Liver transplantation: changing goals in immunosuppression

Hepatitis B in liver transplant recipients

1. The use of low-dose immunosuppressive therapy along with pre- and posttransplantation nucleos(t)ide therapy and posttransplantation hepatitis B immunoglobulin (HBIG) has yielded marked improvements in survival. 2. Lamivudine (Epivir-HBV), adefovir (Hepsera), entecavir (Baraclude), tenofovir (Viread), emtricitabine (Emtriva), and the combination drugs tenofovir + emtricitabine (Truvada) and abacavir + lamivudine (Epzicom) are effective nucleos(t)ide antiviral agents that, in some cases, may help reverse liver disease sufficiently to avoid transplant. 3. In posttransplantation patients, virus suppression with some combination of HBIG and the nucleos(t)ide agents may prevent graft loss and death or the need for a second transplant. 4. In both the pre- and posttransplantation setting, the goal of hepatitis B virus management is complete virus suppression. 5. The use of low-dose intramuscular HBIG is evolving, with studies showing that dosing and cost can be reduced by 50-300% with a customized approach. 6. Elimination of HBIG from the treatment paradigm is currently under evaluation and may be possible with the use of newer medications that have no or low resistance rates. 7. Although there is growing evidence that some types of combination therapy may decrease the chance that drug resistance will develop and increase the likelihood of long-term success in preventing graft loss and death, additional research will be required to determine which combinations will work well in the long term, and which will not.

New concepts in organ transplantation

Over the past several decades, many factors have led to higher rates of patient and graft survival in organ transplantation. These factors include enhanced immunosuppressants available in recent years such as Neoral, Prograf, sirolimus, mycophenolate mofetil and anti-interleukin-2 receptor monoclonal antibodies. In addition, other new drugs, such as FTY 720, FK 778, anti-CD20, anti-CD40, and anti-CH52 monoclonal antibodies, are now being tested in clinical studies. Furthermore, there have been advances in surgical techniques, such as the piggyback method without venovenous bypass, side-to-side anastomosis of the hepatic veins, use of vascular staplers, biliary duct-to-duct anastomosis with or without tube drainage, microsurgical hepatic artery anastomosis and laparoscopic donor nephrectomy. Finally, better patient and donor selection criteria with regard to HBV- and HCV-seropositive donors, diabetic donors, donors with malignancies, older donors, ABO-incompatible donors, and non-heart-beating donors have been combined with optimal timing of transplantation, better options for treating early surgical and late medical complications, and improved management in intensive-care units. Other noteworthy scientific and social development are on the horizon namely genetic advances in xenografting and cell transplantation, and induction of immunologic tolerance. This article reviews the current developments that have significantly improved graft and patient survival among solid-organ transplants.

Reasons for long-term use of steroid in primary adult liver transplantation under tacrolimus

BACKGROUND

Tacrolimus is a potent immunosuppressive agent that provides higher freedom from acute and chronic rejection than cyclosporine after liver transplantation (LTx). Initially, a steroid-free state was observed in about 70% of patients at 1 year; this did not change over the next 5 years. The present study identifies the various reasons why the remaining 30% of adult patients still require steroids even after 5 years after successful LTx.

METHOD

Eight hundred thirty-four consecutive patients who underwent LTx between August 1989 and December 1992 were included in this study. Four hundred ninety-nine patients were alive in January 1999 and were available for this study. The dose of steroid and the reason for steroid use were retrospectively determined from the clinical records.

RESULTS

Three hundred sixty-five patients (73.1%) were off steroid, whereas 134 patients (26.9%) were receiving prednisone (mean dose was 6.4+/-3.7 mg/day) at the time of the study. Four hundred and eight-four patients (97%) were off prednisone at some time after LTx; however, in 119 (23.8%) patients, steroids were reintroduced. Fifteen patients (3%) continued to receive prednisone; eight receive prednisone due to reluctance of the local physician to withdraw the medication; in five patients, the prednisone was not withdrawn because these patients were on cyclosporine; in the remaining two patients, repeated attempts to withdraw steroid resulted in a rise in liver function test. In the 49 (36.6%) of 119 patients in whom the steroid was reintroduced, it was restarted secondary to pathologically proven or clinically suspected rejection (group I). In five patients steroid was reintroduced for abnormal liver function after being off immunosuppression for treatment of a posttransplantation lymphoproliferative disorder. Six patients were noncompliant with their immunosuppressive medication, and the steroid was reintroduced to control rejection. Steroids were reintroduced in 30 patients (22.4%) for recurrence of original disease: primary biliary cirrhosis (n= 19), sclerosing cholangitis (n=6), and autoimmune hepatitis (n=5) (group II). In 24 patients (20.2%), steroids were reintroduced to lower the dose of tacrolimus secondary to nephrotoxicity. Six of these patients received kidney transplantation (group III). In 16 patients (13.4%) the steroid was reintroduced for concomitant medical problems, consisting of ulcerative/Crohn's colitis (n=6), adrenal insufficiency (n=5), hematological disorders (n=3), dermatitis (n=1), and rheumatoid arthritis (n=1) (group IV).

CONCLUSION

Ninety-seven percent of patients under tacrolimus were weaned off steroid; however, 23.8% required steroid reintroduction for late rejection, recurrence of autoimmune process(es), renal impairment, or the concomitant presence of other medical conditions. Although the use of other immunosuppressive agents may reduce the rate of reintroduction of steroid, long-term sustained freedom from steroid may not be possible in all patients under tacrolimus secondary to these conditions.

Low rejection rates with tacrolimus-based dual and triple regimens following liver transplantation

We studied the outcome of 345 liver transplant patients who received tacrolimus-based immunosuppressive therapy either as a dual regimen (with corticosteroids, n=172) or as a triple regimen (with corticosteroids and azathioprine, n=173) for 3 months after transplantation (3-month cohort). A further analysis was conducted for the first 195 patients randomised (dual n=100, triple n=95) who were followed up for 12 months after transplantation (12-month cohort). For the 3-month cohort, patient survival was 90.7% (dual) and 91.9% (triple), graft survival after 3 months was 88.4% (dual therapy) and 89.6% (triple therapy). Acute rejections were experienced by 67/172, 39.0% of patients on dual therapy and by 60/173, 34.7% of patients on triple therapy; corticosteroid-resistant rejections were reported in 9 patients (5.2%) in either treatment group. The overall safety profile was similar for the two treatment groups. Significant differences, however, were found for thrombocytopenia (dual 13/172, 7.6%, triple 37/173, 21.4%, p<0.001) and leukopenia (dual 4/172, 2.3%, triple 24/173, 13.9%, p<0.001). For the 12-month cohort, patient survival was 85.6% (dual) and 88.4% (triple) after 1 year. Graft survival was 81.7% (dual) and 85.2% (triple) 12 months after transplantation. Acute rejections were reported for 38/100, 38.0% of patients on dual therapy and 36/95, 37.9% of patients on triple therapy, corticosteroid-resistant rejections were 7/100, 7.0% (dual) and 7/95, 7.4% (triple) of patients. In the 12-month cohort, no significant differences in the safety profiles of the treatment groups were found. We conclude that both tacrolimus-based dual and triple drug regimens provide effective and safe immunosuppression following orthotopic liver transplantation.

Neoral use in the liver transplant recipient

This review and critical analysis of current trends of immunosuppression management in liver transplantation provides evidence and support for the continued role of Neoral as an indispensable part of immunosuppressive protocols. CyA formulation influences clinical outcomes such as acute rejection; this is confirmed by several multicenter studies. The CyA microemulsion formulation provides more reliable and effective absorption characteristics, and it may provide more rapid and complete immunosuppression in the de novo patient than IV administration. An advanced TDM strategy, particularly a 2-hour post-dose blood level (C-2), can improve the effectiveness and safety of immunosuppression in de novo liver transplant patients. There are potential risks resulting from CyA withdrawal strategies, as there is no evidence supporting this strategy. Neoral is an indispensable part of combination protocols in liver transplantation.

Impact of immunoadsorption on xenogeneic extracorporeal pig liver perfusion: assessment of organ function during autologous reperfusion

The shortage of liver grafts has resulted in an intensive search for alternative strategies of liver support in acute liver failure. Extracorporeal perfusion of pig livers (ECLP) is not a new concept, but recent improvements in cardiopulmonary bypass technology and new knowledge about xenogeneic immunologic mechanisms have made it a potential therapeutic modality. In previous suboptimal experimental and clinical models, no statements about the beneficial effect of long-lasting periods of ECLP were made. The aim of this study was to evaluate the capacity of pig liver for metabolic regeneration after xenogeneic ECLP under largely physiologic conditions. To delay hyperacute rejection (HAR), we utilized immunoadsorption (IA) of naturally preformed xenogeneic antibodies (XNAbs). This led to a stable xenogeneic ECLP for 45 min. However, IA was not able to prevent completely organ damage or loss of function resulting from insufficient autologous reperfusion. The inability to regenerate during autologous reperfusion provides a new measure of the function of a xenogeneic perfused pig liver. In addition, our results implicate that patients with fulminant liver failure will benefit from short perfusions with several fresh organs rather than from long perfusion with a single pig liver.