FIGURE 5.

Longer disease-free survival is associated with an expansion in the repertoire of CD8⁺ T cells targeted at mesothelin epitopes in HLA-A0101⁺ and HLA-0201⁺ patients. IFN gamma ELISPOT assays were performed to measure the frequencies of CD8⁺ T cells specific for mesothelin epitopes as described in Figure 4. Patients were divided into 3 groups: those receiving only 1 treatment (single vaccine, n = 17), those receiving multiple treatments who recurred within 3 years (DFS < 3 year, n = 18), and those receiving multiple treatments who remained disease-free for greater than 3 years (DFS > 3years, n = 8). Shown are the percentage of mesothelin peptides per patient for which a postimmunotherapy enhancement, defined as a 2-fold or greater increase in the number of IFN gamma-producing peptide-specific T cells was measured after the first (postvaccine 1) and the final immunotherapy treatments (posttreatment, only for patients receiving multiple treatments). Bars represent the overall percentage of peptides for which an enhanced response was measured for each group. Group repertoires were compared using logistic regression and the calculated P values are shown.