Determination of the Normal Range of the Number of Intraepithelial Lymphocytes in the Duodenal Mucosa of Healthy Iranian Individuals

An increase in the number of intraepithelial lymphocytes (IEL) in the duodenal mucosa is an important criterion for the histological diagnosis of celiac disease (CD). We determined the normal range for intraepithelial lymphocytes (IEL) in the second part of duodenum in healthy Iranian population.

Four biopsy samples of the endoscopically normal appearing mucosa at the second part of duodenum were obtained from 50 individuals referred to Shariati hospitals (48 for epigastric pain, 2 for esophageal varices). They had no sign, symptoms and evidence for malabsorption or small intestinal disorders in history, physical examination, Laboratory tests and IgA anti tissue transglutaminase (t.T.G). Four-micrometer thick sections were stained with Hematoxillineosine (H&E) and immunohistochemistry (IHC) for leukocyte common antigen (LCA). At least 500-600 cells from the tip and body of villi were counted separately and the number of IEL was given as mean/ 100 epithelial cells.

The mean for IEL count in total villi in IHC method was 21/100 (23/100 in tip, 21/100 in body, p = 0.058) and 19/100 in H&E method (19/100 in tip, 18/100 in body, p =0.035) (p = 0.006). Considering total villi, the normal upper limit (Mean+2SD) was calculated to be 35/100 in IHC and 34/100 in H&E stained sections and normal upper limit of confidence interval (the 95 percentile) was 39/100 in IHC and 37/100 in H&E stained sections. The villus height to crypt depth ratio was 3/94 in average.

Respectively in IHC and H&E methods, the amounts equal or less than 35/100 and 34/100 are considered as normal. values between 35-39/100 and 34-37/100 as border line and counts more than 39/100 and 37/100 represent a pathology. Although the difference between two staining methods was statistically significant, considering cost effectiveness, we recommend H&E staining for routine clinical practice.