According to a study published in the Journal of the National Cancer Institute, the risk of diffuse large B-cell lymphoma (a subtype of non-Hodgkin’s lymphoma) is elevated among patients with rheumatoid arthritis, Sjögren syndrome, systemic lupus erythematosus, or celiac disease. Some of these conditions were also linked with marginal zone lymphoma, lymphoplasmacytic lymphoma, and T-cell lymphoma.
Non-Hodgkin’s lymphoma (NHL) is a form of cancer that begins in the cells of the lymph system. The lymph system includes the spleen, thymus, tonsils, bone marrow, lymph nodes, and circulating immune cells. The main cells in the lymph system are lymphocytes, which exist in two forms: B-cells and T-cells. Each of these cells has a very specific function in fighting infection.
NHL is characterized by the excessive accumulation of atypical (cancerous) lymphocytes. These lymphocytes can crowd the lymph system and suppress the formation and function of other immune and blood cells. NHL is categorized by the type of lymphocyte it involves and by the rate at which the cancer grows-both are determined by the cells’ appearance under a microscope.
Autoimmune disorders are diseases in which the patient’s immune system attacks the body’s own tissues. Previous studies have suggested a link between certain autoimmune diseases and the risk of NHL, but there is less information about how risk varies by subtype of NHL.
To evaluate the relationship between autoimmune conditions and specific subtypes of NHL, researchers in Sweden and Denmark conducted a study among 3055 patients with NHL (cases) and 3187 age- and sex-matched patients without NHL (controls). The subtypes of NHL in the cases were diffuse large B-cell (796 subjects); chronic lymphocytic leukemia/small lymphocytic lymphoma (752 subjects); follicular (586 subjects); T-cell (204 subjects); mantle cell (148 subjects); marginal zone (117 subjects); and lymphoplasmacytic (116 subjects).
Four autoimmune diseases were linked with an increased risk of NHL overall, as well as with an increased risk of at least one subtype of NHL:
- Rheumatoid arthritis was linked with a 50% increase in risk of all NHL, an 80% increased in risk of diffuse large B-cell lymphoma, and a two and a half-fold increase in lymphoplasmacytic lymphoma.
- Primary Sjögren syndrome was linked with a six-fold increase in all NHL, an 11-fold increase in diffuse large B-cell lymphoma, and a 28-fold increase in marginal zone lymphoma.
- Systemic lupus erythematosus was linked with a 4.6-fold increase in all NHL, and a 6-fold increase in diffuse large B-cell lymphoma.
- Celiac disease was linked with a two-fold increase in all NHL, a 2.8-fold increase in diffuse large B-cell lymphoma, and a 17-fold increase in T-cell lymphoma.
- There was no link between any type of NHL and Crohn’s disease, ulcerative colitis, sarcoidosis, or psoriasis.
- Type 1 diabetes was linked with a three-fold increase in chronic lymphocytic leukemia/small lymphocytic lymphoma, but was not linked with NHL overall.
Although there is a link between specific autoimmune diseases and NHL, autoimmune diseases appear to explain only a small proportion of all NHL cases. The researchers estimate that rheumatoid arthritis, Sjögren syndrome, systemic lupus erythematosus, and celiac disease account for roughly 2.3% of NHL cases.
The researchers conclude that these results confirm that a link exists between certain autoimmune conditions and risk of NHL. The links may apply only to specific subtypes of NHL. Individuals with autoimmune diseases may wish to speak with their physician about their individual risks of developing NHL.
Reference: Ekström Smedby KE, Hjalgrim H, Askling J et al. Autoimmune and Chronic Inflammatory Disorders and Risk of Non-Hodgkin Lymphoma by Subtype. Journal of the National Cancer Institute. 2006;98:51-60.
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