A Short History of B-Cell HLA Epitopes

Abstract

<b><i>Background:</i></b> HLA epitopes are currently in the focus of transplantation immunogenetics. The main reason is the complexity of the HLA system with >38,000 alleles, the number of which increases steadily. These alleles are determined by the current state-of-the art typing methods like second- and third-generation sequencing. Screening for HLA antibodies is hampered by the lack of specific target beads with all possible alleles described. <b><i>Summary:</i></b> A way to circumvent the problem is to define HLA epitopes. The number of antibody-confirmed epitopes, on the other hand, was found to be 72 for HLA class I and 74 for HLA class II. Here, we elaborate on the current knowledge on these HLA epitopes. Absolute definitions of these structures are not yet available. <b><i>Key Messages:</i></b> Making use of eplets is a comparable way allowing statistical analyses. However, one should keep in mind that the results obtained are approximative or perhaps better associative. Continuous collaboration is needed for the full understanding of the HLA epitopes. The reactivity toward epitopes remains patient-specific.

HLA in Transplantation: Challenges and Perspectives

“…It is well known that in the long term following transplantation the indirect allorecognition pathway may lead to the activation of B lymphocytes and formation of HLA antibodies. Doxiadis et al [3] summarize in their review our past and current knowledge of the immunogenic basis of the HLA molecule, i.e., epitopes. In the beginning, HLA antigens have been revealed by the reaction of antibodies isolated from the serum of pregnant women.…”