Final answer:
Infections, particularly CMV, are common in solid organ transplant patients due to immunosuppressive therapy. Graft-versus-host disease is a significant risk in bone marrow transplants. Success in transplantation relies heavily on matching MHC molecules and managing immunosuppression.
Step-by-step explanation:
Patients who undergo solid organ transplants are at a high risk of infectious complications, mainly due to the required immunosuppressive therapy to avoid transplant rejection. In the case of Cytomegalovirus (CMV) infections, approximately 60% of transplant recipients will contract the CMV infection, and over 20% develop symptomatic disease. This situation can be exacerbated with liver damage, transplant rejection, or even death. Furthermore, graft-versus-host disease (GVHD) is a severe complication predominantly observed in bone marrow transplant recipients, where donor immune cells attack the recipient's tissues.
Additionally, MHC (HLA) gene differences play a vital role in both solid organ and tissue transplantation. MHC molecules are a common cause of transplant rejection due to the variety of MHC proteins and alleles present among individuals, necessitating a close genetic match between donor and recipient to increase the chances of a successful transplant. Even with good genetic matching, immunosuppressive treatments are typically required to mitigate the immune response and prevent transplant rejection, but they also leave the patient vulnerable to infections and malignancies.
Lastly, strategies such as attempting to match MHC molecules between donor and recipient and the use of immunosuppressive drugs like cyclosporine A have improved transplant success rates despite the issues related to the polymorphic nature of MHC molecules.