A 15-year-old boy develops severe cardiomyopathy following myocarditis from Coxsackie virus and is placed on the cardiac transplant list. Two weeks following his cardiac transplantation from a matched donor, he develops dyspnea on exertion. Extensive evaluation is undertaken including cardiac catheterization and endomyocardial biopsy to assess for acute allograft rejection. Which of the following histologic findings is most consistent with this diagnosis?

Question

A 15-year-old boy develops severe cardiomyopathy following myocarditis from Coxsackie virus and is placed on the cardiac transplant list.  Two weeks following his cardiac transplantation from a matched donor, he develops dyspnea on exertion.  Extensive evaluation is undertaken including cardiac catheterization and endomyocardial biopsy to assess for acute allograft rejection.  Which of the following histologic findings is most consistent with this diagnosis?

Quizplus · Accepted Answer

11ec160b_37c6_3316_9249_a5d906762a25_MD0001_00 Acute cardiac transplant rejection typically occurs within 6 months of transplantation and can be diagnosed via endomyocardial biopsy. Acute rejection can be cell-mediated (ie, acute cellular rejection [ACR]) or, less commonly, antibody-mediated (ie, acute antibody-mediated rejection). In ACR, host T-lymphocytes are sensitized against foreign human leukocyte antigens (HLA) in the cardiac allograft, which leads to inflammation and injury to the transplanted organ. Microscopic features of ACR include an interstitial lymphocytic infiltrate (primarily T-lymphocytes) and damaged myocytes. Symptoms consistent with progressive rejection include those found in systolic dysfunction (eg, dyspnea on exertion). However, cardiac transplant recipients undergo close surveillance with regular endomyocardial biopsies, and acute rejection is often diagnosed before patients become symptomatic. (Choice A) Concentric intimal thickening of the coronary arteries can be seen in cardiac allograft vasculopathy, an important cause of ischemic damage and long-term graft dysfunction. The pathogenesis is complex and includes the release of cytokines that cause smooth muscle cell proliferation in the vessel wall. (Choice C) Patchy necrosis with granulation tissue is indicative of ischemic damage to the donor heart. Ischemia in a donor heart can occur in a variety of situations including during attempted resuscitation of the donor patient, during transport of the organ from the donor to the recipient, and acutely during initial perfusion of the organ after transplantation. (Choice D) Perivascular infiltrate with abundant eosinophils is a histopathologic feature of hypersensitivity myocarditis. Hypersensitivity myocarditis often represents an immunologic response to a newly initiated drug. (Choice E) Interstitial fibrosis with scant inflammation can be seen in chronic rejection of solid organ transplants. Chronic rejection is mediated by host T-lymphocytes as well as antibodies and classically occurs months to years following transplantation. Educational objective: Acute cardiac transplant rejection usually occurs weeks to months following transplantation and is primarily a cell-mediated process. In acute cellular rejection, endomyocardial biopsy shows an interstitial lymphocytic infiltrate with myocyte damage.

A 15-Year-Old Boy Develops Severe Cardiomyopathy Following Myocarditis from Coxsackie