Intraepithelial lymphocytosis is an elevated white blood cell count in your gastrointestinal tract. It can be a sign of celiac disease, Crohn’s disease, or other gastrointestinal conditions.

The lining of your gastrointestinal (GI) tract plays a critical role in preventing infections. The outermost layer of your GI tract is called the epithelium. It contains T-cells that activate your body’s inflammation response.

T-cells are a type of white blood cells called lymphocytes. Most of the lymphocytes in your GI tract are T-cells.

Intraepithelial lymphocytosis is when doctors can see an increased number of lymphocytes in a tissue sample of your GI tract. It can be a sign of GI conditions such as Crohn’s disease or celiac disease. It goes by other names, such as duodenal lymphocytosis, depending on where in your GI tract these lymphocytes are detected.

Read on to learn about which conditions can cause intraepithelial lymphocytosis and how to manage them.

Intraepithelial lymphocytosis is an elevated lymphocyte count in your GI tract. It goes by several more specific names depending on where this elevated count is detected in your GI tract.

NamePart of GI affected
gastric intraepithelial lymphocytosis stomach
duodenal intraepithelial lymphocytosis first part of small intestines
jejunal intraepithelial lymphocytosismiddle of small intestines
ileal intraepithelial lymphocytosisend of small intestines
colonic intraepithelial lymphocytosislarge intestines

Intraepithelial lymphocytosis can be a sign of an issue with your gut. It’s characterized by 20–25 lymphocytes per 100 epithelial cells, the main cells that line your GI tract. In a healthy gut, there are usually fewer than 5–10 lymphocytes per 100 epithelial cells.

It’s thought that excessive lymphocyte activity in the GI tract is responsible for the gut damage seen in people with celiac disease and some other GI disorders.

Some of the functions of intraepithelial lymphocytes include:

  • producing molecules that reduce inflammation
  • activating natural killer cells that destroy infected or damaged cells
  • producing molecules that increase inflammation

Excessive activity of natural killer cells has been linked to autoimmune conditions such as Crohn’s disease and ulcerative colitis.

In the following microscopic images taken from tissue samples, intraepithelial lymphocytes show up as dark purple spots.

Intraepithelial lymphocytosis is your body’s response to injury to your GI tract. A wide number of conditions can stimulate the overproduction of intraepithelial lymphocytes. They include:

In a 2019 study, researchers examined the prevalence of gastrointestinal conditions in a group of 694 people with intraepithelial lymphocytosis of the stomach. The researchers reported:

ConditionPrevalence in people with gastric intraepithelial lymphocytosis
severe obesity, previously known as “morbid obesity”23.5%
H. pylori infection23.5%
celiac disease14.7%
lymphocytic gastritis14.7%
nonspecific gastritis11.4%
gastroesophageal reflux disease (GERD)1.9%

Half of the people in the study had intraepithelial lymphocytosis in both their stomach and small intestine.

Intraepithelial lymphocytosis can be a sign of an underlying gut disorder, but it isn’t a disorder itself. Symptoms can vary based on the underlying gut issue. Here are some examples:

Crohn’s disease

Celiac disease

Doctors may take a small tissue sample of the lining of your GI tract to help confirm the presence of a GI condition such as celiac disease. This tissue sample is called a biopsy.

Doctors can look at your biopsy under a microscope to see if you have an abnormal number of lymphocytes.

Learn more about how celiac disease is diagnosed.

Treatment for intraepithelial lymphocytosis aims to target the underlying condition. Here are some of the potential treatment options:

ConditionTreatment options
celiac diseasegluten-free diet
topical sprueantibiotics
Crohn’s disease• medications such as biologics and anti-inflammatory drugs
• dietary changes
ulcerative colitis• medications such as biologics and anti-inflammatory drugs
• dietary changes
• surgery
bacterial overgrowthantibiotics
autoimmune enteropathyimmunosuppressants

The outlook for conditions that cause intraepithelial lymphocytosis varies widely, but it’s often positive with proper treatment.

The outlook for people with celiac disease who follow a gluten-free diet is usually excellent. Some people need steroids to manage their symptoms.

Crohn’s disease may decrease quality of life. Life expectancy is slightly reduced due to an increased risk of gastrointestinal cancers and other complications.

Life expectancy rates of people with ulcerative colitis are comparable to those of people without the condition. About 5% of people with ulcerative colitis develop colon cancer.

Intraepithelial lymphocytosis is when there is a higher than normal number of lymphocytes in the lining of your gastrointestinal tract. It can be a sign of gastrointestinal conditions such as celiac and Crohn’s disease.

Intraepithelial lymphocytosis isn’t a GI disorder. It’s a sign of an underlying problem. Treatment for intraepithelial lymphocytosis involves treating the underlying cause.