Faculty Bibliography

Incompatibility between the candidate recipient and the prospective donor is a major obstacle to living donor kidney transplant. Kidney paired donation (KPD) can circumvent the incompatibility by matching them to another candidate and living donor for an exchange of transplants such that both transplants are compatible. KPD has faced legal, logistical, and ethical challenges since its inception in the 1980s. Although the full potential of this modality for facilitating transplant for individuals with incompatible donors is unrealized, great strides have been made. In this review article, we detail how several impediments to KPD have been overcome to the benefit of ever greater numbers of patients. Limitations and questions that have been addressed include blood group type O imbalance, reciprocal match requirements, simultaneous donor nephrectomy requirements, combining KPD with desensitization, the role of list-paired donation, geographic barriers, legal barriers, concerns regarding living donor safety, fragmented registries, and inefficient matching algorithms.

BACKGROUND: The crisis in organ availability has triggered innovative approaches to meet a rapidly expanding worldwide demand for donor kidneys. HLA and ABO incompatibility represents one of the most significant barriers to optimizing the utilization of living donors. Kidney paired donation (KPD) allows patients with incompatible live donors to receive compatible or better-matched organs by exchanging donors. SOURCES OF DATA: The data presented in this review have been published and represent the most up-to-date sources of the theory and practice of KPD. AREAS OF AGREEMENT: There is wide agreement that in most cases the best transplant solution for a patient with an incompatible donor is to receive a compatible organ in a KPD. AREAS OF CONTROVERSY: There has been disagreement about the capacity of KPD to solve the incompatibility problem. However, it is now clear that not all phenotypes will benefit from KPD. GROWING POINTS: Combining KPD with desensitization greatly expands the boundaries of each of these modalities.

The humoral arm of the immune system provides robust protection against extracellular pathogens via the production of antibody molecules that neutralize or facilitate the destruction of microorganisms. However, the humoral immune system also provides a significant barrier to solid organ transplantation due to the antibody-mediated recognition of non-self proteins and carbohydrates expressed on transplanted organs. Historically, the presence of donor-specific antibodies (DSA) that recognize donor HLA molecules, incompatible ABO blood group antigens and other endothelial or xenogeneic antigens was considered a contraindication to transplantation. However, recent advances in antibody testing and immunosuppressive therapies have made it possible to cross certain antibody barriers successfully. In this article, we review our current understanding of antibody-mediated processes in solid organ transplantation and discuss the clinically available treatment options for preventing and treating antibody-mediated rejection.

The OPTN classifies high infectious risk donors (HRDs) based on criteria originally intended to identify people at risk for HIV infection. These donors are sometimes referred to as 'CDC high risk donors' in reference to the CDC-published guidelines adopted by the OPTN. However, these guidelines are also being used to identify deceased donors at increased risk of window period (WP) hepatitis C virus (HCV) infection, although not designed for this purpose. The actual risk of WP HCV infection in HRDs is unknown. We performed a systematic review of 3476 abstracts and identified 37 eligible estimates of HCV incidence in HRD populations in the United States/Canada. Pooled HCV incidence was derived and used to estimate the risk of WP infection for each HRD category. Risks ranged from 0.26 to 300.6 per 10,000 donors based on WP for ELISA and 0.027 to 32.4 based on nucleic acid testing (NAT). Injection drug users were at highest risk (32.4 per 10,000 donors by NAT WP), followed by commercial sex workers and donors exhibiting high risk sexual behavior (12.3 per 10,000), men who have sex with men (3.5 per 10,000), incarcerated donors (0.8 per 10,000), donors exposed to HIV infected blood (0.4 per 10,000) and hemophiliacs (0.027 per 10,000). NAT reduced WP risk by approximately 10-fold in each category.

OBJECTIVE: On November 13, 2007, the first reported case in 20 years of HIV (human immunodeficiency virus) transmission from a Centers for Disease Control and Prevention high-risk donor (HRD) made national headlines. We sought to characterize change in the practice of transplant surgeons resulting from this rare event. DESIGN: We performed a survey between January 17, 2008, and April 15, 2008, assessing attitudes and practices of transplant surgeons regarding HRDs. Descriptions of changes in practice after the event were categorized, and associations between responses and regional-, center-, and physician-level factors were studied. SETTING: Transplant centers in the United States. PARTICIPANTS: Four hundred twenty-two transplant surgeons in current practice. MAIN OUTCOME MEASURE: Changing practice following the 2007 HIV transmission event. RESULTS: Among surgeons who responded to the survey, 31.6% changed their practice following the event. Also, 41.7% decreased use of HRDs, 34.5% increased emphasis on informed consent, 16.7% increased use of nucleic acid testing, and 6.0% implemented a formal policy. Ranking fear of being sued or hospital pressure as important disincentives to HRD use was associated with more than 2-fold higher odds of changing practice. Ranking medical risks of HIV as an important disincentive was associated with 8.29-fold higher odds of decreasing HRD use. CONCLUSION: The most common responses to this rare event were avoidance (decreased HRD use) and assurance (increased emphasis on informed consent) behaviors rather than patient safety measures (increased use of nucleic acid testing and implementation of formal policies), suggesting that fear of legal or regulatory consequences was the biggest driver of physician decision making and that the current litigious environment is failing to protect patient interests.