Experience on Identification of Cross-Reactive Group Specificity Performed by Anti-human Globulin Panel Reactive Antibody Tests / 대한진단검사의학회지

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.

Establishment of an HLA-matched Platelet Donor Registry for the Management of Patients with Platelet Refractoriness / 대한수혈학회지

BACKGROUND: Heavily transfused patients commonly become refractory to platelet transfusion. Patients with platelet refractoriness due to HLA alloimmunization need HLA-matched platelet transfusion. We have established an hospital-based donor registry of HLA-typed platelet donors for the first time in Korea and evaluated the possibility of HLA-matched platelet supplies. METHODS: A total of 450 donors were registered and typed for HLA class I (A, B, C) antigens. A computer program was developed and used for the donor registry and HLA-matched donor search. A simulation study was performed on the availability of HLA-matched platelets for 100 patients from a pool of 450 donors. The availability of HLA-matched and cross reactive epitope group (CREG)-matched donors were analysed for HLA-A, B antigens. The CREGs defined by Fuller, Rodey, and UCLA criteria were used. RESLUTS: Among 100 patients, 63% had HLA-identical or HLA-matched (match grade: A, B1U, B2U) donors with only a low number of donors (mean 1.4) available per patient. Including CREG-matches (match grade: B1X, B2UX, B2X), majority (98%) of the patients had HLA- or CREG-matched (match grade: A~B2X) platelet donors with a higher number of donors (mean 26.6~40.5 by different CREG criteria) available per patient. Majority (86-98%) of the patients had 20 or more A~B4X matched donors, and about two thirds (61-74%) of the patients had 20 or more A~B2X matched donors. However, the number of ABO-identical matched donors was less than 30% of the total HLA- or CREG-matched donors. CONCLUSION: We established an HLA-matched platelet donor registry and using a donor pool size of < 500 donors, attainable in an hospital-based donor registry, the possibility of HLA-matched platelet supplies was confirmed in this study. However, for more satisfactory and ABO-matched platelet supplies a larger pool size is needed.