A method of treating inflammation, by administering an effective amount of a &bgr;2 integrin agonist to a patient, and reducing inflammation. A method of treating cancer, by administering an effective amount of a &bgr;2 integrin agonist to a patient, and reducing tumor growth. A method of treating a patient exposed to radiation, by administering an effective amount of a &bgr;2 integrin agonist to the patient after radiation exposure, and mitigating the effects of radiation exposure in the patient. A method of preventing effects of radiation, by administering an effective amount of a &bgr;2 integrin agonist to the patient prior to radiation exposure, and preventing the effects of radiation exposure on the patient. A method of treating acquired bone marrow failure (BMF), by administering an effective amount of a &bgr;2 integrin agonist to a patient. Methods of improving the health of damaged vasculature in a patient and activating &bgr;2 integrins.