Heterogeneous increase in CD34-positive alveolar capillaries in idiopathic pulmonary fibrosis

Am J Respir Crit Care Med. 2004 Jun 1;169(11):1203-8. doi: 10.1164/rccm.200308-1111OC. Epub 2004 Jan 30.


To elucidate the apparent contradictions in vascular remodeling in the lungs of patients with idiopathic pulmonary fibrosis, we evaluated alveolar vascularity in relation to the various degrees of fibrosis in surgically biopsied lungs of usual interstitial pneumonia. Alveolar capillary endothelial cells were intensely immunoreactive with CD34 but not with von Willebrand factor. Vascular density, that is, the relative ratio of capillary area to total area of alveolar walls, was significantly higher at low grades of fibrosis than in control lungs, whereas vascular density gradually decreased as the degree of fibrosis increased and was lower than that of control lungs in the most extensively fibrotic lesions. No vessels were observed inside fibroblastic foci. The potent angiogenic factors vascular endothelial growth factor and interleukin-8 were abundantly produced by capillary endothelial cells and alveolar epithelial cells in highly vascularized alveolar walls. In contrast, venules with CD34-negative but von Willebrand factor-positive endothelial cells localized in the center of the fibrotic lesions were slightly increased and identified as postcapillary venules by three-dimensional reconstructed images. These results indicate the presence of heterogeneous vascular remodeling in usual interstitial pneumonia.

Publication types

  • Comparative Study
  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigens, CD34 / metabolism*
  • Biomarkers / analysis
  • Capillaries / immunology
  • Capillaries / pathology
  • Endothelial Cells / metabolism
  • Endothelial Cells / pathology
  • Humans
  • Image Processing, Computer-Assisted
  • Imaging, Three-Dimensional
  • Immunohistochemistry
  • Interleukin-8 / metabolism
  • Ki-67 Antigen / metabolism
  • Pulmonary Alveoli / blood supply*
  • Pulmonary Alveoli / immunology*
  • Pulmonary Alveoli / physiopathology
  • Pulmonary Fibrosis / etiology*
  • Pulmonary Fibrosis / metabolism*
  • Pulmonary Fibrosis / physiopathology
  • Pulmonary Veins / metabolism
  • Pulmonary Veins / pathology
  • Pulmonary Veins / physiopathology
  • Severity of Illness Index
  • Statistics as Topic
  • Thrombomodulin / metabolism
  • Vascular Endothelial Growth Factor A / metabolism
  • von Willebrand Factor / metabolism


  • Antigens, CD34
  • Biomarkers
  • Interleukin-8
  • Ki-67 Antigen
  • Thrombomodulin
  • Vascular Endothelial Growth Factor A
  • von Willebrand Factor