Consensus on definition and severity grading of lymphatic complications after kidney transplantation.

BACKGROUND: The incidence of lymphatic complications after kidney transplantation varies considerably in the literature. This is partly because a universally accepted definition has not been established. This study aimed to propose an acceptable definition and severity grading system for lymphatic complications based on their management strategy. METHODS: Relevant literature published in MEDLINE and Web of Science was searched systematically. A consensus for definition and a severity grading was then sought between 20 high-volume transplant centres. RESULTS: Lymphorrhoea/lymphocele was defined in 32 of 87 included studies. Sixty-three articles explained how lymphatic complications were managed, but none graded their severity. The proposed definition of lymphorrhoea was leakage of more than 50 ml fluid (not urine, blood or pus) per day from the drain, or the drain site after removal of the drain, for more than 1 week after kidney transplantation. The proposed definition of lymphocele was a fluid collection of any size near to the transplanted kidney, after urinoma, haematoma and abscess have been excluded. Grade A lymphatic complications have a minor and/or non-invasive impact on the clinical management of the patient; grade B complications require non-surgical intervention; and grade C complications require invasive surgical intervention. CONCLUSION: A clear definition and severity grading for lymphatic complications after kidney transplantation was agreed. The proposed definitions should allow better comparisons between studies.

ANTECEDENTES: La incidencia de complicaciones linfáticas tras el trasplante renal (post-kidney-transplantation lymphatic, PKTL) varía considerablemente en la literatura. Esto se debe en parte a que no se ha establecido una definición universalmente aceptada. Este estudio tuvo como objetivo proponer una definición aceptable para las complicaciones PKTL y un sistema de clasificación de la gravedad basado en la estrategia de tratamiento. MÉTODOS: Se realizó una búsqueda sistemática de la literatura relevante en MEDLINE y Web of Science. Se logró un consenso para la definición y la clasificación de gravedad de las PKTL entre veinte centros de trasplante de alto volumen. RESULTADOS: En 32 de los 87 estudios incluidos se definía la linforrea/linfocele. Sesenta y tres artículos describían como se trataban las PKTL, pero ninguno calificó la gravedad de las mismas. La definición propuesta para la linforrea fue la de un débito diario superior a 50 ml de líquido (no orina, sangre o pus) a través del drenaje o del orificio cutáneo tras su retirada, más allá del 7º día postoperatorio del trasplante renal. La definición propuesta para linfocele fue la de una colección de líquido de tamaño variable adyacente al riñón trasplantado, tras haber descartado un urinoma, hematoma o absceso. Las PKTL de grado A fueron aquellas con escaso impacto o que no requirieron tratamiento invasivo; las PKTL de grado B fueron aquellas que precisaron intervención no quirúrgica y las PKTL de grado C aquellas en que fue necesaria la reintervención quirúrgica. CONCLUSIÓN: Se propone una definición clara y una clasificación de gravedad basada en la estrategia de tratamiento de las PKTLs. La definición propuesta y el sistema de calificación en 3 grados son razonables, sencillos y fáciles de comprender, y servirán para estandarizar los resultados de las PKTL y facilitar las comparaciones entre los diferentes estudios.

Increased natural killer cell subsets with inhibitory cytokines and inhibitory surface receptors in patients with recurrent miscarriage and decreased or normal subsets in kidney transplant recipients late post-transplant.

Patients with recurrent miscarriage (RM) show up-regulated cytotoxic natural killer (NK) cells that are suspected to play a causal role in abortion. In the present study, we investigated counter-regulating inhibitory mechanisms and compared the results in RM patients with those of healthy controls (HC), patients with end-stage renal disease (ESRD) and kidney transplant recipients late post-transplant (TX). NK, NK T and T cell subsets were analysed in the peripheral blood of 31 RM, 14 female ESRD and nine female TX patients as well as 21 female HC using eight-colour fluorescence flow cytometry. Compared with HC, RM patients showed significantly higher absolute numbers of CD56+ NK cells co-expressing the phenotype interferon (IFN)-γR+ , IL-4+ , transforming growth factor (TGF)-ß+ , IL-4+ human leucocyte antigen D-related (HLA-DR)+ , TGF-ß+ HLA-DR+ , IL-4+ TGF-ß+ , IL-4+ TGF-ß- , IFN-γ+ and/or IL-10- IFN-γ+ (all P ≤ 0·01), more IL-17+ CD56bright (P = 0·028) NK cells and more CD56dim CD16+ NK cells co-expressing IFN-γR, IFN-γ, IL-4 and/or TGF-ß (all P ≤ 0·01). When the same cell subsets were analysed in ESRD or TX patients, cytokine-producing NK cell subsets were not significantly different from those of HC. RM patients showed significantly higher absolute numbers of CD158a+ , CD158b+ , CD158a- CD158e+ (all P < 0·05), NKG2D+ NKG2A+ , NKG2D + NKG2A- , NKG2D+ and/or NKG2A+ (all P ≤ 0·01) CD56+ NK cells and higher CD158a+ , CD158b+ (all P < 0·05), NKG2D+ and/or NKG2A+ (all P < 0·01) CD56dim+ CD16+ NK cells than HC. In contrast, ESRD patients had normal and TX recipients had lower CD158a+ and NKG2D+ NKG2A- CD56+ NK cells and lower CD158a+ CD56dim+ CD16+ NK cells (all P < 0·05) than HC. RM patients have abnormally high circulating NK cells expressing inhibitory cytokines and inhibitory surface receptors which might contribute to the pathogenesis of RM.

Association of peripheral NK cell counts with Helios+ IFN-γ- Tregs in patients with good long-term renal allograft function.

Little is known about a possible interaction of natural killer (NK) cells with regulatory T cells (Treg ) in long-term stable kidney transplant recipients. Absolute counts of lymphocyte and Treg subsets were studied in whole blood samples of 136 long-term stable renal transplant recipients and 52 healthy controls using eight-colour fluorescence flow cytometry. Patients were 1946 ± 2201 days (153-10 268 days) post-transplant and showed a serum creatinine of 1·7 ± 0·7 mg/dl. Renal transplant recipients investigated > 1·5 years post-transplant showed higher total NK cell counts than recipients studied < 1·5 years after transplantation (P = 0·006). High NK cells were associated with high glomerular filtration rate (P = 0·002) and low serum creatinine (P = 0·005). Interestingly, high NK cells were associated with high CD4+ CD25+ CD127- forkhead box protein 3 (FoxP3+ ) Treg that co-express the phenotype Helios+ interferon (IFN)-γ- and appear to have stable FoxP3 expression and originate from the thymus. Furthermore, high total NK cells were associated with Treg that co-express the phenotypes interleukin (IL)-10- transforming growth factor (TGF)-ß+ (P = 0·013), CD183+ CD62L- (P = 0·003), CD183+ CD62+ (P = 0·001), CD183- CD62L+ (P = 0·002), CD252- CD152+ (P < 0·001), CD28+ human leucocyte antigen D-related (HLA-DR- ) (P = 0·002), CD28+ HLA-DR+ (P < 0·001), CD95+ CD178- (P < 0·001) and CD279- CD152+ (P < 0·001), suggesting that these activated Treg home in peripheral tissues and suppress effector cells via TGF-ß and cytotoxic T lymphocyte-associated protein 4 (CTLA-4). The higher numbers of NK and Treg cell counts in patients with long-term good allograft function and the statistical association of these two lymphocyte subsets with each other suggest a direct or indirect (via DC) interaction of these cell subpopulations that contributes to good long-term allograft acceptance. Moreover, we speculate that regulatory NK cells are formed late post-transplant that are able to inhibit graft-reactive effector cells.

[Modern immunosuppression after solid organ transplantation]. / Moderne Immunsuppression nach Organtransplantation.

The one common factor in solid organ transplantation is the need for lifelong maintenance immunosuppression. Drug regimens after organ transplantation typically comprise a combination of different immunosuppressive drugs. In most cases a triple drug regimen with different mechanisms of action is used. The aim is to improve both patient and graft survival while minimizing potential side effects of immunosuppressive medication. The basis of most immunosuppressive regimens is calcineurin inhibitors in combination with mycophenolic acid. There are various stages of immunosuppression after solid organ transplantation involving induction therapy, initial and long-term maintenance therapy. In each phase an individual combination of immunosuppressants is set up depending on the risk profile of the individual patient to prevent transplant rejection and organ loss. Based on these considerations, concepts of calcineurin inhibitor or steroid reduction have been established in transplant medicine in recent years. The key role in terms of development of new immunosuppressive strategies is taken by kidney transplantation, the most common solid organ transplantation performed.

Influence of test technique on sensitization status of patients on the kidney transplant waiting list.

The exquisitely sensitive single antigen bead (SAB) technique was shown to detect human leukocyte antigen (HLA) antibodies in sera of healthy male blood donors. Such false reactions can have an impact on critical decisions, especially with respect to the determination of unacceptable HLA-antigen mismatches in patients awaiting a kidney transplant. We tested pretransplant sera of 534 patients on the kidney waiting list using complement-dependent cytotoxicity (CDC), enzyme-linked immunosorbent assay (ELISA) and SAB in parallel. Evidence of HLA antibodies was obtained in 5% of patients using CDC, 14% using ELISA, and 81% using SAB. Among patients without history of an immunizing event, 77% showed evidence of HLA antibodies in SAB. In contrast 98% of these patients were negative in ELISA and CDC. In patients without an immunizing event, SAB-detected antibodies reacted not always weakly but with mean fluorescence intensity (MFI) values as high as 14 440. High-MFI-value antibodies were found in some of these patients with HLA specificities that are rather common in general population, consideration of which would lead to unjustified exclusion of potential kidney donors. False SAB reactions can be unveiled by testing with additional antibody assays. Denial of donor kidneys to recipients based on HLA-antibody specificities detected exclusively in the SAB assay is not advisable.

Current approaches to the management of highly sensitized kidney transplant patients.

With the introduction of sensitive antibody detection techniques, effective antibody elimination devices, therapeutic agents, such as bortezomib and eculizumab, and new concepts, such as Heidelberg algorithm, kidney paired exchange, and acceptable mismatch programs, several effective options are now available for the management of highly sensitized kidney transplant patients. However, as the number of human leukocyte antigen-mismatched transplantations is increasing with each year and as long as the elimination or long-term control of donor-specific antibody-producing clones remains an unresolved issue, sensitization will continue to represent a major problem in kidney transplantation.

Immunosuppression after kidney transplantation.

Today kidney transplantation features excellent short-term outcomes with decreasing acute rejection episodes. In contrast, improvement of long-term allograft survival is much less impressive over the last decades. Thus, the goal of current immunosuppressive therapies is keeping the balance between the reduction of acute rejection episodes and organ specific and systemic side effects. With the development of a broad armamentarium of new immunosuppressive agents with different mechanisms of action, the minimization or avoidance of corticosteroids and calcineurin inhibitors became feasible.

Angiotensin-converting enzyme inhibitors and angiotensin II type 1 receptor blockers after renal transplantation.

Renin-angiotensin system blockade retards the progression of diabetic and non-diabetic chronic kidney disease of the native kidneys. Though most patients suffer from a significant renal insufficiency (chronic kidney disease stage III) and a concomitant heart disease after renal transplantation, there is up to now no evidence supporting the use of inhibitors of the renin-angiotensin system in these patients. We wish to summarize the available evidence on the use of inhibitors of the renin-angiotensin system after renal transplantation. We specifically discuss potential beneficial as well as adverse effects of a renin-angiotensin system blockade. In addition, we review their influence on morphologic and biochemical markers as well as on renal function, graft and patient survival after renal transplantation.

Simultaneous pancreas-kidney transplantation in type 1 diabetes.

The outcome of simultaneous pancreas-kidney (SPK) transplantation in type 1 diabetes has dramatically improved in recent years because of optimized surgical techniques and new immunosuppressive drug regimens. Normoglycemia is followed by stabilization or even regression of diabetic lesions, i.e., of heart and kidneys. However, these effects are only visible after more than five yr of normoglycemia (achieved by a functioning allograft). This is also a likely explanation for the conflicting results of studies that investigated patient or kidney graft survival in SPK transplantation compared to kidney transplantation alone. Most studies had too short follow-up periods, i.e., less than five yr, to compare effectively different transplant strategies in patients with type 1 diabetes and therefore failed to discover a survival benefit in favor of simultaneously transplanted patients. Recent data now indicate that, with a longer follow-up, there is an increasing survival benefit for simultaneously transplanted patients compared to patients who received a single kidney transplant. This is paralleled by the comparison of simultaneously transplanted patients to patients who received a single kidney transplant from a living donor. A survival benefit for the combined procedure was here visible after 10 yr of follow-up. We give a short overview on SPK transplantation, with a focus on the effects of this procedure on diabetic complications as well as patient and kidney graft survival.

Effects of mycophenolic acid on human fibroblast proliferation, migration and adhesion in vitro and in vivo.

Mycophenolic acid (MPA) is a potent inhibitor of the inosine monophosphate dehydrogenase and used as an immunosuppressive drug in transplantation. MPA inhibits proliferation of T- and B-lymphocytes by guanosine depletion. Since fibroblasts rely on the de novo synthesis of guanosine nucleotides, it is assumed that MPA interacts with fibroblasts causing an increased frequency of wound healing problems. We show a downregulation of the cytoskeletal proteins vinculin, actin and tubulin in fibroblasts exposed to pharmacological doses of MPA using microarray technology, real-time polymerase chain reaction (PCR) and Western blot. This reduction in RNA and protein content is accompanied by a substantial rearrangement of the cytoskeleton in MPA-treated fibroblasts as documented by immunofluorescence. The dysfunctional fibroblast growth was validated by scratch test documenting impaired migrational capacity. In contrast, cell adhesion was increased in MPA-treated fibroblasts. The results of the cultured human fibroblasts were applied to skin biopsies of renal transplant recipients. Skin biopsies of patients treated with MPA expressed less vinculin, actin and tubulin as compared to control biopsies that could explain potential wound healing problems posttransplantation. The perspective of MPA-induced cytoskeletal dysfunction may go beyond wound healing disturbances and may have beneficial effects on (renal) allografts with respect to scarring.

Activity of nuclear factor of activated T cells is independent of the number of peripheral lymphocytes in FTY720-treated patients.

UNLABELLED: We studied the inhibition of nuclear factor of activated T-cell (NFAT)-regulated gene expression (interleukin-2 [IL-2], interferon-gamma [IFN-gamma], granulocyte-macrophage colony-stimulating factor [GMCSF]) in cyclosporine (CsA)-treated de novo patients with and without lymphopenia due to FTY720. MATERIALS AND METHODS: Sixteen CsA-treated de novo renal transplant recipients received either FTY720 (n = 8) or mycophenolic acid (MPA; n = 8) in combination with low-dose steroids. Expressions of IL-2, INF-gamma, and GMCSF were measured at 1 (visit 1), 2 (visit 2), and 14 (visit 3) months postoperatively using peripheral lymphocytes obtained at 0 hour versus 2 hours after CsA intake. Gene expression was assessed by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS: CsA 0- and 2-hour levels were comparable in both groups. Absolute NFAT-regulated gene expression was significantly lower among FTY720-treated patients at visits 1 and 2. Median residual NFAT-regulated gene expression was 5.9% in the FTY720 group and 4.2% in the MPA-treated group at visit 1, increasing to 7.2% and 7.0%, respectively, at visit 3. One borderline rejection occurred in the MPA group. Median serum creatinine was 1.5 mg/dL among FTY720 and 1.8 mg/dL among MPA patients. CONCLUSIONS: Despite significantly lower expression of NFAT-regulated genes, the relative reduction in NFAT gene expression was comparable in both groups. The absolute number of lymphocytes was not relevant for this immune response. In addition, gene expression increased to comparable levels after FTY720 was switched to MPA. The relative residual gene expression increased with reduction in CsA dose.

Four cases of sirolimus-associated interstitial pneumonitis: identification of risk factors.

Sirolimus-associated interstitial pneumonitis is a severe side effect of sirolimus therapy; fatal outcomes have been described. We report 4 patients with sirolimus-associated interstitial pneumonitis and review the literature for risk factors for the development of disease. Until June 2005, 48 patients received either de novo sirolimus treatment (n = 7) or were switched from a calcineurin inhibitor-containing regimen to a sirolimus-based protocol for various indications (n = 41). Compared with the 44 patients on sirolimus therapy with no evidence of a disorder, the 4 patients (8.3%) who developed suspected sirolimus-associated interstitial pneumonitis showed no difference in gender, immunosuppressive therapy, days posttransplantation, comorbidity, or preexistent lung disease. Several points, however, are of interest. None of the de novo-treated patients except 4 patients (9.8%) with late administration of sirolimus developed interstitial pneumonitis. The 4 patients with interstitial pneumonitis tended to be older (58.7 +/- 5.5 vs 46.9 +/- 1.7 years) and received higher sirolimus doses (3.5 +/- 0.5 vs 1.4 +/- 0.2 mg/d) with greater trough levels (15.4 +/- 2.9 vs 8.0 +/- 1.2 micro g/L) at the onset of symptoms. Most notably, all patients with interstitial pneumonitis had a loading dose at the start of therapy, and an increase in sirolimus dose (or trough level) within 3 weeks prior to the onset of symptoms. Additional potential risk factors identified from the literature include allograft dysfunction, hypervolemia, and male gender. With careful monitoring (or even exclusion from therapy) of patients at risk for the development of disease, we have had no case of sirolimus-associated interstitial pneumonitis since September 2004.

Isolation and characterization of complementary DNA clones corresponding to genes induced in mouse epidermis in vivo by tumor promoters.

Complementary DNA clones representing genes in SENCAR mouse epidermis, the expression of which is induced 4 h after one topical application of the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) were isolated. Of 56 isolated complementary DNA clones, 32 were identified to be identical to either metallothioneins (MT-I and MT-II) or endogenous retroviral like (VL30) sequences. In situ hybridization and analysis of mRNA levels in cell fractions separated by density gradient centrifugation revealed that MT induction was restricted to keratinocytes in the basal cell layer. Immunohistochemistry and time-kinetic studies on mRNA levels in mouse epidermis showed that the increase in MT and VL30 RNAs coincide in time with a TPA-induced transient block in basal cell proliferation (3-12 h after TPA treatment). MT immunoreactivity and transcript levels had returned to control values at a time point (24 h after treatment) when epidermis is known to hyperproliferate. Treatment with other types of tumor promoters showed that MT-I and MT-II mRNAs were coordinately induced and indicated that sn-1,2-dioctanoylglycerol, 12-O-retinoylphorbol-13-acetate, and mezerein induced MT to a lesser degree than TPA. The calcium ionophore A23187 induced mRNA levels for MTs as well as VL30. VL30 and MT mRNA levels were not found to be elevated in epidermal tumors whereas the mRNA level corresponding to glyceraldehyde-3-phosphate dehydrogenase was elevated in tumors and induced by TPA with time-kinetics that correlate with a TPA-induced hyperproliferation. These complementary DNA clones provide useful tools in the study of the gene-regulating effects of TPA in a target tissue relevant for tumor promotion.

Tissue Expression of Aquaporin 2 Is Correlated to Urine Output and Allograft Function in Sensitized Kidney Transplant Patients.

BACKGROUND: Salt and water disturbances often occur during acute kidney allograft dysfunction that contribute to graft failure, but this condition has been poorly investigated in the alloreactivity setting. We evaluated the tissue expression of aquaporins (AQP1 and AQP2) and the epithelial sodium channel (ENAC) in kidney biopsy specimens from sensitized kidney transplant recipients. METHODS: Eighty-six biopsy specimens from 33 sensitized patients were divided into 3 groups according to clinical context: time-zero (n = 9), protocol (n = 9), and indication (n = 68). The indication biopsy specimens were further divided into 3 subgroups according to the presence of acute tubular necrosis or rejection. Normal kidney tissue samples (n = 6) served as the control specimens. Immmunohistochemical expression of AQP1, AQP2, and ENAC was determined by using image analyzing software. RESULTS: Significantly lower AQP1 expression was observed in the time-zero and indication biopsy specimens with rejection compared with control specimens (P = .03 and P = .04, respectively). AQP2 expression was significantly lower in patients with an indication biopsy specimen compared with control and protocol biopsy specimens (P = .05 and P = .005). For ENAC, a lower expression was noted in the indication biopsy specimens compared with the control specimens (P = .04). Both AQP1 and AQP2 tissue expressions were significantly correlated to urine output (r = 0.45 and r = 0.32; P = .001 and P = .02), and AQP2 was correlated with the glomerular filtration rate estimated by using the Modification of Diet in Renal Disease Study equation at biopsy (r = 0.23; P = .05). CONCLUSIONS: These findings partially confirm previous experimental data showing downregulation of AQP1 expression after ischemia/reperfusion injury and during rejection. AQP2 downregulation seems to be rejection-independent, occurring during deteriorating or poor kidney graft function.

Pre-transplant soluble CD30 in combination with total DSA but not pre-transplant C1q-DSA predicts antibody-mediated graft loss in presensitized high-risk kidney transplant recipients.

Presensitized kidney transplant recipients are at high-risk for early antibody-mediated rejection. We studied the impact of pre- and post-transplant donor-specific human leukocyte antigen (HLA) antibodies (DSA) and T-cell-activation on the occurrence of antibody-mediated rejection episodes (AMR) and graft loss (AMR-GL) in a unique cohort of 80 desensitized high-risk kidney transplant recipients. Patients with pre-transplant DSA demonstrated more AMR episodes than patients without DSA, but did not show a significantly increased rate of AMR-GL. The rates of AMR and AMR-GL were not significantly increased in patients with complement split product (C1q)-binding pre-transplant DSA. Pre-transplant C1q-DSA became undetectable post-transplant in 11 of 13 (85%) patients; 2 (18%) of these 11 patients showed AMR but no AMR-GL. In contrast, the post-transplant presence of C1q-DSA was associated with significantly higher rates of AMR (86 vs 33 vs 0%; P < 0.001) and AMR-GL (86 vs 0 vs 0%; log-rank P < 0.001) compared with post-transplant DSA without C1q-binding or the absence of DSA. Patients with both pre-transplant DSA and evidence of pre-transplant T-cell-activation as indicated by soluble CD30-positivity showed a significantly increased risk for AMR-GL [HR = 11.1, 95% confidence interval (CI) = 1.68-73.4; log-rank P = 0.013]. In these high-risk patients, AMR-GL was associated with total DSA in combination with T-cell-activation pre-transplant, and de novo or persistent C1q-binding DSA post-transplant.

A Single-center Experience on the Value of Pancreas Graft Biopsies and HLA Antibody Monitoring After Simultaneous Pancreas-Kidney Transplantation.

BACKGROUND: In simultaneous pancreas-kidney transplantation (SPKT), monitoring of the pancreas allograft is more complex than the kidney allograft due to difficulties in obtaining pancreas histology and weak clinical evidence supporting the role of donor-specific antibodies (DSA). METHODS: We performed a single-center retrospective analysis of all 17 SPKT recipients who underwent a total of 22 pancreas allograft indication biopsies from October 2009 to September 2012. Fifteen patients had at least 2 DSA measurements: pretransplantation and at the time of biopsy. RESULTS: All 7 patients (100%) with post-transplantation DSA-positivity (de novo: n = 6; persistent: n = 1) at biopsy had at least 1 rejection episode either of the pancreas (n = 4) or the kidney (n = 3), with 3 antibody-mediated rejections (AMR). In contrast, only 4 of 8 patients (50%) without post-transplantation DSA had evidence of rejection, with 1 AMR. Findings during pancreas allograft biopsy procedures led to a change of immunosuppressive therapy in 11 of 15 (73%) patients. Patient survival, graft survival, and function were not adversely affected by the presence of post-transplantation DSA. One major and 2 minor procedure-related complications occurred during the pancreas biopsies. CONCLUSIONS: In this small retrospective analysis, pancreas allograft histology provided the most therapeutically relevant information, rather than the kidney histology or DSA monitoring.

Effects of manganese on the nervous system.

The acute effect of manganese on the synaptosomal sodium-dependent choline uptake was studied. Manganese (Mn) revealed a mixed competitive-noncompetitive inhibition of the choline uptake, at Mn concentrations in the mM range. We do not believe that lack of choline for transmitter synthesis is of importance in Mn poisoning. Manganese chloride intubation of neonatal rats resulted in reduced homovanillic acid content in the striatum and hypothalamus. No other alteration in the dopamine or serotonin metabolism was revealed. A mechanism of cytotoxic action of manganese is discussed in terms of its transition metal properties and interaction with reactive oxygen compounds which result in the production of substances that alkylate or oxidize the cellular thiols.

Review of the antiproliferative properties of mycophenolate mofetil in non-immune cells.

Mycophenolate mofetil (MMF), the prodrug ofmycophenolic acid (MPA), is a selective, non-competitive and reversible inhibitor of inosine monophosphate dehydrogenase (IMPDH) and of the type II isoform in particular. IMPDH is the rate-limiting enzyme in the de novo biosynthesis of guanosine nucleotides. MMF strongly inhibits both T- and B lymphocyte proliferation and has been used in the prevention of acute and chronic allograft rejection since the mid 1990s. Recent evidence, however, suggests that MMF is also capable of inhibiting the proliferation of non-immune cells. In various cell lines, i.e. smooth muscle cells, renal tubular cells and mesangial cells, MPA reduced or even abrogated proliferation in response to proliferative stimuli. Furthermore, data from our own laboratory demonstrate a dose-dependent inhibition of dermal fibroblast proliferation by MPA. In animal studies, MMF ameliorated renal lesions in immune-mediated disease, i.e. in the anti-thy 1.1 model and experimental lupus nephritis, but was also effective in non-immune-mediated renal damage in the rat remnant-kidney model. These observations prompted several investigators to study the effects of MMF in proliferating (renal) disease of non-immune origin in humans. MMF significantly reduced proteinuria in minimal-change disease and focal segmental glomerulosclerosis. In addition, MMF showed beneficial effects in the treatment of chronic allograft nephropathy and calcineurin inhibitor toxicity through reduction of immune- and non-immune-mediated renal damage. MMF is well tolerated and has proven to be a relatively safe drug causing only minor bone marrow suppression. Taken together, there is a growing body of evidence pointing to therapeutic applications of MMF other than immunosuppression, in particular the prevention of fibrosis.

Contrast-enhanced ultrasonography in the early period after kidney transplantation predicts long-term allograft function.

INTRODUCTION: Real-time contrast-enhanced sonography (CES) can assess microvascular tissue perfusion using gas-filled microbubbles. The purpose of the study was to evaluate the feasibility of early CES in predicting long-term kidney allograft function in comparison to color Doppler ultrasonography (CDUS). METHODS: We prospectively studied 68 consecutive kidney transplant recipients using CES and conventional CDUS investigation 1 week after transplantation. Transplant tissue perfusion imaging was performed by low-power imaging during intravenous administration of the sonocontrast SonoVue. Renal tissue perfusion was assessed quantitatively using flash replenishment kinetics of microbubbles to estimate renal blood flow (RBF). The obtained sonography values were correlated with clinical data 1 week up to 1 year after transplantation. RESULTS: In contrast with conventional CDUS resistive indices, RBF estimated by CES 1 week posttransplantation significantly correlated with kidney function after 1 year (r = 0.67; P < .001). Determination of RBF by CES revealed a significant correlation with donor age but not recipient age, whereas conventional CDUS resistive index was significantly correlated to recipient age (r = 0.54; P < .001) but not donor age. Furthermore RBF was associated with vascular fibrosis and intimal thickening of the engraftment biopsies. CONCLUSION: This is the first prospective study demonstrating the prognostic value of CES early after kidney transplantation. In contrast with CDUS, CES reveals information about kidney allograft perfusion independent of recipient vascular compliance.