Rituximab for Anti-cytokine Autoantibody-Associated Diseases

Background: * Healthy people have white blood cells that protect them against bacteria, viruses, and fungi. However, some people have diseases which cause the body to make white blood cells that do not work properly. These white blood cells can attack the body s own proteins. These types of diseases are called anti-cytokine autoantibody-associated diseases. They can cause severe illnesses and even death. They are also difficult to treat with standard drugs. * Rituximab is a drug used to treat rheumatoid arthritis. It attacks white blood cells that do not work properly. Currently, it is not approved for treating anti-cytokine autoantibody-associated diseases. However, researchers think that it may be able to help treat people with these immune diseases. Objectives: \- To see if rituximab is a safe and effective treatment for anti-cytokine autoantibody-associated diseases. Eligibility: * Individuals at least 18 years of age who have anti-cytokine autoantibody-associated diseases. * Participants must also be enrolled in a related immune disorder study at the National Institutes of Health. Design: * The study will last 24 months. Participants will take rituximab for 6 months and have follow-up visits for the remaining 18 months. * Participants will be screened with a physical exam and medical history. Blood and urine samples will be collected. Other samples will be collected as needed if participants currently have an infection. * Participants will enter the hospital for 1 week at the start of treatment. They will have four doses of rituximab given 2 days apart. This first treatment will be monitored with frequent blood tests. * Over the next 6 months, participants will have four more doses of rituximab given about 1 month apart. Treatment will be monitored with frequent blood tests and sample collections as needed. * There will be four follow-up study visits at 3, 6, 12, and 18 months after the last dose of rituximab.