Melody first off, www.gbsfi.com and www.gbs/org.uk are very thorough sites to explore. Another resource is https://nord.clinicalhealth.com
Lastly is a publication about IVIG called IG Living....read their back features and it'll explain the whole shebang.

Historically CIDP was considered a chronic form of GBS, but, look at the westul.neuro categories and you can see that many acquired and not inherited forms of neuropathies either are in or closely parallel to the inherited forms of GBS. Many acquired auto-immune conditions are crossing the line to the CIDP category daily, if I'm reading what insurance companies cover. Conditions approved for IVIG therapy are being expanded frequently. As for it having a 'mild' presentation...I guess I would have to differ strongly about that description. I am 95% sure my auto-i condition is acquired as there are zero indications in any family history and it is possibly connected as a para-neoplastic syndrome in my case, but there is no true way to prove it.

As for IVIG, the first intro to it is usually super-cautious, as it's a somewhat invasive procedure, similar to chemo. Some reactions, tho very rare, can be serious. After it's been seen to cause little or no reactions, and shows benefits, it's usually outpatient at either a hospital, an infusion clinic or at home. I've been in all 3 settings and there are good or bad aspects to each. With it I can WALK, I can sleep, I have moments almost pain free!
I can and DO feel pain, my seeking answers, getting second opinions and all that enabled me to receive treatments needed before it had progressed to the ultimate debilitation CIDP can cause. It is true tho that IVIG is used for many inherited conditions, but, it's also used for many acquired ones as well.

Depending on what statistics you read, it is effective in 60-40% of recipients, and how long a treatment 'lasts' is unique to each person. If it works for Alan, and insurance covers it [meeting the catastrophic deductible is a real trip each year] give it a try.

As for me, IF I were no longer able to get IVIG, I hate to consider what would be going through my mind. Options are very few.

Hugs and good thoughts to all! - j