IL4 and lymphedema: Using a variety of techniques, including immunofluorescent staining and flow cytometry using tissues from the mouse tail surgery and ALND models, as well as clinical biopsy specimens collected from patients with unilateral upper extremity breast cancer-related lymphedema, Avraham et al. and Zampell et al. found that lymphatic injury resulted in a Th2-biased response with infiltration of large numbers of CD4+ IL-4+ IL-13+ Th2 cells (Figure 2) [41,51].