Antitumor systemic responses detected in the blood of patients with localized UM tumors. (A and B) Analysis of matched blood and tumor samples. (A) Dual color HLA-A2:Melan-A staining of CD8⁺ T cells in the tumor and blood in two patients. (B) Proportion of non-naïve HLA-A2:Melan-A-tetramer⁺ T cells in the blood according to the number of Melan-A–specific T cells in the primary tumor. (C–F) Frequency and phenotype of Melan-A–specific CD8⁺ T cells in the blood of patients with D3 or M3 tumors. (C) Dot plots of Melan-A–specific CD8⁺ T cells in the blood of two patients. (D) Frequency of HLA-A2:Melan-A-tetramer⁺ in blood CD8⁺ T cells. (E) Examples of CCR7-CD45RA staining of blood A2:Melan-A CD8⁺ T cells. (F) Frequency of non-naïve HLA-A2:Melan-A T cells in the blood of patients with D3 or M3 tumors. (G–J) Detection of CD8⁺ T cells specific for SF3B1^mut related neo-epitopes in the blood of patients with UM tumors mutated (SF3B1^mut) or not (SF3B1^WT) for SF3B1. (G) Example of HLA-A2:14 (top) and HLA-A2:37 (bottom) tetramer staining. (H) Frequency of tetramer-positive cells in blood CD8⁺ T cells of patients with SF3B1^mut or SF3B1^WT tumors. The dashed line indicated the quantitation limit. (I) Examples of naïve/memory phenotype of tetramer-positive T cells. (J) Frequency of non-naïve tetramer-positive T cells in the blood of patients with SF3B1^mut or SF3B1^WT tumors. (K) Frequency of patients with memory responses against SF3B1^mut-related neo-peptides according to mutational status of SF3B1. Coh1 (n = 20) was used in A. Coh1 and coh4 were used in B. Coh5 was used in C–K. Non-parametric Mann–Whitney test was used in D, F, H, and J. Only P < 0.05 are shown. ND: non detected; NA: not applicable; the phenotype was not calculated when less than five tetramer-positive cells were detected.