Colonic mucosal inflammatory cells in children and adolescents with lactase deficiency

Introduction and objectives: Many of the symptoms of patients with lactose intolerance are due to fermentation of undigested lactose in the colonic lumen, which may also lead to inflammatory cell changes in the colonic mucosa. The objective of our project was to understand the histopathological changes involving infiltration of eosinophils and mast cells in the colonic mucosa of children with lactase deficiency (LD). Methods: In this retrospective study we studied colonic mucosa of children and adolescents with LD to determine if any pathological changes or inflammatory cell changes were present. Pathology reports and Hematoxylin and eosin stained slides were reviewed. Tryptase immunohistochemistry was performed for mast cell assessment. Result: There were 30 subjects in the study who had a LD and 15 presented with diarrhea and 15 without diarrhea. The colonic mucosa of 35.5 % of the subjects revealed increased mucosal eosinophils. There was no increase of mast cells or lymphocytic colitis in any of the subjects. Excepting for the increased eosinophils in a subset of the subjects, all had a normal appearance of the colonic mucosa. Conclusion: Colonic mucosa of children and adolescents with LD has a normal histological appearance in majority of the patients. However, 35 % of the patients could demonstrate elevated eosinophils. In primary LD without any comorbidity there is no increase of mast cells and lymphocytic cells in the colonic mucosa.