It is established that development of mixed chimerism following allotransplantation is associated with induction of tolerance to allotransplants. Although chimerism in peripheral blood can be detected and measured with flow cytometry, local chimerism at other interested sites (eg, lymph nodes, spleen, bone marrow or allograft) was not easily accessed. Herein we developed a chimerism-detection system based on the level of specific short tandem repeat (STR), which displays various lengths at different rat strains. Mixture of genomic DNA from LEW and BN rats with predetermined gradients was amplified with polymerase chain reaction (PCR) and subjected to capillary electrophoresis. The prepared standard curve was in excellent linearity (r² > 0.999) and suitable for detection of strain-specific signal quantitatively. With this system, as low as 0.2% of BN DNA in the mixture is detectable. We have applied this methodology to vascularized composite allotransplantation (VCA) and found that at early rejection, graft chimerism was low at around 40%. For those recipients that recovered from rejection and eventually developed tolerance, graft chimerism was gradually increased to 70%. By contrast, the chimerism was dropped to 15% for the allograft at the end-stage rejection. This result suggests that the evolution of local chimerism is correlated with allograft fate. This system may complement the currently available methodologies such as flow cytometry and immunohistochemistry and provide information of chimerism systematically as well as locally during development of tolerance or rejection following solid organ or vascularized composite allotransplantation.

CITATION INFORMATION: Huang X.-T, Cheng H.-Y, Lin C.-F, Qiu S.-S, Shih L.-Y, Wei F.-C. Developing a PCR-Based System to Access the Correlation of Local Chimerism and Fate of the Vascularized Composite Allotransplant. Am J Transplant. 2016;16 (suppl 3).

« Back to 2016 American Transplant Congress