What characterizes acute rejection?

What characterizes acute rejection?

• A. Occurs 1 week to 6 months after transplant and is reversible with increased drug therapy.
• B. Occurs within minutes to 48 hours of surgery.
• C. Chronic inflammation and scarring that occurs over months or years.
• D. Graft attacks the host, recognizing host cells as foreign.

Answer: (A)

Acute rejection is a host immune response against donor antigens that develops after a transplant, typically over a period of about one week to several months. It is usually reversible with intensified immunosuppressive therapy, because the rejection is driven by T cells that can be suppressed or dampened if treatment is promptly adjusted. The process reflects sensitization to donor MHC antigens and a cellular-mediated attack on the graft, which can compromise function but is not an immediate, preformed antibody reaction. In contrast, a reaction occurring within minutes to hours after surgery is hyperacute rejection, caused by preformed antibodies that rapidly damage the graft. Chronic rejection develops over months to years and is characterized by progressive fibrosis and scarring, leading to gradual loss of graft function. Graft-versus-host disease occurs when donor immune cells attack the recipient’s tissues, a concern mainly with hematopoietic stem cell transplants rather than solid organ transplants.

Acute rejection is a host immune response against donor antigens that develops after a transplant, typically over a period of about one week to several months. It is usually reversible with intensified immunosuppressive therapy, because the rejection is driven by T cells that can be suppressed or dampened if treatment is promptly adjusted. The process reflects sensitization to donor MHC antigens and a cellular-mediated attack on the graft, which can compromise function but is not an immediate, preformed antibody reaction.

In contrast, a reaction occurring within minutes to hours after surgery is hyperacute rejection, caused by preformed antibodies that rapidly damage the graft. Chronic rejection develops over months to years and is characterized by progressive fibrosis and scarring, leading to gradual loss of graft function. Graft-versus-host disease occurs when donor immune cells attack the recipient’s tissues, a concern mainly with hematopoietic stem cell transplants rather than solid organ transplants.