Evaluation of immune response profiles between composite tissue transplant patients and solid organ transplant patients

Objective: Composite Tissue Allotransplantation (CTA); is the process of transplanting complex structures containing tissues such as muscles, bones, nerves, tendons and skin originating from multiple different embryological structures. Recently, it is a popular type of transplant that can be applied when surgical knowledge and equipment are available. Although the number of CTA has increased, studies on the immune response created by such transplants are very limited in the literature. Our study is based on the evaluation of the immune response generated against the transplanted tissue after CTA. Method: Four face transplants, two upper extremity transplants and one uterus transplant, which were carried out within the Akdeniz University Department of Plastic, Reconstructive and Aesthetic Surgery, were included in the project. To compare the immune response that develops in CTA, 15 kidney and 15 liver transplant individuals, which were carried out within the AU Transplantation Center, were also included in the project. Also, immunological analyses of 15 healthcare individuals as a control group were carried out within the study's scope. The cells forming the immune system were analyzed by flow cytometry analysis from volunteers' peripheral blood samples. Serum levels of cytokines were analyzed by the ELISA method, and mRNA expression levels were analyzed by RT-qPCR. Results: It was observed that the ratio of CD3 + T cells in the peripheral blood circulation in individuals with CTA was higher than in the kidney transplant group. It was observed that the mRNA levels of IL-4 and IL-6 cytokines in composite tissue transplants were statistically significantly higher than the liver transplant group and the IL-10 level was significantly higher than healthy individuals. When the levels of cytokines in the peripheral blood circulation were examined, no significant difference was found in terms of CTA. Conclusion: Our study has shown that the response to composite tissue transplants may be different from the immune response in solid organ transplants. Keywords: Composite Tissue Allotransplantation, Rejection, Immune Response, Tolerance