Novelties in diagnostics and therapy of antibody mediated rejection

Antibody mediated rejection (AMR) is becoming an increasing challenge in renal allotransplantation. AMR is usually associated with profound allograft dysfunc-tion and inferior allograft survival. In the era of refined crossmatch-techniques and improved solid-phase assays, hyperacute rejections in presensitized patients are less common. Majority of AMRs occur due to de novo production of donor specific antibodies. AMR appears to stand for a spectrum of histologic changes paralled with immunohistochemical positivity for C4d along peritubular capillaries. Removal of antibodies with plasmapheresis or immunoadsorption in combi-nation with neutralizing and immunomodulatory intravenous immunoglobulin are therapy standards in majority of transplant centers worldwide. The addition of anti-CD20 (rituximab) with the aim to reduce the number of B-cells may offer advantage in some cases. Apart from donor specific HLA-antibodies, non-HLA antibodies reacting to arterial antigens have been speculated to be responsible for rejections in some patients. More precise definition of antigen targets for non-HLA antibodies is emerging. The analysis of the subtle mechanistic and diagnostic differences among rejection subtypes will help to identify patients at particular risk and improve outcome of AMR