"Helminthic therapy" is the treatment of autoimmune disorders via deliberate exposure to parasitic worms. I know this for two reasons: One, I live within easy driving distance of what is apparently the quack capitol of the United States. Two, the parents of the kids I work with often have no common sense whatsoever.
If you've reached the obvious conclusion, you are entirely correct. I now know more than I ever wanted to about this, including the name of a company that will ship whipworm eggs from Thailand.
There really isn't much on the 'net about helminthic therapy and autism as of yet, but what I have found is suitably disturbing. The rationale is discussed here and here. The first part of a three-part video lecture is available here (with parts two and three available here and here, respectively). A very disgusting blog post can be found here.
Any other sources would be greatly appreciated.