Frequencies of Donor-Reactive Helper T Lymphocytes Correlate with Rejection of Aortic Valve Allografts in Rats
Frank J. M. F. Dor MD, Frans B. S. Oei MD, Leonard M. B. Vaessen PhD, Richard L. Marquet PhD, Ad J. J. C. Bogers MD,, Willem Weimar MD

In clinical valve allografting, a substantial part of graft failure can be attributed to immunological processes. An objective means of monitoring the graft longitudinally in valve allograft recipients with respect to rejection is not available. One method of determining immune activity in the recipient would be to measure helper T-lymphocyte frequencies (HTLf) in peripheral blood and spleen. HTLf have been correlated with transplantation outcome in solid organ transplantation. In this study, the value of this survey was assessed in a rat model for aortic valve transplantation in relation to histopathology and valve dysfunction, which is impossible in the clinical situation. After allogeneic aortic valve transplantation in rats, a significant increase in donor-reactive HTLf was found in both peripheral blood and spleen in correlation with histologically proven rejection and valve dysfunction. In conclusion, the determination of donor-reactive HTLf may be a useful tool to monitor aortic valve allograft recipients.