Donor KIR3DL1/receptor HLA-Bw4-80I Combination Reduces Acute Leukemia Relapse after Umbilical Cord Blood Transplantation without in Vitro T-cell Depletion.

BACKGROUND: Donor natural killer (NK) cell alloreactivity in umbilical cord bone marrow transplantation (UCBT) can lead to leukemic relapse. However, NK cell function is calibrated by interaction with human leukocyte antigens (HLAs). This study aimed to investigate graft-resistant leukemia after transplantation and compared specific genotypes of killer immunoglobulin-like receptors (KIRs) in donors and human leukocyte antigen ligands in patients. METHODS: We retrospectively analyzed 232 patients with acute leukemia from a single center. Patients had undergone UCBT with myeloablative conditioning and without anti-thymocyte globulin. We identified the KIR genotypes of cord blood donors using polymerase chain reaction with sequence-specific primers. All of the donors contained KIR3DL1. RESULTS: The patients were divided into three groups according to the HLA-B locus. The donor KIR3DL1 and recipient HLA-Bw4-80I combination was predictive of being highly educated and was associated with a lower relapse (P=0.006) and better overall survival (probability of relapse=0.13, P < 0.001) than the uneducated group. We found no significant increase in the incidence of acute or chronic graft-versus-host disease. CONCLUSIONS: Our data suggest that the donor KIR3DL1/receptor and HLA-Bw4-80I combination in UCBT results in stronger graft-versus-leukemia effects and improved outcomes in patients with acute leukemia.

Decitabine prior to salvaged cord blood transplantation for acute myeloid leukaemia/myelodysplastic syndrome not in remission.

WHAT IS KNOWN AND OBJECTIVE: Many refractory/relapsed haematological malignancies, in non-remission state, still have poor prognosis even after allogeneic haematopoietic stem cell transplantation. Recently, decitabine or umbilical cord blood transplantation (UCBT) seemed to be effective in these patients. However, few studies have added decitabine to myeloablative conditioning regimens for UCBT in patients with haematological malignancies not in remission. Therefore, the objective was to evaluate the clinical outcomes of patients with refractory/relapsed acute myeloid leukaemia (AML) or myelodysplastic syndrome (MDS) using decitabine as part of a myeloablative conditioning regimen prior to salvaged unrelated UCBT at our centre. METHODS: We enrolled 20 consecutive patients with refractory/relapsed AML/MDS between 2013 and 2018. All patients were in non-remission state before transplantation. All transplants were performed with decitabine as part of the myeloablative conditioning regimen, which was decitabine + fludarabine/busulfan/cyclophosphamide. RESULTS AND DISCUSSION: All patients achieved neutrophil and platelet engraftment. Incidence of grade III/IV acute graft-vs-host disease (GVHD) was 20.0%, which was also decreased compared to non-decitabine group (P = .025). The median follow-up time after UCBT was 29 months (range 14-64 months). The 2-year probability of GVHD-free relapse-free survival (GRFS) was higher in the decitabine group. Univariate showed that the decitabine group was associated with a higher GRFS than the non-decitabine group. The estimated probability of overall survival and relapse was 55% and 20.0%, respectively. WHAT IS NEW AND CONCLUSIONS: Our results suggest that addition of decitabine as part of the myeloablative conditioning regimen prior to UCBT for refractory/relapsed AML/MDS in patients who are not in remission is safe and might be an effective treatment option.

Protective Effects of Cytomegalovirus DNA Copies ≧1000/mL for AML Patients in Complete Remission After Single Cord Blood Transplantation.

INTRODUCTION: Current consensus recommends a protective effect of cytomegalovirus (CMV) infection on relapse after peripheral blood or bone marrow hematopoietic stem cell transplantation. However, in cord blood transplantation (CBT), studies of CMV infection, especially CMV viral load, on relapse are limited. PATIENTS AND METHODS: Wct e retrospectively analyzed the effect of CMV infection on 3-year outcomes in 249 AML patients according to CMV DNA load (DNA copies <1000/mL and DNA copies ≧1000/mL) within 100 days after CBT. Furthermore, eight-colour flow cytometry was used to detect peripheral blood lymphocyte subsets in 38 patients who received CBT in the last year, and 10 healthy volunteers were included as controls. RESULTS: The results showed that CMV DNA load did not affect the cumulative incidence of relapse in the whole study population. However, in patients with complete remission status before transplantation, the high CMV DNA load group showed a significantly reduction of relapse than the low CMV DNA load group (3.9% vs 14.6%, p=0.012, respectively), which was confirmed by multivariate analysis (HR 0.23; 95% CI, 0.07-0.73, p = 0.012). Surprisingly, high or low CMV DNA load did not significantly affect non-relapse mortality or overall survival (18.0% vs 17.0%, p=0.777 and 79.0% vs 74.6%, p=0.781, respectively). Besides, the absolute number of CD8+ T cells were increased in the high CMV DNA load group compared with the low DNA load group 1 month after CBT (0.20×109/L vs 0.10×109/L, p=0.021, respectively). CONCLUSION: DNA copies ≧1000/mL for AML patients in complete remission was associated with a lower incidence of relapse after CBT, which might partly result from the expansion of CMV-related CD8+ T cells.

[Expression and abscission of activated receptors and their ligands on/from NK cells in peripheral blood of patients with acute leukemia].

This study was aimed to explore the immune escaping mechanisms based on expression and abscission of human natural killer (NK) cell activating receptors NKG2D and their ligands MICA/B, ULBP-1, 2, 3 in patients with acute leukemia (AL). 30 de novo AL patients and 10 healthy persons (control) were enrolled in study. Flow cytometry was used to detect the expression levels of MICA/B, ULBP-1, 2, 3 on leukemic cells. ELISA was used to detect the levels of soluble MICA (sMICA), solube MICB (sMICB) and soluble ULBP-1, -2, -3 in the serum. The results showed that sMICA, sMICB and ULBP-1, -2, -3 were not expressed or expressed at very low levels on leukemia cells of the patients; the levels of free sMICA and sMICB in serum of AL patients were higher than that in serum of healthy persons, there was significant difference (p<0.01). But the levels of ULBP 1-3 in serum of AL patients did not show obvious statistical difference as compared with healthy persons (p>0.05). It is concluded that the negative or low expression of NKG2D ligands (MICA, MICB and ULBPs) on surface of acute leukemia cells may lead to the immune escape of leukemia cells, the abscission of MICA and MICB, and the deficiency of ULBP expression on leukemia cells may be one of immune escape mechanisms of leukemia cells.