Human Leukocyte Antigen‐Based Risk Stratification in Heart Transplant Recipients—Implications for Targeted Surveillance

Figures

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  Figure 1. A, The human leukocyte antigen (HLA) gene complex encoding the major histocompatibility complex (MHC), class I (A, B, and C) and class II (DP, DQ, and DR). B, The HLA nomenclature ( http://hla.alleles.org/nomenclature/naming.html). Each allele has a unique number, which consists of a sequence of 2 to 4 sets of digits separated by colons. All alleles receive at least a 4‐digit name. The letters/number defines the locus/gene, the first field the allele group, and the second field the specific HLA protein. C, A 3‐dimensional structure of an HLA‐DQ molecule in which the pink amino acids compose the DQ α‐chain, the blue amino acids compose the DQ β‐chain, and the brown amino acids represent the peptide stuck within the peptide binding groove. The specific eplet identified is highlighted in blue. The crystalline model was downloaded from the National Center for Biotechnology Information website http://www.ncbi.nlm.nih.gov/Structure using Cn3D software. HLA indicates human leukocyte antigen; MHC, major histocompatibility complex.

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  Figure 2. Histograms of the distribution of human leukocyte antigen epitope mismatch (mm). A, HLA‐A/B/C eplet mismatch. B, HLA‐DR/DQ eplet mismatch. The frequencies of total eplet mismatch are normally distributed with an average of 16.1±87.3 and 29.6±17.2, respectively. HLA indicates human leukocyte antigen.

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  Figure 3. Kaplan–Meier graft loss curves stratified by the number of HLA‐A/B/DR allele mismatch (mm). HLA indicates human leukocyte antigen.

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  Figure 4. Kaplan–Meier graft loss curves by the number of HLA allele and HLA eplet mismatch (mm) for recipients aged <60 years. A, Stratified by the number of HLA‐A/B/C allele mismatches. B, Stratified by the number of HLA‐A/B/C eplet mismatches. C, Stratified by the number of HLA‐DR/DQ allele mismatches. D, Stratified by the number of HLA‐DR/DQ eplet mismatches. HLA indicates human leukocyte antigen; mm, mismatch.