I'm not sure I understand your question. The low IgG is a primary immunodeficiency disease...a completely different medical condition from the neuropathy. I just happen to have both conditions and receive the IVIG for both. It replaces the IgG my body is unable to make on it's.

The dosing of IVIG for neuropathy is completely different and usually about 3 times more then required for an immune deficiency.

So basically, if I understand your question, NO, the low IgG has nothing to do with the neuropathy and therefore not required to have a low IgG for it to work. The IVIG helps the low IgG (of an immune deficiency) by bringing the level up. The IVIG for neuropathy works as an immune modulator to help organize better immune function in autoimmune types of neuropathy. But the actual mechanics of how the IVIG helps neuropathy isn't completely understood yet...they just know it helps.

Hope this helps.