Expression of transforming growth factor β pathway components in chronic graft-versus-host disease after allogeneic...

Chronic graft-versus-host disease (cGvHD), an immunological complication of allogeneic cell transplantation, is the principal cause of non-relapse mortality and morbidity. Even though advances have been made in understanding the pathophysiology of this disorder, many questions remain. We sought to evaluate gene expression of transforming growth factor β (TGF-β) pathway components, through quantitative RT-PCR and PCR array, in patients with cGvHD with different disease activity. We observed an upregulation of SMAD3, BMP2, CDKN1A, IL6, and TGF-β2 genes in the clinical tolerance group, which had never developed cGvHD, or which had been withdrawn from all immunosuppressive treatments (IST) for at least 1 year. In addition, SMAD5 gene upregulation was observed in cGvHD patients undergoing IST, and ordinal regression showed a correlation between SMAD5 expression and disease severity. Our data support the evidence of the important role of TGF-β effects in the pathological process of cGvHD.