Fluorescence automatic cell sorter and immunohistochemical investigation of CD68-positive cells in meningioma

Infiltration of brain neoplasms by mononuclear cells including monocytes/ma crophages has attracted little attention since they have marked morphologic al heterogeneity. Twenty-seven meningiomas were studied by anti-CD68 antibo dy-gated flow cytometry and by immunohistochemical analysis using the anti- CD68 antibodies. Flow cytometric analysis divided cells contained within tu mor tissues into CD68-positive and -negative cells. In addition, eight glio mas, eight metastatic brain tumor, and 12 pituitary adenomas were investiga ted in the same way to compare meningiomas. The mean contents of CD68-posit ive cells were 24.0 +/- 3.7% in meninggiomas, 4.4 +/- 1.4% in gliomas, 9.5 +/- 3.9% in metastatic brain tumors, and 4.5 +/- 1.8% in pituitary adenomas . Immunohistochemically, CD68-positive cells showed significant heterogenei ty and were detected as round, rod-shaped, ameboid and ramified cells in me ningiomas. Although the infiltrated mononuclear cells in gliomas have been investigated to some degree and showed that they express cytokines and/or g rowth factors, these infiltrated cells in meningioma have barely been studi ed. The CD68-positive cells detected in this study are likely to be monocyt es, macrophages and microglias, and are presumed to be in various functiona l stages and to play important roles in growth regulation in meningioma. (C ) 1999 Elsevier Science B.V. All rights reserved.