HISTOLOGY AND CYTOCHEMISTRY OF HUMAN SKIN .3. POLYMORPHISM AND CHROMOTROPY OF MAST CELLS

[摘要] In human skin stained with 0.05% toluidine blue buffered to pH 2.7, 3.2, 4.0, and 5, mast cells exhibit pronounced variation in size and shape, in the number and size of their granules, and in the ability of the granules to be stained. The typical, rounded, or oval mast cells form only a fraction of the total mast cell population. There are numerous cells which, with the exception of their cytoplasmic metachromatic granules, are similar to fibroblasts. The fibroblastic mast cells vary from cells with a sparse granulation to cells with the cytoplasm and all of its processes replete with granules. This suggests that mast cells develop from fibroblast-like cells. The typical mast cells contain many coarse granules whereas the fibroblastic ones contain both coarse and fine granules. At pH 2.7 and 3.2, most of the coarse mast granules stain metachromatically, but the fine granules usually stain a pale orthochromatic color. At pH 4 or 5, all of the mast granules are stained metachromatically. These differences in size, and particularly in the stainability of mast granules, may indicate stages in their maturation.