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X-linked lymphoproliferative syndrome (Duncan syndrome): causes, symptoms, diagnosis, treatment
Last reviewed: 20.11.2021
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The lymphoproliferative syndrome linked to the X chromosome is the result of a defect of T-lymphocytes and natural killers and is characterized by an abnormal response to infections caused by the Epstein-Barr virus, leading to liver damage, immunodeficiency, lymphoma, fatal lymphoproliferative disease, or bone marrow aplasia.
The lymphoproliferative syndrome linked to the X chromosome causes a mutation in the X chromosome gene, which encodes a protein specific for T-lymphocytes and natural killers, called SAP. Without SAP, in response to infection with the Epstein-Barr virus (EBV), uncontrolled proliferation of lymphocytes is noted, and natural killers do not function.
The syndrome is asymptomatic before contact with EBV. After that, most patients develop a fast or fatal mononucleosis with liver damage (caused by cytotoxic T cells that affect VEB-affected B lymphocytes and other cellular elements); In survivors of the primary infection, B-cell lymphomas, aplastic anemia, hypogammaglobulinemia (like OID), or a combination of these.
The diagnosis of the VEB survivors after primary infection is based on the revealed hypogammaglobulinemia, reduced antigen response to the antigen (especially the nuclear antigen of EBV), impaired proliferation of T-lymphocytes in response to mitogens, reduced function of natural killers, inversion of the CD4: CD8 relationship. Before infection with EBV and the development of symptoms, genetic diagnosis of the mutation is possible.
Most patients survive for no more than 10 years, the rest die before the age of 40 unless bone marrow transplantation is performed, which has a significant therapeutic effect if performed prior to infection with EBV.