Figure 2.

The interaction between Hodgkin and Reed–Sternberg (HRS) cells and CD4+ type 2 T helper (Th2) cells most likely initiates a positive feedback loop. First, the secretion of TARC (blue circles) by HRS cells causes a consequent attraction and homing of Th2 cells to the tumor microenvironment. These attracted Th2 cells can secrete IL-4, IL-5 and IL-13 (yellow circles) that activate JAK/STAT signaling leading to activation of STAT6. STAT6 activation in HRS cells further increases TARC secretion. This leads to a feedback loop of constant stimulation of HRS cells.