Myeloid Cells and Related Chronic Inflammatory Factors as Novel Predictive Markers in Melanoma Treatment with Ipilimumab

Abstract

Purpose: Immunotherapy with ipilimumab improves the survival of patients with metastatic melanoma. Because only around 20% of patients experience long-term benefit, reliable markers are needed to predict a clinical response. Therefore, we sought to determine if some myeloid cells and related inflammatory mediators could serve as predictive factors for the patients' response to ipilimumab.Experimental Design: We performed an analysis of myeloid cells in the peripheral blood of 59 stage IV melanoma patients before the treatment and at different time points upon the therapy using a clinical laboratory analysis and multicolor flow cytometry. In addition, the production of related inflammatory factors was evaluated by ELISA or Bio-Plex assays.Results: An early increase in eosinophil count during the treatment with ipilimumab was associated with an improved clinical response. In contrast, elevated amounts of monocytic myeloid-derived suppressor cells (moMDSC), neutrophils, and monocytes were found in nonresponders (n ¼ 36) as compared with basal levels and with responding patients (n ¼ 23). Moreover, in nonresponders, moMDSCs produced significantly more nitric oxide, and granulocytic MDSCs expressed higher levels of PD-L1 than these parameters at baseline and in responders, suggesting their enhanced immunosuppressive capacity. Upon the first ipilimumab infusion, nonresponders displayed elevated serum concentrations of S100A8/A9 and HMGB1 that attract and activate MDSCs.Conclusions: These findings highlight additional mechanisms of ipilimumab effects and suggest levels of eosinophils, MDSCs, as well as related inflammatory factors S100A8/A9 and HMGB1 as novel complex predictive markers for patients who may benefit from the ipilimumab therapy. Clin Cancer Res; 21(24); 5453-9. Ó2015 AACR.

Clinical Significance of Circulating CD33+CD11b+HLA-DR− Myeloid Cells in Patients with Stage IV Melanoma Treated with Ipilimumab

“…This is supported by our results showing that the CD247 is sole TCR molecule to be downregulated in the course of chronic inflammation while the CD3 or any other TCR subunit are unchanged (15,26), and is in contrast with a normal T-cell activation process that leads to the downregulation of the entire TCR complex (26). Indeed, recent reports showed increased levels of proinflammatory cytokines in the serum of patients with melanoma, generating an immunosuppressive environment enriched by MDSCs and Tregs (7,19,34,35). Additional studies in renal cell carcinoma (36) and melanoma (17) patients support our observations as they show that CD33 þ MDSCs isolated from patients but not from HDs are able to suppress antigen specific T-cell responses in vitro, a phenomenon that is reversible upon inhibition of hROS production or maturation of these cells into antigen-presenting precursors.…”

“…In the course of our study, we used a flow-cytometry test applied on whole-blood fresh and frozen samples, unlike many published studies, which used a Ficoll density gradient centrifugation step for PBMC preparation, before freezing the samples and evaluating MDSC frequencies (9,17,(19)(20)(21). We found that in contrast to blood samples separated by Ficoll density gradient (fresh or cryopreserved/thawed), only cryopreservation/thawing of the whole-blood sample preserves the levels of CD33þCD11bþHLA-DR À MDSCs as detected in fresh samples.…”

“…In the course of our analysis, we used a flow cytometry test to detect CD33 þ CD11b þ HLA-DR À MDSC frequencies in whole-blood frozen samples; unlike many of the published studies, which used a Ficoll density gradient centrifugation step for peripheral blood mononuclear cells (PBMCs) preparation, before freezing the samples and evaluating MDSC frequencies (9,17,(19)(20)(21). To determine the effect of cryopreservation/thawing and Ficoll centrifugation on MDSCs as well as on T-cell frequency, blood samples from 15 HD were analyzed.…”

“…Indeed, recent studies have shown that circulating CD14 þ CD11b þ HLA-DR À/low monocytic MDSC, but not Tregs could be used as prognostic biomarkers for predicting survival rates in patients with advanced melanoma (9) and that increased levels of this unique monocytic MDSC population correlates with lack of response in patients with melanoma treated with anti-CTLA4 therapy (19,20). However, whether high levels of the global population of MDSCs, CD33 þ CD11b þ HLA-DR À , containing both the granulocytic and monocytic subpopulations also correlate with lack of response and short-term survival in patients treated with anti-CTLA4 remains an open question.…”

Thyrotoxicosis and Adrenocortical Hormone Deficiency During Immune-checkpoint Inhibitor Treatment for Malignant Melanoma

“…They report clinical benefits of a sequential administration of nivolumab followed by ipilimumab in patients with advanced melanoma, albeit associated with a higher frequency of adverse events. Gebhardt et al reported that an early increase in eosinophils during the treatment with ipilimumab was associated with preferable clinical response (17).…”