Monoclonal antibody therapy with ciclosporin and steroids in nonmatched cadaveric renal transplants

Monoclonal antibodies in renal transplantation: a review

OKT3 is the first anti-CD3 monoclonal antibody available for treatment in humans. Over the last few years it has proven to be a very powerful immunosuppressive agent in renal transplantation. Clinical studies have shown that OKT3 is superior to high-dose steroids as first-line treatment for acute renal allograft rejection. Furthermore, it is comparable to antithymocyte globulin (ATG) in treating steroid-resistant rejection and is also effective as rescue treatment in ATG- and antilymphocyte globulin-(ALG-) resistant rejection. Despite its excellent rejection-reversal rate, OKT3 treatment is followed by a substantial percentage of re-rejections, most of which respond well to steroids. In the early post-transplantation period, a prophylactic course of OKT3 is very effective in preventing acute rejections, and in this respect it is probably equivalent to ATG. Indirect evidence exists that a prophylactic course of OKT3 may be beneficial in immunologically high-risk patients and in patients with delayed graft function. However, more clinical studies are required to answer the question whether OKT3 should be given as induction treatment, as first-line treatment, or as rescue treatment. To answer this question, the side effects of OKT3 should also be taken into account. First-dose-related side effects, although frequent and disturbing, are usually transient and seldom life-threatening, provided overhydration has been corrected and steroids have been given before the first administration. These side effects are attributed to the release of cytokines as a result of T-cell activation or lysis. After exposure of patients to OKT3 an increased incidence of infections and malignancies has been reported. However, it is not yet clear whether this is due to OKT3 as such, or whether it merely reflects the total burden of immunosuppression. Xeno-sensitization represents an important limitation to OKT3 treatment, although a second or third course can still be effective in patients with low antibody titers. The precise immunosuppressive mechanism of anti-CD3 monoclonal antibodies is yet unknown. Monitoring of patients treated with OKT3 revealed CD3 and/or T-cell antigen receptor depletion and immunological incompetence of remaining T cells. More clinical data are required to establish the correct dose and duration of OKT3 treatment. In conclusion, OKT3 is a powerful immunosuppressive agent but its real value in renal transplantation remains to be determined. A practical approach may be to reserve it for the treatment of steroid-resistant rejections.(ABSTRACT TRUNCATED AT 400 WORDS)

Prophylactic use of OKT3 in liver transplantation. A review

Liver rejection in the era of cyclosporine-based immunosuppression is approximately 60-70%. Approximately 15-25% of liver transplant patients will require hemodialysis following transplantation. These facts argue for a potent, less nephrotoxic immunosuppressive regimen, especially during the period of vulnerability to these events. Prophylactic use of OKT3 has been suggested as a means to decrease the need for hemodialysis while maintaining potent immunosuppression. The goal of this review is to examine potential benefits and pitfalls of this regimen. A lack of documentation of long-term patient and graft survival, the potential susceptibility to infectious complications, development of sensitization, and the cost must be weighed against the decreased need for hemodialysis and the control of early rejection episodes.

Muromonab CD3. A review of its pharmacology and therapeutic potential

Muromonab CD3 (Orthoclone OKT3, Orthoclone, OKT3) is the first monoclonal antibody to become available for therapy in humans. In effect it blocks all cytotoxic T cell function. Clinical trials show that muromonab CD3 is effective in reversing acute renal, hepatic, cardiac and combined kidney-pancreas transplant rejection episodes. It has also been shown to be effective in the treatment of rejections resistant to conventional treatment. As such it offers a significant alternative when no other therapeutic option remains open. Other clinical trials have shown that muromonab CD3 is more effective than high-dose corticosteroids in reversing first episodes of acute renal and hepatic rejection. Additionally, it appears effective as a prophylactic treatment against acute renal and cardiac rejection in the immediate post-transplantation period. Preliminary studies also indicate that it may be effective in preventing or reversing graft-versus-host disease in bone marrow transplant patients. The development of neutralising antibodies may limit the effectiveness of a second course of muromonab CD3 therapy in some patients. In conclusion, muromonab CD3 offers a significant new approach to immunosuppressive therapy and has provided a valuable therapeutic alternative for the treatment of acute solid organ transplant rejection.

Experience with Orthoclone OKT3 monoclonal antibody in liver transplantation

Experience with the use of Orthoclone OKT3 monoclonal antibody for the treatment of acute cellular rejection in a series of 130 human orthotopic liver transplantations is reviewed. Treatment was highly effective in reversing rejection, in reducing the rate of retransplantation, and in lowering patient mortality. OKT3 was also useful for cyclosporine sparing in patients with poor renal function, hypertension, or CNS toxicity. There was a significant incidence of opportunistic infection associated with the use of OKT3.