HLA Class I Typing for Umbilical Cord Blood

Yang, Yoon Sun; Kim, Dae Won

Abstract

BACKGROUND
Accurate HLA typing is important for umbilical cord blood (UCB) transplantation as well as bone marrow transplantation. However, HLA class I typing by standard microcytotoxicity method has been often unsatisfactory for UCB samples. This study was conducted to investigate the characteristics of cytotoxic reaction in HLA class I microlymphocytotoxicity testing for UCB.
METHODS
We compared the strength index (SI) and the frequencies of HLA antigens with weak reaction between 87 UCB and 103 adult peripheral blood samples by analysis of reaction score in microlymphocytotoxicity typing using Terasaki Oriental HLA-ABC (72) Well Tray (One Lambda, USA).
RESULTS
The mean SI of UCB samples in HLA class I typing was significantly lower than that of adult blood (78.5% vs. 96.8%). The SI of 100% among UCB and adult blood samples were 24.1% and 71.8%, respectively. Among HLA-A, B, C antigens, those showing significantly high frequencies of weak reaction in UCB were HLA-A31, B48, B51, B59, B61, Cw3 and Cw7. Cytotoxic reactions of Bw4 and Bw6 in UCB were significantly weaker than those in adult blood.
CONCLUSIONS
The strategy of using a supplementary DNA typing method in selected cases with doubtful or unreliable results in serological typing would be effective for an accurate HLA class I typing of UCB samples.