FIGURE 4.

Postimmunotherapy enhancement of mesothelin-specific CD8⁺ T cell responses in HLA-A0101⁺ and HLA-A201⁺ patients correlates with disease-free survival. IFN gamma ELISPOT assays were performed to measure the frequencies of CD8⁺ T cells specific for (A) mesothelin epitopes and (B) the CEF pool in peripheral blood leukocytes isolated from HLA-A1⁺ and HLA-A2⁺ patients for which pre- and posttreatment lymphocytes were available. Patients were divided into 3 groups: those receiving only one 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 > 3 years, n = 8). Mesothelin responses are reported for the epitope to which each individual patient showed a maximum response. Shown for each group is the median number of IFN gamma-secreting CD8⁺ T cells per 1 × 10⁶ CD8⁺ T cells above background measured against irrelevant tumor antigens with the interquartile range. The maximum value for each group is listed above each column. Responses were measured before treatment (pretreatment), 14 days after the first immunotherapy treatment (postvaccine 1) and if given multiple treatments, 28 days after the final immunotherapy treatment (posttreatment). Postimmunotherapy responses were compared to pretreatment responses using 2-tailed Wilcoxon sign-rank tests and the calculated P-values are shown.