Activated Eosinophils Predict Longer Progression-Free Survival under Immune Checkpoint Inhibition in Melanoma

• Published in: Cancers Vol. 14; no. 22; p. 5676
• Main Authors: Ammann, Nadine L, Schwietzer, Yasmin F, Mess, Christian, Stadler, Julia-Christina, Geidel, Glenn, Kött, Julian, Pantel, Klaus, Schneider, Stefan W, Utikal, Jochen, Bauer, Alexander T, Gebhardt, Christoffer
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 18.11.2022; MDPI
• Subjects: Antibodies; Antigens; Autoimmune diseases; Biomarkers; Blood levels; Cell activation; Chemokines; Committees; Dermatology; Development and progression; Drug therapy; Effector cells; Eosinophil cationic protein; Eosinophils; Ethics; Health aspects; Hepatitis; HIV; Human immunodeficiency virus; Immune checkpoint inhibitors; Immune response (cell-mediated); Immunofluorescence; Inflammation; Leukocytes (eosinophilic); Ligands; Lymphocytes T; Melanoma; Metastases; Metastasis; Patients; Peroxidase; Prognosis; Proteins; Skin cancer; Therapeutic targets; Tomography; Tumor cells; Tumor microenvironment; Tumor-infiltrating lymphocytes; Tumors; Viral infections; Germany; United Kingdom > UK; United States > US; T-cells; ECP; immune checkpoint inhibition; inflammation; eosinophils; melanoma; tumor microenvironment; EPX; biomarker
• ISSN: 2072-6694; 2072-6694
• DOI: 10.3390/cancers14225676

Immune checkpoint inhibition (ICI) has yielded remarkable results in prolonging survival of metastatic melanoma patients but only a subset of individuals treated respond to therapy. Success of ICI treatment appears to depend on the number of tumor-infiltrating effector T-cells, which are known to be influenced by activated eosinophils. To verify the co-occurrence of activated eosinophils and T-cells in melanoma, immunofluorescence was performed in 285 primary or metastatic tumor tissue specimens from 118 patients. Moreover, eosinophil counts and activity markers such as eosinophil cationic protein (ECP) and eosinophil peroxidase (EPX) were measured in the serum before therapy start and before the 4th infusion of ICI in 45 metastatic unresected melanoma patients. We observed a positive correlation between increased tumor-infiltrating eosinophils and T-cells associated with delayed melanoma progression. High baseline levels of eosinophil count, serum ECP and EPX were linked to prolonged progression-free survival in metastatic melanoma. Our data provide first indications that activated eosinophils are related to the T-cell-inflamed tumor microenvironment and could be considered as potential future prognostic biomarkers in melanoma.