Background: As crucial secondary lymphoid organs located at the kunction between allograft and host, the complex cellular and molecular processes within lymph nodes (LNs) following vascularized composite allotransplantation (VCA) are poorly understood. Additionally, the connection between these processes and the eventual outcome of the allograft remains to be clarified.
Materials and Methods: The lymph nodes were collected from within the hindlimb-derived osteomyocutaneous VCA and the draining lymph nodes in recipients confirmed to either undergo rejecting the transplants or develop donor-specific tolerance. Flow cytometry was used to assess lymphocyte compositions, while RNA sequencing (RNAseq) was employed to analyze gene expression.
Results and Discussions: Flow cytometric analysis revealed significant different B cells levels and dentrici cell population in LNs associated with the VCA outcome and the LN origins. Biased donor chimerism levels were also observed. The RNAseq analsysis unveiled a wealth of alterations of gene expression witin donor-versus recipient-derived LNs linked to rejection, comprising approximately 1000 up-regulated abd 370 down-regulated genes. Notable changes in cytokines, chemokine, receptors, major histocompatibility complexes (MHC) genes, as well as genes implicated in cytoskeleton remodeling and metabolism control were observed. The ongoing investigation aims to explore the mechanistic roles played by these genes, seeking to unravel their intricate interplay with cellular dynamics and studying their potential as therapeutic targets to enhance VCA outcomes.
Conclusion: Our investigation unveiled LN cellular and molecular changes linked to rejection of VCA and development of donor-specific tolerance. Further detailed exploration holds promise for developing targeted interventions to enhance VCA survival and establish tolerance.