Rapid quantitation of immunoglobulin G antibodies specific for blood group antigens A and B by surface plasmon resonance

BACKGROUND: The measurement of immunoglobulin (Ig) G blood group A/B anti body(anti-A/B) levels is important for ABO-unmatched organ recipients because the effective removal of the antibodies improves their prognosis. Currently existing methods to detect IgG anti-A/B suffer limitations owing to high costs, low throughput, and poor adaptability to automation. STUDY DESIGN AND METHODS: We have developed a rapid means to quantitate IgG anti-A/B by surface plasmon resonance (SPIR). To investigate the accuracy, a serially diluted plasma sample from a donor was measured with the SPR method. Moreover, IgG anti-A/B titers in 45 healthy volunteers were measured both by the SPR and by the standard tube test (TT) method, as were plasma samples from two ABO-unmatched organ recipients. RESULTS: The change in titers when the same plasma was diluted was precisely reflected by the SPR method. The coefficients of correlation between SPR and TT methods for IgG anti-A and anti-B were 0.85 and 0.56, respectively. The SPR values also paralleled the TT values, which showed a decline in titers after the removal of antibodies by double-filtration plasmapheresis or plasma exchange. CONCLUSION: This SPR method can be used to measure IgG anti-A/B titers in the plasma very quickly and quantitatively.