Effects of Repeated Infusions of Adoptively Transferred Syngeneic Lymphocytes on the Immune Systems of HIV-1 Infected Identical Twins

This study will evaluate the safety and immune system effects of infusing HIV-infected patients with multiple doses of lymphocytes (white blood cells) from their non-infected identical twin. It will determine whether the donated lymphocytes can improve immune function and reduce viral load in the infected twin.

Identical twin pairs-one who is infected with HIV-1 and one who is negative for the virus-may be eligible for this study. Candidates will be screened with blood tests, a medical history and physical examination.

Both twin participants will receive a tetanus booster shot, if needed. The non-infected twin will undergo apheresis to collect white blood cells. For this procedure, whole blood is collected, similar to the procedure for donating a unit of blood from a needle in the arm. The blood flows through a cell separator machine where the white cells are removed, and the rest of the blood (red cells, plasma and platelets) is returned to the donor through a catheter in the opposite arm.

The collected lymphocytes will be given intravenously (through a vein) to the infected twin over a 60-minute period. This procedure-apheresis and infusions-will be repeated 4 days a week to complete one cycle. The cycles will be repeated about every 8 weeks for 6 cycles (about 1 year).

The infected twin will have blood samples drawn on the first day of each cycle, 2 weeks after the beginning of each cycle, and 4 weeks after each cycle to evaluate immune status, viral load and other safety parameters. The frequency of these blood tests may change as the study progresses. The infected twin will also undergo apheresis immediately before each cycle of infusions and one month later to test the white cells for certain immune features. The number of apheresis procedures may be reduced as the study proceeds.