BCG dose reduction by decreasing the instillation frequency: effects on local Th1/Th2 cytokine responses in a mouse model.

Objectives: Based on the requirement of a Th1 immune response for clinical efficacy, and incited by the arbitrary induction scheme, frequent side effects and the empirical approach in improving BCG immunotherapy for superficial bladder cancer, an alternative intravesical BCG treatment schedule for dose reduction was investigated without compromising Th1 cytokine induction in the bladder in a mouse model.

Methods: Mice were submitted to 6 weekly BCG instillations and treatment schedules omitting intermediate instillations during this standard scheme. Th1 (IFN-gamma, IL-2, IL-12p40), and Th2 (IL-10, IL-4) cytokine responses in individual mouse bladders were measured by a semiquantitative RT-PCR based method.