Figure 3. Protocol for the first gene transfer to human joints.

Surgery of the joints of the hand or foot (step 1) provided autologous synovium, which was used to establish cultures of synovial fibroblasts (step 2). Half the cells were transduced with the retroviral vector (step 3), and all cells were tested for replication competent retrovirus and adventitious agents (step 4) before injection into MCP joints numbers 2–5 on one hand (step 5). In a double-blinded fashion, two joints received transduced cells, and two received control cells. One week later, the injected joints were surgically removed during total joint replacement surgery (step 6), and the retrieved tissues were analyzed for evidence of successful gene transfer and gene expression (step 7).

From reference 23 with permission.