Experience of HLA Antibody Testing in the International Serum Exchange Program

Park, Yoon June; Kim, Me Ae; Kim, Sun Mee; Park, Myoung Hee

Abstract

BACKGROUND: When organ transplantation or HLA-matched platelet transfusion is considered, accu-rate identification of HLA antibody specificity in the recipient's serum is very important. In this study, we report our experience in an international quality control program.
METHODS
For external quality control in a HLA antibody test, the International Serum Exchange Program distributes serum samples, generally showing polyspecific reactivity for cross-reactive epitope groups (CREGs), to participating laboratories: 4 samples per survey, 10 surveys per year. Participating in the program from May 1998 to August 2000 (24 surveys), we performed HLA antibody identification of 96 serum samples by the AHG-CDC (anti-human globulin-complement dependent cytotoxicity) method using frozen lymphocyte trays (36 lymphocyte panels). We compared the results of our laboratory with those of the total participants (all methods combined, 72 to 92 laboratories per survey) using the analyzed survey results distributed by the program organizer.
RESULTS
We analyzed the survey results for the antibodies to relatively common HLA antigens in Koreans (antigen frequency >1%). For the HLA antibodies detected in >or=20% of participants, our detection rate was higher by 10-15% than that of all laboratories (HLA-A, 76% vs 65%; HLA-B, 73% vs 57%). And for the HLA antibodies detected in >or=50% of the participants, our detection rate was as high as 88% for HLA-A and 87% for HLA-B. Our detection rate for a few antibody specificities was lower than that of all laboratories, namely HLA-A1, A3, B35, and B55. Among these, A1, A3, and B55 were of lower incidence antigens in Koreans (antigen frequency 3-4%), indicating that the low detection rate was due to a limitation in the composition of lymphocyte panels.
CONCLUSIONS
In general, our detection rate of HLA antibodies was superior to the average detection rate of the total participant laboratories. We would be able to improve the low detection rate for a few antibody specificities to lower incidence antigens by refining the composition of lymphocyte panels.