Hi, Megan:
I have corresponded with several people with AS and resultant amyloidosis. The increased IgA (immunoglobulin) when the disease is active somehow preferentially forms depositions in various tissues--like kidneys and liver--in some smaller portion of those with AS.
One fellow in Australia had this and might have tried long-term fasting (being in a state of dietary ketosis might help to eliminate the amyloid) to help him, but I lost touch after a few months and sorry that I do not know the outcome.
Good luck with this,
John
