Insights into Recovery from Acute Fulminant Myocarditis Following Successful Treatment with Ruxolitinib by Comprehensive Single-Cell Profiling

Acute fulminant myocarditis (AFM) is characterized by sudden, severe cardiac inflammation, often leading to death due to hemodynamic instability or arrhythmia1. Currently, no approved medical therapy exists for AFM. Interferon/cytokine signals mediated by Janus kinases (JAK) are critical for immune activation, with JAK inhibitors proving effective for several immune-mediated conditions2. Herein, we report the first use of ruxolitinib, a non-selective JAK inhibitor, in treating a patient with AFM. Single-cell technologies, including RNA sequencing (scRNA-seq), T- and B-cell receptor sequencing, and cellular indexing of transcriptomes and epitopes sequencing (CITE-seq) were employed to profile peripheral immune populations before and after treatment3.We performed single-cell assessments of PBMCs using 10x Genomics technology in this patient at four-time points: before ruxolitinib treatment but following treatment with corticosteroids (Pre Rux) and on days 5, 8, and 2 months after ruxolitinib treatment.