Since the actual cause is not yet known (though it may be speculated) approved treatments seek to deal with the effects. That is, inflammation arising from the immune response.
Medications are used to minimize the response, and therefore the damage done. Unfortunately their are few meds that do this locally rather than body-wide. Entocort is one of the localized meds that doesn't universally suppress the immune system. However there is a newer Biologic (Vedolizumab) which targets immune response inside the intestinal tract only!
LDN is considered an immune regulator, however that regulation is downward for inflammatory bowel disease. Nonetheless the aim is to bring the immune system into normal range.
So if the meds are used properly they will not overly suppress the system, simply bring it back to balance.
Massage, acupuncture, and other soothing techniques also work to down-regulate the immune response without over suppression.