Autoimmune Lymphoproliferative Syndrome (ALPS)

Illustration of fas protein.
Credit: NIAID

The Fas protein spans the cell membrane, with part of the protein located outside the cell (blue) and part within the cell (grey). 

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 a type of white blood cell called a lymphocyte accumulate in the lymph nodes, liver, and spleen, which can lead to enlargement of these organs. ALPS can cause numerous autoimmune problems, such as anemia (low level of red blood cells), thrombocytopenia (low level of platelets), and neutropenia (low level of neutrophils, the most common type of white blood cell in humans). These problems can increase the risk of infection and hemorrhage.

Why Is the Study of Autoimmune Lymphoproliferative Syndrome (ALPS) a Priority for NIAID?

ALPS can cause debilitating symptoms and put those affected at an increased risk for developing autoimmune diseases and lymphoma. Researchers at NIAID hope to develop safe and effective treatments targeting the genetic defects in children with ALPS and related disorders.

How Is NIAID Addressing This Critical Topic?

Researchers at NIAID focus on gaining a better understanding of the clinical and genetic characteristics of people with ALPS and related disorders. By identifying the genes responsible for symptoms in these people, NIAID researchers not only help affected families but also increase understanding of how the immune system works. Whole genome sequencing is one of the tools the scientists are using to investigate these aspects of ALPS. 

To learn about resources for the diagnosis and management of ALPS and sources of support and advocacy, visit the National Library of Medicine, Genetics Home Reference autoimmune lymphoproliferative syndrome site.

Causes

Most cases of ALPS are caused by mutations in the FAS gene. The FAS gene produces a receptor that, when activated, leads to programmed cell death, or apoptosis. This programmed death is an important part of the normal cell lifecycle. When cells do not receive the message that it is time for them to die, an abnormal buildup of cells can result. In the case of ALPS, mutations in the FAS gene cause an abnormal buildup of white blood cells.

Symptoms & Diagnosis

The major clinical symptoms of ALPS, including fatigue, nosebleeds, and infections, result from a proliferation of lymphocytes and autoimmune destruction of other blood cells. The diagnosis of ALPS is based on clinical findings, laboratory findings, and identification of mutations in genes.

Treatment

There currently is no standard cure for ALPS. The disorder can be managed by treating low blood-cell counts and autoimmune diseases that occur in people with ALPS, as well as monitoring for and treating lymphoproliferation, an enlarged spleen, and lymphoma.

Related Autoimmune Research

More than 80 diseases occur because the immune system attacks the body’s own organs, tissues, and cells. Some of the more common autoimmune diseases include type 1 diabetes, rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and inflammatory bowel diseases (IBD). ALPS also falls within this category of diseases.

Content last reviewed on November 30, 2017