Duodenal intraepithelial lymphocyte-count revisited

Area of Science:

• Gastroenterology
• Histopathology
• Immunology

Background:

• The established upper limit for duodenal intraepithelial lymphocytes (IELs) is over 30 years old.
• Previous normal upper limit for IELs was set at 40 lymphocytes per 100 epithelial cells.

Purpose of the Study:

• To establish a more accurate normal upper limit for duodenal intraepithelial lymphocytes (IELs).
• To differentiate normal IEL counts from those indicative of coeliac disease and other gastrointestinal conditions.

Main Methods:

• Analysis of duodenal biopsies from healthy individuals and patients with gastrointestinal symptoms.
• Staining of tissue sections with haematoxylin and eosin (H&E) and CD3.
• Counting of IELs per 100 epithelial cells and statistical analysis.

Main Results:

• Healthy individuals had a mean of 10.8 (H&E) and 13.2 (CD3) IELs/100 epithelial cells.
• The upper limit of the confidence interval for CD3 staining was 29 IELs/100 epithelial cells.
• No significant difference in IEL counts was observed between normal individuals and most clinical groups, except for active coeliac disease.

Conclusions:

• A two-step approach for IEL determination is proposed: semi-quantitative H&E and quantitative CD3 staining.
• The suggested upper normal limit for CD3+ IELs is 25 per 100 epithelial cells.
• Values between 25-29 are borderline, while 30+ indicate pathologic intraepithelial lymphocytosis.