PURPOSE: Composite face allograft contains various antigenic tissues and skin constitutes one of the most antigenic components. Using hemiface transplantation model under different cell therapy protocols, we have determined gene expression for cytokines which play a crucial role in allograft survival (IL-10, TGFβ) or contribute to allograft rejection (IL-2, TNFα).
METHODS: Forteen hemiface transplantations were performed in 4 experimental groups. Group 1: isotransplantations between Lewis rats (RT1^l) without treatment. Hemiface allotransplantations performed between ACI (RT1^a) donors and Lewis (RT1^l) recipients. All allografts recipients were treated with anti- αβTCR/CsA protocol for 7 days only. Immunosuppressive protocol was augmented with one of supportive cells therapies: Group 2- 100x10⁶ bone marrow cells (BMC), Group 3- 15x10⁶ bone marrow stromal cells (BMSC), and Group 4- 4x10⁶ donor-recipient chimeric cells (DRCC). Skin biopsies from donor face allograft and adjacent recipient skin were harvested at day 7 and 21 day post-transplant. Gene expression levels for proinflammatory cytokines (IL-2 and TNFα) and potentially tolerogenic cytokines (IL-10 and TGFβ) were evaluated in donor and recipient skin biopsies using Taqman® real-time PCR.
RESULTS: All isografts survived indefinitely. Allografts survival: group 2 - 53 days, group 3 - 46 days and group 4 - 43 days post-transplant.
Gene expression of proinflammatory cytokines in skin biopsies from face allograft transplant: At 7 day post-transplants levels of IL-2 were downregulated for all types of cellular therapies, whereas the levels of TNFα were comparable to naïve controls. At 21 day post-transplants IL-2 gene expression was comparable to naïve controls for all therapies except DRCC group.
Gene expression of tolerogenic cytokines in skin biopsies from face allograft transplant: At day 7 post-transplants level of IL-10 was downregulated whereas expression of TGFβ was comparable to naïve controls under all cellular therapies. At day 21 post-transplants gene expressions of both IL-2 and TGFβ was upregulated under BMSC and DRCC therapies. In BMC therapy IL-10 levels were downregulated and TGFβ expression was comparable to naïve controls.
Gene expression of proinflammatory cytokines in skin biopsies adjacent to face allograft transplant: The level of IL-2 was downregulated whereas expression of TNFα was comparable with naïve controls in both 7 and 21 day post-transplants under all cell therapies.
Gene expression of tolerogenic cytokines in skin biopsies adjacent to face allograft transplant: At day 7 and 21 post-transplants the levels of IL-10 were downregulated and levels of TGFβ were comparable to naïve controls under all cellular therapies except DRCC group.
CONCLUSION: Gene expression levels of proinflammatory cytokines were upregulated at 21 day post-transplants in all recipients of face allografts. The tolerogenic cytokines (Il-10 and TGFβ) were upregulated only in face allograft recipients under BMSC and DRCC therapies. Interestingly, the longest allograft survival under BMC therapy was associated with downregulation of both proinflammatory (IL-2) and tolerogenic (IL-10) cytokines. To best of our knowledge this is the first report on cytokine gene expression in face allograft under different type of bone marrow derived cell therapies. These preliminary results may help to evaluate markers for allograft acceptance and rejection in the future studies.