Interinstitutional variation in the measurement of anti-A/B antibodies: The Japanese ABO-Incompatible Transplantation Committee survey

Exact measurement of antiblood groups A and B antibody (Ab) titers is critical for successful ABO-incompatible living kidney transplantation (ABO-ILKT). However, no standard method for quantitative determination has yet been established. In most institutions performing ABO-ILKT, serial-doubling dilution of serum using a tube technique (TT) is a standard method for determining anti-ABO Ab titers, but there are very large interinstitutional variations in the titration of anti-ABO Abs using the TT. The Japanese ABO-Incompatible Transplantation Committee has conducted a national survey to measure anti-ABO Ab titers among more than 30 Japanese institutions. Interinstitutional differences between maximum and minimum values were as large as 32-fold in immunoglobulin M (IgM) and 256-fold in immunoglobulin G (IgG). There seem to be many detailed technical differences in the TT among the institutions. Consequently, in the present study we tried to find the most reliable technique for measuring anti-ABO Ab titers. We compared four different techniques, the TT, BioVue Column Agglutination Technology, DiaMed-ID Micro Typing System, and flow cytometry (FCM). Theoretically, FCM seems to be the most reliable technique because it does not require a great number of agents, each of which may affect the results. The FCM technique yielded a very consistent outcome in repeated measurements and it is one of the most objective techniques because measured data are automatically analyzed by a computer system. In our experience, FCM shows very good reproducibility and seems to be the best technique for titration since it can be performed without use of agents.