SH2D1A is an inhibitor of the signaling lymphocyte activation molecule (SLAM) self-association. This protein is expressed at a high level in thymus and lung, with a lower level of expression in spleen and liver. Defects in SH2D1A are a cause of X-linked lymphoproliferative disease (XLPD) also known as Duncan disease. XLPD is characterized by a rare congenital immunodeficiency following Epstein-Barr virus (EBV) infection. Recombinant human SH2D1A protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography.