Clinical use of rabbit antihuman lymphocyte globulin in cadaver-kidney transplantation

Thirty Years of Tacrolimus in Clinical Practice

Tacrolimus was discovered in 1984 and entered clinical use shortly thereafter, contributing to successful solid organ transplantation across the globe. In this review, we cover development of tacrolimus, its evolving clinical utility, and issues affecting its current usage. Since earliest use of this class of immunosuppressant, concerns for calcineurin-inhibitor toxicity have led to efforts to minimize or eliminate these agents in clinical regimens but with limited success. Current understanding of the role of tacrolimus focuses more on its efficacy in preventing graft rejection and graft loss. As we enter the fourth decade of tacrolimus use, newer studies utilizing novel combinations (as with the mammalian target of rapamycin inhibitor, everolimus, and T-cell costimulation blockade with belatacept) offer potential for enhanced benefits.

Tailored Rabbit Antithymocyte Globulin Induction Dosing for Kidney Transplantation

Background

Rabbit antithymocyte globulin (rATG) is the most widely used kidney transplant induction immunotherapy in the United States. It was recently Food and Drug Administration approved for this indication with typical dose recommendations of 1.5 mg/kg for up to 7 days given via a central line.

Methods

We theorized that reduced rATG dosing when compared with conventional dosing (6-10.5 mg/kg) is safe and effective, leading to development of a risk-stratified treatment protocol. Five-year data from a retrospective cohort of 224 adult kidney transplants (2008-2013) with follow-up through 2015 is presented. Cumulative rATG doses of 3 mg/kg were administered peripherally to nonsensitized living donor recipients, 4.5 mg/kg to nonsensitized deceased donor recipients. A subset of higher immunologic risk recipients (defined as history of prior transplant, panel reactive antibody greater than 20%, or flow cytometry crossmatch positivity) received 6 mg/kg.

Results

There were no differences in patient or graft survival between the 3 groups. One-year rejection rates in the first 2 groups were 8.3% and 8.8%, respectively, comparable to contemporaneous rates reported to the Scientific Registry of Transplant Recipients. Dose tailoring permitted substantial cost savings estimated at US $1 091 502. Mean length of stay fell by almost 3 days as the protocol was refined. There were no episodes of phlebitis. Infection rates were comparable with those reported to the Scientific Registry of Transplant Recipients.

Conclusions

The novel findings of the current study include peripheral administration, reduced dosing, favorable safety, excellent allograft outcomes, and clear associative data regarding reduced costs and length of stay.

Results of the double-blind, randomized, multicenter, phase III clinical trial of Thymoglobulin versus Atgam in the treatment of acute graft rejection episodes after renal transplantation

BACKGROUND

Thymoglobulin, a rabbit anti-human thymocyte globulin, was compared with Atgam, a horse anti-human thymocyte globulin for the treatment of acute rejection after renal transplantation.

METHODS

A multicenter, double-blind, randomized trial with enrollment stratification based on standardized histology (Banff grading) was conducted. Subjects received 7-14 days of Thymoglobulin (1.5 mg/kg/ day) or Atgam (15 mg/kg/day). The primary end point was rejection reversal (return of serum creatinine level to or below the day 0 baseline value).

RESULTS

A total of 163 patients were enrolled at 25 transplant centers in the United States. No differences in demographics or transplant characteristics were noted. Intent-to-treat analysis demonstrated that Thymoglobulin had a higher rejection reversal rate than Atgam (88% versus 76%, P=0.027, primary end point). Day 30 graft survival rates (Thymoglobulin 94% and Atgam 90%, P=0.17), day 30 serum creatinine levels as a percentage of baseline (Thymoglobulin 72% and Atgam 80%; P=0.43), and improvement in posttreatment biopsy results (Thymoglobulin 65% and Atgam 50%; P=0.15) were not statistically different. T-cell depletion was maintained more effectively with Thymoglobulin than Atgam both at the end of therapy (P=0.001) and at day 30 (P=0.016). Recurrent rejection, at 90 days after therapy, occurred less frequently with Thymoglobulin (17%) versus Atgam (36%) (P=0.011). A similar incidence of adverse events, post-therapy infections, and 1-year patient and graft survival rates were observed with both treatments.

CONCLUSIONS

Thymoglobulin was found to be superior to Atgam in reversing acute rejection and preventing recurrent rejection after therapy in renal transplant recipients.

Transplantation immunology

A major function of the immune response is the discrimination of self from nonself. It is this response that must be overcome in transplant rejection. Progress in understanding these basic immune mechanisms has helped to improve clinical outcome and lays the foundation for a new generation of therapies.

Chronic renal failure in infants and children

Chronic renal failure is an uncommon problem for pediatricians, but early recognition is important for maximizing growth and minimizing complications. Marked strides have been made in understanding and treating renal osteodystrophy. Recombinant erythropoietin holds the promise of reversing the anemia associated with renal insufficiency. Dialysis remains an important therapy for sustaining these children, and transplantation offers realistic hope for a functioning kidney.

Enzyme-linked immunosorbent assay for HLA determination on fresh and dried lymphocytes

HLA-A and -B antigens were detected on fresh and dried peripheral blood lymphocytes by an enzyme-linked immunosorbent assay. Intact cells fixed to plates with glutaraldehyde were used as antigen and anti-HLA alloantisera as a source of antibodies. Determination of HLA antigens by the ELISA technique was comparable with the complement-dependent cytotoxicity test. The relative stability of HLA antigens as shown in this report and the extensive polymorphism of the HLA system make the ELISA technique a promising tool for the analysis of HLA antigens on non-living cells including, for example, medicolegal investigation of blood stains.

Antithymocyte globulin in cadaver kidney transplantation: a randomized trial based on T-cell monitoring

The influence of horse antihuman thymocyte globulin (ATG) on renal allograft survival was assayed between March 1977 and August 1978. Fifty consecutive patients were randomly assigned to the treatment or the control group. Patients in both groups received azathioprine and prednisolone. ATG was added in the experimental group. The daily dosage was such as to maintain the rosette-forming cell (RFC) level at 10% of baseline values. The number of renal failure episodes (RFE's)was significantly lower in the experimental group during the period (1 month) ATG was given than it was in the control group during that same period of time. Two years after transplantation, kidney survival was 79% in the ATG group and 52% in the control group. The amount of steroids necessary to control RFE's was significantly lower in the ATG group. The dosages of ATG used in the experimental group were relatively small (average daily dose, 3.08 +/- 0.26 mg/kg of body wt), and adverse reactions were mild. Blood tolerance was excellent. T-cell monitoring thus appears to be an effective method in evaluating the daily dosage of ATG.

Studies on the effects of heterologous antisera against subcellular thymocyte fraction

Subcellular fractions of mice thymocytes were used for sensitization of rabbits. The antisera were examined for their immunosuppressive potency in vivo by allogeneic murine tumor metastases system and on skingraft survival and in vitro by leukocyte agglutination tests. The results indicated that the most potent immunosuppressive antisera was that against the second fraction (Fr. 2) of the detergent soluble endoplasmic reticulum fraction from thymocytes.

115 patients with first cadaver kidney transplants followed two to seven and a half years. A multifactorial analysis

One hundred fifteen consecutive patients received first transplants from cadaver donors at the University of Minnesota between January 1, 1968, and May 31, 1973. All patients have been followed for at least two years. The two-year survival rate is 70 per cent and the two-year transplant function rate is 58 per cent. Considerable improvement in both patient survival and transplant function has been noted since 1971. The success of transplantation appears to depend to a large degree on the age of the transplant recipient, the number of HLA antigens matched between donor and recipient, and the dose of antilymphoblast globulin (ALG) administered to the recipient during the first two weeks after transplantation. Each of these factors appears to be important even when the other factors are controlled, and when patients with diabetes, suffering technical failure or hyperacute rejection, are excluded. The results utilizing well-matched cadaver kidneys plus large doses of ALG appear to be equivalent to those obtained with the use of mismatched kidneys from relatives, but further analysis will be required to draw a definite conclusion. Patients receiving poorly-matched cadaver kidneys do far less well than patients receiving mismatched related grafts, however, even when ALG is utilized.

A controlled clinical trial of treatment with ALG in established rejection of renal allografts

A controlled clinical investigation of the effect of equine anti-human-lymphocyte globulin (ALG) on established rejection after transplantation has been carried out in a group of 31 patients. Compared with a control group, the treated group showed a significantly positive effect of ALG in the form of a faster reversal of rejection episodes (p less than 0.05). Leucocytes, lymphocytes, erythrocytes, thrombocytes and immunoglobulins were unaffected by the treatment, but there were signs of a complement-consuming process and an influence on blast transformation tests. No rise in antibody titre against equine globulin was seen.

Clinical evaluation of equine antithymocyte globulin in recipients of renal allografts: Analysis of survival, renal function, rejection, histocompatibility, and complications

Equine antithymocyte globulin combined with azathioprine and prednisone as immunosuppressive therapy in 50 transplant recipients prolonged allograft survival and seemed to modify the severity of rejection episodes. Although nine patients died from a variety of causes, only three kidneys were lost to rejection, one of which was hyperacute. There were no serious untoward hematologic or systemic effects caused by the ATG, and all patients completed the course of therapy. Infection, a serious and frequent complication of transplant patients, was encountered no more often than in other transplant series not using ALG. The data pertaining to the clinical value of ATG, although suggestive in terms of its immunosuppressive effects, is still not conclusive; and a definitive answer to this question awaits further evaluation in a series of cadaveric recipients in a randomized-double-blind study.

Effect of rabbit ALG on cadaver kidney transplant survival

Images