I have my doubts that it's crohns. You have an autoimmune attack on the stomach, due to the PA. Do you have both parietal cell and intrinsic factor antibodies?
What kind of immunosuppressants are you talking about, since they are not all created equally? Steroids reduce the gel coating of the stomach, which leaves you open to more pain and infections. Steroids are antiprostaglandin drugs. Our bodies need prostaglandins, like to ensure that gel coating of the stomach thick and stays healthy!
B12 will ALWAYS be an issue.
It's a forever thing for you.
Sublingual B12 is not the same as B12 tablets. B12 tablets are swallowed, which are NOT good for someone with PA. Maybe your doctor didn't know a lot about sublingual tablets. They are absorbed under the tongue and go to work in the bloodstream, bypassing the GI tract. It's the same principle as taking baby aspirin or nitroglycerin, which both go right to work in the bloodstream. Sublingual methyl B12 is the best choice for those with PA or a lack of stomach acid. Yeah, I've done s-loads of research on that one. So has Rose, who was on the gluten forum a lot. At least I think she's still there.
Your B12 levels were low, right? Now they should be high whenever they are checked. That is normal. And you can't get too much B12! Mine are always high. Totally normal when you take B12 daily. Did they check your homocysteine or methylmalonic acid levels too? They can be elevated in a B12 deficiency. My homocysteine level was high (back in 1999).
Look up autoimmune polyglandular (or polyendocrine) syndrome. You may not have this but it's interesting.
http://www.fpnotebook.com/Endo/Adren...SyndrmTypI.htm
http://emedicine.medscape.com/article/124183-overview
I hope doctors will not throw drugs at you without figuring out or sure what is going on first. And I hope you will ask for the celiac antibodies to be checked (gliadin, reticulin, endomysial and tissue transglutaminase).
Adding fish oil or flax or good nuts like walnuts to your diet that contain omega 3's may help with the stomach issue. I take good omega's daily. Before taking Betaine, I had a lot of infections, reactive hypoglycemia from my undigested food "dumping" into my small intestine, etc.
I'm sure you and your doctor can figure all this out. Hang in there. It isn't easy having MG but lupus is a major challenge.
Annie