News from Mayo Clinic Print 2025Mayo Clinic researchers discover the immune system's 'fountain of youth' Aug. 14, 2025, 04:00 p.m. CDT Request an appointment Costs & insuranceReferrals April 01, 2020 Share on: FacebookTwitter SectionsRequest an AppointmentOverviewTests & proceduresConditions treatedDoctorsSpecialty groupsExpertise & rankingsClinical trialsResearchPatient storiesCosts & insuranceNews from Mayo ClinicReferrals ORG-20476802 Medical Departments & Centers Rheumatology