Induction with T-cell receptor antibody leads to long-term laryngeal allograft function

Ten-Month Laryngeal Allograft Survival with Use of Pulsed Everolimus and Anti—αβ T-Cell Receptor Antibody Immunosuppression

Objectives:

The risks of daily immunosuppression limit the use of laryngeal transplantation as a reconstructive option. Pulsed immunosuppressive dosing can lessen these risks. The study objective was to develop a long-term pulsing regimen that minimizes exposure to immunosuppressive agents.

Methods:

Rat laryngeal transplantation was performed. Everolimus (1 mg/kg per day) and anti–αβ T-cell receptor (TCR) antibodies (250 μg) were given for 7 days beginning 1 day before transplantation and for 5 days beginning on day 90 after transplantation. On day 180, group 1 (n = 5) received the initial regimen for 3 days, and group 2 (n = 5) received everolimus (1 mg/kg per day) until euthanization, which occurred when parathyroid hormone (PTH) levels dropped to less than 11 pg/mL or at 300 days.

Results:

Four of the 5 rats in group 1 had normal PTH levels at 300 days. The PTH level for 1 rat was less than 11 pg/mL at 270 days. In group 2, none of the 5 rats had normal PTH levels at 300 days. Two had PTH levels below 11 pg/mL at 270 days, and 3 had PTH levels below 11 pg/mL at 300 days. The allografts that survived beyond 300 days had an essentially normal histologic appearance.

Conclusions:

Pulsed immunosuppression prevented allograft rejection for 10 months and was more effective than daily everolimus. Short-term perioperative therapy followed by pulsed, tapered dosing is a viable alternative to traditional regimens and may decrease associated risks.

Anti-αβ-T-cell receptor antibodies in the setting of laryngeal transplantation

Inhibiting T-cell activation is critically important to the induction of transplantation tolerance. Monoclonal antibodies directed against the αβ-T-cell receptor have been shown to cause selective immunodepletion of this T-cell population and can provide long-term allograft acceptance. This article discusses the role of this promising immunosuppressive agent in scientific research and clinical utilization. Specifically, the article focuses on its efficacy and mechanism of tolerance induction in solid tissue and composite tissue allograft transplantation with a particular focus on laryngeal transplantation.