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Asthma is a common chronic disease of childhood, but for unknown reasons disease activity sometimes subsides as children mature. To understand why, we exposed mice across a range of ages to viral and allergic triggers of asthma exacerbations and airway pathology. We found that pathology induced by Sendai virus (SeV) or influenza A virus (IAV) occurred selectively in juvenile mice in a microbiome-independent manner, while the same phenotypes induced by allergens were insensitive to age. Age-specific responses to SeV included a juvenile bias towards type-2 airway inflammation that emerged early in infection and was lost with maturation. With aging, we observed progressive transcriptional changes to alveolar macrophages (AMs) including the acquisition of high-level MHC-II expression. Importantly, depleting AMs canceled the protective effects of maturity on post-viral airway pathology. Thus, aging of the lung-immune microenvironment influences chronic outcomes of respiratory viral infection and may help to explain childhood asthma remission.

Background. In a retrospective study of the first 75 primary renal transplant patients given alemtuzumab induction at our center, 20 were African American (27%), 32 were Hispanic (43%), and 23 were non-African American, non-Hispanic (31%). Methods. Alemtuzumab was given intraoperatively and 4 days later (0.3 mg/kg), with planned low-dose maintenance mycophenolate mofetil (500 mg twice daily) and tacrolimus (targeted trough levels of 5 to 7 ng/ml) and no corticosteroid therapy after the first week. Median follow-up among ongoing survivors with a functioning graft was 45 months. Results. Three-year actuarial patient and graft survival rates were 95% and 85% in African Americans, 89% and 78% in Hispanics, and 96% and 96% in non-African Americans, non-Hispanics, respectively (not significant). Bioavailability of tacrolimus was significantly lower among African Americans in comparison with the other patient subgroups (P≤.002). While the incidence of biopsy-proven acute rejection was 20% (4/20) in African Americans, 19% (6/32) in Hispanics, and 13% (3/23) in non-African American, non-Hispanic (not significant), chronic allograft dysfunction occurred more frequently among African Americans (10/20) in comparison with Hispanics (8/32) and non-African American, non-Hispanics (8/23) (P=0.08, log-rank test). In addition, there was a trend at 6 and 12 months posttransplant for the mean serum creatinine to be less favorable among African American patients (P=0.08 and 0.07). No group had increased infection or malignancy. Conclusions. This immunosuppressive protocol appears reasonably safe for 3 years after renal transplantation but suggests higher incidences of biopsy-proven acute rejection, chronic allograft dysfunction, and borderline poorer renal function among African Americans in comparison with the other patient subgroups.

Introduction: A long-term prospective randomized trial evaluating alemtuzumab, a humanized anti-CD52 monoclonal antibody, in a predominantly non-Caucasian population has yet to be reported. Methods: Ninety deceased donor (DD) first renal transplant recipients were randomized into three different antibody induction groups: group A, thymoglobulin (Thymo); group B, alemtuzumab; group C, daclizumab (Dac). In groups A and C, the target trough levels of tacrolimus were 8–10 ng/mL, mycophenolate mofetil (MMF) 1 g administered twice daily, and maintenance methylprednisolone. In group B, target tacrolimus trough levels were 4–7 ng/mL, 500 mg MMF administered twice-daily, without methylprednisolone. African-Americans and Hispanics comprised more than 50% in each group. Results: A minimum follow-up of 27 months showed no overall group differences in patient or graft survival (p = 0.89 and 0.66), but a trend towards worse death-censored graft survival in group B (p = 0.05). Acute rejection rates were not significantly different: six (20%), seven (23%), and seven (23%) in groups A, B, and C, respectively. The incidence of chronic allograft nephropathy was higher in group B than in A and C (p = 0.008). The mean calculated creatinine clearance at 24 months was 81.1 ± 5.5, 64.4 ± 4.5, and 80.7 ± 5.7 in groups A, B, and C, respectively (p = 0.01 for B vs. average of A and C). Conclusion: In this randomized 27-month minimum follow-up trial of predominantly non-Caucasian DD renal transplant recipients with alemtuzumab induction, lower maintenance tacrolimus, MMF, and steroid avoidance appear less effective than either Thymo or Dac with higher maintenance immunosuppression.

Background. We update more favorable 10-year deceased donor kidney transplant survival in 63 recipients infused perioperatively with donor vertebral body bone marrow (DBMC-i) vs. 219 noninfused controls having equivalent immunosuppression and demographics. We questioned if this was associated with putatively regulatory FoxP3 mRNA and cell phenotypes (CD4+CD25+ high percentages and high DC2:DC1 ratios) in DBMC-i vs. noninfused controls. Methods. Baseline studies were performed on peripheral blood lymphocytes (PBLs) vs. marrow in normal laboratory volunteers of CD4+CD25+ high percentages and DC2:DC1 by flow cytometry, and FoxP3 mRNA in CD3 + cells by real-time polymerase chain reaction. Similar studies were performed on PBL of the majority of the 10-year patients remaining with graft function: 21 (of the remaining 37) DBMC-i vs. 55 (of the remaining 105) controls. Results. In normal subjects, all parameters were significantly higher in marrow than in PBL, supporting our previous reports of ex vivo DBMC immunoregulation. At 9.8±.02 years posttransplant in DBMC-i vs. controls, death-censored percent graft failure was 17.5% vs. 32.9% (P=0.02) with 247.6±24vs. 79.9±3.1 (mean±SE) FoxP3 copies/5,000 CD3 + cells (P=0.0001). PBL CD4 +CD25 +high percentages were lower, but DC2:DC1 values higher in both recipient groups than in end-stage renal disease patients who had lower FoxP3 levels (40.8±5.9, P

Approximately 25% of patients who undergo kidney transplantation develop HLA-specific antibodies, the strength of which has not been previously correlated with graft failure. The strength of these de novo antibodies is investigated in this study. Serial dilution of strong HLA-specific allo-antibodies (up to 1:25,600) and testing with HLA-antigen-coated beads showed that the titer of the reaction to different HLA antigens is directly correlated to maximum fluorescence values and the molecules of equivalent soluble fluorochrome (MESF) values obtained by Luminex machines. Thus, the strength of antibodies can be measured utilizing maximum fluorescence and MESF. The strength of antibodies in the sera from 39 patients who subsequently had graft failure were markedly higher than those in the sera of 26 patients who continued to have good graft function (p = 0.0084). A clear increase in the strength of antibodies was identified in nine patients with a subsequent increase in serum creatinine levels. If analyzed for donor specificity, a strong association was noted for donor-specific MESF and failure (p = 0.00000027). Our results suggest that it is important to monitor the strength of antibodies when evaluating patient sera posttransplant.

Background New trends in immunosuppression in clinical transplantation include the use of antibody induction agents in protocols that emphasize reduction or avoidance of steroids and calcineurin inhibitors. Methods In a randomized trial using three different antibody induction agents in 90 first renal transplant recipients from cadaver donors, group A received Thymoglobulin, group B received Alemtuzumab, and group C received Daclizumab. Maintenance immunosuppression included tacrolimus and mycophenolate in all three arms, and methylprednisolone in groups A and C only (standard clinical institutional practice). The targeted trough level of tacrolimus was between 8 and 10 ng/mL for groups A and C, respectively, with a targeted mycophenolate dose of 1 g twice daily. However, in group B, the target tacrolimus trough level was 4 to 7 ng/mL to reduce long-term nephrotoxicity, with 500 mg twice-daily doses of mycophenolate, without steroid maintenance. Results In this 15-month median postoperative interval report, there were no notable differences in demographics and patient and graft survivals. Acute rejection rates at 1 year were equivalent, that is, 5 of 30 in all three groups (16.6%). In group B, there was slightly lower renal function at 1 month, but no difference at 1 year. There was also significantly more leukopenia, but a greater percentage of T-regulatory cells and number of Fox-P3 mRNA copies by flow cytometry and semiquantitative polymerase chain reaction analysis, respectively, in group B. Conclusions This preliminary analysis indicates that 80% of the patients in group B remained steroid-free 1 year postoperatively, with lower tacrolimus trough levels and no difference in other adverse events.

Background In an attempt to reduce both initial and long-term (nephrotoxic) calcineurin inhibitor maintenance dosage and totally eliminate maintenance corticosteroids, alemtuzumab (Campath-1H) was used as induction therapy in first cadaver and non-HLA-identical living donor renal transplantation. Methods Forty-four de novo renal allograft recipients were treated with Campath-1H (0.3 mg/kg) on days 0 and 4 postoperatively, preceded by methylprednisolone boluses. Maintenance target 12-hr tacrolimus trough levels of 5 to 7 ng/mL were operational from the outset as well as (reduced) mycophenolate mofetil dosage of 500 mg twice daily. No corticosteroids were planned to be given after the first week postoperatively. Results With a median follow-up of 9 (range, 1-19) months, patient and graft survival rates are each at 100%. Biopsy-proven acute rejection was diagnosed in four patients. Infections requiring hospitalization developed in four patients. Thirty-eight recipients remain without the need for long-term corticosteroid therapy. Conclusions In an early assessment, the combination of Campath-1H, low dosing of tacrolimus and mycophenolate mofetil, and avoidance of maintenance corticosteroid use seems to be safe and effective for kidney transplant recipients. Long-term outcomes will be reported in the future.

Background. To reduce long-term nephrotoxic calcineurin inhibitor dosage, adjunctive sirolimus or mycophenolate mofetil (MMF) was used in a 150-patient, randomized, three-armed trial in cadaveric or human leukocyte antigen non-identical living-donor first renal transplant recipients (n=50/group). Methods. Group A received tacrolimus and sirolimus. Target tacrolimus trough levels postoperatively were 10, 8, and 6 ng/mL at 1 month, 6 months, and 1 year, respectively. Group B received tacrolimus and MMF. Target tacrolimus trough levels were 10 and 8 ng/mL at 1 month and 1 year, with a targeted dose of MMF of 1 g twice daily. Group C received cyclosporine A (CsA) (Neoral, Novartis, Basel, Switzerland) and sirolimus with target CsA trough levels of 225 and 175 ng/mL at 1 month and 1 year. Maintenance sirolimus target trough levels were 8 ng/mL in groups A and C. Each group received daclizumab induction and methylprednisolone maintenance. This first of two companion 1-year reports details demographics, drug-dosing interactions, and rejection. Results. There were no notable differences in group demographics, but a somewhat less favorable course occurred in group C, despite higher bioavailability of sirolimus in group C versus group A (P

Limited data are available on the use of tacrolimus and mycophenolate mofetil in conjunction with anti-IL-2 receptor antibody, in groups of kidney transplant recipients considered to be at higher risk. This study compared the incidence of acute rejection between African-American (AA), Hispanic (H), and non-African-American, non-Hispanics (non-AA, non-H) first renal transplant recipients. We studied 233 sequential first renal transplants. Of the 233, 37 recipients (16%) were AA, 85 (36.5%) were H and 111 (47.5%) were non-AA, non-H. All received daclizumab induction therapy (1 mg/kg) on the day of surgery, and every other week for a total of 5 doses, as well as mycophenolate mofetil, tacrolimus, and steroids. At 1 year, patient and graft survival were 97% and 95% in AA, 98% and 98% in H, and 96% and 95% in non-AA, non-H, respectively (not statistically different). Biopsy-proven acute rejection episodes were 8.1% in AA, 4.7% in H, and 4.5% in non-AA, non-H (also not statistically different). This immunosuppressive protocol appears to be safe and effective in helping to minimize biopsy-proven acute rejection and optimize renal allograft survival in African-American and Hispanic renal transplant recipients in the first year post transplantation.

Background In a previously reported series of donor-specific bone marrow cell (DBMC) infusions in cadaver kidney transplant recipients, there appeared to be an improvement in long-term graft survival (6 years) and fewer chronic rejections, which correlated with increasing DBMC chimerism (approximately 1.4% in the iliac crest bone marrow compartment now at 6 years). Prompted by this, we embarked on a study of DBMC infusion in living-related donor (LRD) kidney transplant recipients. Methods Between November 1996 and May 2000, 47 LRD kidney transplant recipients received donor iliac crest marrow (1.8 x 10(8)+/-1.9 x 10(8) cells/kg body weight+/-SD) in a single infusion 4 days postoperatively. Either OKT3 (n=26) or daclizumab (n=21) were used for induction therapy, with maintenance tacrolimus, mycophenolate mofetil, and methylprednisolone immunosuppression. These recipients were prospectively compared with 39 noninfused LRD kidney transplants (control group), which received equivalent immunosuppression in the same time period. Clinical follow-up ranged from 19.0 months to 61.6 months (mean 33.2 months). Polymerase chain reaction-flow chimerism analysis and in vitro assays of immunoregulatory activity of chimeric cells were performed. Results The incidence of acute rejection over this period of time was 10.6% and 10.3%, respectively (i.e., did not differ between groups). Immunosuppressive dosages were somewhat (but not statistically) lower over time in the DBMC group. Four-year actuarial patient and graft survival for the DBMC-infused group was 98% and 98%, and 98% and 95% for the control group, respectively ( =NS). DBMC infusion was well tolerated, with no increase in infectious episodes. DBMC chimerism in recipient iliac crest marrow has increased more rapidly than might be predicted from results previously seen in the cadaver group, despite four times fewer DBMC infused. DBMCs and (donor) peripheral blood mononuclear cells purified by immunobeads from recipient blood or bone marrow (recipient-derived donor cells) inhibited mixed leukocyte responses of the recipient to the donor more strongly than freshly obtained peripheral blood cells drawn from the donors or even compared with bone marrow cells aspirated from the donors in a previously reported group of experiments. Additionally, similarly purified recipient-derived recipient cells from the same chimeric recipient more strongly inhibited the same mixed leukocyte response reactions autologously than a large group of nonchimeric (autologous) bone marrow modulating cells in similar reactions. Conclusions These observations confirm that an immunoregulatory process appears to have been generated by DBMC infusion, encouraging a further decrease in immunosuppressive dosing using such assays in the future.

Background. Recent reports have demonstrated the efficacy of interleukin-2-receptor blockers in lowering the incidence of early acute rejection in cyclosporine-treated kidney recipients when compared to patients not induced with an antibody product. The addition of daclizumab to a tacrolimus-mycophenolate mofetil-based immunosuppressive protocol was tested to evaluate whether there might be an additional reduction of the risk of rejection after renal transplantation. Methods. Since March 1998, we studied the effect of daclizumab in a nonrandomized, prospective study of 233 sequential recipients of first renal transplant. They were retrospective compared with a control group of 225 renal transplant recipients receiving a 10-day course of OKT3 induction, and tacrolimus, mycophenolate mofetil, and methylprednisolone maintenance. The study group received the same immunosuppressive regimen with the addition of daclizumab at 1 mg/kg for five doses over 10 weeks in the place of OKT3 therapy. There was at least 1HLA DR antigen compatibility match present between all donors and recipients. Patients were followed for 1 year after renal transplantation for the incidence of biopsy-proven acute rejection, patient and graft survival, and adverse events. Results. At 12 months, patient and graft survival for the daclizumab was 98 and 96 vs. 96 and 94% for the OKT3 group, respectively, and were not statistically different. Acute rejection rates (

Background. To date, several single- and multicenter clinical trials have attempted to induce specific immunological unresponsiveness using donor bone marrow cell infusions to augment solid organ transplantation, but the outcomes have not been definitive. Methods. Between September 1994 and May 1998, 63 cadaver (CAD) renal transplant recipients of either one or two postoperative donor bone marrow cell (DBMC) infusions were prospectively compared with 219 non-infused controls given equivalent immunosuppression. There was at least a 1 HLA DR antigen match present between donors and recipients. The immunosuppressive regimen included a 10-day course of OKT3 induction, and tacrolimus, mycophenolate mofetil, and methylprednisolone maintenance. A total 7.01 × 10 8± 1.9 × 10 8 (SD) DBMC/kg was infused into the CAD recipients on either days 4 and 11 (n=42) or one half of that dose on day 4 (n=21) postoperatively. Clinical follow-up has ranged from 2.9 to 6.3 years (mean, 4.7 years). Studies were also performed of humoral immunity and quantitative cellular chimerism. Results. There is clear-cut equivalence in immunosuppressive dosaging and in the other major demographic variables in both groups. However, only 2/63 DBMC recipients had biopsy-proven chronic rejection, whereas 41/219 showed chronic rejection in the controls (P=

BACKGROUND Even though a number of transplant centers have adopted donor-specific bone marrow cell (DBMC) infusions to enhance donor cell chimerism, to date there has been no direct evidence linking chimerism with tolerance induction in human organ transplant recipients. METHODS Cells of donor phenotype were isolated 1 year postoperatively from the peripheral blood lymphocytes and iliac crest bone marrow of 11 living-related-donor (LRD) renal transplant recipients, who had received perioperative donor bone marrow cell infusions. These recipient-derived donor (RdD) cells were characterized phenotypically by flow cytometric analysis and functionally as modulators in mixed lymphocyte reaction (MLR) and cell-mediated lympholysis (CML) assays. RESULTS The yield of RdD cells ranged from 0.1 to O.9% of the starting material with the majority being TcRalphabeta, CD3 positive T cells, a substantial percentage of which coexpressed CD28. At 1 year posttransplant almost 50% of the LRD-kidney/DBMC recipients tested so far exhibited donor-specific unresponsiveness in MLR (7/17) and CML (6/13) reactions and this trend was further enhanced at 23 years. In the recipients with residual positive antidonor immune responses, the RdD cells inhibited recipient antidonor MLR and CML responses significantly more strongly than freshly isolated and similarly treated iliac crest bone marrow cells from the donor. RdD cells also inhibited the MLR of the recipient to third party allogeneic stimulator cells; however, this nonspecific effect was significantly weaker than specific inhibition. We also established long-term bone marrow cultures stimulated every 2 weeks with irradiated alogeneic feeder cells, that had similar functional properties thus possibly providing us with an in vitro correlate the RdD cells. CONCLUSIONS These results clearly support the notion that the infused donor cells play a positive role in the induction and/or maintenance of transplant tolerance.

Ex vivo identification of donor-specific unresponsiveness in organ transplant recipients is important for immunosuppression (IS) minimization. We tested three groups of stable living, related-donor kidney transplant patients up to 11 years postoperatively, i.e., 20 haploidenticals with donor bone marrow cell (DBMC) infusions, eight noninfused haploidentical controls (haplo controls), and 11 HLA-identical controls (HLA-id), using multiple ex vivo immune assays. We observed that no patients developed donor-specific antibodies. The majority showed donor-specific CTL unresponsiveness from year 1 onward. Thirteen of 20 DBMC recipients became specifically donor MLR nonreactive. Depletion of donor cells in DBMC recipients still MLR reactive increased donor-specific reactivity by 75% +/- 36% (p = 0.04). Adding them back in low concentration caused antigen specific inhibition. The frequencies of ELISPOT granzyme-B and interferon-gamma-producing cells somewhat paralleled the CTL and MLR responses. In the trans vivo DTH, 14 of 19 DBMC recipients demonstrated donor-specific unresponsiveness and 16 of 19 showed "linked suppression," vs none of eight and one of eight haplo controls and vs six of 10 and one of 10 HLA-ids, respectively. Most importantly, when all six assays were performed simultaneously, 10 of 18 DBMC, five of 10 HLA-ids, and no haplo controls were specifically donor unresponsive long term. We propose that a cluster analysis combining these assays will reveal tolerant recipients in whom IS minimization may safely be tested. This appears to have occurred in many DBMC-infused recipients.

Background It was of interest to compare enteric-coated mycophenolate sodium (EC-MPS) versus mycophenolate mofetil (MMF) among renal transplant recipients receiving a tacrolimus-based immunosuppressive regimen. Methods Between December 2004 and February 2006, a single-center, open-label randomized trial of MMF (group A, n=75) versus EC-MPS (group B, n=75) was performed in primary renal transplant recipients receiving combined thymoglobulin/daclizumab induction along with reduced tacrolimus dosing and elimination of corticosteroids 1 week postoperatively. The primary endpoint was the incidence rate of acute rejection (AR) during the first 12 months posttransplant; secondary aims were to compare graft and patient survival, renal function, drug dosing and monitoring, gastrointestinal side effects, and other adverse events at 12 months of follow-up. Results Patient/graft survival in groups A and B were 100%/96% versus 99%/96%, respectively (N.S.). At 12 months, a total of nine patients (6%) experienced biopsy-proven AR, 3% (2/75) vs. 9% (7/75) in the MMF and EC-MPS arms, respectively (N.S.). At 12 months, the geometric mean*/SE serum creatinine concentration and arithmetic mean+/-SE calculated glomerular filtration rate in groups A and B, respectively, were 1.30*/1.03 and 61.4+/-2.0 vs. 1.26*/1.03 and 66.0+/-2.1 (N.S.). Incidence of new onset diabetes mellitus (11% vs. 11%), infections requiring hospitalization (13% vs. 15%), and gastrointestinal side effects (36% vs. 32%) appeared equivalent (N.S.). Conclusions Early efficacy and toxicity were equivalent between the two study arms. Optimizing either MMF or EC-MPS along with a combined thymoglobulin/daclizumab induction, low tacrolimus dosing and steroid avoidance resulted in a low AR rate and an acceptably high renal function at 12 months.

The role of HLA antibodies in chronic allograft rejection was examined utilizing a unique resource of sera collected annually and stored over a 12-year period from patients with rejected or retained grafts. In patients selected for not having preformed HLA antibodies, 679 postoperative serial serum samples from 39 patients who rejected their grafts and 26 with functioning grafts were tested for HLA Class I and Class II antibodies by flow cytometry and for MICA antibodies by cytotoxicity on recombinant cell lines. HLA antibodies were found in 72% of patients who rejected grafts, compared to 46% with functioning transplants (p < 0.05). In addition, the incidence of IgG HLA plus MICA antibodies was higher (77%) among those with failed transplants than those with functioning transplants (42%) (p < 0.01). Finally, if patients with IgM anti-HLA antibodies were included, 95% of the 39 patients who rejected their grafts had HLA or MICA antibodies, compared to 58% with functioning grafts (p < 0.01). Patients who rejected transplants had HLA and MICA antibodies more frequently than those with functioning grafts. These antibodies found in the peripheral circulation, were not necessarily donor-specific, but their association with failure is consistent with a causality hypothesis.

The infusion and persistence in a transplant recipient of donor-derived bone marrow cells (DBMC) of multi-lineage can lead to a state of permanent chimerism. In solid vascular organ transplantation, the donor bone marrow lineage cells can even be derived from the transplant organ, and these cells can be detected in very small numbers in the recipient. This has been called microchimerism. Much controversy has developed with respect to the function of chimeric cells in organ transplantation. One idea is that the occurrence of these donor cells found in microchimerism in the recipient are coincidental and have no long-term beneficial effect on engraftment. A second and opposing view, is that these donor cells have immunoregulatory function that affect both the acute and chronic phases of the recipient anti-donor responses. It follows that detecting quantitative changes in chimerism might serve as an indication of the donor-specific alloimmune or regulatory response that could occur in concert with or independent of other adaptive immune responses. The latter, including autoimmune native disease, need to be controlled in the transplant organ. The safety and immune tolerance potential of DBMC infusion with deceased and living donor renal transplants was evaluated in a non-randomized trial at this center and compared with non-infused controls given identical immunosuppression. Overall DBMC infusions were well tolerated by the recipients. There were no complications from the infusion(s), no episodes of graft-vs-host disease (GVHD) and no increase infections or other complications. In the deceased DBMC-kidney trial, actuarial graft survival at 5 years was superior especially when graft survival was censored for recipient death. Acute rejections were significant reduced in patients given two DBMC infusions, and chronic rejection was dramatically reduced in all DBMC treated patients. The most interesting finding was that the degree of microchimerism slowly increased over the years the DBMC group that had exhibited no rejection episodes. In the DBMC-living related trial, the incidence of acute rejection did not differ between groups. However, DBMC chimerism in recipient iliac crest marrow had increased more rapidly than might be predicted from results previously seen in the cadaver group, despite four times fewer DBMC infused, with the generation of T- regulartory cells in-vitro assays.

Cytomegalovirus, seen in more than 50% of solid organ transplant recipients, is responsible for numerous direct and indirect consequences, including infection with opportunistic pathogens and allograft rejection. Prophylaxis with intravenous ganciclovir has been the gold standard for prevention; however, intravenous treatment is expensive and carries risks of its own. Oral ganciclovir, to be effective, must be given in large, divided doses. Valganciclovir, the valine ester of ganciclovir, at 900 mg/day, provides oral bioavailability equivalent to that of intravenous ganciclovir and superior to that of oral ganciclovir. This retrospective study assessed the efficacy of 3 months prophylaxis with valganciclovir in kidney, simultaneous pancreas-kidney, and pancreas transplantation. Of 161 patients, all of whom received potent immunosuppressive regimens and were followed for a mean of 440 days, only one developed cytomegalovirus infection, at 120 days post-transplantation. Two patients died, and two others lost their grafts. There were seven incidents of acute rejection. Only seven patients discontinued treatment early, five because of leukopenia. These results suggest that prophylaxis with 900 mg/day of valganciclovir for at least 3 months safely and effectively prevents cytomegalovirus infection in kidney, simultaneous pancreas-kidney and pancreas transplant recipients on highly potent immunosuppression.

Background. In an attempt to reduce chronic calcineurin inhibitor induced allograft nephropathy in first cadaver and human leukocyte antigen non-identical living-donor renal transplantation, sirolimus (Siro) or mycophenolate mofetil (MMF) was tested as adjunctive therapy, with planned dose reductions of tacrolimus (Tacro) over the first year postoperatively. Adjunctive Siro therapy with a similar dose reduction algorithm for Neoral (Neo) was included for comparison. Methods. The detailed dose reduction plan (Tacro and Siro, group A; Tacro and MMF, group B; Neo and Siro, group C) is described in our companion report in this issue of Transplantation. The present report documents function, patient and graft survival, protocol compliance, and adverse events. Results. As mentioned (in companion report), group demographics were similar. The present study shows no significant differences in 1-year patient and graft survival but does show a trend that points to more difficulties in group C by way of a rising slope of serum creatinine concentration (P=0.02) and decreasing creatinine clearance (P=0.04). There were more patients who discontinued the protocol plan in group C. Thus far, no posttransplant lymphomas have appeared, and infectious complications have not differed among the groups. However, a greater percentage of patients in group C were placed on antihyperlipidemia therapy, with an (unexpected) trend toward a higher incidence of posttransplant diabetes mellitus in this group. Group A required fewer, and group B the fewest, antihyperlipidemia therapeutic interventions (P

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, p0.02). 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.