Increased monocyte activation following Prostate GVAX/ipilimumab therapy is associated with prolonged survival. Frequencies and activation status of circulating CD14+ monocytes were determined before (w0), during (w4, w8, w12, w16, w20, w24) and after (fu) Prostate GVAX/ipilimumab treatment by flowcytometric analysis. A) Mean percentage (of PBMC) ± SEM and B) mean activation ± SEM of CD14+ monocytes is shown before, during and after Prostate GVAX/ipilimumab treatment for 28 patients, divided by clinical PSA response: partial PSA response (PR; black squares), disease stabilization or (SD; white squares) or disease progression (PD; grey squares). Activation is given as med. Fluorescence Index (med. FI) and calculated by dividing the med. fluorescence (med. fl) of CD40 antibody by the med. fl of the isotype control antibody. C) Kaplan Meier curve for treatment-induced increases in activation of monocytes. Number of patients and corresponding median survival for each group are given. Differences between pre- and on- or post-treatment were analyzed with the repeated measures ANOVA with a post-hoc Dunnett's multiple comparisons test. Differences were considered significant when p?<?0.05, as indicated with asterisks (* p?<?0.05, ** p?<?0.01).