Lymphoma-induced regression of high endothelial venules impairs homeostatic lymphocyte trafficking

Lymphoma growth is facilitated by the well-balanced infrastructure of the microenvironment in lymph nodes (LN). LNs undergo rapid expansion during lymphoma progression, often accompanied by excessive blood vessel growth. Here we report that aggressive lymphoma cause severe high endothelial venule (HEV) regression which impairs lymphocyte recirculation. In this study, we used transferred (i.v.) Eµ-Myc tumor cells as a mouse model of aggressive lymphoma. Blood endothelial cells from tumor bearing and control LNs were isolated by FACS and processed for single-cell RNA sequencing. The results revealed a detrimental mechanisms causing HEV-dedifferentiation during lymphoma growth with potential implications on tumor-targeting immune surveillance and strategies of immune therapy in LNs