With the advances in renal transplantation surgical techniques and immunosuppressive agents, the near-term survival rate of kidney transplantation has been substantially improved, but the long-term survival rate has not been substantially improved. The factors that affect the long-term survival of transplanted kidneys include chronic rejection, death of the transplanted kidney with work, recurrence of transplanted kidney disease, BK virus infection of the transplanted kidney, and immunosuppressive toxicity of the transplanted kidney. Drug toxicity and death of the transplanted kidney with work were previously thought to be the main causes of transplant renal failure, but recent advances in research suggest that the main cause of transplant renal failure is chronic humoral rejection. What is chronic humoral rejection? After kidney transplantation, the kidney transplant recipient receives blood transfusion, multiple pregnancies or certain allogeneic cell implants, and the transplanted kidney is a foreign individual. Therefore, the body will continue to produce antibodies against these foreign cells, and these antibodies are called population reactive antibodies (PRA for short). Some of these antibodies are directed against the transplanted kidney and are called donor-specific antibodies (DSA for short). These donor-specific antibodies will cause damage to the transplanted kidney and lead to chronic humoral rejection. This is characterized by a gradual increase in blood creatinine, in some cases proteinuria and, in rare cases, a small amount of hematuria. This chronic humoral rejection is clinically insidious and many people do not have any discomfort and can only be detected by regular blood creatinine checks, but the damage has actually occurred long before the blood creatinine rises, only that the self does not feel any discomfort. Therefore, this kind of rejection reaction is very hidden, and when the blood creatinine rises, the damage is already relatively obvious. Is there any way to detect the occurrence of this damage even before the blood creatinine rises? There is a method to detect antibodies in the body that can help achieve this goal. The new method for detecting PRA is extremely sensitive and can determine whether the transplanted kidney is potentially at risk for chronic humoral rejection by detecting the amount of antibodies in the blood and the presence of antibodies against the donor. Therefore, for all patients after kidney transplantation, PRA level in blood should be tested regularly. If there is an elevation, it is necessary to adjust the medication or further treatment in time to lower the PRA level to avoid further damage. And active treatment. For kidney transplant patients with stable blood creatinine and negative PRA for the first time, it is sufficient to check once in 6 months and 1 year after surgery, and once a year thereafter. For the kidney transplant patients with positive PRA initial test room, they need to be further checked for PRA class I, class II and MICA antibodies. Further check is to clarify the type and concentration of antibodies so as to determine whether it is for their transplanted kidney (DSA). If there is DSA, it needs to be treated aggressively, if it is not an antibody against your own transplanted kidney, it just needs to be observed regularly. If found positive, the recommendation is to check every six months to observe the change of antibodies and then decide whether to treat it symptomatically. Some patients have been checked for elevated PRA and diagnosed with chronic humoral rejection, these people need to be checked every 3 months or June to observe the effect of treatment, and if it does not go down or goes up, some special treatment needs to be applied. The treatment of antibody reduction includes the following three aspects: 1. physical methods to remove antibodies: plasma replacement, immunosorbent, dual plasma filtration, etc. 2. drugs to remove antibodies: anti-CD20 monoclonal antibody, bortezomib (Vanco) and other drugs 3. drugs for complement: Icuzumab, etc. In summary, regular check of PRA in blood after kidney transplantation can help to detect problems at an early stage and deal with them early to avoid or slow down the occurrence of chronic humoral rejection. It is recommended that each kidney transplant recipient should have regular checkups if their financial condition permits.