I’m immensely grateful to all the individuals that supported and contributed to this work! Hannah Kalinoski, Dr Robin Welsh, Wonyoung Jo, Camille Jaime and most importantly the mentorship of Professors Ashley Kiemen & @danielacihakova.bsky.social. Our work can be accessed at: doi.org/10.1093/cvr/...

Our work has shown for the first time that T cells and Macrophages are not distributed homogeneously in myocarditis but rather occupy distinct 3D niches. Yet, so much remains to be seen: What drives T cell recruitment to the front & how does this framework mediate pathogenesis?

Why do T cell-rich foci prefer the front of the heart? We conducted 3D vascular analysis & found that T cell-rich immune foci tended to occupy highly vascularized regions. Do T cells extravasate to the front by virtue of anatomic vasculature or does pathology play a bigger role?

For the first time, we can see how T Cells & Macrophages (MФ) are distributed throughout myocarditis hearts. Intriguingly we show that T cell-rich foci are more concentrated in the front of the heart while MФ-rich foci accumulate in the back. This is confirmed by both flow & PCR.

Endomyocardial biopsies (EMBs) have sensitivities that range 20%-80% for myocarditis. 3D compartment analysis showed that immune foci are mostly found in myocardial regions of the Left Ventricle. This further favors a multimodal EMB approach over a blinded endocardial septal one.

Focusing on the ventricles, we 3D reconstructed immune foci (purple) and blood vessels (red). We showed that myocarditis was mostly made of large branching elongated immune foci that followed vasculature.