Lymphoma and autoimmune diseases both involve the immune system. This article clarifies the distinct nature of lymphoma as a cancer and autoimmune diseases as conditions where the immune system misdirects its attack, while exploring their observed associations.
Understanding Lymphoma
Lymphoma is a cancer originating in lymphocytes, a type of white blood cell. These cells are part of the immune system, fighting infections. Lymphocytes are found throughout the body, including in lymph nodes, the spleen, and bone marrow. In lymphoma, these lymphocytes change and grow uncontrollably.
This uncontrolled growth of abnormal lymphocytes can lead to their accumulation in various parts of the body, often resulting in enlarged lymph nodes in areas like the neck, armpits, or groin. Lymphoma has many subtypes, broadly categorized into Hodgkin lymphoma and non-Hodgkin lymphoma, with non-Hodgkin lymphoma being more common. While the exact causes of these cellular changes are not fully understood, they involve alterations in the DNA of lymphocytes.
Understanding Autoimmune Diseases
Autoimmune diseases occur when the body’s immune system mistakenly attacks its own healthy tissues. Normally, the immune system distinguishes between the body’s own cells and harmful substances like bacteria or viruses. In autoimmune conditions, this recognition process fails, causing the immune system to attack healthy cells and tissues.
Over 80 recognized autoimmune diseases exist, affecting nearly any body part, including joints, muscles, skin, and various organ systems. Common examples include rheumatoid arthritis, attacking the joints, and systemic lupus erythematosus, affecting multiple organs. While the exact cause is often unknown, genetic predisposition and environmental factors play a role in their development.
The Relationship Between Lymphoma and Autoimmune Conditions
Lymphoma is not an autoimmune disease; it is a cancer involving the uncontrolled growth of abnormal lymphocytes. In contrast, autoimmune diseases involve the immune system attacking the body’s own healthy tissues. However, a significant association exists between pre-existing autoimmune diseases and an increased lymphoma risk. Most individuals with autoimmune conditions do not develop lymphoma, but the risk can be elevated in some cases.
This increased risk stems from factors like chronic inflammation and prolonged immune system activation that are hallmarks of autoimmune conditions. Persistent lymphocyte stimulation can lead to genetic changes predisposing these cells to malignant transformation. For instance, B lymphocyte overactivity in Sjögren’s syndrome can lead to B-cell lymphomas.
Several autoimmune diseases link to an increased lymphoma risk. Sjögren’s syndrome, affecting moisture-producing glands, is associated with a significantly higher risk of non-Hodgkin lymphoma, particularly subtypes like marginal zone lymphoma and diffuse large B-cell lymphoma. Rheumatoid arthritis also carries an increased lymphoma risk, often diffuse large B-cell lymphoma, with risk correlating to inflammatory disease severity. Systemic lupus erythematosus is similarly associated with an elevated lymphoma risk, with studies indicating a three to five-fold increased risk for hematological cancers, including non-Hodgkin lymphoma.
Immunosuppressive treatments used to manage autoimmune conditions may contribute to increased lymphoma risk. While these medications effectively control autoimmune disease activity, they can weaken the immune system’s ability to surveil and eliminate abnormal cells, potentially increasing cancer susceptibility. However, managing the autoimmune disease typically outweighs this potential risk. High inflammatory activity, rather than treatment, is often considered a major risk determinant for lymphoma in autoimmune patients.