Conversion from mycophenolate mofetil to delayed formulation in pediatric renal transplantation: higher mycophenolic acid predose level but no changes in the immune biomarkers.

EC-MPS was designed to improve MPA-related GII because of MMF, by delaying the release of MPA until reaching the small intestine. At present, its immunosuppressive activity in pediatric renal transplant recipients with GII has not been clarified. We studied eight renal transplant recipients before and after three months of the conversion from MMF to equimolar doses of EC-MPS. After three months of treatment with EC-MPA, GII decreased between 100% and 12.5%. The predose levels of MPA were about 60% higher on EC-MPS (6.9 +/- 1.1 microg/mL) compared with MMF administration (4.2 +/- 0.9 microg/mL). Hemoglobin decreased significantly post-conversion (12.0 +/- 0.4 to 11.0 +/- 0.5 g/dL). Serum creatinine, creatinine clearance, and urinary protein excretion did not change. Also, proliferative response and cytotoxic antibodies showed no significant change. The release of interleukin-10 was strikingly augmented with MMF or EC-MPS therapy; meanwhile, gamma-interferon and TNF were low under both treatments. Our data indicate that conversion from MMF to EC-MPS leads to an improvement in GII without altering key elements of immunosuppression.

[Regulatory cytokines in the response to the allogeneic renal transplant]. / Citoquinas reguladoras de la respuesta al trasplante renal alogénico.

The outcome of the kidney allograft mainly depends on the immune response and on its complex regulation, where the cytokine network and other mediators play an important role. At present, kidney biopsy is the most useful tool for monitoring the transplant rejection and the diagnosis of the associated nephropathies, in spite of the invasiveness of the procedure. Thus, it is of great interest to find alternative tools for diagnosis. The evaluation of regulatory cytokines is a simple procedure of low cost that could be useful to increase the sensitivity of the detection of polymorphic differences, to predict the graft acceptance and for the early detection of rejection. Recent studies suggest that the high production of pro-inflammatory mediators, such as Th1 cytokines, could be detrimental, whereas the production of anti-inflammatory regulatory cytokines, such as interleukin (IL)-10 and tumor necrosis factor (TGF)-beta, could be beneficial for graft survival. In the early stages, the cellular cytotoxicity is activated by the Th1 response and the detection of cytotoxic molecules is associated to the acute rejection. Later, the balance between pro and anti-inflammatory mediators and the regulation of their levels could be more important. In this regard, TGF-beta is also fibrogenic and a high local production can contribute to kidney damage. On the other hand, the increased production of IL-10 in response to the allogeneic stimuli could be, in most cases, an important marker of long-term acceptance.

Citoquinas reguladoras de la respuesta al trasplante renal alogénico. / [Regulatory cytokines in the response to the allogeneic renal transplant]

The outcome of the kidney allograft mainly depends on the immune response and on its complex regulation, where the cytokine network and other mediators play an important role. At present, kidney biopsy is the most useful tool for monitoring the transplant rejection and the diagnosis of the associated nephropathies, in spite of the invasiveness of the procedure. Thus, it is of great interest to find alternative tools for diagnosis. The evaluation of regulatory cytokines is a simple procedure of low cost that could be useful to increase the sensitivity of the detection of polymorphic differences, to predict the graft acceptance and for the early detection of rejection. Recent studies suggest that the high production of pro-inflammatory mediators, such as Th1 cytokines, could be detrimental, whereas the production of anti-inflammatory regulatory cytokines, such as interleukin (IL)-10 and tumor necrosis factor (TGF)-beta, could be beneficial for graft survival. In the early stages, the cellular cytotoxicity is activated by the Th1 response and the detection of cytotoxic molecules is associated to the acute rejection. Later, the balance between pro and anti-inflammatory mediators and the regulation of their levels could be more important. In this regard, TGF-beta is also fibrogenic and a high local production can contribute to kidney damage. On the other hand, the increased production of IL-10 in response to the allogeneic stimuli could be, in most cases, an important marker of long-term acceptance.

Mycophenolate mofetil and reduced doses of cyclosporine in pediatric liver transplantation with chronic renal dysfunction: changes in the immune responses.

The aim of this study was to study the incidence of chronic renal dysfunction in patients with more than 5 yr of follow-up following liver transplantation and to evaluate the benefit of decreasing cyclosporine A (CsA) dose combined with mycophenolate mofetil (MMF) on renal function and immune response in these patients. Between 1988 and 1994, 60 children were transplanted, and 86% survived >5 yr post-liver transplantation. Fourteen patients developed chronic renal dysfunction secondary to CsA toxicity as evaluated by renal biopsy. In 11 patients CsA dose was decreased to 40-90 mg/ml target levels and MMF 600 mg/m(2) twice daily was added to the immunosuppressive regimen. Plasma creatinine decreased (from 1.0 +/- 0.03 to 0.8 +/- 0.03 ng/dl, p < 0.007), creatinine clearance increased (from 66.8 +/- 3.0 to 99.2 +/- 6.3 ml/min/1.73 m(2), p < 0.002) and microalbuminuria decreased (from 21.0 +/- 8.6 to 3.6 +/- 1.1 mg/24 h, p < 0.05) after 12 months of CsA combined with MMF therapy. During combined therapy the proliferative, cytolytic response and cytotoxic antibodies showed no significant changes, whereas CD4/CD8 ratio increased (from 1.2 +/- 0.2 to 1.4 +/- 0.1, p < 0.05). Tumor necrosis factor-alpha secretion increased (p < 0.005) during MMF therapy. The release of interleukin-10 was strikingly augmented under both immunosuppressive regimens, but the release of transforming growth factor-beta and interferon-gamma did not change. Our findings indicate that initiation of MMF combined with reduced doses of CsA allowed the recovery of renal function with minor changes in the immune response.

Conversion from cyclosporine A to tacrolimus in pediatric kidney transplant recipients with chronic rejection: changes in the immune responses.

BACKGROUND: Tacrolimus (Tac) has immunosuppressant properties similar to those of cyclosporine A (CsA), but it is more potent. At present, however, its immunosuppressive activity in renal transplant recipients with ongoing chronic rejection has not been clarified. METHODS: We studied changes in kidney function, mixed lymphocyte culture, cell-mediated lympholysis, cytotoxic antibodies, lymphocyte population, and cytokine response before and after the conversion from CsA to Tac in 14 pediatric renal transplant recipients with chronic rejection. CsA (5.9+/-0.2 mg/kg/d) was replaced by Tac (0.1+/-0.004 mg/kg/d). RESULTS: Serum creatinine decreased (2.3+/-0.2-1.9+/-0.2 mg/dL, P <0.005), creatinine clearance increased (36.8+/-2.5-46.1+/-4.4 mL/min/1.73 m, P <0.005), and urinary protein excretion decreased (0.4+/-0.01-0.2+/-0.04 g/24 hr, P <0.03) after 6 months, and these values were maintained after 2 years with Tac treatment. During Tac therapy, anti-donor and anti-control mixed lymphocyte culture decreased 38% and 31% (P <0.05), respectively. Cell-mediated lympholysis did not change. CD3 decreased from 87%+/-2% to 80%+/-2% (P <0.005), and CD8 decreased from 34%+/-3% to 27%+/-2% (P <0.005). The switch to Tac decreased the interferon-gamma production in vitro (P <0.05) and increased tumor necrosis factor-alpha levels (P <0.05). The release of interleukin-10 was strikingly augmented with CsA or Tac therapy (P <0.01), but transforming growth factor-beta secretion was similar. CONCLUSIONS: Our data indicate that conversion from CsA to Tac therapy leads to an improvement in renal function without altering key elements of the immunosuppression in children with ongoing chronic rejection.