Rafael Melo Santos de Serpa Brandão, Adalberto Socorro da Silva, Luís Gustavo Modelli de Andrade, Luiz Claudio Demes da Mata Sousa, João Marcelo Medeiros de Andrade, Frederico Castelo Branco Cavalcanti, Glauco Henrique Willcox, Samuel de Alencar Cavalcante, Ruy de Lima Cavalcanti Neto, Amaro Medeiros de Andrade, Alexandre de Holanda Cavalcanti Pinto, Diogo Buarque Cordeiro Cabral, Tatiana Cristina Manzi Sena Dos Santos, Isa Maria Teixeira Leão, Elizabeth Lima Guimarães, Bruno de Melo Correa, André Bezerra Pereira do Rego, Semiramis Jamil Hadad do Monte
Highly sensitized kidney transplant candidates face major barriers to transplantation because broad anti-HLA antibody reactivity substantially limits donor compatibility. We conducted a retrospective cohort study comparing two allocation eras in Pernambuco, Brazil: a pre-EpViX era (2005-2014; n=3,136) and an EpViX era (2016-2025; n=4,544). We evaluated the association between an epitope-informed definition of unacceptable antigens integrated with virtual crossmatching and access to deceased-donor kidney transplantation. The proportion of candidates who underwent transplantation was higher during the EpViX era (50%) than during the pre-EpViX era (36%) (p<0.001), while median waiting time among transplanted recipients decreased from 22 to 7 months (p<0.001). Among highly sensitized candidates (cPRA ≥80%), the estimated probability of transplantation at 12 months was 17% in the EpViX era compared with 3% in the pre-EpViX era. In adjusted analyses, listing during the EpViX era was associated with a higher likelihood of transplantation (HR 2.55; 95% CI 2.37-2.74; p<0.001). Epitope-level virtual crossmatch demonstrated high concordance with prospective complement-dependent cytotoxicity crossmatch, with sensitivity of 98.7%, specificity of 93.4%, and a negative predictive value of 99.6%. An allocation strategy incorporating an epitope-informed definition of unacceptable antigens was associated with greater access to deceased-donor kidney transplantation, including among highly sensitized candidates, while maintaining high concordance with prospective crossmatch testing.