Significance of Degree of HLA Disparity Using T-cell Replete Peripheral Blood Stem Cells From Haploidentical Donors With Posttransplantation Cyclophosphamide in AML in First Complete Hematologic Remission: A Study of the Acute Leukemia Working Party of the EBMT.

Availability of haploidentical donors has broadened utilization of allogeneic hematopoietic cell transplantation (allo-HCT). Peripheral blood stem cells (PBSC) are being used with increased frequency in haploidentical allo-HCT. We evaluated extent of HLA disparity (2-3/8 versus 4/8 HLA antigen mismatches) on post-allograft outcomes when using T-cell replete PBSC from haploidentical donors for acute myeloid leukemia in first complete remission. Primary objectives entailed assessing cumulative incidence of grade 2-4 acute graft-versus-host disease (GVHD) and chronic GVHD (any grade). A total of 645 patients received a haploidentical allo-HCT from a donor with either 2-3 of 8 HLA antigen mismatches (n = 180) or with 4 of 8 HLA antigen mismatches (n = 465). Presence of 2-3 of 8 versus 4 of 8 HLA mismatches did not affect the incidence of acute GVHD (grade 2-4) and chronic GVHD (any grade). Overall survival (OS), leukemia-free survival (LFS) relapse incidence (RI), nonrelapse mortality and the composite endpoint of GVHD-free relapse-free survival were also similar among the groups. Pertaining to HLA-B leader matching effect, our analysis did not discern any difference in aforementioned post-allograft outcomes for this variable. However, in univariate analysis, absence of an antigen mismatch in HLA-DPB1 showed a trend for better OS. Notwithstanding inherent limitations associated with registry data, our results did not show an advantage of selecting a haploidentical donor with 2-3 of 8 HLA antigen mismatches over one with 4 of 8 HLA antigen mismatches when using PBSC as the cell source. Adverse cytogenetics remains a major adverse determinant of inferior OS and LFS and a higher RI. Using reduced-intensity conditioning yielded worse OS and LFS.

Prediction of Nonrelapse Mortality in Patients With Acute Myeloid Leukemia and Acute Lymphoblastic Leukemia Receiving Allogeneic Stem Cell Transplantation With Posttransplantation Cyclophosphamide-based Graft Versus Host Disease Prophylaxis.

Graft versus host disease (GVHD) prophylaxis with posttransplantation cyclophosphamide (PTCY) has been established to reduce severe GVHD, and thereby potentially reducing nonrelapse mortality (NRM) after allogeneic stem cell transplantation (alloSCT). We evaluated the predictive capacity of established NRM-risk scores in patients receiving PTCY-based GVHD prophylaxis, and subsequently developed and validated a novel PTCY-specific NRM-risk model. Adult patients (n = 1861) with AML or ALL in first complete remission who received alloSCT with PTCY-based GVHD prophylaxis were included. The PTCY-risk score was developed using multivariable Fine and Gray regression, selecting parameters from the hematopoietic cell transplantation-comorbidity index (HCT-CI) and European Group for Blood and Marrow Transplantation (EBMT) score with a subdistribution hazard ratio (SHR) of ≥1.2 for 2-year NRM in the training set (70% split), which was validated in the test set (30%). The performance of the EBMT score, HCT-CI, and integrated EBMT score was relatively poor for discriminating 2-year NRM (c-statistic 51.7%, 56.6%, and 59.2%, respectively). The PTCY-risk score included 10 variables which were collapsed in 3 risk groups estimating 2-year NRM of 11% ± 2%, 19% ± 2%, and 36% ± 3% (training set, c-statistic 64%), and 11% ± 2%, 18% ± 3%, and 31% ± 5% (test set, c-statistic 63%), which also translated into different overall survival. Collectively, we developed an NRM-risk score for acute leukemia patients receiving PTCY that better predicted 2-year NRM compared with existing models, which might be applicable to the specific toxicities of high-dose cyclophosphamide.

Nonleukemic myeloid dendritic cells obtained from autologous stem cell products elicit antileukemia responses in patients with acute myeloid leukemia.

BACKGROUND: Dendritic cell (DC)-based immunotherapeutic protocols are being developed to treat acute myeloid leukemia (AML). So far, DCs for clinical use are obtained from leukemic blasts or from monocytes, after 6 to 10 days of ex vivo culture. However, DC precursors are easily driven to DCs in short-term culture. We tested if DC precursors contained in peripheral blood stem cell (PBSC) products obtained from AML patients can be used to induce antileukemia responses. STUDY DESIGN AND METHODS: PBSCs obtained from 30 consecutive AML patients were tested. Myeloid DCs (MDCs) were purified by immunomagnetic selection and screened for cytogenetic and/or molecular abnormalities by fluorescence in situ hybridization (FISH) or polymerase chain reaction (PCR) assays. MDCs were matured and pulsed with autologous blast lysates and tested for stimulatory capability against AML cells. RESULTS: A median of 0.62 × 10(6) MDCs (range, 0.04-3.25)/mL were quantified in PBSC products. Isolated MDC expressed Class I and II HLA but CD86, CD54, and CCR5 partially. By FISH or PCR assay, these MDCs lacked cytogenetic or molecular abnormalities detected in leukemia cells at diagnosis. MDCs achieved a maturated stage (mature-MDCs) after 24-hour ex vivo culture with tumor necrosis factor-α and autologous blast lysates. These mature-MDCs were capable of stimulating autologous peripheral blood effectors to exert cytotoxicity against autologous leukemia cells and HL-60 cell line. CONCLUSION: We conclude that PBSCs obtained for autologous stem cell transplantation can constitute a novel source of MDCs to design feasible vaccination trials.

Tumor necrosis factor-α-secreting CD16+ antigen presenting cells are effectively removed by granulocytapheresis in ulcerative colitis patients.

BACKGROUND AND AIM: In human blood, two main subsets of antigen-presenting-cells (APCs) have been described: plasmocytoid dendritic cells (pDC) and myeloid dendritic cells (mDC) which are further subdivided in CD11c-mDC and CD16-mDC DC. In ulcerative colitis patients (UC) peripheral blood APCs express significant levels of the activation and lack immature-tolerogeneic APCs. Adacolumn selective granulocytapheresis (GCAP) has been associated with clinical efficacy in patients with UC. In the present study we sought the effect of sequential GCAP procedures in peripheral blood APCs in patients with UC and the effect on soluble cytokines. METHODS: We used multiparametric flow cytometry to quantify peripheral blood APCs and serum cytokines in 210 samples obtained from seven patients with steroid-dependent or steroid resistant UC undergoing GCAP treatment. Samples were drawn before, after 30 and 60 min of each session. RESULTS: Each GCAP session resulted in a dramatic tenfold reduction of peripheral blood CD16-mDC (P < 0.01), pDC decreased twofold (P = 0.05) but CD11c-mDC remained unchanged. This depletion was reached after 30 min and maintained at 60 min. The depletion of CD16-mDC and monocytes was associated with a reduction of serum tumor necrosis factor levels and a raise in interleukin-10 levels, although no statistical difference was reached. CONCLUSION: The effect of GCAP in peripheral blood APC consisted mainly on a significant depletion of tumor necrosis factor-α secreting CD16-mDC. This finding could suggest a potential mechanism of GCAP beneficial effect that must be confirmed in larger series.