Method for activating regulatory T cells agonist adrenergic receptor alpha 2B

An alpha 2B receptor for use in a method of treating dry eye disease, wherein the alpha-2 agonist is selected from the group consisting of: i) an imidazoline, wherein said imidazoline is a compound of the formula ** ** formula or a pharmaceutically acceptable salt thereof; and ii) an imidazole, wherein the imidazole is a compound selected from the group consisting of: ** ** Formula