Langerhans-type dendritic cells electroporated with TRP-2 mRNA stimulate cellular immunity against melanoma: Results of a phase I vaccine trial.

Purpose: We conducted a phase I vaccine trial to determine safety, toxicity, and immunogenicity of autologous Langerhans-type dendritic cells (LCs), electroporated with murine tyrosinase-related peptide-2 (mTRP2) mRNA in patients with resected AJCC stage IIB, IIC, III, or IV (MIa) melanoma. Experimental Design: Nine patients received a priming immunization plus four boosters at three week intervals. Vaccines comprised 10 × 106 mRNA-electroporated LCs, based on absolute number of CD83+CD86brightHLA-DRbrightCD14neg LCs by flow cytometry. Initial vaccines used freshly generated LCs, whereas booster vaccines used viably thawed cells from the cryopreserved initial product. Post-vaccination assessments included evaluation of delayed-type hypersensitivity (DTH) reactions after booster vaccines and immune response assays at one and three months after the final vaccine. Results: All patients developed mild DTH reactions at injection sites after booster vaccines, but there were no toxicities exceeding grade 1 (CTCAE, v4.0). At one and three months post-vaccination, antigen-specific CD4 and CD8 T cells increased secretion of proinflammatory cytokines (IFN-γ, IL-2, and TNF-α), above pre-vaccine levels, and also upregulated the cytotoxicity marker CD107a. Next-generation deep sequencing of the TCR-V-ß CDR3 documented fold-increases in clonality of 2.11 (range 0.85-3.22) for CD4 and 2.94 (range 0.98-9.57) for CD8 T cells at one month post-vaccines. Subset analyses showed overall lower fold-increases in clonality in three patients who relapsed (CD4: 1.83, CD8: 1.54) versus non-relapsed patients (CD4: 2.31, CD8: 3.99). Conclusions: TRP2 mRNA-electroporated LC vaccines are safe and immunogenic. Responses are antigen-specific in terms of cytokine secretion, cytolytic degranulation, and increased TCR clonality, which correlates with clinical outcomes.

T-cell Exhaustion in Multiple Myeloma Relapse after Autotransplant: Optimal Timing of Immunotherapy.

Multiple myeloma is the most common indication for high-dose chemotherapy and autologous stem cell transplantation (ASCT), and lenalidomide maintenance after transplant is now standard. Although lenalidomide doubles progression-free survival, almost all patients eventually relapse. Posttransplant immunotherapy to improve outcomes after ASCT therefore has great merit but first requires delineation of the dynamics of immune reconstitution. We evaluated lymphocyte composition and function after ASCT to guide optimal timing of immunotherapy and to identify potential markers of relapse. Regulatory T cells (Treg) decline as CD8(+) T cells expand during early lymphocyte recovery after ASCT, markedly reducing the Treg:CD8(+) effector T-cell ratio. These CD8(+) T cells can respond to autologous dendritic cells presenting tumor antigen in vitro as early as day +12 after transplant, becoming antigen-specific cytolytic T-lymphocyte effectors and thereby demonstrating preservation of cellular reactivity. CD4(+) and CD8(+) T cells express the negative regulatory molecules, CTLA-4, PD-1, LAG-3, and TIM-3, before and after ASCT. A subpopulation of exhausted/senescent CD8(+) T cells, however, downregulates CD28 and upregulates CD57 and PD-1, characterizing immune impairment and relapse after ASCT. Relapsing patients have higher numbers of these cells at +3 months after transplant, but before detection of clinical disease, indicating their applicability in identifying patients at higher risk of relapse. PD-1 blockade also revives the proliferation and cytokine secretion of the hyporesponsive, exhausted/senescent CD8(+) T cells in vitro. Collectively, these results identify T-cell exhaustion/senescence as a distinguishing feature of relapse and support early introduction of immunotherapy to stimulate antitumor immunity after ASCT.

Neutrophil gelatinase-associated lipocalin and cystatin C for the prediction of clinical events in patients with advanced heart failure and after ventricular assist device placement.

BACKGROUND: Progressive renal dysfunction develops in patients with advanced HF. We evaluated neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C compared with established markers of renal function in patients with heart failure (HF) because they might improve prognostic assessment of patients with HF. METHODS: Serum samples were collected from 40 patients with stable HF (age: 58 ± 8 years, body mass index [BMI]: 28.4 ± 6.4 kg/m(2)), 40 HF patients undergoing ventricular assist device (VAD) implantation (age: 53 ± 11 years, BMI: 26.8 ± 5.5 kg/m(2)), 40 patients undergoing VAD removal at cardiac transplantation, and 24 controls (age: 48 ± 7 years, BMI: 29.4 ± 4.2 kg/m(2)). Clinical data were collected from institutional medical records. NGAL and cystatin C levels were measured by enzyme-linked immunosorbent assay and estimated glomerular filtration rate (eGFR) calculated using the Modification of Diet in Renal Disease formula. RESULTS: Patients with stable HF showed elevated NGAL and cystatin C levels compared with controls (NGAL: 114.9 ± 48.3 ng/mL vs 72.0 ± 36.6 ng/mL, p < 0.0001; cystatin C: 1490.4 ± 576.1 ng/mL vs 954.7 ± 414.2 ng/mL, p = 0.0026). Unlike cystatin C, NGAL increased in advanced HF patients requiring VAD implantation (158.7 ± 74.8 ng/mL, p < 0.001). On VAD support, NGAL levels decreased (127.1 ± 80.4 ng/mL, p = 0.034). NGAL was higher in patients who developed right ventricular failure (187.8 ± 66.0 vs 130.9 ± 67.0 ng/mL, p = 0.03) and irreversible renal dysfunction (190.0 ± 73.8 ng/mL vs 133.8 ± 54.2 ng/mL, p < 0.05), whereas cystatin C, creatinine, and eGFR were not different. NGAL correlated with eGFR (r = -0.2188, p = 0.01). CONCLUSIONS: NGAL levels correlate with HF severity and hemodynamic improvement after VAD placement. Our findings suggest a role of this novel biomarker as a marker of severity and prognosis in patients with HF.

Langerhans-type and monocyte-derived human dendritic cells have different susceptibilities to mRNA electroporation with distinct effects on maturation and activation: implications for immunogenicity in dendritic cell-based immunotherapy.

BACKGROUND: mRNA electroporation of dendritic cells (DCs) facilitates processing and presentation of multiple peptides derived from whole antigen, tailored to different HLA molecules. Clinical responses to electroporated moDC vaccines, however, have been suboptimal. Human Langerhans-type DCs (LCs) are the most potent conventional DC subtype for inducing CD8+ cytotoxic T lymphocytes (CTLs) in vitro. We recently demonstrated that Wilms' tumor 1 (WT1) mRNA-electroporated LCs are superior to moDCs as stimulators of tumor antigen-specific CD8+ CTLs, even though they are comparable stimulators of allogeneic T cell proliferative responses. A detailed comparative evaluation of the effects of mRNA electroporation on LCs versus moDCs, however, is needed. METHODS: Immature and partially-matured human moDCs and LCs electroporated with mRNA were compared for transfection efficiency, phenotypic changes, viability, retention of transgene expression after cryopreservation, and immunogenicity. Student t test was used for each pairwise comparison. One-way analysis of variance was used for multiple group comparisons. RESULTS: Transfection efficiency after electroporation with enhanced green fluorescent protein (eGFP) mRNA was higher for immature than for partially-matured moDCs. In contrast, transfection efficiency was higher for partially-matured than for immature LCs, with the additional benefit that electroporation itself increased maturation and activation of CD83+HLA-DRbright LCs but not moDCs. Electroporation did not impair final maturation and activation of either DC subtype, after which both mRNA-electroporated LCs and moDCs were functionally similar in stimulating allogeneic T cell proliferation, a standard assay of DC immunogenicity. CONCLUSIONS: These findings support mRNA electroporation of DCs, and in particular LCs, as an effective non-viral method to stimulate specific, potent CD8+ CTL responses. The differences between LCs and moDCs regarding this form of antigen-loading have important implications for DC-based immunotherapies.