A one-year-old otherwise healthy girl presented with a progressively enlarging patch on the lateral aspect of her right ankle. Her parents stated that the lesion was not remarkable at birth but became more apparent with aging. There was no history of trauma or bleeding and family history for similar lesions was unremarkable. Physical examination showed an erythematous patch of superficial telan...

Although originally described as a potent T cell growth factor in vitro, the main non redundant role of interleukin-2 (IL-2) in vivo is now known to be the maintenance of peripheral T cell tolerance. As well as promoting the proliferation and survival of recently activated effector T cells, IL-2 also plays a critical role in regulatory T cell (Treg) homeostasis and has been variously described ...