Emerging Concepts and Controversies in Renal Pathology: C4d-Negative and Arterial Lesions as Manifestations of Antibody-Mediated Transplant Rejection

Antibody-medicated rejection after heart transplantation: diagnosis and clinical implications

PURPOSE OF REVIEW

The present article will review the diagnosis of antibody-mediated rejection in heart transplant recipients and further explore the clinical implications.

RECENT FINDINGS

Improved diagnostic techniques have led to increased recognition of antibody-mediated rejection and better understanding of the long-term consequences in heart transplant recipients. Endomyocardial biopsy remains the gold standard for the diagnosis of antibody-medicated ejection; however, several advances in molecular testing have emerged, including the use of gene expression profiling, messenger RNA, and microRNA. Routine surveillance of donor-specific antibodies identifies recipients at high risk for graft compromise. Additionally, new monoclonal antibody therapies have broadened our repertoire in the treatment of rejection.

SUMMARY

Advances in molecular testing for antibody-mediated rejection may improve the associated long-term complication, while minimizing risk to the patient.

Antibody-mediated rejection in heart transplantation: new developments and old uncertainties

PURPOSE OF REVIEW

Antibody-mediated rejection (AMR) currently represents one of the main problems for clinical management of heart transplant because of its diagnostic complexity and poor evidences supporting treatments.

RECENT FINDINGS

Disorder-based diagnosis is a cornerstone in defining AMR. The limitations of the current classification have been partially overcome by novel studies improving the description of the immune-pathological graft abnormalities, and by new molecular approaches allowing a better understanding of the mechanisms behind AMR and of its relationship with cellular rejection and chronic vasculopathy. In-depth characterization of donor-specific antibodies showed to provide additional prognostic information and guide for treatment. Clinical relevance of AMR is bound to appropriate detection of graft dysfunction. In addition to traditional longitudinal evaluation by echocardiogram, cardiac magnetic resonance and detection of cell-free DNA may represent novel sensitive markers for graft injury that could prompt treatment before dysfunction becomes clinically manifest.

SUMMARY

Despite improvements in the diagnostic process, therapeutic strategies made little progress in addition to the consolidation of practices supported by limited evidences. Novel complement inhibitors appear promising in changing this scenario. Nevertheless, collaborative multicenter studies are needed to develop standardized approaches tailored to the highly variable clinical and laboratory features of AMR.