SH2D1A and X-linked lymphoproliferative disease: However, while a T cell product could treat several of the most severe clinical manifestations of XLP and offer a life-saving bridge to HSCT, studies have shown that NKT cells (which are absent in XLP patients) have an important role in tumour surveillance (Das et al., 2013; Weng et al., 2014), and SAP-replete NK cells can aid with clearing EBV-infected cells (Parolini et al., 2000).