The Balance of CD8-Positive T Cells and PD-L1 Expression in the Myocardium Predicts Prognosis in Lymphocytic Fulminant Myocarditis

Abstract

Plain Language SummaryMyocarditis is a heart condition caused by inflammation of the heart muscle. Fulminant myocarditis (FM) is a severe form that can lead to sudden heart failure, shock, or dangerous heart rhythms. Understanding how the immune system is involved in FM is crucial for finding better treatments. In this study, we examined heart tissue from 16 patients with lymphocytic FM to understand the role of specific immune cells (T cells) and molecules (PD-1 and PD-L1) in the disease. We followed the patients for about 5 months to track their outcomes. We found that patients with more CD8+ T cells (a type of immune cell) in their heart tissue had a higher risk of cardiac events such as heart failure. Furthermore, when a specific molecule called PD-L1 was more abundant in heart cells, it indicated a poorer prognosis. This suggests that high levels of CD8+ T cells and PD-L1 in the heart tissue can predict a worse outcome for patients with lymphocytic FM. Understanding these markers may help doctors identify patients at higher risk and tailor treatments to improve their prognosis. However, more research with larger groups of patients is needed to confirm these findings and guide treatment decisions.