In addition to the above procedures, patients with a baseline CD4 lymphocyte count less than 100 cells per cubic millimeter of blood will be asked to undergo apheresis periodically to obtain the most accurate results for determining how long the NeoR gene persists in the blood. The procedure will be done weekly for the first 6 weeks after each infusion of cells, then at week 8, and then every 4 weeks until the gene can no longer be detected in the lymphocytes. The schedule may change, but will not require more frequent apheresis.