Electronmicroscopic evidence of synthetic activity in Langerhans cells of human epidermis

The nature of Langerhans cells granules: an ultrastructural study

Langerhans cells and macrophages have been studied in both oral lichen planus lesions and histiocytosis X. Many of the macrophages in both lesions contained phagolysosomes in various stages of degradation. Some of these phagolysosomes were found to develop slender processes and very narrow extensions containing little processed phagocytosed material. These latter structures were indistinguishable from Langerhans granules and were termed Langerhans granule-like structures. There is enough evidence in the present study to suggest that typical Langerhans granules evolve from Langerhans granule-like structures and to confirm that Langerhans cells are a type of macrophage which at one stage of their development show Langerhans granules.

The Langerhans cell density of palatal epithelium in denture and non-denture wearers, as correlated with other parameters of the palatal mucosa

A quantitative histological investigation was carried out on biopsy specimens taken from patients suffering from denture sore mouth. The results were compared with those obtained in investigations on denture and non-denture wearers. The sections were studied by standardized quantitative morphometric methods. After 4 years the denture bearing palatal epithelium from both groups, normal denture wearers and the patients suffering from denture sore mouth did not show changes in mean thickness of the epithelium as compared with the controls. The mitotic index in denture bearing epithelium from patients suffering from denture sore mouth was three times lower than in the epithelium of the normal denture wearers. The number of Langerhans cells correlated with the mitotic indices of the group of denture wearers and non-denture wearers. The group of denture sore mouth patients showing a low mitotic index showed a high number of Langerhans cells in their palatal epithelium. The three groups of patients investigated did not show differences in density of mast cells in the lamina propria of their palatal epithelium.

Langerhans cells in human apocrine ducts

Electron microscopic observations revealed for the first time a few number of Langerhans cells within the intradermal apocrine duct of the normal human axillary skin. In many respects the fine structural features of Langerhans cells were noted to be identical with those described in the epidermis. Our present results suggest that Langerhans cells could be a stable and constant cellular constituent for the normal apocrine ducts. The significance of this presence of Langerhans cells remains to be investigated.

Cells containing Langerhans cell granules in human lymph nodes of "atypical hyperplasia" with fatal outcome and leukemic reticuloendotheliosis

Langerhans cell granules could be found in atypical histiocytes in lymph nodes of three patients with "atypical hyperplasia" with fatal outcome and one patient with leukemic reticuloendotheliosis. These atypical histiocytes might be derived from immature mesenchymal cells in lymph nodes and the Langerhans cell granules might be induced in these cells by a particular condition. Only one of the Langerhans cell granules seemingly associated with the plasma membrane could be observed in these atypical histiocytes and all of the granules were seen within the cytoplasm. Quite a number of Langerhans cell granules were located near the Golgi apparatus. Several atypical granules very similar to the Langerhans cell granules could also be observed in these atypical histiocytes. These Langerhans cell granules were assumed to be directly derived from the Golgi apparatus and/or derived from the atypical granules which were secreted from the Golgi apparatus. The relationship between the Langerhans cell granules and the microtubules must also be considered, because Langerhans cell granules were found near the centrioles and microtubules.