So we can say that intestinal permeability means that the intestinal barrier is permeable and that the “door” between the intestines an bloodstream are open which makes the gluten, lectin and other undigested and partly digested proteins and toxins to go into the bloodstream. Our immune system recognizes those undigested proteins as foreign bodies which alarms the immune response.
So gluten cause production on zonulin, zonulin effects the intestines to become permeable and permeable intestines lead to autoimmune diseases.