Rapid Generation of EBV-Specific Cytotoxic T Lymphocytes Resistant to Calcineurin Inhibitors for Adoptive Immunotherapy

Epstein–Barr virus (EBV)-associated posttransplant lymphoproliferative disorder (PTLD) remains a major cause of morbidity and mortality after hematopoietic stem cell (HSCT) or solid organ transplant (SOT). Strategies to reconstitute immunity by adoptive transfer of EBV-specific cytotoxic T lymphocyte (CTL) therapy while highly effective in the HSCT setting where immunosuppression can be withdrawn have been less successful in the SOT setting where continued immunosuppression therapy is necessary. Additionally, the complexity and time taken to generate EBV-CTLs for adoptive transfer limit the clinical applicability. We have developed a system for the rapid generation of EBV-CTLs resistant to immunosuppression based on selection of interferon-gamma (IFN-γ) secreting EBV-CTLs and retroviral transduction with a calcineurin B mutant. With this methodology, EBV-CTLs resistant to the calcineurin inhibitor Tacrolimus (TAC) can be produced in 14 days. These CTLs show high specificity for EBV with negligible alloreactivity in both proliferation and cytotoxicity assays and are able to proliferate and secrete IFN-γ in response to antigen stimulation in the presence of therapeutic doses of TAC. This strategy will substantially facilitate clinical application of this approach for the treatment of PTLD in SOT recipients (read more)

Postoperative management of severe acute anemia in a Jehovah's Witness

Background : Low levels of hemoglobin (Hb) are not rare in patients who refuse blood components but this case is unique due to the severity of anemia and the possibility that her previous episode of acute normovolemic hemodilution has influenced her outcome.
Case Report : We report an incident involving acute blood loss after surgery with an extremely low hematocrit. Despite her Hb levels (2.8 g/dL) she remained lucid, expressing her wish not to receive transfusion. When the patient lost consciousness (Hb, 1.4 g/dL) she was promptly sedated, curarized, and put onto mechanical controlled ventilation. Aggressive erythropoietin therapy increased the patient's Hb level by 240% in 10 days, despite a high platelet count. This case demonstrates that critical levels of oxygen delivery may be lower than previously thought possible.
Conclusion : This case is an example of the resilience of the human body in an extreme circumstance. It might be the most severe case of anemia that a person has survived without any sequelae (read more)

Complement-Binding Anti-HLA Antibodies and Kidney-Allograft Survival

Background : Anti-HLA antibodies hamper successful transplantation, and activation of the complement cascade is involved in antibody-mediated rejection. We investigated whether the complement-binding capacity of anti-HLA antibodies plays a role in kidney-allograft failure.
Methods : We enrolled patients who received kidney allografts at two transplantation centers in Paris between January 1, 2005, and January 1, 2011, in a population-based study. Patients were screened for the presence of circulating donor-specific anti-HLA antibodies and their complement-binding capacity. Graft injury phenotype and the time to kidney-allograft loss were assessed.
Results : The primary analysis included 1016 patients. Patients with complement-binding donor-specific anti-HLA antibodies after transplantation had the lowest 5-year rate of graft survival (54%), as compared with patients with non–complement-binding donor-specific anti-HLA antibodies (93%) and patients without donor-specific anti-HLA antibodies (94%) (P<0.001 for both comparisons). The presence of complement-binding donor-specific anti-HLA antibodies after transplantation was associated with a risk of graft loss that was more than quadrupled (hazard ratio, 4.78; 95% confidence interval [CI], 2.69 to 8.49) when adjusted for clinical, functional, histologic, and immunologic factors. These antibodies were also associated with an increased rate of antibody-mediated rejection, a more severe graft injury phenotype with more extensive microvascular inflammation, and increased deposition of complement fraction C4d within graft capillaries. Adding complement-binding donorspecific anti-HLA antibodies to a traditional risk model improved the stratification of patients at risk for graft failure (continuous net reclassification improvement, 0.75; 95% CI, 0.54 to 0.97).(read more)

Acute Cellular and Antibody-Mediated Rejection of the Pancreas Allograft: Incidence, Risk Factors and Outcomes

Antibody-mediated rejection (AMR) after pancreas transplantation is a recently identified entity. We describe the incidence of, risk factors for, and outcomes after AMR, and the correlation of C4d immunostaining and donor-specific antibody (DSA) in the diagnosis of AMR. We retrospectively analyzed 162 pancreas transplants in 159 patients who underwent 94 pancreas allograft biopsies between 2006 and 2009. Univariate and multivariate analyses were performed to evaluate risk factors for pancreas graft AMR. One-year rejection rates and survival after rejection were calculated by Kaplan–Meier methods. AMR occurred in 10% of patients by 1-year posttransplant. Multivariate risk factors identified for AMR include nonprimary simultaneous pancreas–kidney (SPK) transplant, primary solitary pancreas (PAN) transplant and race mismatch. After pancreas rejection, patient survival was 100% but 20% (8 of 41) of pancreas grafts failed within 1 year. Graft survival after acute cellular rejection (ACR), AMR and mixed rejection was similar. Of biopsies that stained >5% C4d, 80% were associated with increased Class I DSA. In summary, AMR occurs at a measurable rate after pancreas transplantation, and the diagnosis should be actively sought using C4d staining and DSA levels in patients with graft dysfunction, especially after nonprimary SPK and primary PAN transplantation (read more)

RIPK3-Mediated Necroptosis Promotes Donor Kidney Inflammatory Injury and Reduces Allograft Survival

Kidney transplant injury occurs with ischemia and alloimmunity. Members of the receptor interacting protein kinase family (RIPK1,3) are key regulators of “necroptosis,” a newly recognized, regulated form of necrosis. Necroptosis and apoptosis death appear to be counterbalanced as caspase-8 inhibition can divert death from apoptosis to necrosis. Inhibition of necroptosis in donor organs to limit injury has not been studied in transplant models. In this study, necroptosis was triggered in caspase inhibited tubular epithelial cells (TEC) exposed to tumor necrosis factor alpha in vitro, while RIPK1 inhibition with necrostatin-1 or use of RIPK3−/−TEC, prevented necroptosis. In vivo, short hairpin RNA silencing of caspase-8 in donor B6 mouse kidneys increased necroptosis, enhanced high-mobility group box 1 release, reduced renal function and accelerated rejection when transplanted into BALB/c recipients. Using ethidium homodimer perfusion to assess necrosisin vivo, necrosis was abrogated in RIPK3−/− kidneys postischemia. Following transplantation, recipients receiving RIPK3−/− kidneys had longer survival (p = 0.002) and improved renal function (p = 0.03) when compared to controls. In summary, we show for the first time that RIPK3-mediated necroptosis in donor kidneys can promote inflammatory injury, and has a major impact on renal ischemia–reperfusion injury and transplant survival. We suggest inhibition of necroptosis in donor organs may similarly provide a major clinical benefit (read more)

Kidney Intragraft Donor-Specific Antibodies as Determinant of Antibody-Mediated Lesions and Poor Graft Outcome

Allograft pathology, antibody–tissue interaction as demonstrated by C4d deposition and serological evidence of donor-specific antibodies (DSA) are the cardinal diagnostic features of antibody-mediated lesions (AML) in kidney transplantation. However, discrepancy between histological and serological findings is common, and more reliable diagnostic tools are called for. Here, we asked whether the in situ detection of DSA could serve as marker for AML. To that end, we applied the anti-HLA single antigen flow bead assay to eluates from 51 needle core graft biopsies performed for cause. Intragraft antibody profiles were correlated to serum DSA (sDSA), histological data and transplant outcome. The prevalence and the mean number of intragraft DSA (gDSA) were lower than that of sDSA (15/51 gDSA+ vs. 37/51 sDSA+ patients; 1.64 gDSA vs. 2.24 sDSA per patient). DSA were detected in all anti-HLA antibody-positive biopsies (15/15). The presence of gDSA was significantly associated with (1) microcirculation lesions taken individually (g, cg) and analyzed in functional clusters (ptc + g + cg > 0, cg + mm > 0), (2) C4d positivity and (3) a worse short-term transplant outcome (p = 0.05). These associations were not found for patients presenting only sDSA. Taken together, these results indicate that gDSA is a severity marker of antibody-mediated pathogenic process (read more)

HLA class II upregulation during viral infection leads to HLA-DP-directed graft-versus-host disease after CD4+ donor lymphocyte infusion

CD8+ T cell–depleted (TCD) donor lymphocyte infusion (DLI) after TCD allogeneic hematopoietic stem cell transplantation (alloSCT) has been associated with a reduced risk of graft-versus-host disease (GVHD) while preserving conversion to donor hematopoiesis and antitumor immunity, providing a rationale for exploring CD4+ T cell–based immunotherapy for hematologic malignancies. Here, we analyzed the clinical course and specificity of T cell immune responses in 2 patients with acute myeloid leukemia (AML) who converted to full-donor chimerism but developed severe acute GVHD after prophylactic CD4+ DLI after 10/10-HLA–matched, but HLA-DPB1–mismatched TCD-alloSCT. Clonal analysis of activated T cells isolated during GVHD demonstrated allo-reactivity exerted by CD4+ T cells directed against patient-mismatched HLA-DPB1 molecules on hematopoietic cells and skin-derived fibroblasts only when cultured under inflammatory conditions. At the time of CD4+ DLI, both patients contained residual patient-derived T cells, including cytomegalovirus (CMV)-specific T cells as a result of CMV reactivations. Once activated by CMV antigens, these CMV-specific T cells could stimulate HLA-DPB1–specific CD4+ T cells, which in turn could target nonhematopoietic tissues in GVHD. In conclusion, our data demonstrate that GVHD after HLA-DPB1–mismatched CD4+ DLI can be mediated by allo-reactive HLA-DPB1–directed CD4+ T cells and that ongoing viral infections inducing HLA class II expression on nonhematopoietic cells may increase the likelihood of GVHD development. This trial is registered at http://www.controlled-trials.com/ISRCTN51398568/LUMC as #51398568. (read more)