Search

Background: Antibody-mediated rejection (AMR) in cardiac transplant recipients is a serious form of rejection with adverse patient outcomes. The International Society of Heart and Lung Transplantation (ISHLT) has published a consensus schema for the pathologic diagnosis of various grades of antibody-mediated rejection (pathology antibody-mediated rejection [pAMR]). We sought to determine whether the ISHLT pAMR grading schema correlates with patient outcomes., Methods: Using our database, which contains a semi-quantitative scoring of all pathologic descriptors of pAMR, we retrospectively used these descriptors to convert the previous AMR categories to the current ISHLT pAMR categories. Cox proportional hazard models were fit with cardiovascular (CV) death or retransplant as the outcome. The pAMR value was included as a categorical variable, and cellular rejection (CR) values were included in a separate model., Results: There were 13,812 biopsies from 1,014 patients analyzed. The pAMR grades of pAMR1h, pAMR1i, and pAMR2 conferred comparable increased risk for CV mortality. Significantly increased risk of CV mortality was conferred by biopsies graded as severe AMR (pAMR3)., Conclusions: The new ISHLT pAMR grading schema identifies patients at increased risk of CV mortality, consistent with risks published from several programs before 2011. The current schema is validated by this analysis in a large biopsy database. Because pAMR1h, pAMR1i, and pAMR2 have similar CV risks associated with them, the threshold for a positive diagnosis of pAMR should be re-evaluated in future iterations of the ISHLT schema., (Copyright © 2016 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.)

Background: Little is known about mixed cellular and antibody-mediated rejection (MR) in heart transplantation. It remains unclear whether cardiac MR has distinctive pathologic and clinical features beyond those of simultaneous cellular rejection (CR) and antibody-mediated rejection (AMR). In this study we systematically explore the pathologic and clinical characteristics of MR in heart transplantation., Methods: The UTAH Cardiac Transplant Program database was queried for transplant recipients who survived long enough to have at least one endomyocardial biopsy (EMB) between 1985 and 2014. Only EMBs with both CR and AMR scores documented were included. In addition to detailed pathologic analyses, we also examined the incidence and prevalence of MR, the likelihood to transition from and to MR, and mortality associated with MR., Results: Patients (n = 1,207) with a total of 28,484 EMBs met the study inclusion criteria. The overall prevalence of MR was 7.8% and it was nearly twice as frequent within the first year post-transplant. Mild MR was by far the most common occurrence and was typically preceded by an immune active state. When CR increased in severity, AMR tended to follow, but the reverse was not true. On pathology, individual features of CR and AMR were more easily separated in cases of mild MR, whereas they substantially overlapped in more severe cases. MR was associated with a significant cardiovascular death risk that was incremental with severity., Conclusions: MR is not common, usually occurs early after transplant, and is associated with worse outcomes. MR reflects a complex interplay between cellular and humoral processes, which varies with rejection severity., (Copyright © 2016 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.)

Background: There is greater awareness of the pathologic features and clinical implications of antibody-mediated rejection (AMR) after heart transplantation (HT). Yet, compared with adults, the lack of routine surveillance for AMR has limited the growth of evidence in the pediatric population. Herein, we compared outcomes of pediatric HT recipients with and without AMR., Methods: All recipients ≤18 years of age with at least 1 endomyocardial biopsy (EMB) between 1988 and 2009 were included in this study. Assessment for AMR was routine. AMR severity was assigned retrospectively using the proposed 2011 ISHLT grading schema for pathologic AMR (pAMR). Outcome comparisons were made between patients with histologic and immunopathologic evidence for AMR (pAMR 2), those with severe AMR (pAMR 3), and those without evidence of AMR (pAMR 0) or without both histologic and immunopathologic findings (pAMR 1)., Results: Among 1,406 EMBs, pAMR 2 or higher was present in 258 (18%), occurring in 45 of 76 (59%) patients. Of the 17 episodes of pAMR 3 in 9 patients, 6 (35%) were sub-clinical. Mortality was not different between groups. Patients with at least 1 pAMR 3 episode had lower freedom from cardiovascular (CV) mortality or cardiac allograft vasculopathy within 5 years of HT than those without pAMR 3 (45% vs 91%, p < 0.001)., Conclusions: Biopsy findings of AMR (pAMR 2 or higher) are common after pediatric HT. Like cellular rejection, biopsy grading of AMR seems important to delineate those at risk of adverse events. Our results suggest that pAMR 3 is associated with worse CV outcomes. Widespread surveillance for pAMR with a uniform grading system is an important next step to further validate these findings in the pediatric HT population., (Copyright © 2012 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.)

Background: Growing evidence suggests worse cardiac allograft vasculopathy and mortality in patients with asymptomatic antibody-mediated rejection (AMR). Debate continues about whether therapeutic intervention is warranted to avoid adverse outcomes. In this study we examine the course of individual episodes of untreated asymptomatic AMR on follow-up endomyocardial biopsy (EMB)., Methods: The U.T.A.H. Cardiac Transplant Program database was queried for transplant recipients between 1985 and 2009 who survived beyond 1 year and had at least 1 episode of lone AMR with a follow-up EMB. All EMBs were screened for AMR by immunofluorescence and graded for severity. Data were analyzed based on time from transplant (early, ≤12 months; late, >12 months)., Results: Nine hundred fifty-eight patients with a total of 15,448 biopsies qualified for the study. Average age at transplant was 46.7 years; 13% of the patients were female. Within the first year post-transplant, asymptomatic AMR was diagnosed in 13.6% of biopsies compared with 5.2% beyond 1 year. AMR resolved in 65% (early) vs 75% (late) on follow-up EMB. More severe AMR was less likely to improve regardless of time from transplant. Furthermore, after an episode of AMR had resolved, the recurrence rate at 3, 6 and 12 months was 44%, 50.1% and 56.2%, respectively., Conclusions: The incidence of AMR is higher in the first year post-transplant and the likelihood of resolution is less on follow-up EMB, especially when more severe. A small but significant number of cases became worse or did not change. These new findings may be helpful in planning future studies that test whether therapeutic interventions on asymptomatic AMR favorably impact outcomes., (Copyright © 2012 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.)

Background: Recent efforts are being undertaken to update and refine current diagnostic criteria for antibody-mediated rejection (AMR) in heart transplantation. We believe that the appropriate reactants are those that best predict the adverse consequences of AMR and therefore tested various models using different reactants to find the best predictors of cardiovascular mortality in pathologically defined AMR., Methods: The study group included only patients in whom all immunofluorescence antibodies of interest had been tested on biopsy specimens obtained after 2002 when C4d was routinely added. We analyzed our data using 3 Cox proportional hazard models with time-varying covariates using an end point of cardiovascular mortality, as previously defined., Results: In 3,712 biopsy specimens from 422 patients, the 2-antibody model achieved a value of R(2) = 0.930 using C3d and C4d antibodies alone. A model that used 4 antibodies--C3d, C4d, human leukocyte antigen-D related (HLA-DR) and fibrin--was superior (R(2) = 0.988). The model that best predicted cardiovascular mortality included all 6 antibodies: HLA-DR, immunoglobulin (Ig) G, IgM, C3d, C4d, and fibrin (R(2) = 0.989). The models using 4 or 6 antibodies were significantly superior to the model using only C3d and C4d (for each interaction, p < 0.0001)., Conclusions: The combination of complement components, HLA-DR and fibrin, is valuable in defining AMR in patients at risk for allograft loss from cardiovascular causes. Fibrin is particularly important for detecting the presence of severe AMR, with a high likelihood of poor long-term patient outcome., (Copyright © 2011 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.)