I'm not a doctor, so I don't know much about IgG and IgA. But, from what I've read, those could be characteristics of someone having CD, or celiac disease(high levels if IgG). I would stop eating any processed foods, such as the peanut butter crackers (wheat and yeast in those which may not be helping you) and try to stick with foods that your body needs to heal...whole, natural foods that you are able to tolerate. Beans may cause gas. Not sure if that means green beans, as well. Definitely look into reputable probiotics. One size does not fit all, however. I had to experiment with a few before I found one that improved my symptoms (Primadophilus Reuteri by Nature's Way).
Were you ever on antibiotics? When was your last colonoscopy? My IBS symptoms progressed to UC within a few years. My first scope showed NOTHING and they told me it was just IBS, so keep an eye on those symptoms.