A pilot study of immunosuppression minimization after pancreas-kidney transplantation utilizing thymoglobulin induction and sirolimus maintenance therapy

Aims. To determine outcomes utilizing thymoglobulin and sirolimus immunosuppression, with early steroid withdrawal in low-immune responder pancreas-kidney (SPK) recipients, and conversion from cyclosporine (CsA) to mycophenolic acid (MPA) in all recipients at 6 months posttransplantation. Methods. SPK recipients received thymoglobulin, sirolimus, and reduced-dose CsA immunosuppression. Low immune responders (non-African-Americans with a pretransplant PRA < 30%) were withdrawn from prednisone on posttransplant day 5 and high immune responders were continued on prednisone. All recipients were converted from CsA to MPA at 6 months posttransplantation. During conversion, recipient immune response was monitored by flow PRA and a T-cell stimulation assay (Cylex). Results. With a mean follow-up of 9 +/- 4 months, one pancreas was lost to pancreatitis, with no patient or kidney losses and no acute rejection episodes. All eight low immune responder patients were steroid-free at 9 +/- 5 months posttransplantation. Seven patients (five low and two high immune responders) with at least 6-month follow-up were converted from CsA to MPA. One high immune responder with a pretransplant PRA of 43% remained with a PRA of 53% +/- 2% postconversion. The second high immune responder had a pretransplant PRA of 34% and a postconversion PRA of 0%. The five low immune responders had a mean pretransplant PRA of 16% +/- 15% and a postconversion PRA of 0% (P < .01). The Cylex assay resulted in 67% low responsiveness for both high and low immune responders. Conclusion. Thymoglobulin induction with sirolimus maintenance therapy permitted immunosuppression minimization in selected pancreas transplant recipients. Posttransplant evaluation revealed a diminished (regulated) immune response in six of seven patients.