What Is Lymphocytic Colitis?
Lymphocytic colitis is a microscopic inflammation of the large intestinal mucosa with infiltration of lymphocytes (IELs) that is characterized by non-bloody secretory diarrhea.
Secretory diarrhea describes bowel movements that consist of a large volume of liquid stool.
Q: What are IELs?
A: IELs is an abbreviation for intraepithelial lymphocytes, which are white blood cells that infiltrate within epithelial cells or between them. Epithelial cells form the surface mucosa of the large intestine also called the colon.
The histopathological criteria (biopsy) for lymphocytic colitis are a density of at least 20 IELs per 100 surface epithelial cells; chronic inflammatory infiltrate of mononuclear cells in the lamina propria; epithelial damage; and a subepithelial collagen layer of less than 10 µm. The increased collagen band consists basically of collagen type I and III, which are the subtypes produced by repair functions, indicating a reactive origin.1That is, the mucosa is reacting to some irritative substance.
Up to 10% of adults undergoing colonoscopy for investigation of chronic diarrhea and having visibily normal appearing mucosa may have lymphocytic colitis.2
Bile acid malabsorption has been shown to coexist in 60% of patients with lymphocytic colitis.1
Lymphocytic colitis (LC) is categorized as primary or secondary. Primary LC is a clinical and histopathological disease of unknown cause. Secondary LC may develop as the result of iritating factors acting on the colon such as smoking or many medications. In one study, the most common drug treatments as a percentage of the study group were corticosteroids (32.1%), proton pump inhibitors (26.0%), antidepressant drugs, specifically selective serotonin reuptake inhibitors (21.4%), angiotensin-converting enzyme inhibitors or angiotensin II receptor antagonists (18.3%), statins (17.6%), thyroid hormones (17.6%), and beta-blockers (16.0%).3
Secondary lymphocytic colitis is associated with several concomitant diseases including celiac disease. This is why lymphocytic changes must be interpreted with caution before considering them as a separate entity of autoimmune origin, instead of secondary reactions to ischemia and toxic stimulants. Efforts must be made to better classify and diagnose patients with real, primary lymphocytic colitis to avoid over-prescription of corticosteroids for treatment.3
What Is Lymphocytic Colitis In Celiac Disease and/or Gluten Sensitivity?
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- Ohlsson B. New insights and challenges in microscopic colitis. Therap Adv Gastroenterol. 2015 Jan;8(1):37-47. doi: 10.1177/1756283X14550134.
- Abdo AA, Urbanski SJ, Beck PL. Lymphotcytic and collagenous colitis: the emerging entity of microscopic colitis. An update on pathophysiology, diagnosis and management. Canadian Journal of Gastroenterology. Jul 2003;17(7):425-32.
- Roth B, Manjer J, Ohlsson B. Drug Target Insights. 2013 Aug 11;7:19-25. doi: 10.4137/DTI.S12109.