Japanese Society for Histocompatibility and Immunogenetics (JSHI) has a certification system for HLA technologist and Director for Histocompatibility testing, in which ability and knowledge about the Histocompatibility and Immunogenetics is required. To evaluate the ability and knowledge, a paper examination is obliged. Here I will comment on several questions of which percentage of correct answer was below 40% in the last year 2018.

Fluorescent bead-based methods have been the main techniques in HLA antibody testing in recent years, and are used in many transplantation and transfusion medical facilities. When measuring HLA antibodies using fluorescent bead-based methods, assessments are made with the normalized mean fluorescence intensity (nMFI) values of anti-human immunoglobulin G (IgG) as an indicator. Thus, these methods have been adopted due to their great convenience for clinicians. However, as progress is being made in the characteristics of fluorescent bead reagents and verification of clinical assessments, an increasing number of reports are questioning whether these methods accurately reflect patients’ conditions. HLA antibodies exhibit complex specificity with multiple epitopes and there is intermingling of various properties, such as IgG, immunoglobulin M, and complement binding. To establish proper criteria for judgments and to interpret the results appropriately, it is important to: (1) properly understand the characteristics of the reagent, (2) arrive at an evaluation suited to the treatment the patient is receiving, and (3) properly control the test accuracy. In this article, we present examples of methods to establish judgment criteria (cutoff values) and examine their validity. Validity was seen with the screening reagents. In contrast, confirmation tests using single beads revealed difficulties in terms of establishing specific nMFI values for the cutoff because of the relationship with epitope analysis. In interpreting the results, we explain the clinical importance from the perspectives of comparison between the cross-reactivity group and epitope analysis, HLA antibody diversity, and HLA antibody properties. We discuss HLA antibody testing with regard to the judgment criteria and interpretation of the results, and hope this will provide insight for future efforts.

Umbilical cord blood (UCB) transplantation, launched without waiting for 20 years after the establishment of current method for allogeneic bone marrow transplantation (allo-BMT), has been increasingly and widely accepted as a new strategy for hematopoietic stem cell transplantation (HSCT) on the grounds that HSC in UCB have extensive proliferation capacity, that a donor UCB can be used even if it has 2-loci HLA incompatibility to the recipient, and that cryopreserved and readily qualified UCB can be shipped immediately after order. On the other hand, clinical utility of UCB has been verified, not only for HSCT, but also in the field of cell therapy against various diseases in many countries including recent Japan.

Genotyping methods for non-human MHC by using next generation sequencing (NGS) require different approaches from the HLA genotyping, because the structure of non-human MHC genes is quite different from the human MHC and lack of sufficient reference information. In this review, we will introduce representative NGS-based MHC genotyping methods for non-human species, focusing on data analyses of sequence data obtained for non-human MHC.