My TTG IgA and IGA are elevated mildly, right at borderline positive,e but my EMA is negative. All my vitamin levels are normal as well as cbc and metabolic panel. What is the likely cause of this? I have been on gluten-free diet for 15 yrs nearly. 

They do work for me. I am feeling much better now that I am watching my histamine intake and only take the DAO once  a day.   I had acid reflux for 12 years and was prescribed PPI's.  which I refused to take. Ranitidine was prescribed as an option that I did use only as and when I had chest pain. They were prescribed for me to reduce the acid in my body.

This is difficult for me to deal with.  B complex is what stands between me and migraines.  Whenever I stop B for just a few days, I get a migraine.  All my adult life I would get a violent migraine for 3 days like clockwork until a doctor told me to try B complex and it worked.  The only time I get a migraine is when I've run out of B.  This has worked for me for over 15 years.  I am soon to be 79.   My cardiologist has me stop all vitamins for about 3 days and I always have a migraine when I go in for the bloodwork.   D level is nearly at optimal.  I don't take A, I get enough from food.   What a dilemma!

I think the best approach is to lean how to read product labels, especially the allergen warnings, and these lists might be helpful:      

It looks like you are referring to this product: https://shop.kingarthurbaking.com/items/gluten-free-bread-flour Their site says: "Made with gluten-free wheat starch to give baked goods incredible taste and texture, it’s ideal for classic yeasted recipes like artisan boules, bagels, cinnamon rolls, and burger buns", and it is true that Codex quality wheat starch is gluten-free, and does make better baked goods. However, it also contains very low levels of gluten (under 20ppm), and some celiacs do react to this level, so if you are super sensitive it's best to avoid it. They also make this very similar product, which doesn't include any wheat ingredient, and is certified gluten-free: https://shop.kingarthurbaking.com/items/gluten-free-bread-flour Although labeling products in the USA as "gluten-free" that contain such wheat starch is relatively new, it has been offered in Europe for decades. You can read more about studies on it here: https://www.celiac.com/celiac-disease/miscellaneous-information-on-celiac-disease/gluten-free-diet-celiac-disease-amp-codex-alimentarius-wheat-starch/