The impact of asymptomatic antibody-mediated rejection on outcome after heart transplantation.

PURPOSE OF REVIEW: Defining criteria for antibody-mediated rejection (AMR) in heart transplantation were standardized a few years ago, but very little is known about asymptomatic cardiac AMR. We will start the review with a background summarizing the timeline of cardiac AMR. Then we will cover past and current knowledge about asymptomatic cardiac AMR and its impact on outcome after transplantation, with added insight from experience with other solid-organ transplants. RECENT FINDINGS: The incidence of asymptomatic cardiac AMR had likely been under-estimated because biopsy surveillance for it in the absence of clinical manifestation was not the norm. Recent data indicate that it may be more common especially when counting concomitant acute cellular rejection (mixed rejection). Also a higher risk of cardiac allograft vasculopathy (CAV) and cardiovascular mortality have been linked to it. The primary implication of these findings is whether therapeutic intervention is warranted, but the appropriate target patient population likely to benefit from treatment is yet to be determined. SUMMARY: Asymptomatic cardiac AMR is not uncommon and it negatively impacts outcome after heart transplantation.