Rejection is the main cause of transplantation failure. Currently, the specificity and sensitivity of clinical parameters are relatively poor, which cannot accurately prompt the exact cause of rejection. It is of great clinical significance to explore novel biomarkers for monitoring the rejection. In this article, the latest research progress on the biomarkers of rejection risk in organ transplantation were summarized from the perspectives of transplantation pathology, immune cells and regulatory immune cells, non-human leukocyte antigen antibodies, exosomes, cell-free DNA and combination gene prediction, aiming to provide reference for early warning and treatment of rejection in organ transplantation.

Xenotransplantation is the most promising method to resolve the organ shortage problem in the future. In recent years, the advances in gene editing and immunological technique have driven the rapid development of xenotransplantation. However, there are still many insurmountable obstacles in the clinical application of xenotransplantation, among which the rejection is the most important cause of the xenotransplantation failure. Regulatory immunological cells are a group of immunological cells with the negative regulation function in the body, which can inhibit allotransplantation rejection and prolong the survival time of the graft. This paper summarized the research progress of regulatory immunological cells in the xenotransplantation application in recent years, providing reference for the prevention and treatment of xenotransplantation rejection.

Objective:To evaluate the efficacy of arthroscopic suture combined with perforator tendon double reduction and Endobutton plate technique for the treatment of tibial avulsion fracture of posterior cruciate ligament (PCL).Methods:A retrospective case series study was conducted to analyze the clinical data of 32 patients with tibial avulsion fracture of PCL, who were admitted to First People′s Hospital of Huizhou from January 2018 to October 2022. There were 19 males and 13 females, with age range of 18-65 years [(42.8±15.0)years]. By the Meyers-Mckeever classicfication, 27 patients were type II, and 5 type III. All the patients were treated with arthroscopic suture combined with perforator tendon double reduction and Endobutton plate technique to fix PCL tibial avulsion fracture at the insertion point. The fracture reduction was observed by X-ray films before discharge. Three months postoperatively, the fracture healing was observed by CT imaging, and the stability of knee joint was evaluated by posterior drawer test. The knee active range of motion, visual analogue score (VAS), Lysholm score, and International Knee Documentation Committee (IKDC) score were used to evaluate the pain and knee function before operation, at 3 months after operation, and at the last follow-up. Intraoperative and postoperative complications were observed.Results:All the patients were followed up for 6-36 months [(19.7±8.7)months]. The X-ray films showed satisfactory reduction of the fracture before discharge, and the CT showed that the fracture line was blurred to various degrees at 3 months after operation. Two patients had degree I positive posterior drawer test at 3 months after operation, and the rest were negative. The knee active range of motion was improved from 54.2°(45.0°, 70.0°) preoperatively to 124.8°(120.0°, 130.0°) at 3 months postoperatively and to 130.6°(125.0°, 135.0°) at the last follow-up (all P<0.01). The VAS was decreased from 5.1(3.0, 7.0)points preoperatively to 1.2(1.0, 2.0)points at 3 months postoperatively and to 0.1(0.0, 0.0)points at the last follow-up (all P<0.01). The Lysholm score was improved from 31.2(24.3, 37.0)points preoperatively to 73.6(69.3, 78.8)points at 3 months postoperatively and 92.6(91.0, 95.0)points at the last follow-up (all P<0.01). The IKDC score was increased from (20.9±7.1)points preoperatively to (59.2±8.9)points at 3 months postoperatively and to (77.5±7.0)points at the last follow-up (all P<0.01). Compared with 3 months after operation, the last follow-up showed significantly improved knee active range of motion, significantly decreased VAS, and significantly increased Lysholm score and IKDC score (all P<0.05). No intraoperative nerve vascular injury, postoperative incision infection, or lower limb venous thrombosis was observed. Conclusion:Arthroscopic suture combined with perforator tendon double reduction and Endobutton plate technique can achieve good reduction and high healing rate in patients with tibial avulsion fracture of PCL, with improved joint mobility, relieved pain, good recovery of knee joint function, and few complications.