TGF-β1 expression in kidney allograft protocol biopsies during cyclosporine: a therapy

Background: TGF-beta(1) expression has been described to increase along with time from transplantation and has also been linked to allograft dysfunction and toxic effects of cyclosporine. Our aim was to correlate intragraft TGF-beta(1) expression with cyclosporine exposure after kidney transplantation. Methods: Altogether 53 kidney allograft protocol biopsies from 42 patients on a low-dose cyclosporine-based regimen obtained at 3, 6, and 12 months were classified according to Banff and the chronic allograft damage index (CADI). TGF-beta(1) expression in tubules, glomeruli, vessels, and inflammatory cells was semi-quantitatively scored and correlated with cyclosporine concentrations (C0 and C2), CADI, and graft function. Results: TGF-beta(1) expression was mildly increased along time from transplantation, but the results were not statistically significant. TGF-beta(1) expression was neither related to CADI nor to the use of ACE inhibitors/ARB. TGF-beta(1) expression in the kidney was not correlated with C0 or C2 levels or kidney graft function during follow-up. Conclusion: In protocol biopsies from patients on low-dose cyclosporine regimen, expression of TGB-beta(1) was not significantly increased along time since transplantation, and did not correlate with cyclosporine exposure. Our findings suggest that the toxic effects of low-dose cyclosporine on TGF-beta expression may be milder than previously thought.