Detection of host and donor cells in sex-mismatched rat nerve allografts using RT-PCR for a Y chromosome (H-Y) marker

The donor and host source of support cells, such as Schwann cells, in nerve allograft segments have been the subject of debate. The objective of the p resent study was to assess the utility of a molecular technique that probes for a Y chromosome expressed gene (H-Y) in distinguishing host from donor tissue in sex-mismatched nerve allograft segments. Forty-two Lewis rats rec eived bilateral syngeneic Lewis or allogeneic ACI rat peroneal nerve grafts , with or without cyclosporin A (CsA) treatment. At different times thereaf ter animals were sacrificed and samples were harvested. We transplanted mal es and females reciprocally, to study both survival of donor cells (persist ing H-Y mRNA in male grafts by transcription polymerase chain reaction (RT- PCR), and graft infiltration by host cells (detectable H-Y mRNA in female g rafts). A kinetic analysis revealed a progressive loss of viable donor cell s (loss of H-Y mRNA signal) from allografts, beginning 2-3 weeks, and culmi nating at 4 weeks, with little detectable H-Y in the absence of CsA treatme nt. CsA treatment led to prolonged survival of allograft cells, confirmed b y detectable H-Y mRNA. By studying female grafts in male rats we could conf irm that loss of viable donor tissue in allografts was accompanied by infil tration of host (H-Y mRNA positive) cells, whereas no H-Y mRNA signal was s een in males receiving autografts from females or in immunosuppressed allog raft segments. These data suggest that reverse RT-PCR analysis for a Y chro mosome gene product can be a valuable tool to assess the origin of viable c ells in sex-mismatched nerve allotransplantation tissue.