Henning Zelba

Myeloid-Derived Suppressor Cells Predict Survival of Patients with Advanced Melanoma: Comparison with Regulatory T Cells and NY-ESO-1- or Melan-A–Specific T Cells

Purpose: To analyze the prognostic relevance and relative impact of circulating myeloid-derived suppressor cells (MDSC) and regulatory T cells (Treg) compared with functional tumor antigen–specific T cells in patients with melanoma with distant metastasis. Experimental Design: The percentage of CD14+CD11b+HLA-DR−/low MDSCs, CD4+CD25+FoxP3+ Tregs, and the presence of NY-ESO-1- or Melan-A–specific T cells was analyzed in 94 patients and validated in an additional cohort of 39 patients by flow cytometry. Univariate survival differences were calculated according to Kaplan–Meier and log-rank tests. Multivariate analyses were performed using Cox regression models. Results: NY-ESO-1–specific T cells, the M-category, and the frequency of MDSCs were associated with survival. The absence of NY-ESO-1–specific T cells and the M-category M1c independently increased the risk of death. In a second Cox model not considering results on antigen-specific T cells, a frequency of >11% MDSCs showed independent impact. Its association with survival was confirmed in the additional patient cohort. Median survival of patients with a lower frequency of MDSCs was 13 months versus 8 months for others (P < 0.001, combined cohorts). We observed a strong correlation between high levels of MDSCs and the absence of melanoma antigen–specific T cells implying a causal and clinically relevant interaction. No prognostic impact was observed for Tregs. Conclusions: Circulating CD14+CD11b+HLA-DR−/low MDSCs have a negative impact on survival and inversely correlate with the presence of functional antigen–specific T cells in patients with advanced melanoma. Our findings provide a rationale to investigate MDSC-depleting strategies in the therapeutic setting especially in combination with vaccination or T-cell transfer approaches. Clin Cancer Res; 20(6); 1601–9. ©2013 AACR.

Functional T Cells Targeting NY-ESO-1 or Melan-A Are Predictive for Survival of Patients With Distant Melanoma Metastasis

PURPOSE To analyze the prognostic relevance of circulating T cells responding to NY-ESO-1, Melan-A, MAGE-3, and survivin in patients with melanoma with distant metastasis. PATIENTS AND METHODS We examined 84 patients with follow-up after analysis (cohort A), 18 long-term survivors with an extraordinarily favorable course of disease before analysis (> 24 months survival after first occurrence of distant metastases; cohort B), and 14 healthy controls. Circulating antigen-reactive T cells were characterized by intracellular cytokine staining after in vitro stimulation. RESULTS In cohort A patients, the presence of T cells responding to peptides from NY-ESO-1, Melan-A, or MAGE-3 and the M category according to the American Joint Committee on Cancer classification were significantly associated with survival. T cells responding to NY-ESO-1 and Melan-A (hazard ratios, 0.29 and 0.18, respectively) remained independent prognostic factors in Cox regression analysis and were superior to the M category in predicting outcome. Median survival of patients possessing T cells responding to NY-ESO-1, Melan-A, or both was 21 months, compared with 6 months for all others. NY-ESO-1-responsive T cells were detected in 70% of cohort A patients surviving > 18 months and in 50% of cohort B patients. Melan-A responses were found in 42% and 47% of patients in cohorts A and B, respectively. In contrast, the proportion was only 22% for NY-ESO-1 and 23% for Melan-A in those who died within 6 months. CONCLUSION The presence of circulating T cells responding to Melan-A or NY-ESO-1 had strong independent prognostic impact on survival in advanced melanoma. Our findings support the therapeutic relevance of Melan-A and NY-ESO-1 as targets for immunotherapy.

High Response Rate After Intratumoral Treatment With Interleukin-2: Results From a Phase 2 Study in 51 Patients With Metastasized Melanoma

Systemic high‐dose interleukin‐2 (IL‐2) achieved long‐term survival in a subset of patients with advanced melanoma. The authors reported previously that intratumorally applied IL‐2 induced complete local responses of all metastases in >60% of patients. The objectives of the current study were to confirm those results in a larger cohort and to identify patient or regimen characteristics associated with response.

Intralesional Treatment of Stage III Metastatic Melanoma Patients with L19-IL2 Results in Sustained Clinical and Systemic Immunologic Responses

Weide and colleagues show that intralesional therapy using the immunocytokine L19–IL2 elicited a high rate of clinical and systemic immune responses in patients with stage III melanoma and report their observation of favorable distant metastasis-free and overall survival in these patients after treatment. L19–IL2 is a recombinant protein comprising the cytokine IL2 fused to the single-chain monoclonal antibody L19. In previous studies, intralesional injection with IL2 has shown efficacy for the locoregional treatment of cutaneous/subcutaneous metastases in patients with advanced melanoma. The objectives of this study were to investigate whether (i) intralesional delivery of a targeted form of IL2 would yield similar results, with reduction of injection frequency and treatment duration; and (ii) systemic immune responses were induced by the local treatment. Patients with stage IIIB/IIIC melanoma and cutaneous/subcutaneous injectable metastases received weekly intratumoral injections of L19–IL2 at a maximum dose of 10 MIU/week for 4 consecutive weeks. Tumor response was evaluated 12 weeks after the first treatment. Twenty-four of 25 patients were evaluable for therapy-induced responses. A complete response (CR) by modified immune-related response criteria (irRC) of all treated metastases was achieved in 6 patients (25%), with long-lasting responses in most cases (5 patients for ≥24 months). Objective responses were documented in 53.9% of all index lesions [44.4% CR and 9.5% partial responses (by irRC)], and 36.5% of these remained stable, while 9.5% progressed. Toxicity was comparable with that of free IL2, and no serious adverse events were recorded. A significant temporary increase of peripheral regulatory T cells and natural killer cells, sustained increase of absolute CD4+ lymphocytes, and decrease of myeloid-derived suppressor cells were observed upon treatment. Finally, we recorded encouraging data about the progression time to distant metastases and overall survival. Cancer Immunol Res; 2(7); 668–78. ©2014 AACR.

Induction of HIF-1α and the glycolytic pathway alters apoptotic and differentiation profiles of activated human T cells

The majority of in vitro studies involving lymphocytes is performed in AtmO2, and the PhysO2 that T cells encounter are variable but commonly much lower. Previous studies showed changed kinetics and delayed proliferation of human T cells at PhysO2. Here, we show that CD3/CD28‐dependent T cell activation induces faster cell cycling at AtmO2 than at PhysO2 (here taken to be 2%). Concomitantly with HIF‐1α expression, we observed a switch in the T cell respiratory pathway toward glycolysis at PhysO2. Thus, modulating available glucose levels showed that at PhysO2, T cells rely more on glycolysis, associated with a higher phosphorylation of Aktser473. Although no difference in spontaneous apoptosis of resting cells was detected, it was increased significantly at PhysO2 after T cell activation and was different within the different T cell subsets. This may explain at least partly the differently altered proliferation and subset distribution observed in CD4+ and CD8+ T cells as a result of differences in naïve and memory subset distribution. Together, these findings suggest that T cell activation thresholds, subsequent proliferative capacity, and susceptibility to apoptosis, hitherto studied in air and thought to be crucial for monitoring immune responsiveness, may require re‐assessment.

Circulating CD4+ T cells that produce IL4 or IL17 when stimulated by Melan-A but not by NY-ESO-1 have negative impacts on survival of patients with stage IV melanoma

Purpose: We initially observed that the presence of circulating NY-ESO-1– and/or Melan-A–specific T cells in patients with stage IV melanoma was significantly associated with prolonged survival. Here, we report the ways in which the phenotypes and functions of these T cells differentially affect survival in patients preselected for NY-ESO-1 and/or Melan-A reactivity. Experimental Design: We assayed functional antigen-reactive T cells recognizing NY-ESO-1 and/or Melan-A after in vitro stimulation using overlapping peptide pools. After restimulation, we assayed six cytokines simultaneously by intracellular cytokine staining. This allowed us to analyze the functional antigen response of both CD4+ and CD8+ T cells at the single-cell level. Results: We observed that NY-ESO-1 stimulated mainly CD4+ T cells, whereas Melan-A more often stimulated CD8+ T cells. NY-ESO-1 reactivity was not associated with an additional impact on survival, whether CD4+ T cells, CD8+ T cells, or both types of T cells were responding. In contrast, recognition of Melan-A by CD4+ T cells was associated with reduced survival in our cohort of patients preselected for NY-ESO-1 and/or Melan-A reactivity (that is, in patients with exceptionally long survival). We further observed a negative effect on survival in patients with CD4+ T cells producing IL4 and IL17 upon Melan-A stimulation. Their prognosis was comparable to patients without any Melan-A reactivity. Conclusions: The nature and prognostic impact of specific T-cell responses is different according to targeted antigen. Independent from phenotype and functional aspects, NY-ESO-1 reactivity is associated with good prognosis. In terms of Melan-A, antigen-specific CD8+ but not CD4+ responses are associated with prolonged survival. Clin Cancer Res; 20(16); 4390–9. ©2014 AACR.

Reduced oxygen tension results in reduced human T cell proliferation and increased intracellular oxidative damage and susceptibility to apoptosis upon activation

Cell culture and in vitro models are the basis for much biological research, especially in human immunology. Ex vivo studies of T cell physiology employ conditions attempting to mimic the in vivo situation as closely as possible. Despite improvements in controlling the cellular milieu in vitro, most of what is known about T cell behavior in vitro is derived from experiments on T cells exposed to much higher oxygen levels than are normal in vivo. In this study, we report a reduced proliferative response and increased apoptosis susceptibility after T cell activation at 2% oxygen compared to in air. To explain this observation, we tested the hypothesis of an impaired efficacy of intracellular protective mechanisms including antioxidant levels, oxidized protein repair (methionine sulfoxide reductases), and degradation (proteasome) activities. Indeed, after activation, there was a significant accumulation of intracellular oxidized proteins at more physiological oxygen levels concomitant with a reduced GSH:GSSG ratio. Proteasome and methionine sulfoxide reductase activities were also reduced. These data may explain the increased apoptotic rate observed at more physiological oxygen levels. Altogether, this study highlights the importance of controlling oxygen levels in culture when investigating oxygen-dependent phenomena such as oxidative stress.

Establishing High Dimensional Immune Signatures from Peripheral Blood via Mass Cytometry in a Discovery Cohort of Stage IV Melanoma Patients.

The identification of blood-borne biomarkers correlating with melanoma patient survival remains elusive. Novel techniques such as mass cytometry could help to identify melanoma biomarkers, allowing simultaneous detection of up to 100 parameters. However, the evaluation of multiparametric data generated via time-of-flight mass cytometry requires novel analytical techniques because the application of conventional gating strategies currently used in polychromatic flow cytometry is not feasible. In this study, we have employed 38-channel time-of-flight mass cytometry analysis to generate comprehensive immune cell signatures using matrix boolean analysis in a cohort of 28 stage IV melanoma patients and 17 controls. Clusters of parameters were constructed from the abundance of cellular phenotypes significantly different between patients and controls. This approach identified patient-specific combinatorial immune signatures consisting of high-resolution subsets of the T cell, NK cell, B cell, and myeloid compartments. An association with superior survival was characterized by a balanced distribution of myeloid-derived suppressor cell-like and APC-like myeloid phenotypes and differentiated NK cells. The results of this study in a discovery cohort of melanoma patients suggest that multifactorial immune signatures have the potential to allow more accurate prediction of individual patient outcome. Further investigation of the identified immune signatures in a validation cohort is now warranted.

Monocytic myeloid-derived suppressor cells in advanced melanoma patients: Indirect impact on prognosis through inhibition of tumor-specific T-cell responses?

The percentage of circulating CD14+CD11b+HLA-DR−/low myeloid-derived suppressor cells (MDSCs) inversely correlates with survival among advanced melanoma patients. High levels of MDSCs are associated with the absence of T lymphocytes specific for melanoma-derived antigens, implying a causal and clinically relevant interaction between these cell subsets. MDSCs might therefore represent prognostic markers as well as targets for the development of novel therapeutic interventions against melanoma.

The prognostic impact of specific CD4 T-cell responses is critically dependent on the target antigen in melanoma

The melanoma-associated antigens Melan-A and NY-ESO-1 stimulate different T-cell responses in late-stage melanoma patients. Either CD4+ or CD8+ T-cell reactivity against NY-ESO-1 was associated with better prognosis, but for Melan-A, only CD8+ but not CD4+ T-cell responses were associated with longer survival.