The abnormal expression of IL-15 and serum IL-15Rα in LGLL is a major player in the pathogenesis of the disease due to their role in regulating T-and NK-cells activation and cytotoxicity, and overexpression of IL-15 in the cellular environment can easily initiate the progression of LGLL, as shown in several studies (44–46). The gene discussed is IL15RA; the disease is T-cell large granular lymphocyte leukemia.