Imiquimod activates the body’s innate immune response, including dendritic cells and cytokines. Because toll-like receptors have a central role in the immune response, toll-like agonists like imiquimod can activate the body’s innate and adaptive immunity simultaneously. Imiquimod serves to upregulate Th1 response and downregulate Th2 response.
Imiquimod locally induces cytokines and chemokines via toll-like receptor 7 on dendritic cells, macrophages and monocytes in vitro. There is less chance of recurrence after use of imiquimod because of cellular memory. The current data also suggests that imiquimod may induce tumour apoptosis. The 2002 pilot study of the treatment of AKs with imiquimod, launched by Prof Stockfleth, found that imiquimod completely cleared 84% of cases within 14 weeks.