Journal of Clinical Immunology

, Volume 34, Issue 7, pp 772–779

XLP: Clinical Features and Molecular Etiology due to Mutations in SH2D1A Encoding SAP

Key Review Article

DOI: 10.1007/s10875-014-0083-7

Cite this article as:
Tangye, S.G. J Clin Immunol (2014) 34: 772. doi:10.1007/s10875-014-0083-7


X-linked lymphoproliferative disease (XLP) is a rare primary immunodeficiency affecting approximately 1–2 per 1 million males. A key feature of XLP is the exquisite sensitivity of affected individuals to disease induced following EBV infection. However, patients can also develop hypogammaglobulinemia and B-cell lymphoma independently of exposure to EBV. XLP is caused by loss-of function mutations in SH2D1A, which encodes the intracellular adaptor molecule SAP. SAP is predominantly expressed in T cells and NK cells, and functions to regulate signal transduction pathways downstream of the SLAM family of surface receptors to control CD4+ T cell (and by extension B cells), CD8+ T cell and NK cell function, as well as the development of NKT cells. The study of XLP had shed substantial light on the requirements for lymphocyte differentiation and immune regulation, which in turn have the potential to be translated into novel treatments for not only XLP patients but individuals affected by EBV-induced disease, impaired humoral immunity and malignancy.


XLP SAP EBV hypogammaglobulinemia infectious mononucleosis lymphoma PID 

Copyright information

© Springer Science+Business Media New York 2014

Authors and Affiliations

  1. 1.Immunology Research ProgramGarvan Institute of Medical ResearchSydneyAustralia
  2. 2.St Vincent’s Clinical SchoolUniversity of New South WalesSydneyAustralia