Fibrocytes are associated with vascular and parenchymal remodelling in patients with obliterative bronchiolitis.
BACKGROUND
The aim of the present study was to explore the occurrence of fibrocytes in tissue and to investigate whether the appearance of fibrocytes may be linked to structural changes of the parenchyme and vasculature in the lungs of patients with obliterative bronchiolitis (OB) following lung or bone marrow transplantation.


METHODS
Identification of parenchyme, vasculature, and fibrocytes was done by histological methods in lung tissue from bone marrow or lung-transplanted patients with obliterative bronchiolitis, and from controls.


RESULTS
The transplanted patients had significantly higher amounts of tissue in the alveolar parenchyme (46.5 +/- 17.6%) than the controls (21.7 +/- 7.6%) (p < 0.05). The patients also had significantly increased numbers of fibrocytes identified by CXCR4/prolyl4-hydroxylase, CD45R0/prolyl4-hydroxylase, and CD34/prolyl4-hydroxylase compared to the controls (p < 0.01). There was a correlation between the number of fibrocytes and the area of alveolar parenchyma; CXCR4/prolyl 4-hydroxylase (p < 0.01), CD45R0/prolyl 4-hydroxylase (p < 0.05) and CD34/prolyl 4-hydroxylase (p < 0.05). In the pulmonary vessels, there was an increase in the endothelial layer in patients (0.31 +/- 0.13%) relative to the controls (0.037 +/- 0.02%) (p < 0.01). There was a significant correlation between the number of fibrocytes and the total area of the endothelial layer CXCR4/prolyl 4-hydroxylase (p < 0.001), CD45R0/prolyl 4-hydroxylase (p < 0.001) and CD34/prolyl 4-hydroxylase (p < 0.01). The percent areas of the lumen of the vessels were significant (p < 0.001) enlarged in the patient with OB compared to the controls. There was also a correlation between total area of the lumen and number of fibrocytes, CXCR4/prolyl 4-hydroxylase (p < 0.01), CD45R0/prolyl 4-hydroxylase (p < 0.001) and CD34/prolyl 4-hydroxylase (p < 0.01).


CONCLUSIONS
Our results indicate that fibrocytes are associated with pathological remodelling processes in patients with OB and that tissue fibrocytes might be a useful biomarker in these processes.
Andersson-Sjöland
Annika
A
Division of Medicine and Allergology, Department of Clinical Medical Science, Lund University, Sweden. Annika.Andersson_Sjoland@med.lu.se
Erjefält
Jonas S
JS
Bjermer
Leif
L
Eriksson
Leif
L
Westergren-Thorsson
Gunilla
G
D000293:Adolescent; D000328:Adult; D000368:Aged; D056151:Airway Remodeling; D018952:Antigens, CD34 / Q000032:analysis; D001344:Autopsy; D015415:Biomarkers / Q000032:analysis; D016026:Bone Marrow Transplantation / Q000009:adverse effects; D001989:Bronchiolitis Obliterans / Q000209:etiology / Q000401:mortality / Q000473:pathology*; D016022:Case-Control Studies; D002648:Child; D042783:Endothelial Cells / Q000737:chemistry / Q000473:pathology*; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D017493:Leukocyte Common Antigens / Q000032:analysis; D008168:Lung / Q000098:blood supply* / Q000737:chemistry / Q000473:pathology*; D016040:Lung Transplantation / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D011393:Procollagen-Proline Dioxygenase / Q000032:analysis; D011650:Pulmonary Alveoli / Q000737:chemistry / Q000473:pathology*; D019718:Receptors, CXCR4 / Q000032:analysis; D055815:Young Adult
D018952:Antigens, CD34; D015415:Biomarkers; C527276:CXCR4 protein, human; D019718:Receptors, CXCR4; D011393:Procollagen-Proline Dioxygenase; D017493:Leukocyte Common Antigens