Lewis antigens and argyrophilic nucleolar organizer regions staining for assessment of potential malignancy of adenomatous polyps of the gastrointestinal tract in children.

Adenomatous polyps (AP) of the gastrointestinal tract in children are very rare. Because of their potential malignancy, they are of great clinical importance. There is little experience in the management of children with AP. The immunohistochemical expression of the Lewis blood group antigens (BGA) (sialosyl-Le(a), Le(a), Leb, Le(x), and Le(y)) and the number of activated nucleoli with the silver staining method for nucleolar organizer regions (AgNORs) were studied in two children with AP. In a girl with isolated AP of the stomach and colon, it was found that antigens Le(b) and s-Le(a) were expressed extensively in the gastric adenoma, and sialosyl-Le(a) throughout the entire length of the rectal adenoma crypts, but in the AgNORs stain the number of nucleoli ranged from two to four, evidencing changes of a benign character. In the case of familial adenomatous polyposis diagnosed in a 9-year-old boy, in some colonic adenomas the number of activated nucleoli was greater than five, and the Le(b) antigen was expressed in superficial epithelial cells in one of the adenomas. Also, extensive expression of antigens Le(y) and s-Le(a) throughout the entire length of the crypt in another polyp removed was observed. We believe that immunohistochemical study of the intensity and extent of the expression of Lewis BGA in the polyp tissue simultaneously with the determination of the number of activated nucleoli by the AgNORs staining method can be helpful in better analysis of cytological risk factors of a malignant transformation.

Expression of antigens homologous to human retrovirus molecules in normal and severely atrophic thymus.

An immunopathologic study of normal and severely atrophic thymuses (STA) was undertaken in order to evaluate the expression of human retrovirus (envelope and core) molecules in thymic epithelial cells (TEC) in HIV negative children. Both normal and STE thymuses disclosed p19, p24, p39, p45 and p55 viral core proteins as well as gp46, gp63 glicoprotein of envelope origin. No evidence of gp160, gp120 and gp41 molecules were observed in TEC which suggested endogenous lack of receptor molecules for HIV. The results are discussed in the context of possible thymus oriented autoimmune reaction in HIV and non-HIV bearing patients and in consequence, severe injury of TEC forming microenvironment.

Calcyclin as a marker of human epithelial cells and fibroblasts.

The distribution of calcyclin in human tissues was studied using polyclonal antibodies against this protein. In all organs examined (breast, heart, intestine, kidney, liver, ovary, placenta, stomach, thymus, and uterus) only epithelial cells and fibroblasts were stained. This suggests that calcyclin expression is related either to proliferation rate or secretion activity. The data show that calcyclin might be considered as a marker of some human epithelial cells and fibroblasts.