Normal volunteers undergo a physical examination and provide blood, saliva, and urine samples for immune function studies. Patients' family members provide a medical history, have a physical examination, and give blood and urine samples, and possibly a saliva sample. The samples are used for genetic and routine laboratory studies. Investigators may request tissue samples, such as biopsy specimens, previously removed for medical reasons to be sent to NIH for study. Patients undergo the following tests and procedures: