Dear Editors, The number of kidney transplants (KT) performed annually in Brazil is less than half of the estimated necessity, leading to a waitlist containing over 26 thousand patients [1]. A recent Brazilian analysis showed that highly sensitized patients (panel-reactive antibody (PRA)> 80%) make up 7.6% of the waitlist. They have only a 19% chance to receive a transplant after 10 years (vs. 44% chance for patients with PRA 0%) and 20% higher mortality rates [2].

Living donor kidney transplant (LDKT) represents about 20% of the total KT per year in Brazil [1]. Unfortunately, up to 35% of the willing donors will not donate for immunological reasons–ABO incompatibility (ABOi) or positive crossmatch (CDC+)[3]. Desensitization protocols have been developed to overcome incompatibilities, but they are expensive and limited to specialized programs [4]. Besides that, these techniques may be associated with higher patient morbidity and inferior long-term outcomes [4, 5]. Kidney paired donation (KPD) represents a strategy for increasing the number of LDKT, offering an incompatible donor/recipient pair, the chance to exchange with another pair in the same situation [4]. In Brazil, KPD is still prohibited by law. We designed a study to show mathematically how KPD could increase LDKT in a single center in Brazil.