In celiac disease, will antibody levels decrease and small intestine repair occur despite occasional, accidental exposure to gluten?

Usually does: Antibody levels are expected to increase after any gluten exposure.With time (months) they will gradually decline as would their effect on the gut, unless there are other exposures. The abortive surfaces of the gut renew even in non celiac cases faster than many other tissues. A continuous effort for all celiacs is to read all labels & be vigilant.