Neutrophil adsorption by polymyxin B-immobilized fiber column for acute exacerbation in patients with interstitial pneumonia: a pilot study.

Polymyxin B-immobilized fiber (PMX) treatment has beneficial effects in patients with acute lung injury/acute respiratory distress syndrome or acute exacerbation of idiopathic pulmonary fibrosis. This study was aimed to clarify the mechanism of PMX treatment for acute exacerbation of interstitial pneumonia (IP). Sixteen consecutive IP patients with acute exacerbation were included. The patients were treated with PMX once daily for 2 successive days at a flow rate of 80-100 ml/min for 6 h. Cells adsorbed by PMX were analyzed morphologically by electron microscopy. Surface markers of these cells were determined by flow cytometry. Serum matrix metalloproteinase (MMP)-9 was measured before and after PMX treatment. Cells adsorbed by PMX were neutrophils and highly expressed HLA-DR, CD14, CD62L and CD114. Serum MMP-9 levels were significantly decreased after PMX treatment. This pilot study demonstrated neutrophil adsorption by PMX and its possible clinical application for acute exacerbation of IP.