Severe combined immunodeficiency (SCID) is also known as Alymphocytosis. SCID is a genetic disorder of the B and T
cells in the adaptive immune system. These are the cells in the immune system that identify and destroy foreign materials such as pathogens and viruses that would cause the body harm. This happens due to a genetic defect in one of several possible genes. SCID is a hereditary disorder; it is possible to inherit it from ones parents. Patients with SCID must exist in extremely sterile environments, as contact with day-to-day germs, bacteria, and viruses could present lethal, life ending encounters. Common symptoms are chronic diarrhea, ear infections, and pneumonia. Genetic therapy as a solution to the problem has had mixed success. Since 1999, there have been seventeen cases where immune systems have been successfully started due to gene therapy. As with all cures, gene therapy is in its early stages. The manipulation and replacement of the damaged genes would stop the impairing of the B and T cells in the immune system, allowing them to do the job they were intended to do.