Participants will have a complete medical evaluation including laboratory studies. Consultations, X-rays and biopsies of affected organs may also be done if indicated for diagnosis or treatment. Patients with active disease will be given MPM and prednisone, both in tablet form. Patients with inactive disease will receive only prednisone if they are already taking it. In both cases, the prednisone will be reduced gradually and discontinued if the disease improves significantly. MPM therapy will continue for at least 2 years. If after 2 years the disease remains in remission, the MPM dose will be gradually reduced and then stopped. If active disease recurs while on MPM therapy, the treatment plan will likely be changed. The new regimen will be determined by the severity of disease, other medical conditions, and history of side effects to previous medications.