Rituximab use in late antibody-mediated rejection

Abstract

Antibody-mediated rejection (AMR) is an important cause of graft loss after the 1st year of transplant.[1] The standard treatment of AMR consists of steroid pulses, plasmapheresis (PP), and intravenous immunoglobulin (IV IG), however many patients show poor response to treatment and lose their graft. Rituximab has been used as a rescue treatment after resistant rejection or along with standard treatment in case reports and small studies.[1,2] Rituximab is a chimeric murine/human monoclonal antibody directed against B cell surface molecule CD20. The CD20 molecule is found on mature B cells but not on pro-B cells or plasma cells, thus administration of anti-CD20 antibody rituximab leads to elimination of peripheral B cells from the circulation but have no effect on mature plasma cells or B cells in lymphoid organs. There is prolonged depletion of CD20 B cells from peripheral circulation subsequent to use of rituximab.[3] There are reports of reduction in donor-specific antibody (DSA) titers with use of rituximab and also the presence of CD20 positive lymphoid aggregate in patients with steroid-resistant rejection and benefit of using rituximab in these patients. However, there are also reports of increased risks of infection after rituximab use including progressive multifocal leukoencephalopathy.[2] In renal transplantation, rituximab is also used in ABO-incompatible transplant and for desensitization in human leukocyte antigen-incompatible transplant.[2,3]