An analysis of early renal transplant protocol biopsies--the high incidence of subclinical tubulitis

To investigate the possibility that we have been underestimating the true incidence of acute rejection, we began to perform protocol biopsies after kidney transplantation. This analysis looks at the one-week biopsies. Between March 1 and October 1, 1999, 100 adult patients undergoing cadaveric kidney or kidney/pancreas transplantation, or living donor kidney transplantation, underwent 277 biopsies. We focused on the subset of biopsies in patients without delayed graft function (DGF) and with stable or improving renal function, who underwent a biopsy 8.2+/-2.6 d (range 3-18 d) after transplantation (n = 28). Six (21%) patients with no DGF and with stable or improving renal function had borderline histopathology, and 7 (25%) had acute tubulitis on the one-week biopsy. Of the 277 kidney biopsies, there was one (0.4%) serious hemorrhagic complication, in a patient receiving low molecular weight heparin; she ultimately recovered and has normal renal function. Her biopsy showed Banff 1B tubulitis. In patients with stable or improving renal allograft function early after transplantation, subclinical tubulitis may be present in a substantial number of patients. This suggests that the true incidence of rejection may be higher than is clinically appreciated.

Il-12 antagonism enhances apoptotic death of T cells within hepatic allografts from Flt3 ligand-treated donors and promotes graft acceptance

Mouse livers are accepted across MHC barriers and induce donor-specific tolerance without immunosuppressive therapy. By contrast, livers from donors treated with Flt3 ligand, which dramatically increases hepatic interstitial dendritic cells, are rejected acutely (median survival time 5 days). This switch from tolerance to rejection is associated with a marked reduction in apoptotic activity of graft-infiltrating cells. We hypothesized that IL-12 production by enhanced numbers of donor APC might inhibit apoptosis, promote expansion of Th1 cells, and play a key role in liver rejection. Therefore, C3H (H2(k)) recipients of liver grafts from Flt3 ligand-treated B10 donors were given neutralizing anti-IL-12 mAb (200 or 500 microg) on days 0 and 2 after transplant. Graft survival was markedly prolonged at the higher mAb dose, with 50% of grafts surviving >100 days. This effect was associated with reductions in IFN-gamma gene transcripts within the graft-infiltrating cell population and with reductions in circulating IFN-gamma and IL-10 levels, donor-specific CTL and NK cell activities, and circulating alloantibody levels. At the same time, there were marked increases in apoptotic (TUNEL(+)) CD4(+) and especially CD8(+) cells, both within the grafts and in spleens of anti-IL-12 mAb-treated mice. In vitro, exogenous IL-12 inhibited apoptotic death induced in naive allogeneic T cells by liver nonparenchymal cells. These findings suggest that suppression of rejection by IL-12 antagonism, linked to restoration of apoptotic activity within the peripheral alloreactive T cell population, is important for liver allograft survival and tolerance induction.

Replicative senescence of biliary epithelial cells precedes bile duct loss in chronic liver allograft rejection: increased expression of p21(WAF1/Cip1) as a disease marker and the influence of immunosuppressive drugs

Early chronic liver allograft rejection (CR) is characterized by distinctive cytological changes in biliary epithelial cells (BECs) that resemble cellular senescence, in vitro, and precede bile duct loss. If patients suffering from early CR are treated aggressively, the clinical and histopathological manifestations of CR can be completely reversed and bile duct loss can be prevented. We first tested whether the senescence-related p21(WAF1/Cip1) protein is increased in BECs during early CR, and whether treatment reversed the expression. The percentage of p21+ BECs and the number of p21+ BECs per portal tract is significantly increased in early CR (26 +/- 17% and 3.6 +/- 3.1) compared to BECs in normal liver allograft biopsies or those with nonspecific changes (1 +/- 1% and 0.1 +/- 0.3; P: < 0.0001 and P: < 0.02), chronic hepatitis C (2 +/- 3% and 0.7 +/- 1; P: < 0.0001 and P: < 0.04) or obstructive cholangiopathy (7 +/- 7% and 0.7 +/- 0.6; P: < 0.006 and P: = 0.04). Successful treatment of early CR is associated with a decrease in the percentage of p21+ BECs and the number of p21+ BECs per portal tract. In vitro, nuclear p21(WAF1/Cip1) expression is increased in large and multinucleated BECs, and is induced by transforming growth factor (TGF)-beta. TGF-beta1 also increases expression of TGF-beta receptor II, causes phosphorylation of SMAD-2 and nuclear translocation of p21(WAF1/Cip1), which inhibits BEC growth. Because conversion from cyclosporine to tacrolimus is an effective treatment for early CR, we next tested whether these two immunosuppressive drugs directly influenced BEC growth in vitro. The results show that cyclosporine, but not tacrolimus, stimulates BEC TGF-beta1 production, which in turn, causes BEC mito-inhibition and up-regulation of nuclear p21(WAF1/Cip1). In conclusion, expression of the senescence-related p21(WAF1/Cip1) protein is increased in BECs during early CR and decreases with successful recovery. Replicative senescence accounts for the characteristic BEC cytological alterations used for the diagnosis of early CR and lack of a proliferative response to injury. The ability of cyclosporine to inhibit the growth of damaged BECs likely accounts for the relative duct sparing properties of tacrolimus.

Pharmacokinetics of mycophenolic acid after mycophenolate mofetil administration in liver transplant patients treated with tacrolimus

The pharmacokinetics of mycophenolic acid (MPA) was studied after oral administration of mycophenolate mofetil (MMF) in 8 liver transplant patients. The mean (+/- SD) maximum MPA plasma concentration of 10.6 (+/- 7.5) mg/ml was achieved within 0.5 to 5 hours. The mean (+/- SD) steady-state area under the plasma concentration versus time curve (AUC(0-12)) was 40 (+/- 30.9) mg/ml/h. The mean (+/- SD) half-life was 5.8 (+/- 3.8) hours. There was poor correlation between trough blood concentrations of tacrolimus (r = -0.004) or serum creatinine (r = 0.689) with MPA AUC, while the serum bilirubin concentrations correlated (r = 0.743) well with MPA AUC, suggesting impairment in MPA conjugation in patients with liver dysfunction. The mean (+/- SD) ratio of the AUC of mycophenolic acid glucuronide (MPAG) to MPA was 64 (+/- 84), which correlated significantly with serum creatinine (r = 0.72) but not with serum bilirubin concentrations (r = 0.309), indicating accumulation of MPAG in patients with renal dysfunction. In 7 primary liver transplant patients on the same dose of MMF, the trough plasma concentrations of MPA during the first week of therapy ranged from < 0.3 to 1.5 microg/ml. The MPA concentrations increased by several folds during the next few weeks, which correlates well with increases in serum albumin concentrations. Changes in albumin appear to partially contribute to the variations in the pharmacokinetics of MPA in liver transplant patients.

Simultaneous pancreas-kidney transplantation at the University of Pittsburgh

Analysis of the SPK program at the University of Pittsburgh has led to a number of observations: 1. Under tacrolimus-based immunosuppression, without antibody induction, it has been possible to achieve (a) One- and 3-year actuarial patient survival rates of 98% and 95% (b) One- and 3-year actuarial kidney survival rates of 95% and 87% (c) One- and 3-year actuarial pancreas survival rates of 86% and 80% 2. Steroid withdrawal has been achieved in over half of the successfully transplanted recipients, with excellent outcomes and a low rate (4.7%) of subsequent rejection. 3. Bone marrow augmentation has been associated with (a) less rejection (b) less pancreatic graft loss to rejection (c) an increased ability to withdraw steroids 4. Rejection has been associated with a rising serum lipase. 5. Renal allograft rejection in SPK patients with elevated serum lipase levels has been seen in the setting of normal renal function. 6. Enteric drainage has been associated with a reasonably low complication rate. 7. SPK transplantation is a successful therapeutic option in selected type I diabetics with end-stage renal disease.

Kidney transplantation for end-stage renal failure in liver transplant recipients with hepatitis C viral infection

BACKGROUND

End-stage renal failure after successful liver transplantation (LTx) has been described in up to 5% of patients. Kidney transplantation (KTx) has been the treatment of choice in these cases. However, in recipients infected with hepatitis C virus (HCV), the augmentation of immunosuppression after KTx may result in an increased viral load. This, in turn, may adversely affect the liver allograft.

METHOD

The present study retrospectively examined the outcome in 17 patients (3 females and 14 males, mean age 51.1+/-11.3 years) who received KTx after LTx. The mean interval from LTx to KTx was 57.6+/-32.1 months. The mean follow-up was 41.7+/-20.5 months after KTx, and 99.6+/-37.7 months after LTx. Sixteen of the 17 patients received tacrolimus-based immunosuppression at the time of KTx.

RESULTS

During the follow-up period, one patient underwent combined liver and kidney retransplantation 3.7 years after KTx and 12.7 years after LTx. She subsequently died secondary to primary nonfunction. Four other patients died, two of lung cancer, one of pancreatitis/sepsis, and one of severe depression leading to noncompliance. A total of 29 episodes of biopsy-proven acute renal allograft rejection (1.7 episodes/ patient) were encountered and treated with steroids. Seven patients experienced a rise in liver function tests during the period of increased steroid dosage. Four patients received no treatment, and their liver function returned to baseline. The remaining three were treated with interferon. Overall 1- and 3-year actuarial patient and liver allograft survival was 88% and 71% (after renal transplantation); corresponding 1- and 3-year actuarial graft survival was 88% and 61%. Twelve patients are alive with normal liver function. One patient is on dialysis, because of renal allograft loss to noncompliance.

CONCLUSION

In this series, LTx recipients with HCV infection were able to undergo KTx with a reasonable degree of success. KTx should be offered for end-stage renal failure after LTx, even in the presence of HCV infection, to individuals with stable liver function and no signs of liver failure.

Occult nonhematopoietic malignancies present at autopsy in solid organ transplant patients who died within 100 days

BACKGROUND

Patients are at an increased risk for developing malignancies after transplantation. Lymphomas, skin malignancies, Kaposi's sarcomas, and cervical/vulvar neoplasms are the most common, but visceral malignancies are also well documented, with a reported frequency ranging from 1% to 6%. These visceral tumors represent a mix of neoplasms that were clinically occult at the time of transplantation and those that arise de novo after transplantation. Little information, however, is available on the frequency of clinically occult malignancies at the time of transplantation and their contribution to the number of posttransplant malignancies.

METHODS

A retrospective study was performed of all patients who received an organ transplant from January 1981 to June 1997 and died within 100 days, a time interval in which epithelial malignancies found at autopsy were presumed to have been present, but clinically occult, at the time of transplantation.

RESULTS

A total of 375 patients were studied who received the following organ transplants: 231 liver, 52 heart, 26 heart and lung, 32 lung, and 34 kidney. Eleven malignancies were identified for an overall frequency of 2.9% and included three thyroid carcinomas, three carcinoids of the small bowel, two lung carcinomas, one laryngeal carcinoma, one renal cell carcinoma, and one seminoma.

CONCLUSION

The 2.9% frequency of malignancies seen in this study suggests that a small, but significant, number of patients have occult malignancies at the time of transplantation and that these occult tumors contribute substantially to the number of malignancies that present clinically after transplantation.