[Expression of HLA-DR antigen in small intestinal mucosa of children infected with Giardia intestinalis].

HLA-DR Antigen expression was shown in the small intestinal mucosa sampled by aspiration biopsy in 12 children infected with Giardia intestinalis. The studies were performed by using three immunohistochemical techniques, with the best results achieved by use of fluorescein- stained avidin biotin system. HLA-DR Antigen expression in Giardiasis was slightly enhanced in the enterocytes of the absorption region; an increased number of HLA-DR positive cells was also found in the lamina propria of the small intestine as compared with controls. This phenomenon is recognized in various inflammations of the small intestinal mucosa.