Chapter 19: Solid Organ Transplantation
JP is a kidney transplant patient whose biopsy showed cellular rejection. Select the statement that most accurately describes mechanism of JP’s rejection.
a. An orchestrated immune response that involves alloantigen presentation via antigen-presenting cells (APCs) which then leads to alloreactive T lymphocytes.
b. A cytotoxic immune response mediated via preformed antibodies against antigens present on vascular endothelium.
c. A slow process of graft fibrosis and arteriopathy, which results in graft dysfunction.
d. A process which inhibits the entire process of immune activation, including antigen presentation by APCs, the release of cytokines such as IL-1, IL-2, IL-6, and TNF α, and subsequently lymphocyte proliferation.
Answer a is correct. This is a description of acute cellular rejection (ACR). ACR requires the production of alloreactive T cells via T-cell binding at the T-cell receptors on APCs, with subsequent cytokine release and immune activation.
Answer b is incorrect. Antibody-mediated rejection typically occurs hours to days after transplant if donor-specific antibodies are present at the time of transplant. This type of rejection most frequently results from mismatched blood types and positive crossmatches, and the incidence has decreased with the advent of screening.
Answer c is incorrect. This is a description of chronic rejection. The etiology of chronic rejection is not known and there is no treatment for this condition. However, ACR has been shown to be a primary risk factor for the development of chronic rejection, thus prevention is a key modifier.
Answer d is incorrect. This is a description of the ubiquitous immunosuppressive action that steroids have on immune response.
SK is a 16-year-old boy who is waiting for kidney transplantation. He states that he has been doing research on the Internet and heard that acute cellular rejection (ACR) is a major complication of kidney transplantation. What can a pharmacist counsel him regarding the time frame for risk of ACR after transplant?
a. The risk is greatest during the first hours to days after transplantation.
b. The risk is greatest during the first several months after transplantation.
c. The risk increases with increased time from transplant.
d. The risk is the same regardless of time after transplant.
Answer b is correct. The time period of greatest risk for ACR is during the first 6 months after transplantation, with risk dropping precipitously after 1 year.
Answer a is incorrect. This time period describes the time of greatest risk for antibody-mediated rejection.