High proliferative potential colony-forming cells (HPP-CFCs) in the peripheral blood of rheumatoid arthritis patients with interstitial lung disease

Objective: To examine the presence of high proliferative potential colony-forming cells (HPP-CFCs) in the peripheral blood of rheumatoid arthritis ( RA) patients with and without interstitial lung disease (ILD). Methods: Peripheral blood mononuclear cells from 35 RA patients with and without ILD, 12 patients with infectious pulmonary diseases, 10 patients with idiopathic pulmonary fibrosis (IPF), and 20 healthy volunteers, were assayed for in vitro colony formation. R esults: HPP-CFCs were detected significantly more frequently in the peripheral blood of patients with ILD (11/ 14: 78%, p<0.05) than in that of patients without ILD (4/21: 19%). HPP-CFCs were not detected in the peripheral blood of patients with infectious pulmonary diseases, those with IPF or healthy volunteers. Conclusions: HPP-CFCs were frequently found in the peripheral blood of RA patients with ILD compared with those without ILD, suggesting the mobilization of HPP-CFCs from the bone marrow into the peripheral blood in association with ILD in RA.