The iTALK tool (33) was used to predict receptor/ligand interactions enriched in LR-CHL compared to other CHLs and confirmed a significantly increased positive interaction between CXCL13 on helper T cells and CXCR5 on B cells (Fig. 4D), supporting the importance of the CXCR5/CXCL13 axis in the specific pathogenesis of LR-CHL. This evidence concerns the gene CXCR5 and classic Hodgkin lymphoma.