Expression of glucocorticoid receptors in non-neoplastic lymphoid follicles and B cell type malignant lymphomas

Objective: To evaluate the expression of human glucocorticoid receptors (hGRs), such as hGR (4H2), hGR-alpha, and hGR-beta, in non-neoplastic lymphoid follicles and B cell type malignant lymphomas. Methods: The expression of hGRs in non-neoplastic lymphoid follicles and malignant lymphomas, including diffuse large cell lymphoma, mantle cell lymphoma, and follicular lymphoma, was examined immunohistochemically. HGR (4H2) expression was confirmed by double immunostaining of tissues and in isolated cells from tonsillar germinal centres, and by immunoelectronmicroscopy. Results: In secondary lymphoid follicles of any non-neoplastic diseases-such as chronic tonsillitis, reactive lymphadenitis, and Kimura's disease - the germinal centre cells often expressed hGR (4H2) and hGR-alpha. Double immunocytochemical staining of isolated germinal centre cells showed that the majority of hGR (4H2) positive cells were CD20 positive B cells, and that follicular dendritic cells also expressed hGR. Immunoelectronmicroscopy revealed the presence of nuclear hGR (4H2) in the binucleated follicular dendritic cells and germinal centre cells. The frequency of hGR (4H2) expression in diffuse large B cell lymphoma was higher, that in mantle cell lymphoma was lower, and that in follicular lymphoma was intermediate among the types of malignant lymphoma. The hGR (4H2) expression was less frequent in cases of grade I follicular lymphoma. Conclusions: There are differences in hGR expression between the germinal centre and the mantle zone in non-neoplastic lymphoid follicles, and differences of hGR (4H2) expression among the types of malignant lymphoma and grades of follicular lymphoma, which probably contribute to the different steroid sensitivities.