Editing Renal Transplant (section)

== Selection of kidney transplant donors ==

* '''Donors may be declared dead by neurologic (NDD) or''' cardiorespiratory criteria '''(donation after circulatory death,''' '''DCD)'''
** DCD typically occurs when a potential donor does not meet brain death criteria despite being comatose and ventilator dependent
* '''DCD kidneys'''
** '''Subject to varying lengths of warm ischemia time and are thus susceptible to delayed graft function.'''
** '''Long-term graft survival is comparable to that of an NDD kidney'''
* '''Extended criteria donors (ECD)'''
** '''Age ≥ 60 or'''
** '''Age 50 - 59 with ≥ 2 risk factors:'''
**# '''Death from a stroke'''
**# '''Hypertension'''
**# '''Elevated creatinine just before organ recovery'''
* '''Standard criteria donors (SCD)'''
** '''Age < 60 and do not meet any of the criteria for being an ECD'''
* '''ECD organs have a 2-year graft survival of 80% vs. 88% for an SCD organ'''
* '''ABO incompatibility'''
** '''ABO incompatible renal transplants have been achieved'''
*** If a kidney is transplanted between ABO-incompatible individuals, antibodies will bind to the non-inherited antigens expressed on endothelial cells, leading to activation of the complement cascade, coagulation, thrombosis, and rapid graft loss. However, if these antibodies have a low titer at the time of transplantation and production of antibody can be limited with immunosuppressive medications, then ABO incompatible renal transplants have been achieved
**** '''In ABO incompatablity, plasmapheresis and immunoadsorption are used to remove antibodies, while immunoglobulin administration and anti CD-20 antibody are used to prevent antibody reformation'''
** '''Paired exchange is another option'''
* '''Histocompatibility'''
** '''HLA class I genes are expressed by all nucleated cells. HLA class II genes are expressed by antigen-presenting cells (dendritic cells, monocytes, macrophages, and B-lymphocytes) and inflamed tissues, including endothelial cells.'''
*** Class I antigens are HLA-A, HLA-B, and HLA-C.
*** Class II antigens are HLA-DR, HLA-DQ, and HLA-DP
** '''A recipient with mismatched (unshared) HLA antigens in the donor is at risk for development of antibody and cellular rejection.'''
** '''HLA antibodies may be formed by the recipient before transplantation as a result of:'''
**# '''Pregnancies'''
**# '''Previous transplants'''
**# '''Blood transfusions'''
**# '''Possibly some infections'''
** '''Individuals with antibodies directed at 20% of the population are said to be sensitized; those with antibodies to 80% of the population are considered highly sensitized.'''
*** Sensitized transplant candidates, particularly those who are highly sensitized, may face extreme difficulty in finding a donor to whom they will have a negative crossmatch.
** '''The most sensitive test for finding donor-specific HLA antibodies is solid-phase single-antigen bead testing'''
* Crossmatch techniques
** The percentage of donors that cause a positive crossmatch is known as the panel-reactive antibody (PRA); a potential recipient with a PRA of 80% is likely to have a positive crossmatch with 80% of the donor population