The invention relates to a method of treating or monitoring/diagnosing adisease state mediated by activated macrophages. The method comprises the stepof administering to a patient suffering from a macrophage mediated diseasestate an effective amount of a composition comprising a conjugate or complexof the general formula: Ab-X, where the group Ab comprises a ligand capable ofbinding to activated macrophages, and when the conjugate is being used fortreatment of the disease state, the group X comprises an immunogen, acytotoxin, or a compound capable of altering macrophage function, and when theconjugate is being used for monitoring/diagnosing the disease state, Xcomprises an imaging agent. The method is useful for treating a patientsuffering from a disease selected from the group consisting of rheumatoidarthritis, ulcerative colitis, Crohn's disease, inflammation, infections,osteomyelitis, atherosclerosis, organ transplant rejection, pulmonaryfibrosis, sarcoidosis, and systemic sclerosis.
