Aim
This study aimed to compare the intraepithelial lymphocytic (IEL) counts by hematoxylin and eosin (H&E) and by CD3 immunohistochemistry (IHC) in pediatric duodenal biopsies during routine diagnostic practice and to evaluate the interobserver variability between both methods.
Materials and methods
A retrospective study was conducted on 64 pediatric duodenal biopsies received from January 2017 to December 2018 at the Pathology Laboratory of Ain Shams University Hospitals and classified into three groups: group 1 with established coeliac disease by previous biopsy, group 2 with newly received cases suspicious of coeliac disease with positive anti-tissue transglutaminase with present or absent villous atrophy, and group 3 with normal or unknown anti-tissue transglutaminase. IEL count was evaluated by routine H&E and by CD3 immunohistochemistry by the two authors and categorized into normal (<25 lymphocytes), mildly raised (25–40 lymphocytes), and markedly raised (>40 lymphocytes). Agreements between stains, as well as interobserver agreement, were calculated.
Results
The overall mean IEL count per 100 enterocytes for H&E was 21.86 [95% confidence interval=18.34–25.38], and for IHC by CD3, it was 26.19 (95% confidence interval=22.52–29.85). The difference was highly significant (=0.001), with highly significant substantial agreement between H&E and CD3 IHC results (=0.001; =0.694). The overall interobserver agreement for H&E was almost perfect among the cases of all groups, and among groups 1, 2, and 3 (=0.946, 0.825, 0.831, 1, respectively). The overall interobserver agreement for CD3 IHC was almost perfect among the cases of all groups, and among groups 1, 2, and 3 (=0.975, 1, 1, and 0.956, respectively).
Conclusion
CD3 can aid in the detection of IELs but only in the proper clinical and serological setting.