the tumor microenvironment and may be alternative targets for novel immune therapies. In this study, we examined 65 common pediatric solid tumors and characterized the expression of Herpes virus entry mediator, GAL9, and MHC-II on tumor cells and their corresponding receptors B- and T-lymphocyte attenuator, TIM3, and LAG3, respectively, on tumor-infiltrating lymphocytes (TILs) with immunohistochemistry. Whereas the expression of GAL9 and MHC-II was limited, 73% of rhabdomyosarcomas and 100% of osteosarcomas expressed moderate to high levels of Herpes virus entry mediator on the tumor. TILs were detected in all tumor samples except one osteosarcoma. Interestingly, 45% of rhabdomyosarcomas, and 45% of osteosarcomas expressed moderate to high levels of both Herpes virus entry mediator on the tumor cells and B- and T-lymphocyte attenuator on the TILs. Results showed that a subset of pediatric solid tumors expressed tumor-associated checkpoint molecules, and TILs expressed corresponding receptors for these checkpoint molecules. Thus, immunogenic environments may be created, and checkpoint blockade may induce favorable immune responses.

Programming of donor T cells using allogeneic δ-like ligand 4-positive dendritic cells to reduce GVHD in mice.

Alloreactive T cells play a critical role in eliminating hematopoietic malignant cells but are also the mediators of graft-versus-host disease (GVHD), a major complication that subverts the success of allogeneic hematopoietic stem cell transplantation (HSCT). However, induction of alloreactive T cells does not necessarily lead to GVHD. Here we report the development of a cellular programming approach to render alloreactive T cells incapable of causing severe GVHD in both major histocompatibility complex (MHC)-mismatched and MHC-identical but minor histocompatibility antigen-mismatched mouse models. We established a novel platform that produced δ-like ligand 4-positive dendritic cells (Dll4(hi)DCs) from murine bone marrow using Flt3 ligand and Toll-like receptor agonists. Upon allogeneic Dll4(hi)DC stimulation, CD4(+) naïve T cells underwent effector differentiation and produced high levels of interferon γ (IFN-γ) and interleukin-17 in vitro, depending on Dll4 activation of Notch signaling. Following transfer, allogeneic Dll4(hi)DC-induced T cells were unable to mediate severe GVHD but preserved antileukemic activity, significantly improving the survival of leukemic mice undergoing allogeneic HSCT. This effect of Dll4(hi)DC-induced T cells was associated with their impaired expansion in GVHD target tissues. IFN-γ was important for Dll4(hi)DC programming to reduce GVHD toxicities of alloreactive T cells. Absence of T-cell IFN-γ led to improved survival and expansion of Dll4(hi)DC-induced CD4(+) T cells in transplant recipients and caused lethal GVHD. Our findings demonstrate that Dll4(hi)DC programming can overcome GVHD toxicity of donor T cells and produce leukemia-reactive T cells for effective immunotherapy.

The Notch Ligand DLL4 Defines a Capability of Human Dendritic Cells in Regulating Th1 and Th17 Differentiation.

Notch signaling regulates multiple helper CD4(+) T cell programs. We have recently demonstrated that dendritic cells (DCs) expressing the Notch ligand DLL4 are critical for eliciting alloreactive T cell responses and induction of graft-versus-host disease in mice. However, the human counterpart of murine DLL4(+) DCs has yet to be examined. We report the identification of human DLL4(+) DCs and their critical role in regulating Th1 and Th17 differentiation. CD1c(+) DCs and plasmacytoid DCs (pDCs) from the peripheral blood (PB) of healthy donors did not express DLL4. In contrast, patients undergoing allogeneic hematopoietic stem cell transplantation had a 16-fold more DLL4(+)CD1c(+) DCs than healthy donors. Upon activation of TLR signaling, healthy donor-derived CD1c(+) DCs dramatically upregulated DLL4, as did pDCs to a lesser extent. Activated DLL4(+) DCs were better able to promote Th1 and Th17 differentiation than unstimulated PB DCs. Blocking DLL4 using a neutralizing Ab decreased Notch signaling in T cells stimulated with DLL4(+) DCs, and it reduced the generation of Th1 and Th17 cells. Both NF-κB and STAT3 were crucial for inducing DLL4 in human DCs. Interestingly, STAT3 directly activated DLL4 transcription and inhibiting STAT3 alone was sufficient to reduce DLL4 in activated PB DCs. Thus, DLL4 is a unique functional molecule of human circulating DCs critical for directing Th1 and Th17 differentiation. These findings identify a pathway for therapeutic intervention for inflammatory disorders in humans, such as graft-versus-host disease after allogeneic hematopoietic stem cell transplantation, autoimmunity, and tumor immunity.

T-cell-rich HLA-haploidentical hematopoietic stem cell transplantation for relapsed/refractory pediatric Philadelphia chromosome-positive acute lymphoblastic leukemia without posttransplant tyrosine kinase inhibitor therapy.

Intensive chemotherapy with tyrosine kinase inhibitor (TKI) improves the prognosis of patients with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph-ALL). However, the prognosis of cases of relapsed or refractory Ph-ALL remains poor. Here, we aimed to assess the efficacy of T-cell-rich HLA-haploidentical hematopoietic stem cell transplantation (TCR-haplo-HSCT) in eight patients with relapsed or refractory pediatric Ph-ALL. Transplant-related mortality was observed in two patients. All patients discontinued TKI after receiving TCR-haplo-HSCT. The 3-year probability of overall survival and event-free survival was 75.0 and 62.5%, respectively. These results indicate the efficacy of TCR-haplo-HSCT for relapsed/refractory pediatric Ph-ALL.

T cell replete-haploidentical second hematopoietic stem cell transplantation for primary graft failure in pediatric patients with hematologic malignancies.

GF is one of the fatal complications of allogeneic HSCT. To rescue patients with primary GF, a second HSCT should be conducted as soon as possible, but the optimal donor source and technique have yet to be established. In this study, we retrospectively analyzed six children with hematologic malignancies who received TCR-haploidentical second HSCT for primary GF. The median interval between the prior HSCT and the second HSCT was 37.5 days. All patients received fludarabine and ATG containing reduced-intensity re-conditioning before the second HSCT. All patients, except one who died early, achieved both neutrophil and Plt engraftment at a median time of 15 and 33 days, respectively. Chimerism analysis showed that all engrafted patients achieved complete donor chimerism within 3 weeks. Four patients developed acute GVHD, and three patients developed chronic GVHD. TRM occurred in two patients. Median follow-up of the four survivors was 6.8 years, and all remained in sustained remission until the last follow-up. These results suggested that a TCR-haploidentical second HSCT for pediatric patients is feasible, and this approach may provide a potent option for children with primary GF.

Pre-emptive rituximab for Epstein-Barr virus reactivation after haplo-hematopoietic stem cell transplantation.

BACKGROUND: Epstein-Barr virus-related post-transplantation lymphoproliferative disease (EBV-PTLD) is a serious complication in hematopoietic stem cell transplantation (HSCT) recipients. METHODS: We conducted a retrospective study to investigate the incidence and potential risk factors for EBV reactivation and to assess the efficacy of the management of EBV reactivation with pre-emptive rituximab in children who had T-cell-replete haploidentical HSCT (TCR-haplo-SCT) with low-dose anti-thymocyte globulin (ATG). EBV-DNA level in peripheral blood (PB) was measured when suspected EBV reactivation were observed. When the EBV-DNA level in PB increased to >1,000 copies/106 peripheral blood mononuclear cells (PBMC), patients were pre-emptively treated with rituximab (375 mg/m2 /dose). RESULTS: A total of 19 (50%) of 38 patients received rituximab infusion at a median time of 56 days after HSCT (range, 17-270 days). The median viral load at initiation of therapy was 2,900 copies/106 PBMC (range, 1,000-650 000). Pre-emptive therapy was started after a median of 2 days (range, 0-7 days). The median number of weekly treatment cycles was 2 (range, 1-3). None of the patients developed PTLD or other EBV-associated diseases. CONCLUSION: Pre-emptive rituximab therapy could be a useful strategy for EBV-PTLD in TCR-haplo-SCT recipients with low-dose ATG.

Ezh2 regulates transcriptional and posttranslational expression of T-bet and promotes Th1 cell responses mediating aplastic anemia in mice.

Acquired aplastic anemia (AA) is a potentially fatal bone marrow (BM) failure syndrome. IFN-γ-producing Th1 CD4(+) T cells mediate the immune destruction of hematopoietic cells, and they are central to the pathogenesis. However, the molecular events that control the development of BM-destructive Th1 cells remain largely unknown. Ezh2 is a chromatin-modifying enzyme that regulates multiple cellular processes primarily by silencing gene expression. We recently reported that Ezh2 is crucial for inflammatory T cell responses after allogeneic BM transplantation. To elucidate whether Ezh2 mediates pathogenic Th1 responses in AA and the mechanism of Ezh2 action in regulating Th1 cells, we studied the effects of Ezh2 inhibition in CD4(+) T cells using a mouse model of human AA. Conditionally deleting Ezh2 in mature T cells dramatically reduced the production of BM-destructive Th1 cells in vivo, decreased BM-infiltrating Th1 cells, and rescued mice from BM failure. Ezh2 inhibition resulted in significant decrease in the expression of Tbx21 and Stat4, which encode transcription factors T-bet and STAT4, respectively. Introduction of T-bet but not STAT4 into Ezh2-deficient T cells fully rescued their differentiation into Th1 cells mediating AA. Ezh2 bound to the Tbx21 promoter in Th1 cells and directly activated Tbx21 transcription. Unexpectedly, Ezh2 was also required to prevent proteasome-mediated degradation of T-bet protein in Th1 cells. Our results demonstrate that Ezh2 promotes the generation of BM-destructive Th1 cells through a mechanism of transcriptional and posttranscriptional regulation of T-bet. These results also highlight the therapeutic potential of Ezh2 inhibition in reducing AA and other autoimmune diseases.

Long-term remission of HSCT-related NS after a second allogenic stem cell transplant.

BACKGROUND: Hematopoietic stem cell transplantation (HSCT)-related nephrotic syndrome (NS) is a rare event and has been described as a clinical form of chronic graft-versus-host disease (GVHD). Although immunological mechanisms are thought to play important roles in NS after HSCT, the exact mechanisms have not been clarified. CASE-DIAGNOSIS/TREATMENT: We report a 4-year-old boy with acute lymphoblastic leukemia (ALL) who developed NS during the tapering of immunosuppressants 5 months after an allogeneic HSCT (allo-HSCT). A renal biopsy was performed, and light and electron microscopy revealed minimal change disease (MCD). Although the response to treatment with steroids and tacrolimus was favorable, the child experienced two relapses of NS within the first 9 months after the initial response. A second allo-HSCT was performed to treat the relapse of ALL. After the second allo-HSCT, the remission of NS was maintained without recurrence for 5 years, even after the cessation of immunosuppressants. CONCLUSIONS: Our patient who had ALL and developed NS after his first allo-HSCT, maintained remission from NS after a second allo-HSCT. This suggests that the immune cells from the first donor origin were associated with the pathogenesis of NS.

Comprehensive technical and patient-care optimization in the management of pediatric apheresis for peripheral blood stem cell harvesting.

BACKGROUND: Pediatric apheresis for peripheral blood stem cell transplantation should be carried out with due concern for low corporeal blood volume and vulnerability to hypocalcemia-related complications, hypovolemic shock, and hypervolemic cardiac overload. STUDY DESIGN AND METHODS: We retrospectively investigated a total of 267 apheresis procedures from 1990 to 2013 on 93 children between 0 and 10 years old, including 89 patients and 4 healthy donors, with body weights of 6.3 to 44.0 kg. RESULTS: The median CD34+ cell yield per apheresis procedure was 2.3 × 106 CD34+ cells/kg (0.2-77.9 × 106 CD34+ cells/kg). Adverse events occurred in 11.6% of procedures (n = 31), including mild perivascular pain (n = 12), emesis (n = 9), hypotension (n = 3), urticaria (n = 2), numbness (n = 2), chest pain (n = 1), facial flush (n = 1), and abdominal pain (n = 1). Among hypotensive events, shock in a 9.6 kg one-year-old boy required emergency treatment in 1996. Thereafter, we adopted continuous injection of calcium gluconate, ionized calcium monitoring, central venous catheter access and circuit priming with albumin in addition to concentrated red cells. Since then we have had fewer complications: 16.4% per apheresis during 1990-1997 versus 5.8% during 1998-2013. No healthy pediatric donors suffered from any late-onset complications related to apheresis or G-CSF administration. CONCLUSION: By employing appropriate measures, peripheral blood stem cell apheresis for small children can have an improved safety profile, even for children weighing <10 kg.

The histone methyltransferase Ezh2 is a crucial epigenetic regulator of allogeneic T-cell responses mediating graft-versus-host disease.

Posttranscriptional modification of histones by methylation plays an important role in regulating Ag-driven T-cell responses. We have recently drawn correlations between allogeneic T-cell responses and the histone methyltransferase Ezh2, which catalyzes histone H3 lysine 27 trimethylation. The functional relevance of Ezh2 in T-cell alloimmunity remains unclear. Here, we identify a central role of Ezh2 in regulating allogeneic T-cell proliferation, differentiation, and function. Conditional loss of Ezh2 in donor T cells inhibited graft-versus-host disease (GVHD) in mice after allogeneic bone marrow (BM) transplantation. Although Ezh2-deficient T cells were initially activated to proliferate upon alloantigenic priming, their ability to undergo continual proliferation and expansion was defective during late stages of GVHD induction. This effect of Ezh2 ablation was largely independent of the proapoptotic molecule Bim. Unexpectedly, as a gene silencer, Ezh2 was required to promote the expression of transcription factors Tbx21 and Stat4. Loss of Ezh2 in T cells specifically impaired their differentiation into interferon (IFN)-γ-producing effector cells. However, Ezh2 ablation retained antileukemia activity in alloreactive T cells, leading to improved overall survival of the recipients. Our findings justify investigation of modulating Ezh2 as a therapeutic strategy for the treatment of GVHD and other T cell-mediated inflammatory disorders.

Delta-like ligand 4 identifies a previously uncharacterized population of inflammatory dendritic cells that plays important roles in eliciting allogeneic T cell responses in mice.

Graft-versus-host disease (GVHD) reflects an exaggerated inflammatory allogeneic T cell response in hosts receiving allogeneic hematopoietic stem cell transplantation (HSCT). Inhibition of pan-Notch receptor signaling in donor T cells causes reduction of GVHD. However, which Notch ligand(s) in what APCs is important for priming graft-versus-host reaction remains unknown. We demonstrate that δ-like ligand-4 (Dll4) and Dll4-positive (Dll4(high)) inflammatory dendritic cells (i-DCs) play important roles in eliciting allogeneic T cell responses. Host-type Dll4(high) i-DCs occurred in the spleen and intestine of HSCT mice during GVHD induction phase. These Dll4(high) i-DCs were CD11c(+)B220(+)PDCA-1(+), resembling plasmacytoid dentritic cells (pDCs) of naive mice. However, as compared with unstimulated pDCs, Dll4(high) i-DCs expressed higher levels of costimulatory molecules, Notch ligands Jagged1 and Jagged2, and CD11b, and produced more Ifnb and Il23 but less Il12. In contrast, Dll4-negative (Dll4(low)) i-DCs were CD11c(+)B220(-)PDCA-1(-), and had low levels of Jagged1. In vitro assays showed that Dll4(high) i-DCs induced significantly more IFN-γ- and IL-17-producing effector T cells (3- and 10-fold, respectively) than Dll4(low) i-DCs. This effect could be blocked by anti-Dll4 Ab. In vivo administration of Dll4 Ab reduced donor-alloreactive effector T cells producing IFN-γ and IL-17 in GVHD target organs, leading to reduction of GVHD and improved survival of mice after allogeneic HSCT. Our findings indicate that Dll4(high) i-DCs represent a previously uncharacterized i-DC population distinctive from steady state DCs and Dll4(low) i-DCs. Furthermore, Dll4 and Dll4(high) i-DCs may be beneficial targets for modulating allogeneic T cell responses, and could facilitate the discovery of human counterparts of mouse Dll4(high) i-DCs.

Idiopathic Hyperammonemia That Developed During Initial Treatment With Steroid in a Patient With Newly Diagnosed Leukemia.

Idiopathic hyperammonemia (IHA) has been described as a complication of intensive chemotherapy for the treatment of hematologic malignancy but has subsequently been found in patients undergoing bone marrow transplantation and in those with solid tumors treated with 5-fluorouracil. Although IHA is a rare complication, it is sometimes associated with high mortality in hematologic malignancies. Here we report the case of a 15-year-old boy in whom hyperammonemia developed during the initial treatment with prednisolone for newly diagnosed acute lymphoblastic leukemia and who survived after early detection and oral lactulose therapy. To the best of our knowledge, this is the first report of IHA that was not induced by intensive chemotherapy, stem cell transplantation, or asparaginase therapy in a patient with newly diagnosed leukemia, but developed during an initial treatment with a steroid. Early detection of IHA by measuring the plasma ammonia level in patients with neurological symptoms may improve the outcome.

Inhibition of histone methylation arrests ongoing graft-versus-host disease in mice by selectively inducing apoptosis of alloreactive effector T cells.

Histone methylation is thought to be important for regulating Ag-driven T-cell responses. However, little is known about the effect of modulating histone methylation on inflammatory T-cell responses. We demonstrate that in vivo administration of the histone methylation inhibitor 3-deazaneplanocin A (DZNep) arrests ongoing GVHD in mice after allogeneic BM transplantation. DZNep caused selective apoptosis in alloantigen-activated T cells mediating host tissue injury. This effect was associated with the ability of DZNep to selectively reduce trimethylation of histone H3 lysine 27, deplete the histone methyltransferase Ezh2 specific to trimethylation of histone H3 lysine 27, and activate proapoptotic gene Bim repressed by Ezh2 in antigenic-activated T cells. In contrast, DZNep did not affect the survival of alloantigen-unresponsive T cells in vivo and naive T cells stimulated by IL-2 or IL-7 in vitro. Importantly, inhibition of histone methylation by DZNep treatment in vivo preserved the antileukemia activity of donor T cells and did not impair the recovery of hematopoiesis and lymphocytes, leading to significantly improved survival of recipients after allogeneic BM transplantation. Our findings indicate that modulation of histone methylation may have significant implications in the development of novel approaches to treat ongoing GVHD and other T cell-mediated inflammatory disorders in a broad context.

Malignant peritoneal mesothelioma in a child: chemotherapy with gemcitabine and platinum was effective for the disease unresponsive to other treatments.

Malignant peritoneal mesothelioma in children is a very rare disease and has a poor prognosis. Unlike malignant mesothelioma in adults, there is no clear causal association between this very rare malignancy in children and asbestos exposure. We report a case of peritoneal mesothelioma in an 11-year-old boy who presented with ascites. He was diagnosed with malignant mesothelioma on the basis of histopathological findings. His disease showed resistance to pemetrexed, but was treated successfully with platinum-based therapy with gemcitabine. He has achieved long-term survival in partial remission with stable disease.

Loss of mismatched HLA in myeloid/NK cell precursor acute leukemia relapse after T cell-replete haploidentical hematopoietic stem cell transplantation.

Myeloid/natural killer cell precursor acute leukemia (MNKL) is an aggressive disease with a high relapse rate even after allogeneic hematopoietic stem cell transplantation (SCT). We report a patient with MNKL who had a donor lymphocyte infusion (DLI) for relapse after T cell-replete human leukocyte antigen (HLA)-haploidentical SCT, but relapsed again 20 months later with loss of mismatched HLA. This case suggests that a strong graft-versus-leukemia effect of haploidentical SCT can be expected in MNKL patients. In the haploidentical setting, DLI should be considered for patients with relapsed leukemia whose leukemic cells have not lost HLA cell surface expression.

Clinical analysis of combination therapy for febrile neutropenic patients in childhood cancer.

BACKGROUND: The objective of this study was to evaluate the efficacy and safety of our combination therapy in febrile neutropenic children with cancer. METHODS: A total of 109 patients with 251 episodes of febrile neutropenia received antibiotic therapy between January 2003 and December 2008 at a single institution. RESULTS: Blood cultures were positive in 35 episodes (14%). Gram-positive organisms predominated (23/38 organisms isolated). There were 15 gram-negative isolates and no fungal isolates. The recommended empirical first-line antibiotics (cefepime or cefozopran + piperacillin + amikacin) were used in 206 (82%), second-line antibiotics (piperacillin-tazobactam + carbapenem + amikacin + micafungin) in 73 (29%), and third-line antibiotics (meropenem + glycopeptides + micafungin) in 24 (10%) episodes. The overall response rates were 71.4%, 50.7%, and 62.5% for the first-, second-, and third-line antibiotic therapies, respectively. Granulocyte transfusion was performed in seven patients, and the response rate was 57%. Four deaths were recorded. CONCLUSIONS: Although a significant improvement of mortality was not observed, our regimen of empirical antibiotic therapies led to a significant and clinically relevant decrease in glycopeptide use, and it is safe and well tolerated by pediatric neutropenic patients.