Peaks of transforming growth factor-β mRNA in alveolar cells of lung transplant recipients as an early marker of chronic rejection

Chronic lung rejection (CLR) induces a fibroproliferative disorder leading to the occlusion of small airways. It has emerged as the major factor limiting the survival of lung transplant recipients. Predictive markers of CLR are lacking, and its diagnosis is generally ascertained when the fibrosis process is irreversible. We have quantified the expression of transforming growth factor-beta (TGF-beta), a critical mediator of fibrogenesis, in alveolar cells from lung transplant recipients using a competitive reverse transcriptase polymerase chain reaction method. We have shown that patients with CLR presented marked peaks of TGF-beta mRNA expression, in contrast with patients without CLR. These peaks preceded the diagnosis of CLR by several months in two of three patients who died within 2 years of diagnosis. Our data suggest that TGF-beta expression in alveolar cells could serve as an early predictive and prognostic marker of chronic lung rejection.