The Gemini Study: Study of the Long-Term Safety and Persistence of Cells Following Cell Transfers or Gene Therapy in Identical Twins Discordant for HIV Infection

This study will consolidate under one umbrella protocol all NIH studies of the safety and survival of gene-modified lymphocytes in HIV-infected twins. The major purposes of the current study are to:

• place subjects from the various identical twin cell transfer/gene therapy studies on a single, more uniform schedule of visits;
• examine the long-term safety of apheresis procedures in non-HIV-infected lymphocyte donor twins;
• examine the long-term safety of lymphocytes in HIV-infected lymphocyte recipient twins.

Identical twins enrolled in NIH protocols 93-I-0110, 94-I-0206, 96-HG-0051, and 97-I-0165 involving the transfer of lymphocytes for the treatment of HIV infection are eligible to continue their research participation under the current protocol, 02-I-0080.

Participants will not undergo any additional research procedures in this study. They will continue to take their antiretroviral therapy and will be followed at least once a year, or more often if medically indicated, with a medical history, physical examination and blood tests for routine studies and to determine the number of lymphocytes in the blood. Recipient twins will also have blood levels of gene-modified lymphocytes checked.

Recipient twins will have some blood stored for RCR (replication competent retrovirus) testing, should it become necessary. A special virus was used to insert genes into the donated lymphocytes and, although the virus was rendered incapable of growing in the body, a theoretical risk exists that the virus could mix with other viruses and possibly begin growing or reproducing. If a participant subsequently develops medical problems, the stored blood samples can be checked for RCR to see if it may be a cause of the problem.