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).

CD8 T-cell recognition of acquired alloantigen promotes acute allograft rejection.

Adaptive CD8 T-cell immunity is the principal arm of the cellular alloimmune response, but its development requires help. This can be provided by CD4 T cells that recognize alloantigen "indirectly," as self-restricted allopeptide, but this process remains unexplained, because the target epitopes for CD4 and CD8 T-cell recognition are "unlinked" on different cells (recipient and donor antigen presenting cells (APCs), respectively). Here, we test the hypothesis that the presentation of intact and processed MHC class I alloantigen by recipient dendritic cells (DCs) (the "semidirect" pathway) allows linked help to be delivered by indirect-pathway CD4 T cells for generating destructive cytotoxic CD8 T-cell alloresponses.

Operative salvage of radiocephalic arteriovenous fistulas by formation of a proximal neoanastomosis.

Objective: We examined the outcomes of radiocephalic arteriovenous fistulas salvaged by formation of a neoanastomosis in the proximal cephalic vein segment.

Methods: Patients with a radiocephalic arteriovenous fistula revised by formation of a neoanastomosis in the proximal cephalic vein segment were identified from a prospectively maintained database and outcomes retrospectively analyzed.

Results: Eighty patients had 81 radiocephalic arteriovenous fistulas revised by formation of a neoanastomosis in the proximal cephalic vein segment.

Treatment of dialysis access-associated steal syndrome with the "revision using distal inflow" technique.

Purpose: Dialysis access-associated steal syndrome (DASS) is a common, serious complication of antecubital fossa (ACF) arteriovenous fistulas (AVFs). We describe our experience of the "revision using distal inflow" (RUDI) technique for the treatment of DASS and review the literature.

Methods: Patients underwent fistula ligation at the anastomosis with re-establishment of inflow via the proximal radial or ulnar arteries using a venous interposition graft or venous collateral.