Abstract
Thrombomodulin (TM) has been found as a surface glycoprotein on endothelial cells that functions to maintain blood fluidity in the vessels. We have recently shown immunohistochemically that TM-positive inflammatory cells infiltrate the tissue of lupus miliaris disseminatus faciei and sarcoidosis, and suggested the possible usefulness of TM as histiocytic cell marker in chronic granulomatous inflammation. In the present immunohistochemical study TM expression was investigated in sporotrichosis in order to characterize infiltration of TM-positive cells in mixed cellular infectious granulomas in deep mycosis. Tissue sections from sporotrichosis reacted with anti-human recombinant TM polyclonal rabbit antiserum were observed by the avidin-biotin peroxidase complex immunoenzyme-histochemistry or indirect immunofluorescence method. Morphologically immuno-stained TM-positive cells are characterized as round or polygonal cells with dendritic projections. The majority of TM-positive histiocytic cells are not double-stained by other known histiocytic cell markers, such as CD11b, CD14, CD16, CD33, CD68, MAC387 and lysozyme, indicating that TM does not directly correspond to any of the known histiocytic cell markers. We spequlate that TM-positive cells may belong to a unique cell population, and may represent a subset of histiocytic cells in the infectious granulomas. The significance of TM as a tool to investigate cells infiltrating inflammatory tissues is suggested.
