DETECTION OF LARGE MACROPHAGE-COLONY FORMING CELLS IN THE PERIPHERAL-BLOOD OF PATIENTS WITH RHEUMATOID-ARTHRITIS

Objective, To test for the presence of colony forming cells: that form large macrophage colonies (> 2.5 mm in diameter, > 10,000 cells), in the peripheral blood of patients with rheumatoid arthritis (RA) and to determine its association with the clinical and laboratory; features of RA. Methods, Peripheral blood mononuclear cells (PBMC) from 96 pati ents with RA and 20 healthy controls were assayed for in vitro colony formation. In addition, PBMC from 38 patients with other rheumatic dis eases including systemic lupus erythematosus (SLE), progressive system ic sclerosis (SSc), and polymyositis/dermatomyositis (PM/DM); 23 patie nts with infectious inflammatory diseases were also assayed. Results, Large macrophage colony forming cells were detected in the peripheral blood of 19% of patients with RA (18/96), but not in that of healthy c ontrols. In addition, these cells were detected in the peripheral bloo d of 11 of the 38 patients with other rheumatic diseases (7/13 SSc and 4/11 PM/DM), but not in the 23 patients with infectious diseases. In the patients with RA, interstitial lung disease was significantly more frequently observed among patients in whom colony forming cells were found than among those in whom they were not found (p < 0.001). Conclu sion. Based on the size of the colonies they formed, the macrophage co lony forming cells detected in patients with RA probably corresponded to primitive hematopoietic progenitor cells, defined as high prolifera tive potential colony forming cells (KPP-CFC). Our observations provid e preliminary evidence of the appearance of HPP-CFC in the circulation during inflammation of RA, and during that in other rheumatic disease s such as SSc and PM/DM, and of the association of HPP-CFC with inters titial lung disease in patients with RA.