MACROPHAGES (HISTIOCYTES) IN VARIOUS REACTIVE AND INFLAMMATORY CONDITIONS EXPRESS DIFFERENT ANTIGENIC PHENOTYPES

The purpose of this study was to determine whether human tissue macrophages (MΦs) in various inflammatory/reactive conditions express different immunophenotypes. Using a large panel of monoclonal antibodies to monocyte/MΦ-related antigens and a frozen-section immunoperoxidase technique, the following conditions were studied: granulomatous inflammation of unknown etiology, sarcoidosis, cat-scratch fever, toxoplasmosis, Gaucher's disease, and juvenile xanthogranulomas. The results show that there is immunophenotypic variation of the MΦs among the various inflammatory/reactive conditions. For example, the MΦs in cat-scratch fever are nearly unique in the expression of the "early inflammation" antigen identified by antibody 27E10, and the MΦs in juvenile xanthogranulomas, unlike those in most of the other conditions, lacked the antigen detected by antibody 25F9. The MΦs in Gaucher's disease differed from those in the other disorders by the combined absence of CD11b, CD14, G16/1, CD1a, CD25, and CD30. The inflammatory/reactive MΦs also exhibited differences from those in "normal" tissues, namely, a tendency toward acquisition of the antigens identified by antibodies Mac 387 and G16/1 and the more uniform expression of the "activation" antigens CD25, CD30, and CD71. The antigenic variations described here probably reflect differences in antigenic stimuli and MΦ function. In addition to the possible biologic implications, this MΦ immunophenotypic diversity may have practical diagnostic applications. © 1992.