Graft vasculopathy and tolerance: Does the balance of Th cells contribute to graft vasculopathy?

Background Cardiac allograft vasculopathy (CAV) is sometimes observed even though the allograft may survive indefinitely. In this study, me examined w hether or not the preferential activation of Th2-type cells prevents the de velopment of CAV. Methods. Hearts from C56BL/10 mice were transplanted heterotopically into t he abdominal cavities of C3H.He recipient mice, and monoclonal antibodies ( mAbs) to T-cell receptor (TCR) alpha beta or CD80/CD86 were administered af ter transplantation. The incidence of CAV was then examined histologically. To investigate the relative Th1/Th2 balance, the levels of IFN gamma and I L4 in the transplanted hearts were measured. Results. Indefinite heart graft survival was observed in mice treated with either the anti-TCR alpha beta or anti-CD80/CD86 mAbs and these mice accept ed donor-type (C57BL/10) skin grafts but rejected those from a third party (BALB/c). Evidence of CAV was found in the mice treated with the anti-TCR a lpha beta mAb, but CAV did not develop in the mice treated with anti-CD80/C D86 mAbs. Preferential activation of Th2-type cells was dominant in the tol erant mice treated with anti-TCR alpha beta mAb, but it was not dominant in the tolerant mice treated with anti-CD80/CD86 mAbs. Conclusion. These findings suggest that the dominance of Th2-type cells doe s not prevent allograft vasculopathy, (C) 2000 Academic Press.