Focal B cell infiltrates in chronically rejecting kidneys are not recognizing anti-donor MHC antigens.

This result does not support the current thinking that chronic rejection is simply an antibody-mediated disease.

Infiltrates are clonal and the antibodies expressed recognize E. Coli LPS.

This result suggests that one driver of chronic kidney transplant injury is LPS derived from the genito-urinary microbiome.

What can be learned at the nexus of the microbiome and transplantation immunology?

We will review what is already known about the influence of the microbiome and LPS on immune-mediated diseases to consider unifying mechanisms.

Recent studies demonstrate that B cell Toll-like receptors play an important role in promoting antibody responses and also affecting their characteristics. This mechanism comes into play in antibody responses to virus particles, but may be important in other circumstances as well. Recent findings in this area will be summarized.

What You'll Take Away from His Talk:

• Understand that innate recognition via Toll-like receptors can enhance antibody responses.
• Recognize that B cells utilize innate recognition mechanisms to promote germinal center antibody responses and this may be relevant to transplantation.

How do alloantibodies induce the pathogenesis of transplant arteriopathy? We have identified a novel NK-mediated pathway that is complement independent and may explain why current immunosuppression does not prevent chronic rejection.

What You'll Take Away from His Talk:

• Participants will understand that NK cells are necessary but not sufficient for cardiac allograft vasculopathy.
• Participants will understand that complement is not for cardiac allograft vasculopathy.
• Participants will understand the potential mechanisms underlying the NK cell pathway of alloantibody-mediated cardiac allograft vasculopathy.

From the AMR Consensus Conference in Heart Transplantation, the presence of donor-specific antibodies (DSA) was not mandated as a definition for AMR. Yet, DSA has been correlated to subsequent poor outcome. This talk will delve into the importance of DSA with respect to AMR in heart transplantation. In addition, the application and significance of the new C1q assay for complement fixation by DSA will be discussed.

What You'll Take Away from His Talk:

• Understand the importance of developing DSA after heart transplantation.
• Be informed on the practical use of the new C1q assay.
• Determine the clinical relevance of DSA.

Reviewing current diagnostic criteria for antibody-mediated rejection reveals that these are consensus based and empirically developed and thus potentially significantly inaccurate. Recent insights into molecular mechanisms of antibody-mediated rejection have the potential to lead to better, more precise diagnostic tools which are the prerequisite for validating and establishing improved treatments. Thus the most important thing in antibody-mediated rejection is complete understanding of the disease process.

What You'll Take Away from His Talk:

• Understand the limitations in current diagnostic criteria for antibody-mediated rejection.
• Appreciate the different options with potential for improving precision in diagnosing AMR.