Our observations reinforce other works describing moesin as a fundamental molecule for T cell homeostasis, maturation, and function: moesin-/- mice exhibit T cells with reduced activation capacity and IL-2 production; lymphopenia as a consequence of a diminished incapacity to egress from the thymus, CD8+ Treg cells from these animals show decreased proliferation (30–32) and an X-linked moesin-associated immunodeficiency where diminished T cell proliferation is observed has been described in humans (48). The gene discussed is MSN; the disease is immunodeficiency disease.