Donor-recipient HLA matching aims primarily to reduce which adverse outcome?

• A. Infections
• B. Cancer recurrence
• C. Graft rejection
• D. Autoimmune disease development

Answer: (C)

HLA matching reduces the recipient’s alloimmune response to the transplanted tissue. HLA molecules are the primary signals the immune system uses to tell self from non-self. When donor and recipient HLA antigens don’t align well, T cells (and antibodies) recognize the graft as foreign and launch attacks that lead to acute rejection and, over time, chronic rejection. By improving HLA compatibility, the likelihood and strength of that immune attack are diminished, helping the graft survive longer and function better. Infections, cancer recurrence, and autoimmune disease development are influenced by other factors such as immunosuppressive therapy and broader immune regulation, so they’re not the primary focus of HLA matching.