Development of a novel ELISA for detection of anti-A and anti-B antibodies in recipients of ABO-incompatible living donor liver grafts

The survival rate in ABO-incompatible (ABO-I) liver transplantation was much lower than that in ABO-compatible recipients for the early experiences. It is therefore essential to develop the precise and fast measurement of anti-A and anti-B antibodies (Abs) to prevent humoral rejection in ABO-I liver transplantation. Agglutination titer has been the standard method to measure these Abs, but the interpretation of the results is subject to bias. Here, we have developed an objective and quantitative enzyme-linked immunosorbent assay (ELISA) to measure anti-A and anti-B Abs. This test requires only a small amount (10 microl) of recipient's serum. We applied the newly developed ELISA to monitor living donor liver transplant recipients and investigated the correlation between ELISA and agglutination titer. The Spearman's correlation coefficient for Abs ranged from 0.461 to 0.812. Moreover, in one case of humoral rejection, the increase of Abs was detected by ELISA one day earlier than by the agglutination titer. In conclusion, our ELISA method proved useful to detect an increase of anti-A and anti-B Abs titers at an early stage, thereby contributing to a prompt treatment of humoral rejection due to ABO-I.