Relative Frequencies of Alloantigen-Specific Helper CD4 T Cells and B Cells Determine Mode of Antibody-Mediated Allograft Rejection.

Humoral alloimmunity is now recognized as a major determinant of transplant outcome. MHC glycoprotein is considered a typical T-dependent antigen, but the nature of the T cell alloresponse that underpins alloantibody generation remains poorly understood. Here, we examine how the relative frequencies of alloantigen-specific B cells and helper CD4 T cells influence the humoral alloimmune response and how this relates to antibody-mediated rejection (AMR).

Germinal Center Alloantibody Responses Mediate Progression of Chronic Allograft Injury.

Different profiles of alloantibody responses are observed in the clinic, with those that persist, often despite targeted treatment, associated with poorer long-term transplant outcomes. Although such responses would suggest an underlying germinal center (GC) response, the relationship to cellular events within the allospecific B cell population is unclear. Here we examine the contribution of germinal center (GC) humoral alloimmunity to chronic antibody mediated rejection (AMR).

Deposition of C4d and C3d in cardiac transplants: a factor in the development of coronary artery vasculopathy.

Background: Coronary artery vasculopathy (CAV) is the major life-limiting factor in cardiac transplantation, after 1 year. Antibody-mediated rejection (AMR) has been associated with development of both acute and chronic rejection. We analyzed endomyocardial biopsies for pathologic markers of AMR (C4d and C3d), from the first 2 years post-transplantation, to determine complement deposition in relation to the development of CAV.