Concerns about human hand transplantation in the 21st century.

The decision to perform a human hand transplant was justified perhaps on less than an ideal scientific basis-only approximately 60 rat limb transplants and 2 primate limb transplants have survived for longer than 200 days and only 8 of 19 pig limb osteomyocutaneous transplants showed no signs of rejection at 90 days. It seems unlikely that the survival of a human hand transplant will be any better than the survival of a kidney transplant, which has a half-life of approximately 7.5 to 9.5 years. Fourteen hand transplants, however, have now been performed in 11 humans with the skin component of 1 remaining viable up to 3 years after surgery. Intermittent episodes of acute rejection seem to have been relatively simple to reverse by temporarily increasing the dose of immunosuppressive agents and steroids. Chronic rejection has occurred in 1 patient, necessitating re-amputation of the transplanted hand. Active range of motion of the digits has been surprisingly better than would have been expected based on previous results of replantation, but return of sensibility has been less than optimal. The immunosuppression has been well tolerated without any major medical problems or life-threatening episodes, but some patients have developed chronic viral and fungal infections and several have developed posttransplant diabetes. Extrapolating from the previous experience of solid-organ transplants, chronic immunosuppression may predispose a hand transplant patient to an 80% chance of developing an infection, a 20% potential risk of developing posttransplant diabetes, and a 4% to 18% potential risk of developing a malignancy. Even though there is universal agreement that composite tissue allograft transplantation will become the ultimate reconstructive option, no one can predict the eventual role of hand transplantation in the future, but perhaps an international database of these hand transplant patients should be established so that independent reviewers can more objectively evaluate their functional outcome, the incidence of chronic rejection, and the risks of long-term immunosuppression.