Can lymph nodes swell for reasons other than infection?

Yes, lymph nodes can swell for reasons other than infection. While infection is a common cause of lymph node enlargement (lymphadenopathy), other conditions, such as genetic disorders and autoimmune diseases, can also lead to this swelling. For example, in autoimmune lymphoproliferative syndrome (ALPS), abnormal numbers of lymphocytes accumulate, causing enlargement of the lymph nodes, liver, and spleen.

Understanding the Role of the Lymphatic System

The lymphatic system is a complex network of tissues and organs that plays a vital role in immunity and maintaining the body's fluid balance. This system consists of lymph, a fluid containing white blood cells that defend the body against germs, and lymphatic vessels that carry lymph throughout the body. Lymph nodes are glands located along these vessels that, along with the spleen, serve as sites where white blood cells fight infection. If the lymphatic system does not function properly, fluid can accumulate in the tissues, causing swelling known as lymphedema. Other problems that may affect the lymphatic system include inflammation, blockages, and cancer [2].

Autoimmune Lymphoproliferative Syndrome (ALPS) as a Non-Infectious Cause

Autoimmune lymphoproliferative syndrome (ALPS) is a rare genetic disorder in which the body cannot properly regulate the number of immune system cells (lymphocytes). This syndrome is characterized by the production of an abnormally large number of lymphocytes (lymphoproliferation). The accumulation of excess lymphocytes leads to enlarged lymph nodes (lymphadenopathy), an enlarged liver (hepatomegaly), and an enlarged spleen (splenomegaly) [1].

Autoimmune disorders are also common in ALPS, where the immune system attacks the body's own tissues and organs. These disorders often target and damage blood cells, such as red blood cells (autoimmune hemolytic anemia), white blood cells (autoimmune neutropenia), or platelets (autoimmune thrombocytopenia). In some cases, autoimmune disorders may affect other organs and tissues such as the kidneys, liver, eyes, or nerves [1].

Other Genetic Causes of Lymph Node Enlargement

In about 75% of cases, ALPS is caused by mutations in the FAS gene, which provides instructions for making a protein involved in cell signaling that leads to self-destruction of cells (apoptosis). When the immune system is activated to fight an infection, large numbers of lymphocytes are produced. Under normal circumstances, these lymphocytes undergo apoptosis when they are no longer needed. FAS gene mutations result in an abnormal protein that interferes with apoptosis, leading to the accumulation of excess lymphocytes in the body's tissues and organs, often beginning to attack them, which results in autoimmune disorders [1].

In addition to ALPS, other problems in the lymphatic system can include lymphedema, which is swelling caused by fluid accumulation in tissues, cancer, and blockages [2]. It is important to see a doctor to determine the cause of lymph node swelling, especially if the swelling is persistent or accompanied by other symptoms such as fever or night sweats, or if the nodes are increasing in size, feel hard, or do not move when pressed [4].

For more information on lymphatic system diseases, you can visit Lymphatic System Diseases: From Swelling to Infection, Understanding Your Body's Immune Network (Arabic).

Medical references

• Autoimmune lymphoproliferative syndrome
• Lymphatic Diseases
• Swollen glands - NHS