Ex vivo single-cell profiling of acute myocardial infarction patients reveals disproportionate CD66b+ cell secretion response.

Acute myocardial infarction (AMI), a leading cause of death globally, triggers complex inflammatory responses critical to patient outcomes. However, rapid tools for profiling immune responses at the single-cell level are lacking. The integrated Single-cell Enzyme and Antigen Quantification (iSEAQ) system addresses this gap by enabling high-throughput, single-cell analysis of immune cell activity using just 20 μL of blood. This novel tool processes live CD66b and CD3 cells to quantify the secretion of Granzyme B, Neutrophil Elastase, and CD31 within minutes. Longitudinal studies on nine AMI patients revealed that CD66b+ cells are major contributors (up to 95%) to key inflammatory enzymes, including the unexpected secretion of Granzyme B. iSEAQ achieves unparalleled sensitivity (0.4 fg/cell) and predictive accuracy (>90%) for patient profiling across AMI onset, treatment, and discharge. This innovation provides clinicians with a rapid, precise method to monitor immune responses, unveiling new insights into AMI inflammation and therapy.