2013 annual literature review of donor-specific HLA antibodies after organ transplantation.

1. There is still a need to better differentiate clinically relevant from irrelevant DSA in all organs. Modified bead assay testing for different immunoglobulin (Ig) G characteristics (Clq-fixing DSA, C4d-fixing DSA, IgG subclasses, or IgM) often improve the predictive value for rejection and failure compared to standard IgG DSA. A new approach looking for intragraft DSA instead of serum DSA represents a very interesting attempt. The relevance of DSA may not solely be determined by antibody characteristics, but may be in the capacity of an antibody to bind specific antigens on the allograft. If not all circulating DSAs are able to bind the allograft, intrinsic protective mechanisms will have to be investigated. 2. Modern tests that include multi-gene microarrays are now more commonly used and generate an enormous amount of information that can help support conventional diagnostic methods. In kidney transplantation, the discovery of a set of genes and the subsequent development of an ABMR score strongly associated with antibody-mediated rejection (AMR) is not only being used to better define this type of rejection, but also to complement the definition in cases with incomplete phenotypes. 3. Effective therapies to treat AMR and to reduce DSA are still lacking. Multiple case reports and small case series had been published and many more are currently being carried out, but poor study design, heterogeneous population, and therapeutic interventions make these published experiences difficult to be applied clinically.