HLA‐E genotyping and its relevance in kidney transplantation outcome

HLA‐E, a class I nonclassical HLA molecule, is expressed in all tissues and is involved in the regulation of both innate (by interaction with the CD94/NKG2 receptor expressed mainly in NK cells) and adaptive immunity (by interaction with T CD8 + cells), suggesting a possible role in the solid organ transplantation context. Transplanted patients with chronic kidney disease and their respective donors (N = 107 pairs) were genotyped for exons 2 and 3 of the HLA‐E locus by sequence‐based typing (SBT). Groups' genotype frequencies were compared regarding episodes of clinical rejection by global G test, and binary logistic regression was made to demonstrate the contribution of genetic variables vs epidemiological variables. Comparisons of donors' genotype frequencies showed significant differences ( P = .0230), revealing a protective profile of E*01:01/*01:01 compared to the other genotypes ( P = .0099; OR = 0.3088; CI [95%] = 0.1333‐0.7157). The same happened when the aforementioned genotype was combined with the E*01:01/*01:01 recipients' genotype ( P = .0065; OR = 0.1760; CI [95%] = 0.0517‐0.5987). A binary logistic regression analysis was performed, and, of all variables considered, only two were included in the resulting model ( P = .007; R 2 Cox and Snell = 0.243; R 2 Nagelkerke = 0.328)— “End‐Stage Renal Disease” and “ HLA class II Mismatches.” A protective profile ( E*01:01/*01:01 ) was observed between the recipients and donors, suggesting a possible impact of the HLA‐E genotype in rejection episodes.