Chimerism and Immunocompetence

Transplantation

Although, chimerism appears to have its disadvantages, researchers have also been able to conduct experiments in which mixed chimerism may improve transplant tolerance, immunocompetence, and reduced susceptibility to graft-versus-host disease (rejection of donated tissue).  In case study involving rodents, researchers were able to achieve mixed chimerism by conditioning the recipient rodent.  Conditioning the rodent consists of injecting the rodent with antibodies to rid the rodent of T-cells.  Next the rodent is injected with stem cells of the donor or bone marrow of the donor.  The donor cells and recipient cells continue to regenerate cells achieving mixed chimerism.  When transplants were performed on the rodents turned chimera, the incidence of graft-versus-host disease decreased dramatically and immunocompetence was improved. 

Researchers are also trying to use mixed chimerism as a cure for diabetes.  If Islets, which overcome insulin requirements, could be successfully transplanted into the diabetic individual, then they could potentially be cured of diabetes.  In another case study, rodents with diabetes were conditioned as previously explained.  After the diabetic rodents achieved mixed chimerism, the rodents received islet transplantations.  The rodents were observed for the next several weeks following the transplantation.  Once again, the rodents showed signs of improved immunocompetence, risk of rejection decreased, and were cured of diabetes.

Although the results yielded from these experiments provide a promising look into the future of transplantation , researchers have not been able to reproduce the results in larger animals.