We have had success with our 7 year old son. We have been chelating off and on for a year. Mostly off, because of his other problems. The ALA (that chelates the brain..from health food store) tends to activate his reflux. Once the chelation cycle is broken, you have to wait and start again.
After the last chelation round with ALA, he went to summer camp for a week. When I called to check on him that first evening, they happily told me how much more interactive he was than the week he went a month before. They said he was pointing at EVERYTHING. I explained that this was shared learning and that when he points then he wants them to talk about it. I told them that kids with autism generally do NOT have a history of pointing. (though our movies before his regression show that he did point ALL the time) The pointing only lasted for 2 days, though.
His eye contact has improved tremendously, his body is less sensitive, so he is more cuddly, and he sometimes has more spontaneous speech following a "good" chelation round. (one where he doesn't throw up)
One thing that I find particularly interesting, after he finishes a chelation round he has had "typical" mannerisms a few times. Things like standing with the hand on the hip and the arms folded across the chest, or "Indian" style are things that he doesn't do and things that I didn't even know were NOT present until I saw him do them. Then it goes away.
But there is a steady progression. If you watch the movie from University of Calvery, though, it makes more sense to just know that those cells are basically being held hostage by the mercury. Until the bottom mercury is removed, then the cell will never be able to rebuild. The progress I see, I assume is from cells with less mercury that are being "cleared" before some of the ones with more mercury.
And to your question below...yes we have had "challenge" tests done before and since. There is mercury coming out in small amounts.
Good luck! Chelating is hard, but to me it is the only real solution. (autism=mercury poison) ABA is wonderful too, but you are basically "training" cells to take the place of the ones being "held hostage". That still leaves the mercury in the body. But still...I know children that have done SO WELL with ABA, that if your child is young enough, then that is an option too. We did ABA, but our school district at the time did a lousy job. (no kidding, the brain-dead dimwits they hired to do the hours that they would provide would tell us that "we don't really get this" or "we don't really know what we are doing". The only thing worse than no therapy is bad therapy. It is nearly impossible to "unteach" after something has been taught wrong.