AIM: To investigate whether performing immuno-histochemical CD3 staining, in order to improve the detection of intra-epithelial lymphocytosis, has an additional value in the histological diagnosis of celiac disease.METHODS: Biopsies obtained from 159 children were stained by hematoxylin and eosin(HE) and evaluated using the Marsh classification. CD3 staining was subsequently evaluated separately and independently.RESULTS: Differences in evaluation between the routine HE sections and CD3 staining were present in 20(12.6%) cases. In 10(6.3%) patients the diagnosis of celiac disease(Marsh Ⅱ and Ⅲ) changed on examination of CD3 staining: in 9 cases, celiac disease had initially been missed on the HE sections, while 1 patient had been over-diagnosed on the routine sections. In all patients, the final diagnosis based on CD3 staining, was concordant with serological results, which was not found previously. In the other 10(12.3%) patients, the detection of sole intra-epithelial lymphocytosis(Marsh Ⅰ) improved. Nine patients were found to have Marsh Ⅰ on CD3 sections, which had been missed on routine sections. Interestingly, the only patient with negative serology had Giardiasis. Finally, in 1 patient with negative serology, in whom Marsh Ⅰ was suspected on HE sections, this diagnosis was withdrawn after evaluation of the CD3 sections.CONCLUSION: Staining for CD3 has an additional value in the histological detection of celiac disease lesions, and CD3 staining should be performed when there is a discrepancy between serology and the diagnosis made on HE sections. AIM: To investigate whether performing immuno-histochemical CD3 staining, in order to improve the detection of intra-epithelial lymphocytosis, has an additional value in the histological diagnosis of celiac disease. METHODS: Biopsies obtained from 159 children were stained by hematoxylin and eosin ( HE) and evaluated using the Marsh classification. CD3 staining was evaluated as the same as independently .RESULTS: Differences in evaluation between the routine HE sections and CD3 staining were present in 20 (12.6%) cases. In 10 (6.3%) patients the diagnosis of celiac disease (Marsh Ⅱ and Ⅲ) changed on examination of CD3 staining: in 9 cases, celiac disease had initially been missed on the HE sections, while 1 patient had been over-diagnosed on the routine sections. diagnosis based on CD3 staining, was concordant with serological results, which was not found previously. In the other 10 (12.3%) patients, the detection of sole intra-epithelial lymphocytos is (Marsh I) improved. Nine patients were found to have Marsh Ⅰ on CD3 sections, which had been missed on routine sections. Interestingly, the only patient with negative serology had Giardiasis. Finally, in 1 patient with negative serology, in whom Marsh Ⅰ was suspected on HE sections, this diagnosis was withdrawn after evaluation of the CD3 sections. CONCLUSION: Staining for CD3 has an additional value in the histological detection of celiac disease lesions, and CD3 staining should be done when there is a discrepancy between serology and the diagnosis made on HE sections.