“…Several studies have been performed to investigate the expression of chemokine receptors and their ligands in the HRS cells of cHL [15,16,17,18,19,20] These studies found that the chemokine receptors CCR5, CXCR3, CXCR4, CXCR5 and CCR7 are expressed in the HRS cells of cHL in a significant number of cases [15,18,19]. Furthermore, the ligands CXCL10, CXCL12, CXCL13, CCL21, CX3CL1, CCL5 and CCL17 are expressed in cHL cell lines and primary HRS cells [17,18,19,21,22]. CCL17 and CCL5 are capable of attracting T helper 2 (Th2) and regulatory T (Treg) cells, which interact with HRS cells and form what has been named rosettes around them [17,23].…”