Changes in IgG subclasses of donor specific anti-HLA antibodies following bortezomib-based therapy for antibody mediated rejection.

The predominant anti-HLA IgG subclass during antibody mediated rejection episodes is IgG1. Class I DSA IgG subclasses respond to single cycle of bortezomib-based therapy more frequently as compared to Class II DSA IgG subclasses. High titer Class II DSA IgG subclasses are less likely to respond to single cycle bortezomib-based therapy. Future studies are needed to determine if the response to bortezomib-based therapy is dependent on the type of DSA and/or the strength of the DSA at the time of antibody mediated rejection episode.