Search

Background: In the past decade, C4d has emerged as a potential marker for antibody-mediated rejection (AMR); however, evidence on its use as a prognostic tool has been controversial. Although the International Society for Heart and Lung Transplantation guideline recommends early routine surveillance of C4d in heart transplantation, there is no consensus on its value in the pathologic assessment of AMR. Herein we present a correlation analysis of C4d immunoreactivity in endomyocardial biopsies with clinical cardiac dysfunction, cellular rejection, human leukocyte antigen (HLA) status, cardiac allograft vasculopathy (CAV) and death., Methods: A total of 5,840 endomyocardial biopsies from 296 heart transplant recipients (January 2004 to December 2014) were stained prospectively for C4d. Strong, diffuse endothelial staining was considered positive. All patients had at least 1 year of follow-up. Positive C4d staining was present in 53 biopsies from 28 patients. Sixteen of 28 patients had clinically significant cardiac dysfunction at the time of positive biopsy. In C4d-positive patients, the mean panel-reactive antibody (PRA) level was 33%. Ten patients demonstrated a first C4d positivity within the first year post-transplant, whereas 18 patients had C4d positivity after 1 year post-transplant. At autopsy, all 11 C4d-positive patients examined demonstrated cardiac allograft vasculopathy (CAV) as the underlying cause of death. In contrast, only 2 of 8 (25%) C4d-negative patients had CAV at autopsy. In the surviving cohort, there was an angiographic diagnosis of higher-than-moderate CAV in 10 patients (3.8%)., Results: C4d-positive patients contributed to 67% of the overall institutional mortality in heart transplant recipients. Late C4d positivity (>1 year post-transplant) demonstrated an even higher risk for developing CAV and poor prognosis than early C4d positivity (within 1 year). In the C4d-negative group with postmortem examination, 75% (6 of 8) deaths were due to non-cardiac causes., Conclusions: Our findings show a positive association of C4d with CAV and death. We identified a prognostic role for C4d in heart transplantation warranting routine long-term detection of this marker in the pathologic evaluation of cardiac AMR., (Copyright © 2017 International Society for the Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.)

Background: Peri-operative immunosuppression in cardiac transplantation includes the use of intravenous methylprednisolone. During a national shortage, intravenous dexamethasone was substituted for methylprednisolone at standard equivalencies. Methylprednisolone and dexamethasone are used interchangeably in many clinical settings; however, their equivalency has not been demonstrated., Methods: Forty-two consecutive cardiac transplant patients were studied retrospectively. All patients received standard triple immunosuppression. Eighteen patients received dexamethasone and 24 methylprednisolone. Twelve patients were included for comparison after the methylprednisolone shortage resolved. Endomyocardial biopsy (EMB) results graded as > or =1B (ISHLT classification) were considered positive for acute cellular rejection., Results: More patients who received dexamethasone as induction had cellular rejection (12/17; (70%) vs. 14/33; (42%); p=0.05). Four patients were excluded because of deaths unrelated to cardiac function. The increased rate of rejection seen during dexamethasone substitution declined after reinstitution of methylprednisolone (p=0.05)., Conclusions: Peri-operative high-dose dexamethasone in cardiac transplants was associated with higher rates of acute cellular rejection. The equivalencies of dexamethasone and methylprednisolone differ from accepted standards when used in pulse doses. Peri-operative use of glucocorticoids may rely on mechanisms that are different from those considered in the standard equivalency measures. Pulse doses of dexamethasone and methylprednisolone in transplantation may not be interchangeable at standard equivalencies.

Background: Antibody-mediated rejection (AMR) is associated with poorer outcomes in cardiac transplantation. The clinical diagnosis of AMR has been confirmed by immunofluorescence for C4d on fresh-frozen cardiac tissue. Immunohistochemistry (IHC) has been suggested as a more practical diagnostic tool because it can be performed on routine paraffin-embedded tissue. There are few published data about hemodynamics and C4d staining. We prospectively performed C4d staining on endomyocardial biopsies (EMBs) and present the pattern of tissue staining and its correlation with intracardiac hemodynamics., Methods: EMBs were evaluated by IHC for C4d staining and graded for cellular rejection using ISHLT criteria on hematoxylin-and-eosin-stained sections. Hemodynamic measurements were taken concurrently. Staining for C4d was described as absent, present with serum staining, or present with only tissue staining. The pattern of tissue staining was categorized by location of staining and correlated with intracardiac hemodynamics. Patient demographics, cytomegalovirus status, panel-reactive antibody levels and hemodynamics were analyzed by analysis of variance and chi-square statistics., Results: Of the 400 EMBs, 50 had no C4d staining, 330 had tissue and serum staining, whereas 20 had only tissue staining. Forty EMBs had endothelial staining, including 35 with serum and 5 with isolated tissue staining. Endothelial staining correlated with higher intracardiac pressures., Conclusions: IHC staining for C4d has been suggested for the diagnosis of AMR. Our data suggest there is a high rate of background C4d staining, but endothelial staining correlates with poorer hemodynamics. Methods for IHC staining and interpretation need to be standardized for widespread use and clinical studies.