CD244 (NK cell Activation Inducing Ligand, NAIL, NKCR 2B4, Nmtk) is a member of the Signaling Lymphocyte Activation Molecule (SLAM) family, which also includes CD2. It is expressed on NK cells as well as a sub set of T cells. The type of signaling is controlled by the prevalence and type of intracellular adaptor proteins. CD244 is down regulated on monocytes and platelets of SLE patients (1). Its presence maintains proliferation ability of leukemia initiating cells (2). Elevated levels of CD244 associate with disease progression in HIV (3). Levels of its ligand, CD48 on leukocytes of asthma patients vary with severity (4).