Laboratory features of ALPS include increased CD3+ TCRαβ+ CD4− CD8− called “double negative T cells” (αβ DNTs), elevated levels of IgG and/or IgA, increased plasma levels of vitamin B12, interleukin 10 (IL-10) and soluble FAS ligand (sFASLG) [9]. Here, FASLG is linked to autoimmune lymphoproliferative syndrome.