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Published on: August 22, 2019
[Experience on identification of cross-reactive group specificity performed by anti-human globulin panel reactive
Yong-Hak Sohn1, Choong-Hwan Cha, Myeong Hee Kim
1Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea.
Insights
Identifying human leukocyte antigen (HLA) antibody specificities using cross-reactive group (CREG) classification significantly improves detection rates. Both Rodey and Takemoto CREG classifications are effective for interpreting panel reactive antibody (PRA) results.
Area of Science:
- Immunogenetics
- Transplantation immunology
- Histocompatibility testing
Context:
- Panel reactive antibody (PRA) testing is crucial for screening and identifying human leukocyte antigen (HLA) antibodies in patients awaiting transplantation.
- High PRA levels are often associated with antibodies against cross-reactive groups (CREGs), necessitating accurate classification for effective antibody identification.
- Current methods for HLA antibody identification require refinement to improve specificity and detection rates, particularly in complex cases.
Purpose:
- To evaluate the advantage of identifying cross-reactive group (CREG) specificities in human leukocyte antigen (HLA) antibody screening.
- To determine if antibody specificities change based on different CREG classification systems (Rodey and Takemoto).
- To assess the impact of CREG classification on the accuracy and efficiency of panel reactive antibody (PRA) interpretation.
Summary:
- A study analyzed 159 sera from 108 patients with >5% PRA using anti-human globulin (AHG)-complement-dependent cytotoxicity (CDC) assays.
- A tail analysis-based computer program was developed to identify HLA class I antibody specificities, applying both Rodey (R-ABC) and Takemoto (T-ABC) CREG classifications, and compared to results without CREG application (ABC).
- CREG classification enhanced antibody identification rates, with higher detection frequencies in samples with PRA >50%. Specificity was missed in 9 cases without CREG application.
Impact:
- Application of CREG classification significantly enhanced the rate of HLA antibody identification, improving diagnostic yield.
- The study found that antibody specificities identified using Rodey or Takemoto CREG classifications were largely comparable at the individual antigen level.
- These findings suggest that either Rodey or Takemoto CREG classification can be effectively used for interpreting PRA, simplifying the process and improving clinical decision-making in transplantation.
Background:
Panel reactive antibody (PRA) is to screen and identify HLA antibody. Majority of antibody specificities in high-PRA are directed against cross reactive group (CREG). Thus, this study was to know the advantage of identifying CREG specificity and whether antibody specificities are changed according to CREG classification.
Methods:
HLA class I antibodies were identified from 159 sera from 108 patients in Asan Medical Center, who had shown more than 5% PRA by anti-human globulin (AHG)-complement-dependent cytotoxicity (CDC). Tail analysis-based computer program was developed to identify specificities, applying both Rodey (R-ABC) and Takemoto (T-ABC) classification. The results were also compared with those obtained when without CREG application (ABC).
Results:
Among 151 cases in which HLA specificities was identified, the frequency of CREG specificity was 22.5% in R-ABC and 27.2% in T-ABC. Eleven cases showed CREG specificities only in one classification. However, the individual antigen specificities in one hand were all included in the CREG identified in the other hand. CREG specificities in samples with PRA >50% (60%) were more frequently identified than those in samples with PRA < or =50% (9%) (in R-ABC, P<0.0001). Without applying CREG to interpretation, specificity was not identified in 9 cases.
Conclusions:
Application of CREG enhanced the rate of antibody identification. Antibody specificities of those cases where CREG specificities were different between Rodey and Takemoto classifications were almost the same when compared at the individual antigen level. Therefore, it was thought that it makes no difference to use any one of these two classifications in interpreting PRA.
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