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Abstract
Abstract
Background
Acute cellular rejection remains a major cause of morbidity after heart transplantation with up to 30% of patients experiencing at least one rejection episode during the first year. Unfortunately, the mechanism underling rejection remains poorly understood and the gold standard for diagnosing rejection remains frequent cardiac biopsy for rejection surveillance – a process that is both invasive and costly.
Purpose
PD-L1 is a co-inhibitory transmembrane protein that interacts with PD-1 on T cells to inhibit T cell activation. Endothelial PD-L1 expression in the heart has been shown in mouse models to play a key role in attenuating immune-mediated cardiac disease like myocarditis. Recent data that anti-PD-1 and anti-PD-L1 therapy can lead to myocarditis further supports a role for PD-1/PD-L1 signaling in cardiovascular homeostasis. We hypothesize that PD-L1 expression correlates with rejection severity.
Methods
Endomyocardial biopsy from a cohort of 19 heart transplant patients were analyzed for PD-L1 expression using immunohistochemistry and image analysis with HALO software. Each patient had biopsies corresponding to 0R, 1R, and 2R grades of rejection (n=57) and thus each patient served as their own internal control. Detailed clinical data was also collected on these patients from the electronic medical record.
Results
Average PD-L1 levels associated with 0R (n=19), 1R (n=21), and 2R (n=17) rejection were 1.54, 9.15, and 18.90 respectively (P<0.001). In patients who were treated for 2R rejection with increased immunosuppression (n=9), PD-L1 levels decreased from an average of 21.72 before treatment to an average of 5.64 after treatment (P<0.05). A multiple regression was run to see if PD-L1 level was associated with right heart pressures, EKG intervals, echo data, or common lab values. Accounting for age, race, and sex, it was found that PD-L1 was significantly associated with PA pressure (P<0.01, beta = 0.45), PCW pressure (P<0.01, beta = 0.42), and BNP (P<0.01, beta = 0.55).
Conclusions
Upregulation of PD-L1 in the heart is strongly associated with severity of cellular rejection after heart transplantation. Successful treatment of rejection with immunosuppression decreases PD-L1 levels. These data suggest that PD-L1 is a potential biomarker for heart transplant rejection. Further correlation of PD-L1 levels with signs of right heart strain (increased PA and PCW pressure) and systolic dysfunction (BNP) supports a clinical picture of PD-L1 as a useful biomarker for detecting both cellular rejection and reversal of rejection after treatment.
Cohort identification and results
Funding Acknowledgement
Type of funding source: Public grant(s) – National budget only. Main funding source(s): National Institutes of Health grants R56 HL141466 and R01 HL141466
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Predictors of steroid-refractory immune checkpoint inhibitor associated myocarditis. Eur Heart J 2020. [DOI: 10.1093/ehjci/ehaa946.3272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Background/Introduction
Immune checkpoint inhibitor (ICI)-associated myocarditis has a high mortality rate of approximately 50%. Clinical decompensation often occurs despite first-line treatment with corticosteroids. Factors associated with steroid failure are currently unknown.
Purpose
To identify predictors of steroid failure in patients with ICI-associated myocarditis.
Methods
We developed a web-based registry to collect and study 157 cases with clinical manifestations of ICI-associated myocarditis across 16 countries. Steroid failure was defined as patients who were escalated to immunomodulators after ≥1mg/kg daily dose of prednisone or had in-hospital death due to myocarditis despite ≥1mg/kg daily dose of prednisone. Steroid response was defined as all other patients treated with steroids without escalation to immunomodulators and without death due to myocarditis. A multivariate logistic model accounting for age and sex was used to predict association with steroid failure.
Results
Compared to steroid responsive cases, steroid failure was more likely to result in fulminant myocarditis (56.7% vs 19.6%, OR=5.37 [2.62–10.98] p<0.001) and all-cause in-hospital mortality (49.1% vs 12.9%, OR=6.50 [2.86–14.73] p<0.001) with shorter time from presentation to death (27.5 vs 43.0 days HR: 2.56 [1.45–4.50] p=0.001). When adjusting for age and sex, cases were more likely to be steroid-refractory if they were female (46.7% vs 30.1%, OR=2.77 [1.31–5.85] p=0.007), higher body mass index (27.2 vs 22.0, OR=1.09 [1.01–1.18] p=0.012), had higher intake creatine kinase (2800.5 vs 528.0 U/L, OR=1.48 [1.14–1.90] p=0.003) had higher intake troponin T (1.40 vs 0.25 ng/mL OR=1.63 [1.00–2.64] p=0.049), or had one or more concomitant non-cardiac immune-related adverse event (90.0% vs 74.2%, OR=3.10 [1.14–8.25] p<0.026). The only immune-related adverse events independently associated with steroid failure in myocarditis were myasthenia gravis-like syndrome (26.7% vs 8.2%, OR=3.84 [1.47–10.10] p=0.006) and myositis (45.0% vs 24.7%, OR=2.38 [1.16–4.92] p=0.018). Steroid failure was not significantly associated with cardiovascular or autoimmune history but was associated with a history of thymoma (12.0% vs 2.6%, OR=18.86 [0.10–356.7] p=0.05)
Conclusion(s)
Features such as female sex, high body mass index, and pre-existing thymoma as well as findings of elevated cardiac biomarkers and other non-cardiac immune-related adverse events – particularly myositis and myasthenia gravis-like syndrome – may represent a steroid-refractory phenotype of ICI-associated myocarditis. These results suggest that a multidisciplinary approach to diagnosing concomitant non-cardiac immune related adverse events is key to risk-stratifying ICI-associated myocarditis.
Forrest Plot
Funding Acknowledgement
Type of funding source: Private hospital(s). Main funding source(s): National Institutes of Health
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