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.

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.

Improved long-term graft function in kidney transplant recipients with donor antigen-specific hyporeactivity.

We investigated the development of donor antigen-specific hyporeactivity by using donor cells as stimulator cells in the MLC and comparing the pre- and post-transplant responses of peripheral blood mononuclear cells. Twenty-two haploidentical pediatric living-relative donor recipients treated with daclizumab, methylprednisone, mofetil mycophenolate and calcineurin inhibitors were tested for study. Of these, 50% of the recipients developed in vitro donor antigen-specific hyporeactivity. The recipients who did so have higher creatinine clearance levels at 12, 24 and 36 months post-transplant (104, 92 and 81 mL/min/1.73 m(2), respectively) than those who remained responsive to donor antigens (77, 74 and 70 mL/min/1.73 m(2)) (p < 0.05). Acute rejection episodes were not observed; however, no recipients with donor-specific hyporeactivity have been diagnosed with CAN, unlike three recipients who remained responsive to donor antigens (0% vs. 27.3%, p = 0.06). Differences in accumulative doses of methylprednisone and mofetil mycophenolate were observed between hyporeactivity- and response-patients to donor antigens at the three years end-point (1.9 +/- 0.8 g/m(2) vs. 4.2 +/- 0.5 g/m(2), and 277 +/- 89 g/m(2) vs. 672 +/- 16.0 g/m(2); p < 0.01 and <0.02, respectively). We conclude that the development of donor antigen-specific hyporeactivity correlate with improved graft function and may permit lower immunosuppression.

Autoantibodies in Argentine women with recurrent pregnancy loss.

PROBLEM: To determine the presence or absence of subclinical autoimmunity in Caucasian Argentine healthy women with first trimester recurrent pregnancy loss (RPL), the sera of 118 healthy women with a history of three or more consecutive abortions and 125 fertile control women without abortions and two children were analyzed for the presence of autoantibodies: immunoglobulin (Ig)G and IgM anticardiolipin, antinuclear (ANA), antismooth muscle (ASMA), antimitocondrial (AMA), antiliver-kidney-microsomal fraction (LKM), antigastric parietal cells (GPC), antineutrophil cytoplasmatic (ANCA) and antibodies antigliadin type IgA and IgG and IgA antitransglutaminase related with celiac disease (CD). METHOD OF STUDY: ANA, ASMA, AMA, anti-LKM, antibodies to GPC and ANCA were determined by indirect immunofluorescence (IFI) and anticardiolipin, antigliadina and antitransglutaminase antibodies were measured by enzyme-linked immunosorbent assays (ELISA). RESULTS: There was no significant difference between controls and patients with ANA, ASMA, AMA, LKM, ANCA and GPC. The prevalence of anticardiolipin antibodies in RPL was significantly higher than controls (P < 0,01) and the prevalence of positive antibodies for antigliadina type IgA and IgG and IgA antitransglutaminase in RPL was significantly higher than controls (P < 0.04). CONCLUSION: We show that Caucasian Argentine women with RPL showed significantly higher incidence of anticardiolipin antibodies than normal controls and finally we recommended the screening of IgA and IgG antigliadina and IgA antitransglutaminase antibodies in pregnancy, because of the high prevalence of subclinical CD in RPL and the chance of reversibility through consumption of a gluten free diet.

Cytokine gene polymorphisms in recurrent pregnancy loss of unknown cause.

PROBLEM: According to previous investigations, certain cytokines may play a role in recurrent pregnancy loss (RPL). Significantly different levels of Th1/Th2 cytokines are produced by normal pregnant women compared with women with RPL of unknown cause. OBJECTIVE: We have studied the polymorphism of cytokine genes which are related to the amount of the cytokine produced. High (H), intermediate (I) and low (L) cytokine responses can be predicted from the cytokine genotype. MATERIAL AND METHODS: The genetic polymorphism of Th1 cytokine [i.e. interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha] and Th2 cytokines [i.e. interleukin (IL)-6, IL-10] and the transforming growth factor (TGF)-beta were studied by polymerase chain reaction-sequence specific primers (PCR-SSP) in the DNA of PBC from 41 women with RPL and 54 control women who had at least two children and without known pregnancy losses. RESULTS: The results showed: (i) no evidence of associations between patients and controls concerning the Th1: TNF-alpha; the Th2: IL-6 and IL-10 and the TGF-beta genotype, (ii) significative association between RPL versus controls concerning IFN-gamma +874 A --> T: T/A genotype was increased in the patient group in comparison with the control group (65% versus 35.8%) (P = 0.01) and there was a statistical disminution in the frequency of the A/A (L) genotype between the patient groups in comparison with the control group (20% versus 41.5%) (P = 0.04). CONCLUSION: This finding would support the concept of involvement of IFN-gamma +874 A --> T in the pathogenesis of RPL of unknown cause in the Caucasian Argentine population.

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.

Citoquinas reguladoras de la respuesta al trasplante renal alogénicos / Regulating citoquinas of the answer to the algénico renal transplant

La aceptación o el rechazo del riñón alogénico depende principalmente de la respuesta inmune y de su compleja regulación en la cual la red de citoquinas y otros mediadores juegan un importante papel. Actualmente, la biopsia renal es, a pesar de lo invasor del procedimiento, la herramienta de mayor utilidad para el diagnóstico del rechazo y de las nefropatías asociadas. Por ello, es de gran interés encontrar métodos alternativos para el diagnóstico. La evaluación de citoquinas reguladoras de la respuesta inmune es un procedimiento sencillo y de bajo costo que podría ser de utilidad para incrementar la sensibilidad de la detección de diferencias polimórficas, para pronosticar la aceptación del transplante y para la detección precoz del rechazo. los estudios recientes sugieren que la producción exagerada de mediadores pro- inflamatorios, incluyendo a citoquinas Th1, sería desventajoso para la sobrevida del transplante, mientras que la producción de citoquinas reguladoras anti inflamatoria, como la interleuquina (IL) menos 10 y el factor de crecimiento tumoral (TGF) menos B, sería beneficiosa. En las primeras etapas, la respuesta Th1 puede incrementar la actividad citotóxica y la detección de moléculas citotóxicas está asociada al rechazo agudo. luego podría ser más importante considerar el balance entre la producción de mediadores pro y anti inflamatorios y la regulación de sus niveles. Así, el TGF B es también fibrogénico y su excesiva producción local puede contribuir al daño renal. por otro lado, el incremento de la produccion de IL menos 10 en respuesta al estímulo alogénico sería, en la mayoría de los casos , un marcador importante para pronosticar la aceptación prolongada.