Does the use of imiquimod increase the risk of hiv transmission? if so, is it b/c of irritation or b/c of enhanced immune response?

No hard data: Interesting question. Imiquimod is externally used for condyloma (warts) as you already know. There have been no studies showing what you ask. Now...Thinking logically...Anything that causes irritation or a break in the skin surface should put one at higher risk to acquire hiv..Especially when its associated with a mucous membrane. So i would say yes...But there is no data to support this.

Yes (macaque study): Imiquimod (a tlr receptor agonist) may theoretically decrease HIV transmission by increasing ifn Alpha & beta at the affected area. However, it also results in a pro-inflammatory response that can increase HIV transmission via skin irritation. This question was tested in macaques showing that topical application actually led to higher siv viremia in monkeys receiving Imiquimod & no protection.