@rwinney..I have the same question about iVIG. However, I have read some papers about the possibility of idiopathic SFN being potentially cause by an as yet to be discovered autoimmune entity. There are several iVIG trials just for this purpose going on right now including one at the neurologists' office I am going to next week. I will be asking about this clinical trial and have seen a few more out there doing similar trials... Pam