CTLA4

Background: \- The immune system helps the body fight infection and disease. People with immune system problems can get infections, blood disorders, and other health problems. Researchers want to learn more about the immune system, like what causes it to not work properly. Objectives: \- To evaluate people with certain types of immune system disorders. Eligibility: \- Adults and children with an immune disorder or symptoms of one, and their relatives. Some disorders are not included in this study. Design: * Researchers will review participants medical records. * Participants may mail in a blood or saliva sample, or be evaluated at the clinic. At the clinic, they may have a medical history, physical exam, blood tests, and imaging scans (with dye given through a needle in the arm). They may have genetic testing done on a sample of blood, saliva, hair, or nail clipping. * Participants may choose to have a skin biopsy. Up to 2 skin samples will be taken from their arm, back, or other area. A biopsy punch is inserted into the skin and rotated. A small circle of skin is removed. * Participants 10 and older may also choose to have leukapheresis. Blood is taken through a needle in o