INFILTRATION OF LUNG CARCINOMAS WITH MACROPHAGES OF THE 27E10-POSITIVE PHENOTYPE

In order to gain insight into the role of macrophages in human lung ca rcinomas, we investigated material from 35 lung carcinomas and 5 healt hy lungs with 4 different antibodies (CD68, MRP8, MRP14, 27E10) recogn izing different macrophage subtypes. Infiltration with CD68-positive m acrophages was highest and comparable in healthy lungs and lung carcin omas. Compared to healthy lungs, the infiltration of MRP8- and MRP14-p ositive macrophages was reduced in lung carcinomas while the number of 27E10-positive cells was enhanced. No difference in the infiltration of macrophages was observed between the different histological subtype s of carcinomas such as squamous carcinoma, small lung carcinoma, aden ocarcinoma and bronchio-alveolar carcinoma. Furthermore, we present a highly suitable technique for the isolation and enrichment of macropha ges from human lung carcinomas resulting in a 5-10 fold enrichment and a yield of e.g. 2-3 x 10(6) 27E10-positive macrophages/g tumor biopsy . Together with the recent findings that 27E10-positive macrophages ar e prevalent in early acute inflammation and release cytotoxic mediator s [9] and to inhibit tumor cell proliferation [6] our findings suggest that 27E10-positive macrophages may play a role in antitumor cytotoxi city in human lung carcinomas. (C) 1997 Elsevier Science Ireland Ltd.