Identification of early tolerance regulator genes induced by allochimeric therapy using microarray-based genomewide scan.

We have demonstrated that peri- or postoperative delivery of allochimeric [a1h(u)]-RT1.A(a) class I major histocompatibility complex molecules with donor-type (RT1A(u)) immunogenic epitopes presented in recipient-type (RT1A(a)) sequences induced donor-specific tolerance in ACI (RT1a) recipients of WF (RT1u) heart allografts. A genomic scan during the early posttransplant period was performed to elucidate the underlying operative mechanisms. A rat genome study after transplantation was carefully designed using Affymetrix Rat Genome 230 2.0 Array. The allochimeric treatment group is 3-day cyclosporine (CsA)-treated ACI recipients that accepted Wistar Furth RT1u cardiac allografts with postoperative dosage of allochimeric molecules, while the control is 3-day CsA-treated ACI recipients of WF cardiac allografts. All the samples were harvested 5 days after heart transplant as the early stage of tolerance detection. Following array data normalization and modeling, we compared the above two treatment groups and identified a total of 250 tolerance regulator genes induced by allochimeric molecules only.