The U.S. Social Security Administration (SSA) administers the Social Security Disability Insurance program and the Supplemental Security Income program. As part of their process, immune system disorders are evaluated under Listing of Impairments 14.00 for adults and 114.00 for children. At the request of the SSA, the National Academies of Sciences, Engineering, and Medicine assembled a committee to review selected conditions related to the immune system. In particular, the SSA was interested in the current status of the diagnosis, treatment, and prognosis of immune system disorders including systemic lupus erythematosus (SLE), scleroderma, polymyositis, Sjögren's syndrome/disease, and inflammatory arthritis. This report provides an overview of the current status of the diagnosis, treatment, and prognosis of these immune system disorders in the U.S. population and the relative levels of functional limitation typically associated with them, common treatments, and other considerations.