[Distribution of three proteinases in tumor cells of malignant histiocytosis]

Tumor tissues from 36 autopsy cases of malignant histiocytosis were collected for studying the distribution of lysozyme (LyS), alpha 1-antichymotrypsin (ACT) and alpha 1-antitrypsin (AT) by double peroxidase anti-peroxidase staining. The positive rates of LyS, ACT and AT were 97.14%, 91.67% and 77.78% respectively. LyS was seen mainly in the well-differentiated histiocytes. No phagocytosis was found in these cells. ACT existed in some well-differentiated histiocytes in which phagocytosis was often seen. A few atypical histiocytes also showed positive reaction to ACT. AT-positive cells were mainly atypical histiocytes and atypical multinuclear-giant-histiocytes. This study not only confirms that the tumor cels of malignant histiocytosis originate from histiocytes, but also indicates that staining of LyS, ACT and AT is useful for classification and differential diagnosis of tumor cells in malignant histiocytosis.