Genetic characterization of a unique neuroendocrine transdifferentiation prostate circulating tumor cell-derived eXplant model.

Transformation of castration-resistant prostate cancer (CRPC) into an aggressive neuroendocrine disease (CRPC-NE) represents a major clinical challenge and experimental models are lacking. A CTC-derived eXplant (CDX) and a CDX-derived cell line are established using circulating tumor cells (CTCs) obtained by diagnostic leukapheresis from a CRPC patient resistant to enzalutamide. The CDX and the derived-cell line conserve 16% of primary tumor (PT) and 56% of CTC mutations, as well as 83% of PT copy-number aberrations including clonal TMPRSS2-ERG fusion and NKX3.1 loss. Both harbor an androgen receptor-null neuroendocrine phenotype, TP53, PTEN and RB1 loss. While PTEN and RB1 loss are acquired in CTCs, evolutionary analysis suggest that a PT subclone harboring TP53 loss is the driver of the metastatic event leading to the CDX. This CDX model provides insights on the sequential acquisition of key drivers of neuroendocrine transdifferentiation and offers a unique tool for effective drug screening in CRPC-NE management.

Updated technology to produce highly immunogenic dendritic cell-derived exosomes of clinical grade: a critical role of interferon-γ.

Dendritic cell-derived exosomes (Dex) are nanovesicles bearing major histocompatibility complexes promoting T-cell-dependent antitumor effects in mice. Two phase I clinical trials aimed at vaccinating cancer patients with peptide-pulsed Dex have shown the feasibility and safety of inoculating clinical-grade Dex, but have failed to show their immunizing capacity. These low immunogenic capacities have led us to develop second-generation Dex with enhanced immunostimulatory properties. Here, we show that interferon-γ is a key cytokine conditioning the dendritic cell to induce the expression of CD40, CD80, CD86, and CD54 on Dex, endowing them with direct and potent peptide-dependent CD8(+) T-cell-triggering potential in vitro and in vivo. In this study, we describe the clinical grade process to manufacture large-scale interferon-γ-Dex vaccines and their quality control parameters currently used in a phase II trial.

Immune modulation and microchimerism after unmodified versus leukoreduced allogeneic red blood cell transfusion in cancer patients: results of a randomized study.

BACKGROUND: Transfusion of red blood cells (RBCs) has been associated with immunomodulatory effects. Persistence of donor cells in the recipient may be contributive. STUDY DESIGN AND METHODS: A randomized single-center trial was conducted to compare microchimerism and immune responses in 35 patients undergoing cancer surgery and transfused perioperatively with either unmodified RBCs (UN-RBCs, n = 18) or leukoreduced RBCs (LR-RBCs, n = 17). Biologic parameters included microchimerism assessment peripheral blood mononuclear cell (PBMNC) phenotyping, cytokine production by stimulated PBMNCs, FoxP3 gene expression, and T-cell repertoire (TCR) analysis. RESULTS: Microchimerism was documented in 8 of 18 patients after UN-RBC transfusion while absent after LR-RBC transfusion (0/17; p = 0.001). After UN-RBC transfusion, microchimerism was associated with increased interleukin (IL)-10 production (p = 0.02), reduced TCR alteration (p = 0.04), and reduced CD56+ cell counts (p = 0.02) when compared to recipients without evidence for microchimerism. FoxP3 gene expression did not differ significantly between both treatment groups nor with the presence or absence of microchimerism in the UN-RBC group. Finally, after an initial early decrease after surgery and transfusion, IL-12 production increased and more significantly so after UN-RBC transfusion versus LR-RBC transfusion (p = 0.05). CONCLUSION: UN-RBC-induced microchimerism is associated with specific immunomodulatory effects in cancer patients who received transfusions during surgery.

Platelet transfusion containing ABO-incompatible plasma and hepatic veno-occlusive disease after hematopoietic transplantation in young children.

BACKGROUND: Hepatic veno-occlusive disease is a major limiting factor of high-dose chemotherapy in children. The cells lining the hepatic vascular endothelium express blood group A and/or B antigens according to the patient's blood group. We designed a study evaluating the impact of platelet concentrates containing ABO-incompatible plasma transfused to young children with a high risk of hepatic veno-occlusive disease. METHODS: In all, 186 consecutive children (median age: 4 years, range: 0.75-17 years), treated with high-dose chemotherapy containing busulfan followed by hematopoietic stem cell transplantation for neuroblastoma (n=112) or brain tumor (n=74) between 1988 and 1998, were investigated. The main endpoint was the occurrence of hepatic veno-occlusive disease. Multivariate analysis was performed using a Cox's regression model with transfusion of platelet concentrates containing ABO-incompatible plasma as a time-dependent covariate. RESULTS: We found that 73 out of 186 (39%) children developed hepatic veno-occlusive disease after transplantation. Multivariate analysis demonstrated that two factors significantly increased the risk of hepatic veno-occlusive disease occurrence: transfusion of platelet concentrates containing ABO-incompatible plasma (P=0.003) and use of melphalan in the conditioning regimen (P=0.006). Conversely, the number of platelet concentrates transfusions per week, child's age, weight, sex, and use of cyclophosphamide in the conditioning regimen had no effect. CONCLUSIONS: Transfusion of platelet concentrates containing ABO-incompatible plasma increases the risk of hepatic veno-occlusive disease in young children treated with a busulfan-containing regimen. Binding of A and/or B antigens expressed on the surface of hepatic endothelial cells may promote this complication. Transfusion of platelet concentrates containing ABO-incompatible plasma should be avoided in these children.

Increased presence of anti-HLA antibodies early after allogeneic granulocyte colony-stimulating factor-mobilized peripheral blood hematopoietic stem cell transplantation compared with bone marrow transplantation.

We have recently shown that the use of allogeneic granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood hematopoietic stem cell transplantation (PBHSCT), as compared with bone marrow transplantation (BMT), is associated with increased titers of antibodies (Abs) directed against red blood cell ABO antigens. To further evaluate the influence of a G-CSF-mobilized PBHSCT graft on alloimmune Ab responses, we examined the frequency of anti-HLA Abs after transplantation in the setting of the same randomized study, comparing PBHSCT with BMT in adults. Anti-HLA Ab presence was determined by complement-dependent cytotoxicity assay (CDC) and flow cytometry in the recipient before and 30 days after transplantation as well as in the donor before graft donation. The use of PBHSCT was significantly associated with increased detection of anti-HLA immunoglobulin G (IgG) Abs early after transplantation as evidenced by flow cytometry (11 of 24 versus 4 of 27 transplant recipients, P =.03) and, less so, by CDC (5 of 24 versus 1 of 27 transplant recipients, P =.09). The difference between PBHSCT and BMT was further heightened when analysis was restricted to anti-HLA IgG Ab-negative donor/recipient pairs. In such a setting, early anti-HLA Ab was never detected after BMT but was repeatedly detected after PBHSCT (flow cytometry, 6 of 18 versus 0 of 17 transplant recipients, P =.02; CDC, 4 of 23 versus 0 of 26 transplant recipients, P =.04). Importantly, the PBHSCT-associated increase in anti-HLA Ab detection was observed despite a reduction in the median number of platelet-transfusion episodes per patient in PBHSC transplant versus BM transplant recipients (3 platelet-transfusion episodes [range, 1-21] in PBHSCT group vs 6 platelet-transfusion episodes [range, 3-33] in the BMT group; P =.02). In conclusion, this study strongly suggests that G-CSF-mobilized PBHSCT results in an increased incidence of circulating anti-HLA Abs and further confirms that the use of such a graft alters alloimmune Ab responses.