“Immunotherapy” is a process of prevention or treatment of a disease (such as an allergy, autoimmune disorder, or cancer) that involves signaling and modifying the immune system via mechanisms such as suppression, desensitization, stimulation, enhancement, down-regulation, and others.

For allergen immunotherapy, desensitizing and/or true tolerance-building effects (these are different) can occur in the short term due to early immune system modifications actively being directed by the sublingual immunotherapy signaling process.

Desensitization can be maintained in the long term by maintaining continued controlled allergen exposure (essentially continuing a form of immunotherapy indefinitely) such that the desensitized state is not allowed to come undone.

True tolerance can sometimes persist in the long term, often for a number of years after immunotherapy has been discontinued. This is due to more permanent immune system modifications that became established after having been maintained in a state of tolerance-promotion from immunotherapy for a long period of time. If tolerance begins to wane off of immunotherapy, it can be restarted for another (typically quicker) round to help re-modify the immune system, or it can be continued indefinitely to also maintain a desensitized state.