--that IvIg won't help people with axonal degeneration; certainly it has been used 'off-label' for that at certain centers (notably the Jack Miller Center in Chicago and Cornell-Weill in New York) when there is documentable evidence of anti-nerve antibodies (not all of which attack myelin).
Have you had full antibody testing, along the lines of Dr. Latov's/Quest's listing:
http://www.questdiagnostics.com/test...ripheralNeurop
When there is documentable evidence of autoantibody activity some specialists will go to bat against the insurance companies on this (I've seen the Cornell doctors do it). It does take strong advocacy, as the insurance companies are not in the business of saying 'yes', of course.