The distribution of muramidase (lysozyme) in human tissues

The distribution of muramidase (lysozyme) in normal and pathological human tissues has been studied, using an immunohistological technique. The enzyme was demonstrated in a variety of healthy tissues, including serous salivary acinar cells, lactating mammary tissue, Paneth cells, renal tubular cells, myeloid cells (including eosinophils), and histiocytic cells. In pathological tissues the most striking positivity was encountered in reactive histiocytic cells in granulomatous conditions such as tuberculosis and Crohn's disease. The finding of this study are related to previous reports of the distribution of human and animal muramidase and the implications of patterns of muramidase staining in pathological histiocytes are briefly discussed.