Helios—controller of Treg stability and function

Helios is a member of the Ikaros family (e.g., Ikaros, Eos, Pegasus, and Ailos) of zinc-finger transcription factors and was initially cloned by two independent groups (1,2). Initial studies implicated Helios in cancer due to its as aberrant expression in certain types of leukemia and lymphoma (3-7). However, more recent work has described Helios as being expressed in lymphocytes, particularly a unique subset of CD4+ T cells, termed regulatory T cells (Treg) (8,9).