Lymphoproliferative disorders are a set of disorders characterized by the abnormal proliferation of
lymphocytes into a
monoclonal lymphocytosis. The two major types of lymphocytes are
B cells and
T cells, which are derived from
pluripotent hematopoietic stem cells in the
bone marrow. Individuals who have some sort of dysfunction with their immune system are susceptible to develop a lymphoproliferative disorder because when any of the numerous control points of the immune system become dysfunctional,
immunodeficiency or deregulation of lymphocytes is more likely to occur. There are several inherited
gene mutations that have been identified to cause lymphoproliferative disorders; however, there are also acquired and
iatrogenic causes.
X-linked Lymphoproliferative disorder A mutation on the
X chromosome is associated with a T cell and
natural killer cell lymphoproliferative disorder.
Autoimmune lymphoproliferative disorder Some children with autoimmune lymphoproliferative disorders are heterozygous for a mutation in the gene that codes for the
Fas receptor, which is located on the long arm of
chromosome 10 at position 24.1, denoted 10q24.1. This gene is member 6 of the TNF-receptor superfamily (TNFRSF6). The Fas receptor contains a death domain and has been shown to play a central role in the physiological regulation of
programmed cell death. Normally, stimulation of recently activated T cells by antigen leads to coexpression of Fas and Fas receptor on the T cell surface. The engagement of Fas by Fas receptor results in
apoptosis of the cell and is important for eliminating T cells that are repeatedly stimulated by antigens. As a result of the mutation in the Fas receptor gene, there is no recognition of Fas by
Fas receptor, leading to a primitive population of T cells that proliferates in an uncontrolled manner. ==See also==