Growth factor gene expression in bronchoalveolar lavage cells from patients with lung fibrosis

We have studied the gene expression of ten growth factors in bronchoalveolar lavage (BAL) cells from patients with lung fibrosis by using a reverse-transcription-DNA polymerase chain reaction (RT-PCR) technique. IL-1 beta mRNA was detected in almost all of the samples, and TGF beta and IGF-I mRNA were detected in some. The BAL supernatant from the patients was found to have mitogenic activity for lung fibroblasts. Moreover, human recombinant IL-1 beta, TGF beta and IGF-I were found to promote the proliferation of lung fibroblasts. These data suggest that IL-1 beta, TGF beta and IGF-I gene expression in BAL cells might be involved in the development of lung fibrosis.