immunology allergic disorders
X linked Lymphoproliferative Syndrome
Introduction
X-linked lymphoproliferative syndrome is an immunodeficiency disorder that results from a T-cell and natural killer cell defect and is characterized by an abnormal response to Epstein-Barr virus infection, leading to liver failure, immunodeficiency, lymphoma, fatal lymphoproliferative disease, or bone marrow aplasia. (See also Overview of Immunodeficiency Disorders and X-linked lymphoproliferative syndrome (XLP) is a Primary Immunodeficiencies that involves is the most common type (about 60% of cases). It is caused by a mutation in the gene that encodes the signaling lymphocyte activation molecule (SLAM)–associated protein (SAP, also called the SH2 domain protein 1A [SH2D1A] or DSHP). Without SAP, lymphocytes proliferate unchecked in response to Infectious Mononucleosis , and natural killer (NK) cells do not function. is clinically similar to type 1 and predisposes to Hemophagocytic Lymphohistiocytosis (HLH) , an uncommon disorder that causes immunodeficiency in infants and young children. XLP2 is caused by mutations in a gene that encodes the X-linked inhibitor of apoptosis protein (XIAP). 