Clinical Research Of Panel Reactive Antibodies Positive Sensitized Recipients Of Kidney Transplantation

In recent years, kidney transplantation has become the most successful and the most fundamental method in current clinical treatment of end-stage renal disease due to the great progress in the immunologic basis of organ transplantation, tissue typing technology and transplant surgery technology associated with the development and utilization of new potent immune inhibitors and biological agents. Successful kidney transplantation not only can significantly improve the life quality of patients and reduce the complications, and also reduce the mortality rate, thus being the most effective measures and best alternative treatments to save the life of patients with chronic kidney failure. Many factors influence the rate of the operation success and long-term survival of the graft. Of most severe one is the rejection reaction including hyperacute rejection (HAR), accelerated acute rejection (AAR), acute rejection (AR) and chronic rejection (CR). These reactions have been profound in the population with panel reactive antibodies (PRA). Thus, it was still remained a widespread concern in the field of organ transplantation how to increase the operation success and recipient/graft survival rate for a long time and reduce the graft function decline caused by rejection.PRA refers to the HLA antibody produced in transplant recipients due to allergenic immune sensitization induced by human leukocyte antigen (HLA), and is likely induced by multiple transfusions, pregnancy and accepting organ transplants, so that the patients are in the pre-sensitization state. Since Terasaki applied it clinical in1960’s, determination of PRA has gained wide and certainly attention. PRA plays an important role in solid organ transplantation. Its existence and the degree of sensitization are not only closely related with the transplantation rejection, and also the delayed graft function (DGF) and decreased graft survival rate, etc. Since PRA is the main cause of HAR, some scholars in the past agreed that the existence of the PRA is contraindicated of kidney transplantation. PRA can reflect recipients’ immune state. Thus the level of the antibodies in the recipients has a practical significance in prediction the chance of rejection after transplantation, improvement of the success rate of solid organ transplantation and the survival.The subjects in this project were patients with PRA positive sensitization undergone successful renal allograft surgery for uremia and their corresponding donor. Preoperative detection of HLA and PRA performed. And the degree of sensitization, types and specificity of antibody analyzed. The AR incidence of recipients with PRA positive sensitized by kidney transplant and AR reversal rate after anti-rejection therapy examined, and the results compared with the recipients with PRA negative in the same period, to study the clinical characteristics of PRA positive recipients sensitized by kidney transplantation. Finally, combining HLA cross reactive group matches, analyzing the cross group matches of HLA of positive PRA recipients with its corresponding donor, HLA mismatch, sensitized recipients and long-term graft survival were analyzed in order to provide a clinical guideline for kidney transplantation of PRA positive recipients. This paper is subscribed as following two chapters:(1) the clinical analysis on the incidence, reverse the rate of AR in recipients with positive PRA sensitized by kidney transplantation;(2) the effects of HLA cross reactive group matches on recipient/graft survival rate of recipient positive PRA sensitized.Chapter1The clinical analysis on the incidence, reverse the rate of AR in recipients with positive PRA sensitized by kidney transplantation ObjectiveStudy and compare between recipients with positive or negative PRA in the incidence of AR and the reverse rate following treatment in one year in order to explore the clinical characteristics of recipients with positive PRA sensitized.MethodChoose of203cases of patients of allograft kidney transplant with uremia in our hospital from January2006to January2009. All objects were examined with preoperative HLA genotyping, PRA and complement dependent toxicity of trace lymphocyte cross (CDC) assay, and divided into PRA positive sensitization and PRA negative group according to the preoperative PRA test results. Comparison between two groups performed in age, gender, history of the primary disease, dialysis, blood transfusions, pregnancy history, history of transplant, cold/hot ischemia time of donor kidney, postoperative immunosuppression scheme, and the time of graft function returned to normal, postoperative incidence of AR within1year, anti-rejection treatment and AR reversal rate effectively. For PRA positive group, the extent of sensitization, the type and specificity of antibody for kidney transplant recipients analyzed. Preoperative required avoiding donor HLA antigen react with all deposits of HLA antibodies in recipients and the CDC test were negative. For sensitized PRA positive recipients, the preoperative preprocess include taking immunosuppressants or induced by basiliximab in advance. Success follow-up more than1year, and compared between recipients with PRA positive sensitized and PRA negative recipients within1year in the incidence of AR and effective reverse rate after treatment. Diagnostic criteria for AR based on comprehensive judgment such as clinical manifestation, laboratory examination, and Doppler ultrasound examination and biopsy of transplant renal and so on. For AR patients, two groups took the same anti-rejection treatment, initial impact treatment with methylprednisolone (MP) for3days at the dose of0.5g,0.25g and0.25g, respectively. When the rejection with hormone resistant occurred, treated with ATG (3mg/kg/d) for3-5d, and some patients treated with plasma exchange. All data were analyzed statistically using SPSS13.0software. Between PRA positive recipients and PRA negative recipients compared with chi-square test in incidence of AR, AR effectively reverse rate after treatment. The measurement data between two independent samples were compared by using Student t test. P<0.05was considered to have statistical significant difference.ResultsAmong203cases of kidney transplantation recipients,41cases of recipients were preoperative PRA positive sensitized and162cases were the PRA negative. There were no significant differences between the two groups in age, gender, primary disease, dialysis method and cold/hot ischemia time of donor kidney (P>0.05); In the history of blood transfusion, pregnancy history, history of transplant have significant difference (P<0.05). All cases were successful kidney transplantation and not occurrence of postoperative hyperacute rejection and accelerated acute rejection.In41cases of recipients positive for preoperative PRA, the strength ranged from25%-70%. Among which13cases were deposited of positive for only HLA class Ⅰ antibodies,15cases for only HLA class Ⅱ antibodies,13cases there were positive of both HLA class Ⅰ and class Ⅱ antibodies, and the PRA account for50%or more. After transplantation, the renal function of27cases were removed well postoperatively, serum creatinine (SCr) level of15cases down to normal within1week, and12cases dropped to normal within2weeks. Within one year after transplantation there are14cases occurrence of AR, with6cases of male and8females. Of which AR with positive class Ⅰ antibodies occurred in5cases, positive class Ⅱ antibodies in7cases, and both positive class Ⅰ and type Ⅱ antibodies concurrent occurred in2cases. In14cases of recipients with AR,7cases were transplanted for the first time; another7cases were transplanted the second times. Most of AR occurred within1-2weeks postoperatively, the incidence of AR was34.15%(14/41). In162cases of recipients with negative PRA to accept a kidney transplant in the same period, the renal function of103cases were postoperative recovered well, the SCr level of72cases dropped to normal within1week after transplantation,31cases within two weeks. Within1year after transplantation there were59cases occurred of AR, with49cases of male and10females, and however51cases for the first transplantation,8cases for the secondary. The AR general appeared within1-3months after surgery, and the incidence was36.42%(59/162). The incidence of AR between PRA positive sensitized recipients and PRA negative recipients was compared. The difference was no statistically significant (χ2=0.073, P=0.786).In14cases of recipients with positive PRA and AR,12cases were effective by using MP bolus therapy, but2cases not got a satisfactory effect. When administration of ATG for3-5d at dose of3mg/kg/day, the rejection reactions were effectively reversed, and the graft’s function recovered. The average time of AR reversal was25days; the effective reverse rate was100%(14/14). Among59cases of AR recipients with negative PRA, the same anti-rejection treatment was used. Of53cases were effective for MP bolus therapy;6cases occurred of hormone resistant rejection. For the treatment of ATG for3-5days at dose of3mg/kg/day,4cases were effective,2cases were not satisfactory in ATG treatment for5days, and restart blood dialysis after resection graft due to invalid for3times of plasmapheresis and pathological indicated as acute humoral rejection. In PRA negative group, the rate of the effective AR reverse was96.61%(57/59). The recipients with positive PRA sensitized compared with PRA negative group of recipients, the difference between two groups of AR reversal rate has no statistical significance (χ2=0.865, P=0.352).ConclusionsIt was necessary for the success of kidney transplantation of PRA positive recipients of that the HLA antigen of the donor must avoid to contact with all stored HLA antibodies of the recipients, and the preoperative CDC test must be negative. Thus can effectively avoidance the hyperacute rejection and accelerated acute rejection. In our transplant center, no significant difference between the kidney transplant recipients with positive and negative PRA in incidence of postoperative AR, anti-rejection AR reversal rate after treatment indicated that the accuracy in PRA detection on sensitized recipient basis is one of the key technologies to reasonable choice of donor and successful kidney transplantation. By pretreatment, immune induction therapy preoperatively, postoperatively powerful anti-rejection treatment in time, the transplantation of PRA positive recipients may obtain a good effect of transplantation.Chapter2The effects of HLA cross reactive group matches on recipient/graft survival rate of recipient with positive PRA sensitizedObjectiveTo investigate the effects of HLA cross reactive group matches on recipient/graft survival rate of recipients with positive PRA sensitized.MethodDonor-recipients HLA-A, B, DR gene classification were detected by using polymerase chain reaction-sequences specific primer (PCR-SSP). The intensity and the specificity of PRA antibodies from41cases recipients accurately detected before operation to assess the status of sensitization. The best matching donors were selected by using CREGs matches’standard. Gene frequencies at HLA-A, B and DR loci and distribution patterns of class Ⅰand class Ⅱ antibodies were studied. The relationship between the numbers of HLA mismatching, postoperative complications and long-term survival rate of recipient/graft were analyzed.ResultsAmong41cases of recipients positive for preoperative PRA,13cases were deposited of positive for only HLA class Ⅰ antibodies,15cases for only HLA class Ⅱ antibodies,13cases there were positive of both HLA class Ⅰ and class Ⅱ antibodies. High frequency genes were A2(34.15%), A11(30.49%) and A24(17.07%) at the HLA-A locus, B60(18.29%), B46(13.41%) and B13(12.20%) at the HLA-B locus, and DR12(15.85%), DR4(13.41%), DR8(10.98%), DR9(10.98%) and DR11(10.98%) at the HLA-DR locus.72occurrences of14HLA class Ⅰ antibodies and97occurrences of11class Ⅱ antibodies were detected, with higher frequencies of occurrence observed in A2(11.11%), A11(9.72%), A24(8.33%), B40(12.50%), B13(8.33%) and B17(8.33%) of HLA class Ⅰ antibodies, and DR4(16.49%), DR7(15.46%) and DR9(14.43%) of HLA class Ⅱ antibodies.According to conventional six-antigen HLA matching criteria, cases with0-6mismatches at HLA-A, B and DR loci were1,2,3,13,11,7and4, respectively. By use of CREGs the number of cases changed to7,18,7,6,1,2and0, respectively. Compared with conventional HLA matching, CREGs increased the percentages of0and1donor-recipient MM to17.07%and43.90%from2.44%and4.88%, and reduced the percentages of5and6MM to4.88%and0%from17.07%and9.75%. The0,1and2MM are7.32%,36.58%and56.10%at the HLA-B locus and17.07%,41.46%and41.46%at the HLA-DR locus according to conventional HLA matching criteria, in comparison with78.05%,19.51%and2.44%at the HLA-B locus and46.34%,43.90%and9.76%at the HLA-DR locus when using CREGs. The differences in0-2mismatches at the HLA-B and DR loci had a statistical significance (P=0.0001, P=0.001).Among the PRA-positive sensitized kidney transplant recipients,41were observed with neither hyperacute rejection nor accelerated acute rejection of postoperative.14were observed with acute rejection (AR),6of which had delayed graft function (DGF) at the same time and1with AR+DGF died of pulmonary mycotic infection4months after transplantion (graft with functional death).2cases of chronic rejection (CR) were recorded, with the one receiving dialysis again at the function loss of the graft had last4years after operation, and the other having acceptable renal function with the serum creatinine level of around200μmol/L. The recipient and graft survivals have been40vs39, with the1-,3-and5-year recipient/graft survival rates of97.56%(40/41),97.56%(40/41) and95.12%(39/41), respectively.ConclusionsThe distribution of high frequency HLA antigens and that of anti-HLA antibodies among PRA-positive sensitized recipients does not exactly agree. The selection of donors should avoid mismatches between high frequency anti-HLA antibodies and corresponding HLA antigen loci. HLA matching is the most vital factor of long-term graft survival, especially for PRA-positive sensitized recipients. The threshold in donor selection would be3mismatches. In the cases of unsatisfactory conventional matching, CREGs can be used to raise the HLA matching rate. Less mismatches and increase the chances of graft success, reduce the undesired effects caused by PRA, and improve the recipient/graft survival rate.