GENE-EXPRESSION OF PROFIBROTIC MEDIATORS IN BRONCHIOLITIS OBLITERANS SYNDROME AFTER LUNG TRANSPLANTATION

Bronchiolitis obliterans syndrome (BOS) develops in one-third of lung transplant recipients. A fibroproliferative process involving mesenchy mal cells is observed histopathologically. in order further to evaluat e the pathomechanisms of BOS, the gene expression of platelet-derived growth factor (PDGF)-B and transforming growth factor (TGF)-beta(1) in bronchoalveolar lavage (BAL) cells of six lung transplant recipients and appropriate controls was studied. Equal amounts of total RNA were submitted to semiquantitative reverse transcription/polymerase chain r eaction (RT-PCR), amplifying actin, PDGF-B and TGF-beta(1) using estab lished protocols and primer sets. The signal/actin ratio was calculate d based on laser densitometry measurements. TGF-beta(1) transcripts we re detected in all samples, and a slight increase in BOS patients was observed. PDGF-B mRNA was increased in BAL samples from BOS patients c ompared to unaffected recipients and controls. Plotting the FEV1 in pe rcent of vital capacity and the PDGF expression in BOS patients reveal ed an increased PDGF signal preceding lung function deterioration. The data were consistent with the hypothesis based mainly on in vitro fin dings that PDGF and TGF-beta contribute to the development of BOS.