Monica L. Tambutti

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.

Conversion from azathioprine [correction of azathioprina] to mycophenolate mofetil in pediatric renal transplant recipients with chronic rejection.

BACKGROUND Chronic rejection is the leading cause of graft failure. Both nonimmunological and immunological mechanisms contribute to this pathology. METHODS We studied changes in kidney function, mixed lymphocyte culture, cell-mediated lympholysis, serum HLA class I antigens, cytotoxic antibodies, and lymphocyte population before and after 6 months of follow-up in 22 pediatric renal transplanted patients. The immunosuppressive protocol used was: cyclosporine, azathioprine, and corticosteroids. Eight patients demonstrated chronic graft rejection (by biopsy), group I; and eight patients had no clinical evidence of chronic and/or acute rejection, group II. Substitution of mycophenolate mofetil (MMF) (600 mg/m2 bid for azathioprine was done in patients of groups I and II. Another six patients with chronic rejection, did not receive MMF, group III. RESULTS Creatinine clearance increased in group I (44+/-5 vs. 51.1+/- ml/min/1.73 m2, P<0.03) but it decreased in group III (30+/-3 vs. 25+/-2, P<0.01). Urinary protein excretion decreased only in group I (0.3+/-0.03 to 0.06+/-0.03 g/24 hr, P<0.03). During MMF therapy antidonor mixed lymphocyte culture decreased 62 and 70% (P<0.05) in group I and II. Cell-mediated lympholysis against lymphocyte of the donor decreased 65% (P<0.05) in group I. Cell-mediated lympholysis toward control cells decreased 54% (P<0.01) in group II. Serum HLA class I antigens, only decreased from 0.7+/-0.1 to 0.5+/-0.1 microl/ml, P<0.05, in group I. CD19+ decreased from 7.9+/-1.1 to 5.6+/-0.8%, P<0.05, and 7.8+/-1.2 to 5.5+/-0.9%, P<0.05, in groups I and II, respectively. CD16+ increased from 5.7+/-1.1 to 8.6+/-1.3 (P<0.05) only in group I. CONCLUSIONS Our data suggest that substituting MMF for azathioprine therapy leads to an improvement in the immunosuppression and renal function in children with on-going chronic rejection.

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

Abstract:  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/m2 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 m2, 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‐α 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‐β and interferon‐γ 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.

Autoantibodies in Argentine Women with Recurrent Pregnancy Loss

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).

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/1.73m2, 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-&ggr; production in vitro (P <0.05) and increased tumor necrosis factor-&agr; levels (P <0.05). The release of interleukin-10 was strikingly augmented with CsA or Tac therapy (P <0.01), but transforming growth factor-&bgr; 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.

Microchimerism and blocking activity in women with recurrent spontaneous abortion (RSA) after alloimmunization with the partner’s lymphocytes

Alloimmunization therapy using the partners leukocytes has been reported to be effective in preventing the failure of pregnancy in patients who have suffered RSA of unknown cause. After alloimmunization, several investigators have reported the presence of blocking factors (BF) in women with successful pregnancies in in vitro assays of lymphocyte response. The recent discovery of small numbers of ubiquitous donor cells (microchimerism) in human transplants up to 29 years post-transplantation has raised questions about the migration of the chimeric cells and their role in the induction and perpetuation of tolerance. We have investigated the production of BF in the mixed lymphocyte reaction (MLR) before and in some patients after alloimmunization and its possible relation with the development of microchimerism (M). Before the treatment we studied 14 couples with three or more abortions who were evaluated clinically to rule-out genetic, structural, endocrine, infectious and autoimmune causes. The M study was done by nested PCR-SSP technique with HLA-DR alleles, before and after 30 days of the last immunization. Before the treatment only one patient was M positive and none were BF positive with inhibition effect (IE) > 50. Only eight underwent treatment. The patients had between three and nine alloimmunizations (x = 4.7). After treatment, all patients were M positive with IE > 50. Six months after the last immunization, four patients are M positive with IE > 50. In conclusion, the hypothesis proposes that alloimmunization establishes a state of microchimerism that would be the necessary allogeneic stimulus for T-cell activation, and the induction or maintenance of tolerance to the fetus during pregnancy. reserved.

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

Abstract:   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 m2, respectively) than those who remained responsive to donor antigens (77, 74 and 70 mL/min/1.73 m2) (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/m2 vs. 4.2 ± 0.5 g/m2, and 277 ± 89 g/m2 vs. 672 ± 16.0 g/m2; 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.

Soluble HLA class I antigens in pediatric patients with renal transplants from related living donors without acute rejection and treated with triple therapy.

All HLA class I Ag-expressing cells may be the source of serum Ag sHLA I. T and B lymphocytes secrete considerable amounts of Ag sHLA I in a variety of in vitro and in vivo activation systems. The purpose of this study was to evaluate the level of Ag sHLA I in serum of children with kidney transplants from related living donors without acute rejection and with triple therapy. We studied 25 patients (2-21 years) with first kidney transplant, 19 individuals (10-20 years) undergoing hemodialysis without transplant, and 25 normal children (4-21 years). The levels of Ag sHLA in transplant patients was 0.2-3.2 micrograms/ml (mean = 1.04). The hemodialyzed patients was 0.48-4.5 micrograms/ml (mean = 2.09), and the normal control was 0.30-4.38 micrograms/ml (mean = 2.04). A statistically significant reduction was observed in transplant patients compared to normal control and hemodialyzed patients (p < 0.05 in both cases), whereas between normal and hemodialyzed patients no significant difference was seen (p > 0.05). The reduced levels of Ag sHLA I in blood could be an expression of adequate immunosuppressive treatment.

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

Abstract:  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 μg/mL) compared with MMF administration (4.2 ± 0.9 μg/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, γ‐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.