Autoimmune Lymphoproliferative Syndrome (ALPS) is an inherited disorder in which the body cannot properly regulate the number of immune system cells (lymphocytes). Autoimmune Lymphoproliferative Syndrome (ALPS) is characterized by the production of an abnormally large number of lymphocytes (lymphoproliferation). Accumulation of excess lymphocytes results in enlargement of the lymph nodes (lymphadenopathy), the liver (hepatomegaly), and the spleen (splenomegaly).

Autoimmune Lymphoproliferative Syndrome (ALPS) can have varying patterns of signs and symptoms. Most commonly, lymphoproliferation becomes apparent during childhood. Enlargement of the lymph nodes and spleen frequently occur in affected individuals.

Autoimmune Lymphoproliferative Syndrome (ALPS) is a rare genetic disorder of the immune system first described by NIH scientists in the mid-1990s that affects both children and adults. In ALPS, unusually high numbers of white blood cells called lymphocytes accumulate in the lymph nodes, liver, and spleen and can lead to enlargement of these organs.

Additional Autoimmune features are seen in ALPS, often in patterns that appear to be family specific, suggesting the influence of other modifying genes. These features include glomerulonephritis, autoimmune hepatitis, Guillain-Barré syndrome, Uveitis, and iridocyclitis. Autoimmunity affecting endocrine systems or joints is not common in ALPS compared with other immunodeficiency disorders.