金子 千之

In the present study, immunohistochemical and immunoelectron microscopic techniques were used to differentiate Langerhans cells (LC) from interdigitating cells (IDC) in the lymph nodes (LN) of dermatopathic lymphadenopathy. The majority of the dendritic cells that existed in the LN of dermatopathic lymphadenopathy were positive for OKT-6 (CD 1a) antibody. It was concluded that these dendritic cells were not IDC, but LC. Electron microscopically, LC in these LN contained a few Birbeck granules (BG). In order to prove the fact that these dendritic cells were LC, the existence of BG was investigated ultrastructurally by examining serial sections, and immunoelectron microscopically for CD 1a positive cells. Most of the LC in the lymph nodes we examined were negative for the anti-proliferating nuclear antigen (PCNA) antibody. This finding may mean that LC in the LN are fully developed cells and do not divide in the LN. Langerhans cells may migrate from the skin lesions to the paracortical areas in the LN, which then may become enlarged.

The identification of cells in body cavities of cancer patients is sometimes difficult to make. In order to make a definite cytological diagnosis, we observed the same cells by using light microscopy (LM)-scanning electron microscopy (SEM)-transmission electron microscopy (TEM). In this study we first stained cells by the Papanicolaou method after fixation in 1% glutaraldehyde for LM, and then attempted to observe them successively by SEM-TEM after fixation in 1% paraformaldehyde and 1.25% OsO4. Our method and procedures in examining successively one and the same cells in body cavity fluids by using LM, SEM, and TEM ensured accurate discrimination among adenocarcinoma cells, mesothelial cells, and macrophages. The results of this study suggest that LM-SEM-TEM may be of diagnostic value in distinguishing among mesothelial cells, macrophages, and adenocarcinoma cells. This method also succeeded in disclosing differences between the ultrastructure of the cell surfaces, and those of the cytoplasm, and of the nuclei. It is desirable that LM-SEM-TEM observation can be introduced into various aspects in order to obtain an improvement in the diagnosis by cytologic examination, the judgment of therapeutical effects, drug selection, and prognostic presumption. (C) 1994 Wiley-Liss, Inc.

Langerhans cells (LCs) and interdigitating cells (IDCs) are said to have the same morphological and immunological characteristics. We have reported on Birbeck granules (BG)-bearing LCs, which are positive for both OKT-6 (CD1a) and anti S-100 protein antibodies, and IDCs which are only positive for S-100 protein, but negative for OKT-6. In this paper, we examined the characteristics of dendritic cells in dermatopathic lymphadenopathy (DPL) and Histiocytosis X (HCX) using immunohistochemical and immuno-electron microscopic techniques. The majority of the dendritic cells which existed in the lymph nodes of DPL were positive for OKT-6. We concluded that these dendritic cells were not IDCs, but LCs. Electron microscopically, LCs in these lymph nodes contained only a few BG. Most of the LCs were negative for PCNA antibody. This finding means that the proliferative activity of these LCs is very low and that they do not divide or proliferate in the lymph nodes. On the other hand, HCX is considered to be a rare proliferative disorder of LCs. HCX cells were positive for S-100, OKT-6, CD4 (Leu3a) and HLA-DR (Ia), in addition they were highly positivity for PCNA. These findings indicate that HCX cells originate in immature cells which are already part of the Langerhans cell lineage.

Cells immunostained with antibodies against both OKT-6 and S-100 protein were observed only in superficial and hilar lymph nodes draining tissues with predominantly squamous epithelia. In contrast, in mesenteric lymph nodes and the spleen, only S-100 protein-positive, but OKT-6-negative cells were found. We suspect that the S-100 and OKT-6-positive cells might be Langerhans cells (LC) and the S-100-positive, OKT-6-negative cells, interdigitating reticulum cells (IDC). We further postulate that the LC in superficial and hilar lymph nodes might migrate from squamous epithelia, with which contact is required for the formation of Birbeck granules.