Journal of immunotherapy
-
Journal of immunotherapy · Nov 2012
Differing patterns of circulating regulatory T cells and myeloid-derived suppressor cells in metastatic melanoma patients receiving anti-CTLA4 antibody and interferon-α or TLR-9 agonist and GM-CSF with peptide vaccination.
Changes in the biomarkers of host suppressor immune response were evaluated in patients with melanoma enrolled in 2 trials. Two similar cohorts of patients participating in the 2 studies were evaluated. The first (IFN/treme) tested interferon (IFN)-α2b and tremelimumab in metastatic melanoma and reported a response rate of 24%, 6.4 months median progression-free survival, and 21 months median overall survival. ⋯ There were no significant changes in T-reg or MDSC, except for a trend towards decreased (HLA-DR(+) low/CD14(+)) MDSC at day 50 (P = 0.07). Therefore, IFN/treme significantly downregulated MDSC suggesting a role on the significant clinical activity observed in this trial. T-reg findings suggest that IFN/treme induced clinically significant antitumor responses by inhibiting CTLA4 suppressive effects on T effectors, and less so by affecting T-reg.