Intraepithelial lymphocytes, or IELs, are specialized immune cells residing within the lining of various organs, particularly the gastrointestinal tract. These cells are a normal component of the body’s defenses, constantly monitoring the environment for potential threats. When their numbers increase beyond typical levels, it can signal an underlying condition that warrants further investigation. This elevation indicates that the immune system in that specific area might be reacting to something.
Understanding Intraepithelial Lymphocytes
Intraepithelial lymphocytes are immune cells within the epithelial lining of organs like the small intestine and colon. Unlike other immune cells, IELs are directly exposed to substances passing through the gut. They form a first line of defense against pathogens and foreign substances.
They contribute to immune surveillance, identifying harmful elements while tolerating beneficial ones. Their proximity to the intestinal lining allows quick reaction to changes, maintaining gut health.
Conditions Associated with Increased Intraepithelial Lymphocytes
An increase in intraepithelial lymphocytes, or intraepithelial lymphocytosis, signals an underlying condition.
Celiac Disease
Celiac disease is a common cause where IELs increase significantly in response to gluten ingestion. These lymphocytes contribute to small intestinal lining damage, causing malabsorption and abdominal discomfort.
Microscopic Colitis
This condition, which includes collagenous and lymphocytic colitis, features elevated IELs. Patients often experience chronic watery diarrhea. Certain medications, like nonsteroidal anti-inflammatory drugs (NSAIDs), can also induce increased IELs, sometimes causing symptoms similar to microscopic colitis.
Helicobacter pylori Infection
Helicobacter pylori, a common stomach infection, can increase gastric IELs as part of inflammation.
Inflammatory Bowel Disease (IBD)
Inflammatory Bowel Disease (IBD), including Crohn’s disease and ulcerative colitis, may also show increased IELs, though not a primary diagnostic feature.
Other Causes
Less common causes include food sensitivities beyond gluten, parasitic or viral infections, and some autoimmune conditions.
The presence of increased IELs is a broad indicator, requiring thorough clinical correlation to pinpoint the specific cause. Identifying the underlying condition is essential for effective management.
Recognizing and Diagnosing Increased IELs
Increased intraepithelial lymphocytes are identified via biopsy during an endoscopic procedure, such as a gastroscopy or colonoscopy. Endoscopies are performed for persistent gastrointestinal symptoms like chronic diarrhea, abdominal pain, bloating, or weight loss. Tissue samples are collected from the digestive tract lining during endoscopy.
Samples are sent to a pathology laboratory for microscopic examination. A pathologist examines the tissue for abnormalities, including an elevated IEL count. Pathology reports may state “increased intraepithelial lymphocytes” or “intraepithelial lymphocytosis.”
Pathologist findings are correlated with patient symptoms, medical history, and other diagnostic tests (e.g., blood work, imaging). For example, if increased IELs are found in the small intestine, celiac disease antibody blood tests are considered. This comprehensive approach helps determine the specific underlying condition.
Managing Increased Intraepithelial Lymphocytes
Management of increased intraepithelial lymphocytes focuses on treating the specific underlying cause, not the IEL elevation. As IEL elevation is a microscopic finding, treatment targets the underlying disease. For example, a strict gluten-free diet is the primary intervention for celiac disease, typically normalizing IEL counts and symptoms.
For microscopic colitis, medications like budesonide or anti-diarrheal agents may reduce inflammation and control symptoms. If Helicobacter pylori is identified, antibiotics eradicate the bacteria. If NSAIDs are suspected, discontinuing or finding alternative drugs can resolve the issue.
Patients often require follow-up to monitor symptoms and, sometimes, repeat biopsies to assess treatment effectiveness. The goal is to alleviate symptoms and restore healthy digestive function by addressing the root cause.