Impact of malignant B cells on stromal cells in lymphoma-invaded BM. (A) Circos plot showing predicted interactions between ligands from DOHH2 cells and receptors from LepR⁺ MSC at the late stage of graft. D40 DOHH2 were defined as senders, and MSC_Gr.Late as receivers. (B) Heat map representation of ligand activity of D40 DOHH2 vs MSC_Gr.Late cells. Colors correspond to Pearson coefficient (quantifying ligand activities) and text to P values assessed by random permutation. (C) Heat map of the top 50 differentially expressed regulons detected in the 4 LepR⁺ MSC clusters using decoupleR algorithm³⁶ and CollectTri database (left). Violin plots of Smad3 and Smad7 regulon activity for the LepR⁺ MSC clusters (right). (D) Heat map generated with CellPhoneDB repository, representing the number of significative bidirectional interactions between LepR⁺ clusters (MSC_Sh, MSC_Gr.Early, MSC_Gr.Late, and MSC_Ctrl) from this study and human primary FL B cells (left).³³ Diagram of bidirectional interactions detected, by CellPhoneDB, between ligands from human FL B cells and receptors from MSC_Gr.Late, and observed in >8 of 20 patients with FL (right). Interactions also predicted in panel A are highlighted in red.