Recently there was a post on HN about some child whose genetic disease was cured by inserting DNA (can't remember the specifics). I wonder if something similar could be done with HIV. Obviously you'd have to insert a mutation for the CCR5 protein. Then the problem is you have all this bone marrow that's still producing white blood cells of the old type, so you'd need some way of killing off the old bone marrow cells without the right mutation and replacing them with the new ones.