Fig. 4.

IL-18 enhances the efficacy of rituximab in SCID mice with human B cell lymphoma xenografts. SCID–ICR mice (n = 6/group) bearing subcutaneous human Ramos lymphoma xenografts were treated with IL-18 or rituximab monotherapy, or with combination of both agents. a Tumor growth in combination therapy groups was significantly suppressed (*P < 0.05, **P < 0.01, ***P < 0.001, two-way ANOVA followed by Bonferroni post-test) as compared to the rituximab monotherapy groups. Moreover, the number of complete tumor regressions was significantly increased in combination therapy groups as compared to rituximab (Table 2) or IL-18 monotherapy (0/6). Mice in the control group in some of the monotherapy groups (#) had to be euthanized due to ethical reasons before the study ended. b Tumor volumes on day 25 show statistically significant tumor growth suppression in all combination therapy groups as compared to their respective rituximab (*P < 0.05, **P < 0.01, t test) monotherapy groups and to the IL-18 monotherapy group (**P < 0.01, one-way ANOVA followed by Bonferroni post-test)