Lymphedematous skin from clinical biopsy specimens and mouse models of lymphedema are infiltrated with large numbers of CD4+ cells that co-express interferon gamma (IFN-γ; putative Th1 cells) and CD4+ cells that co-express interleukin 4 (IL4) or IL13 (putative Th2 cells). The gene discussed is IFNG; the disease is lymphedema.