Mycophenolate mofetil (MMF) a potent immunosuppressive agent, has recently been approved for clinical use (CellCept) in renal transplant patients in combination with cyclosporine (CsA). With the expanded use of tacrolimus (Prograf) as well in renal transplant patients, there is a lack of pharmacokinetic studies clarifying drug interactions between the three agents. A pharmacokinetic study was performed on 18 stable renal transplant patients receiving MMF and tacrolimus together, and four control groups, one receiving tacrolimus alone, two receiving CsA, in combination with MMF (1.0 or 1.5 g bid), and one receiving CsA microemulsion (Neoral). Area-under-the-curve values were calculated for each drug to assess if there was a reciprocal effect on the respective bioavailability of each. In vitro, the immunosuppressive effect of trough level plasma from each patient group was studied using mixed lymphocyte culture (MLC), as well as MLC reactions spiked with various combinations of each drug. There was a minimal effect of MMF on tacrolimus pharmacokinetics. However, patients receiving tacrolimus and MMF displayed significantly higher levels (Cmin and area under the curve) of mycophenolic acid (MPA) than those receiving CsA (Sandimmune or Neoral) and the same dose of MMF (50.2 +/- 16.5 vs 32.1 +/- 16.7 micrograms h/ml AUC, p < 0.02). Equivalent MPA levels could be attained in patients receiving CsA if the MMF dose was increased by 50% (1.5 g bid). There were also significantly lower levels of the glucuronide metabolite of MPA (MPAG) (755 +/- 280 vs 1230 +/- 250 micrograms h/ml AUC, p = 0.02), suggesting a specific inhibition (either direct or indirect) of the conversion of MPA to MPAG in tacrolimus patients, as opposed to those receiving CsA. For each drug combination, there was a positive correlation between the plasma immunosuppressive effect seen in MLC assays and the MMF dose. In addition, trough plasma from patients receiving tacrolimus and MMF was significantly more MLC inhibitory than from those receiving CsA or CsA microemulsion and equivalent-dose MMF. Culture media containing MPA and tacrolimus equal to clinical therapeutic trough concentrations (10 ng/ml) were significantly more MLC inhibitory than CsA at equivalent clinical therapeutic trough concentrations (200 ng/ml) with equivalent MPA levels. These studies in renal transplant patients suggest that tacrolimus in combination with MMF may result in a greater degree of immunosuppression than may be anticipated.

Adult↗

PubMed1997

Post-transplant lymphoproliferative disease in kidney transplant patients in the new immunosuppressive era.

Although the kidney transplant program at this center has been active for the past 18 yr, five out of the seven cases of post-transplant lymphoma in kidney transplant patients were observed over the past 2 yr. During this period, we have shifted from cyclosporine to tacrolimus (FK506 or prograf) for maintenance immunosuppression and for rescue therapy. We have also introduced mycophenolate (RS-61443) and have continued an antibody induction regimen in the immediate postoperative period. FK506 is 50-100 times more potent than cyclosporine. We have reported a decreased incidence of rejection, improved graft survival, and a general optimalization of patient survival with these newer regimens. Nonetheless, five cases of post-transplant lymphoma out of 233 kidney transplants (2.1%) performed during this time period (December 1993 to December 1995) occurred between 3 months to 1 yr after the transplant. Four of the five patients are still alive between 12 and 24 months after the diagnosis of lymphoma was made. All were without evidence of ongoing disease. Three of the five have grafts with excellent function for longer than 18 months after transplantation, while one is marginal and one patient expired on dialysis. The third and fourth patients had severe rejection before the diagnosis of PTLD was made. While the occurrence of five cases of post-transplant lymphoma over a 2 yr period is alarming, this is still within the 2-4% incidence of post-transplant lymphoma that has been reported in the literature in kidney transplant patients. Our results probably reflect the increasing potency of our immunosuppressive protocols but do not show any increase in the aggressiveness of this entity of post-transplant lymphoma during the continued follow up.

Adolescent↗

PubMed1997

The use of tacrolimus as induction and maintenance immunosuppression in renal cadaveric transplant recipients over the age of 60.

Renal transplantation is a treatment option that should be considered for the elderly (> or = 60 years old) with end-stage renal disease. Little is known regarding the use of tacrolimus (as induction and maintenance immunosuppression) in this age group. We report the outcome of kidney transplantation in 21 patients aged 60 years or more with tacrolimus. During the past few years in kidney transplant maintenance immunosuppressive regimens, we have revised our standard general protocol from cyclosporine to tacrolimus-based therapy for maintenance immunosuppression and for rescue therapy. We also introduced mycophenolate (RS-61443) while we have continued to use ATGAM/OKT3 as induction regimen in the immediate postoperative period. We treated these renal recipients with tacrolimus and steroids in combination with azathioprine or mycophenolate mofetil without antibody induction. This was well tolerated and not associated with a higher rate of rejection (20%) whereas the potential toxicity of antilymphocyte preparations was avoided.

Administration, Oral↗

PubMed1997

Update in transplantation--1997.

Explore the source record for details and available documents.

Animals↗

PubMed1996

An assessment of the effects of cadaver donor bone marrow on kidney allograft recipient blood cell chimerism by a novel technique combining PCR and flow cytometry.

A new technique, the PCR-flow assay is described that has allowed for the serial identification and quantitation of discrete mononuclear cell subsets of donor (or recipient) bone marrow derived cells in cadaver kidney transplant recipients infused postoperatively with donor vertebral body bone marrow cells. With fixed permeabilized cells in flow cytometry the amplification power of the polymerase chain reaction (PCR), using fluorescent-labeled primers to identify single copy HLA class II DRbeta1 genes of either donor or recipient origin, is combined with multi-color fluorochrome-labeled CD epitope-specific monoclonal antibodies. The details of the methodology are described; these support the utility of the assay. Initial observations were made on the chimeric makeup of the peripheral blood as well as iliac crest bone marrow between six months and one year posttransplantation in recipients serially followed weekly and then monthly, concomitantly compared with a control group of stable kidney transplant recipients using similar therapeutic protocols, who did not receive cadaver bone marrow. Several findings are of note. In 14 recipients of two bone marrow infusions totalling a mean of 6.29+/-2.18x10(10) cells, donor CD34 positive (+) (immature) cells were fourteen times as numerous in peripheral blood six months postoperatively as in six recipients given half as many bone marrow cells in one infusion (averaging 3.02+/-0.5x10(10)). These donor CD34+ cells unexpectedly averaged 36+/-7% of the total (donor plus recipient) CD34+ subset counted. Moreover, iliac crest bone marrow aspirates contained an average of thirteen times this number of CD34+ cells than in the peripheral blood, supporting the notion of engraftment. Of additional interest, between six months and one year posttransplant although no donor cells could be detected in peripheral blood of the controls there was an identifiable presence of donor CD34+ cells in their iliac crest bone marrow, albeit 10-fold less than the marrow-infused patients. In the clinical follow-up, although there were three unrelated mortalities, there were no additional kidney losses with current serum creatinine concentrations averaging 1.3+/-0.06 mg/dl. In conclusion, the PCR-flow assay presents the possibility of identifying discrete subsets of donor or recipient cells that may have an immunoregulatory function.

Adoptive Transfer↗

PubMed1996

Early graft loss secondary to massive hemorrhagic necrosis following orthotopic liver transplantation. Evidence for cytokine-mediated univisceral Shwartzman reaction.

Massive hemorrhagic necrosis (MHN) of the liver following orthotopic liver transplantation (OLT) occurs infrequently during an otherwise uneventful recovery 1 week after OLT. It is characterized by fever and sudden deterioration of allograft function leading to failure in the absence of vascular thrombosis. The etiology is unknown, although it is usually preceded by some degree of allograft rejection. Between 6 and 8 days after OLT, four patients (out of 150) became febrile, hypotensive, and experienced a rapid rise in transaminases within 48 hr. Two patients had evidence of mild rejection; the other two had moderate to severe acute cellular rejection. All patients were ABO identical, crossmatch negative. Bolus steroids were given followed by OKT3 in the two patients with severe rejection. Although sepsis was suspected, antibiotic therapy did not ameliorate the clinical course. Each patient progressed to MHN with severe centrilobular necrosis and variable portal infiltrate. High levels of interferon-gamma and tumor necrosis factor-alpha occurred prior to the rise in transaminases in each MHN patient (155 +/- 39 pg/ml and 414 +/- 201 pg/ml, respectively) compared with levels in OLT patients with severe rejection (14 +/- 4 pg/ml and 26 +/- 5 pg/ml, respectively, P < 0.05). These data support the concept of a cytokine-mediated inflammatory response leading to a univisceral Shwartzman reaction in the transplanted liver. Early recognition of this syndrome and retransplantation are critical for survival.

Adult↗