Immunosuppressive therapy as a determinant of transplantation outcomes

An audit of a steriod withdrawal regimen in cardiac transplantation patients

BACKGROUND

Heart transplantation is optimal treatment for many patients with end-stage heart failure. Current data report 1-year graft survival rates of 85% after transplantation. The success of transplantation in large part is attributable to immunosuppression, including steroids, one of the mainstay agents. Despite its efficacy to treat acute graft rejection, steroids show numerous adverse effects. With newer immunosuppressive agents, steroid withdrawal is possible.

MATERIAL AND METHODS

We compared cardiac transplant patients who died versus survived between 2001 and 2006. We obtained Personal, transplant, occurrence of and cause of death data as well as postoperative intervals. Steroid therapy details were gathered, particularly whether the patient had been weaned off these agents. We calculated steroid doses and steroid-free years, as well as the steroid therapy status of posttransplant patients who remained alive in 2006.

RESULTS

Fifty cardiac transplant patients died between 2001 and 2006 excluding 6 who had graft failure and 2 who died of multiorgan failure before initial discharge. Of the 42 patient who died, 29 (69%) were on and 13 (31%) had been withdrawn from steroid therapy at time of death. There were 132 posttransplant patients currently alive in April 2006, including 43 (33%) on and 89 (67%) withdrawn from steroids. The percentages of patients who were on versus off steroids were compared for main causes of death. Thirty-eight percent of patients on steroids at the time of death died of graft vasculopathy compared with 46% of patients who had been weaned off steroids. Fifteen percent of deceased patients taking steroids at the time of death died of chronic rejection.

DISCUSSION

The current literature focuses on early withdrawal or reduction of steroids or steroid avoidance after organ transplantation. Although steroid avoidance remains controversial, steroid withdrawal has been generally incorporated into immunosuppressive protocols. Early steroid withdrawal has a positive influence on the emergence of de novo osteoporosis and cataracts. The benefits of steroid avoidance versus withdrawal are controversial topics being currently debated.

Plasma pharmacokinetics and tissue disposition of novel dextran-methylprednisolone conjugates with peptide linkers in rats

The plasma and tissue disposition of two novel dextran prodrugs of methylprednisolone (MP) containing one (DMP-1) or five (DMP-5) amino acids as linkers were studied in rats. Single 5-mg/kg doses (MP equivalent) of each prodrug or MP were administered intravenously, and blood and tissue samples were collected. Prodrug and drug concentrations were quantitated using HPLC, and noncompartmental pharmacokinetic parameters were estimated. Whereas conjugation of MP with dextran in both prodrugs substantially decreased the clearance of the drug by approximately 200-fold, the accumulations of the drug in the liver, spleen, and kidneys were significantly increased by conjugation. However, the extent of accumulation of DMP-1 in these tissues was substantially greater than that for DMP-5. Substantial amounts of MP were regenerated from both prodrugs in the liver and spleen, with the rate of release from DMP-5 being twice as fast as that from DMP-1. However, the AUCs of MP regenerated from DMP-1 in the liver and spleen were substantially higher than those after DMP-5. In contrast, in the kidneys, the AUC of MP regenerated from DMP-5 was higher than that after DMP-1 administration. These data suggest that DMP-1 may be more suitable than DMP-5 for targeting immunosuppression to the liver and spleen.

Mycophenolate mofetil vs. azathioprine is associated with decreased acute rejection, late acute rejection, and risk for cardiovascular death in renal transplant recipients with pre-transplant diabetes

Outcomes specifically in mycophenolate mofetil (MMF)-treated diabetic renal transplant patients have not been previously reported. This study compared acute rejection (AR), late acute rejection (LAR), patient survival [and specifically death from cardiovascular (CV), infectious and malignant causes], incidence of post-transplant malignancies, and graft loss in MMF- or azathioprine (AZA)-treated renal transplant patients with pre-transplant diabetes. Outcomes were compared between MMF- (n = 14 144) and AZA- (n = 3001) treated diabetic patients using the Scientific Registry of Transplant Recipients data on all U.S. adult renal transplants performed between 1995 and 2002. Statistical analyses included Kaplan-Meier survival analysis, Cox multivariable regression and chi-square tests. MMF patients had less AR compared with AZA-treated patients (23.5% vs. 28.3%, p < 0.001) and less risk for LAR over 4 yr [hazard ratio (HR): 0.64, 95% CI 0.44, 0.92; p = 0.02]. While time to any-cause death did not differ between the groups, MMF treatment was associated with a 20% decreased risk of CV death (HR: 0.80, 95% CI 0.67, 0.97; p = 0.020) compared with AZA treatment. MMF patients also had a lower incidence of malignancies than AZA patients (2.2% vs. 3.7%, p < 0.001). These results suggest treatment with MMF compared with treatment with AZA in diabetic transplant patients is associated with less AR, less risk of LAR, a decreased risk of CV death, and a lower incidence of malignancies.

Clinical and microbiological analysis of periodontally diseased sites after renal transplant

This study compared the clinical and microbiological status of periodontally diseased sites in 42 patients who had a renal transplant and were undergoing immunosuppressive therapy (21 taking azathioprin and corticosteroids [Az-C] and 21 taking cyclosporin-A [Cy-A] with those of 21 systemically healthy matched controls. Probing pocket depth (PPD), bleeding on probing (BOP) and gingival hyperplasia (GH) were measured at 339 sites. Subgingival plaque samples were analyzed for the presence of Porphyromonas gingivalis, Treponema denticola and/or Bacteroides forsythus using the BANA test. Our findings suggest that immunosuppressed patients showed significantly less inflammation and fewer putative anaerobic pathogens using the BANA test, and that patients undergoing therapy with cyclosporin-A have a higher frequency of sites with gingival hyperplasia when compared with patients medicated with azathioprin or corticosteroids.

Intensive Care of the Intra-Abdominal Organ Transplant Recipient

The postoperative care of a patient who receives an intra-abdominal organ transplant is in some ways simi lar to that of any major intra-abdominal procedure. However, certain features unique to organ transplanta tion, such as the variable functional status of the newly transplanted graft, complications that are specific to the organ transplanted, and the side effects from immuno suppressive drugs, suggest that transplantation inten sive care is a distinct subspecialty in critical care medicine. Today, the majority of patients receiving an intra-abdominal transplant will have a relatively uncom plicated postoperative course. However, preoperative disposition, intraoperative misadventure, or immediate postoperative difficulty will require the availability of an intensivist experienced in transplantation. The future of intra-abdominal transplantation will be highly depen dent on progress in immunotherapy. Newer, more spe cific immunomodulators with fewer nonimmune toxici ties should result in improved organ receptance, less graft dysfunction, and improved patient survival.

A randomized trial comparing cyclosporine induction with sequential therapy in renal transplant recipients

Calcium antagonists may reduce the nephrotoxicity of cyclosporine (CsA), allowing CsA to be introduced immediately after renal transplantation and thereby obviating the need for sequential induction therapy with a monoclonal or polyclonal antibody. To test this hypothesis, in a pilot feasibility trial 100 cadaveric or one-haplotype-mismatched living-related renal transplant recipients were randomized to either (1) sequential therapy with anti-thymocyte globulin (ATG) (ATGAM; Upjohn, Kalamazoo, MI) 20 mg/kg/d for 7 to 14 days until renal function was established and CsA (Sandimmune; Sandoz, East Hanover, NJ) was started, or (2) CsA 8 mg/kg/d begun immediately before surgery with diltiazem (Cardizem; Marion Merrell Dow, Kansas City, MO) 60 mg sustained release twice daily. Acute rejection episodes during the first 90 days were not different with ATG versus CsA induction (42% v 28%; P = 0.142 by chi-square analysis). Graft failures (10% v 16%; P = 0.372) and the incidence of delayed graft function (28% v 34%; P = 0.516) were also similar with ATG compared with CsA. ATG caused lower platelet counts (138 +/- 59 x 10(3) v 197 +/- 75 x 10(3) at 7 days; P < 0.001) and lower white blood cell counts (9.6 +/- 4.6 x 10(3) v 12.3 +/- 4.9 x 10(3) at 7 days; P = 0.003). Diltiazem reduced the dose of CsA required to maintain target blood levels (479 +/- 189 mg/d v 576 +/- 178 mg/d at 14 days; P = 0.015). There were no statistically significant differences between the groups in serum creatinine levels at days 1, 3, 5, 7, 14, 28, 60, or 90. The results of this pilot feasibility trial suggest that prophylactic treatment with CsA and diltiazem may be equally effective and less toxic than ATG induction after renal transplantation.

Clinical chemistry and post-liver-transplant monitoring

Liver transplantation is an accepted therapy for end-stage liver disease. After allografting, a variety of clinical problems may require laboratory involvement for accurate and timely diagnosis and intervention. Critical factors in the choice of a laboratory test menu to support a transplant program include turnaround times that support clinical decisionmaking, real diagnostic value, and real value for money. Particular clinical problems, whose early presentation must be anticipated, include graft ischemia, primary nonfunction, and hepatic artery thrombosis. Acute rejection is common at 5-10 days posttransplantation, the principal target being the biliary tree. Longer-term problems are associated with the therapeutic drug measurement of cyclosporin A and, increasingly, tacrolimus (FK506); the side effects of immunosuppressant therapy also require monitoring. A successful liver transplant program can be adequately supported with a simple battery of automated tests that are cheap, fast, and available at all times.

The long-term course of hepatitis C after kidney transplantation

Patients with chronic hepatitis run the risk of developing progressive liver disease during immunosuppressive therapy after kidney transplantation. To determine the impact of chronic hepatitis C on morbidity and mortality we analyzed 162 anti-HCV positive of 1241 renal-grafted patients (prevalence 13.1%; 84.9% HCV RNA positive) regularly surveyed in our outpatient clinic between 1992 and 1994. The mean age at transplantation was 44.5 (6-69) years, and follow-up after grafting was 7.4 (0.1-23.9) years. The immunosuppressive regimen and frequency of rejection episodes in HCV-infected patients were comparable to the total population. Only 4.3% (5/117) of the anti-HCV positive, HBV negative patients living with functioning grafts developed a markedly compromised liver function. Fifteen (9.3%) of the HCV-infected patients died, but none suffered from posthepatitic cirrhosis. An additional retrospective analysis of causes of death after transplantation prior to 1992 revealed that liver disease had only been responsible for 2% of the deaths (7 of 324) in the HBsAg negative population (n= 1901). In contrast, the predominant cause of death in the HBsAg positive population (n=76) was posthepatitic cirrhosis in 58% (15 of 26). Thus, kidney transplantation in patients with replicative hepatitis C and normal liver function appears to be justified because of low early and late morbidity and mortality due to chronic liver disease. HBV infection and hemosiderosis substantially increase the risk of chronic liver disease in renal transplant recipients with hepatitis C.

Developments and dilemmas in renal transplantation

The number of patients waiting for a kidney transplant is about three times greater than the number of transplants performed each year. This article highlights current immunosuppression protocols and the newer immunosuppressive drugs under investigation in a number of multicenter trials. These hold out the promise of reducing the frequency of acute rejection and of prolonging graft survival. They are divided into three groups. The first, like cyclosporine, interferes with the action of interleukin 2. The second, like azathioprine, are antimetabolites; and the third, new monoclonal antibodies. The use of antibody-induction therapy is compared with standard regimens. There are risks related to prednisone withdrawal protocols and inadequate cyclosporine dosing that may lead to accelerated graft loss. Cardiovascular disease is a significant problem in older diabetic patients for whom coronary angiography is recommended. A defined set of risk factors is outlined that predicts which younger diabetic patients should have a cardiovascular evaluation. Chronic liver disease is a growing problem and rational strategies are emerging from studies of patients with biopsy-proven active hepatitis. The presence of hepatic inflammation is associated with progressive liver disease and patients must be made aware of this risk when seeking transplantation. A large number of studies of various prophylactic regimens are starting to provide data on the cost-effective reduction of cytomegalovirus disease in transplant recipients. It is recommended that patients receiving antibody therapy also receive preemptive gangciclovir. The issue of chronic allograft rejection is discussed briefly. The most important predictors of chronic allograft rejection are the frequency of acute rejection, inadequate immunosuppression, and infections.(ABSTRACT TRUNCATED AT 250 WORDS)