Methylprednisolone therapy for acute rejection: too much of a good thing?

Acute and Chronic Rejection After Liver Transplantation: What A Clinician Needs to Know

While antibody mediated hyper-acute vasculitic rejection is rare in liver transplant recipients, acute and chronic rejection have clinical significance. The liver allograft behaves differently to other solid organ transplants as acute rejection generally does not impair graft survival and chronic rejection (CR) is uncommon. The incidence of acute and chronic rejection has declined in current era due to improved immunosuppressive regimens. Acute rejection generally improves with steroid boluses and steroid resistant rejection is uncommon. CR may improve with escalation of immunosuppression or may result in irreversible loss of graft function leading to retransplantation or death. The current review discusses diagnosis and management of acute and chronic liver allograft rejection.

Management of Immunosuppression in Liver Transplantation

Liver transplantation outcomes have significantly improved over the past few decades owing largely to the introduction of effective immunosuppression medications. Further comprehension of the unique immune microenvironment of the liver has led to the development of newer molecular targeted therapeutics. Understanding the mechanism of action and adverse effect profiles of these medications is crucial for appropriate management of posttransplant patients. In this review, the author describes the immunologic response elicited by liver transplantation, chronicles the various immunosuppressant drug classes, discusses the evidence behind their use, and evaluates the management of special subpopulations of posttransplantation patients.

Management of immunosuppressant agents following liver transplantation: Less is more

Immunosuppression in organ transplantation was revolutionary for its time, but technological and population changes cast new light on its use. First, metabolic syndrome (MS) is increasing as a public health issue, concomitantly increasing as an issue for post-orthotopic liver transplantation patients; yet the medications regularly used for immunosuppression contribute to dysfunctional metabolism. Current mainstay immunosuppression involves the use of calcineurin inhibitors; these are potent, but nonspecifically disrupt intracellular signaling in such a way as to exacerbate the impact of MS on the liver. Second, the impacts of acute cellular rejection and malignancy are reviewed in terms of their severity and possible interactions with immunosuppressive medications. Finally, immunosuppressive agents must be considered in terms of new developments in hepatitis C virus treatment, which undercut what used to be inevitable viral recurrence. Overall, while traditional immunosuppressive agents remain the most used, the specific side-effect profiles of all immunosuppressants must be weighed in light of the individual patient.

A short course of mycophenolate immunosuppression inhibits rejection, but not tolerance, of rat liver allografts in association with inhibition of interleukin-4 and alloantibody responses

BACKGROUND

Some immunosuppressive drug therapies inhibit transplant tolerance in animal models, and we have shown that treatment of recipients with methylprednisolone, but not cyclosporine, inhibits spontaneous acceptance of liver transplants. This study investigates the effects of mycophenolate mofetil (MMF) on liver acceptance and rejection.

METHODS

Piebald Virol Glaxo rat livers were transplanted into Dark Agouti recipients, which spontaneously tolerate (TOL) the liver, or into Lewis recipients, which reject (REJ) the liver. MMF (40 mg/kg/day subcutaneously) was given for 5 days from days 0 to 4 (early) or from days 3 to 7 (late). In separate experiments, liver grafts were collected for assessment of infiltrate and of interleukin (IL)-2, IL-4, IL-10, and interferon-gamma mRNA expression.

RESULTS

TOL liver transplants had a median survival time (MST) of more than 100 days (n=6), and neither early nor late MMF treatment of TOL transplants reduced survival (MST 85 days, P=0.19 and 78 days, P=0.08, respectively). Liver failure in most of these animals was the result of biliary problems, not rejection. There were few consistent differences between treated and untreated TOL animals in infiltrate or liver cytokine expression, although there was a moderate reduction in T-cell infiltrate in MMF-treated TOL animals (P=0.003 on day 5 TOL). In contrast, REJ transplants had an MST of 13 days (n=10), and early MMF treatment led to five of six animals surviving more than 100 days (P=0.0002), whereas late treatment was much less effective, with one of six animals surviving more than 100 days. REJ livers had significantly more IL-4 mRNA expression and immunoglobulin G1 deposition in the graft than TOL livers, and this was inhibited by early, but not late, MMF treatment.

CONCLUSIONS

MMF treatment inhibited rejection but not acceptance of liver allografts. Early administration was more effective in preventing rejection and demonstrated a more marked effect on IL-4 expression and alloantibody deposition than on graft T-cell infiltrate and expression of other cytokines.

Steroid-free liver transplantation using rabbit antithymocyte globulin and early tacrolimus monotherapy

BACKGROUND

In 2001, we published early results of a prospective randomized trial of 71 patients who received either steroids or rabbit antithymocyte globulin (RATG) for orthotopic liver transplantation (OLT). We now report follow-up on these patients and additional patients undergoing steroid-free OLT.

METHODS

A total of 119 adult OLT recipients were prospectively randomized to receive either methylprednisolone 1,000 mg followed by a 3-month steroid taper or a steroid-free regimen of RATG 1.5 mg/kg during the anhepatic phase followed by a 1.5 mg/kg dose on posttransplant day 1. Maintenance immunosuppression consisted of tacrolimus and mycophenolate mofetil in both groups. Mycophenolate mofetil was weaned over 3 months in the first 71 patients and over 2 weeks in the last 48 patients, achieving tacrolimus monotherapy by 2 weeks posttransplant. Subsequently, a group of 24 sequential OLT recipients received the steroid-free (RATG) protocol. Endpoints of the study were survival, rejection, infectious complications, posttransplant diabetes, and recurrent hepatitis C virus.

RESULTS

One-year patient survival was 85% in each group of the prospective randomized trial with a mean follow-up of 18.5 months. One-year graft survival was 82% in the RATG group and 80% in the steroid group (P=not significant). Patient and graft survival of the 24 nonrandomized RATG patients was 96% with a mean follow-up of 3 months. The incidence of rejection was not significantly different; however, 50% of the patients in the steroid group required pulse steroids to reverse the rejection compared with only one patient (1.6%) in the RATG group (P=.03). The incidence of cytomegalovirus infection (P<.05) and posttransplant diabetes was higher in the steroid group (P=.03). There was a trend toward decreased severity of hepatitis C virus in the RATG group.

CONCLUSIONS

Steroid-free liver transplantation using RATG and early tacrolimus monotherapy effectively reduces immunosuppression-related complications with excellent survival.