A systematic review of conversion from calcineurin inhibitor to mammalian target of rapamycin inhibitors for maintenance immunosuppression in kidney transplant recipients.

This was a systematic review of randomized controlled trials comparing delayed conversion of mammalian target of rapamycin inhibitors (mTORi) for calcineurin inhibitors (CNIs) versus CNI continuation in kidney transplantation. Databases (2000-2012) and conference abstracts (2009-2012) were searched giving a total of 29 trials. Outcomes analyzed included GFR, graft loss, rejection and adverse events and were expressed as weighted mean differences (WMDs) or as risk ratios (RRs). Patients converted to mTORi up to 1 year posttransplant in intention-to-treat analysis had higher GFR compared with those remaining on CNI (WMD 0.28 mL/min/1.73 m(2) , 95% confidence interval [CI] 0.21-0.36; I(2) = 68%, p < 0.001). Stratifying trials by time posttransplant or type of mTORi did not change the overall heterogeneity. For on-treatment population, mTORi was associated with higher GFR (14.21 mL/min/1.73 m(2) , 10.34-18.08; I(2) = 0%, p = 0.970) 2-5 years posttransplant. The risk of rejection at 1 year was higher in mTORi trials (RR 1.72, 1.34-2.22; I(2) = 12%, p = 0.330). Discontinuation secondary to adverse events was more common in patients on mTORi, whereas the incidence of skin cancers and cytomegalovirus infection was lower in patients on mTORi. Conversion from CNI to mTORi is associated with short-term improvements in GFR in a number of studies but longer-term follow-up data of graft and patient survival are required.

Association between calcineurin inhibitor treatment and peripheral nerve dysfunction in renal transplant recipients.

Neurotoxicity is a significant clinical side effect of immunosuppressive treatment used in prophylaxis for rejection in solid organ transplants. This study aimed to provide insights into the mechanisms underlying neurotoxicity in patients receiving immunosuppressive treatment following renal transplantation. Clinical and neurophysiological assessments were undertaken in 38 patients receiving immunosuppression following renal transplantation, 19 receiving calcineurin inhibitor (CNI) therapy and 19 receiving a calcineurin-free (CNI-free) regimen. Groups were matched for age, gender, time since transplant and renal function and compared to normal controls (n = 20). The CNI group demonstrated marked differences in nerve excitability parameters, suggestive of nerve membrane depolarization (p < 0.05). Importantly, there were no differences between the two CNIs (cyclosporine A or tacrolimus). In contrast, CNI-free patients showed no differences to normal controls. The CNI-treated patients had a higher prevalence of clinical neuropathy and higher neuropathy severity scores. Longitudinal studies were undertaken in a cohort of subjects within 12 months of transplantation (n = 10). These studies demonstrated persistence of abnormalities in patients maintained on CNI-treatment and improvement noted in those who were switched to a CNI-free regimen. The results of this study have significant implications for selection, or continuation, of immunosuppressive therapy in renal transplant recipients, especially those with pre-existing neurological disability.

Access to the kidney transplant waiting list: a time for reflection.

The limited availability of deceased donor kidneys for transplantation in Australia continues to be a matter of concern. Analysis of registry data suggests that the current renal transplant waiting list under-represents the real demand for three reasons. Firstly, a very low proportion of dialysis patients across all age groups are wait-listed for kidney transplantation; secondly, the percentage of dialysis patients listed for transplantation has fallen over time across all Australian states and territories; and thirdly, the number of patients wait-listed varies significantly across the country. We explore possible reasons for these issues and call for new eligibility criteria that are both transparent and justifiable and balance equity and utility.

Explaining failure through success: a critical analysis of reduction in road and stroke deaths as an explanation for Australia's low deceased organ donation rates.

BACKGROUND/AIM: During the past two decades, Australian federal and state governments have funded many initiatives to bolster organ donation. Despite large investments of time, effort and money, Australia's deceased donation rate is in the bottom half of the Organisation for Economic Co-operation and Development countries and has only marginally increased from 11.9 donors per million people (pmp) in 1990 to 14.9 donors pmp in 2011. An often-cited explanation for this situation is that Australia's success in increasing levels of public health and safety through reduced traffic and stroke fatalities has reduced its number of potential deceased organ donors. We refer to this as the 'Failure Because of Success' hypothesis. Although commonly accepted, this hypothesis is largely untested. METHODS: By analysing data from international donation and transplantation organisations and international public health and safety organisations, we compared historical deceased organ donation rates with traffic and stroke fatality rates in Australia and the seven countries with the world's highest deceased organ donation rates (Spain, Portugal, France, USA, Belgium, Austria and Italy). RESULTS: Traffic fatality rates across all countries in the study have fallen dramatically during the time period, with Spain having the lowest traffic fatality rates. Stroke fatality rates demonstrate similar reductions, with France showing the lowest cerebral vascular accident mortality rates. CONCLUSION: When compared with countries with the world's highest deceased donation rates, Australia's improvements to public health and safety through reductions in traffic and stroke fatalities were neither unique nor exemplary and do not provide an adequate explanation for its low organ donor rates.

Human fibronectin metabolism.

The metabolic behavior of fibronectin (Fn), a highly adhesive glycoprotein (440,000 mol wt), was studied in eight healthy control subjects and in 11 patients, six of whom were critically ill. Fn was purified from fresh human plasma, radiolabeled, and shown to retain function both in vitro and in vivo. Results showed that, in normal controls, Fn is a rapidly catabolized protein with a fractional catabolic rate (FCR) of 4.81%/h (range, 4.00-6.27), a half-life (t1/2) of 25 h (20-30), extravascular/intravascular diffusion ratio (EV/IV) of 2.04 (1.52-3.30), and a synthesis rate (SR) of 0.71 mg/kg body weight per h (0.61-0.87). There was evidence for extravascular catabolism in each subject. Plasma levels correlated with SR but not with t1/2 or FCR. Patients had a lower EV/IV ratio, and in two critically ill patients with low plasma Fn concentration the SR was markedly depressed. These findings suggest that reduced synthesis of Fn, rather than increased FCR or increased extravascular distribution, is responsible for Fn deficiency in critically ill patients.

Factors influencing reticulophagocytic function in insulin-treated diabetes.

The splenic component of reticulophagocytic function (RPF) was examined in 29 insulin-treated diabetic subjects (13 type I and 16 type II) by measurement of clearance of altered, radiolabeled, autologous erythrocytes. Double-isotope studies were performed with cells altered by: (1) preincubation with N-ethylmaleimide (NEM) and (2) coating with IgG antibody to the Rhesus (Rh) D antigen, labeled with 99mTc and 51Cr, respectively. HLA typing for the A, B, and DR loci was performed in those patients showing a defect in the clearance of IgG-coated cells. Values for half-life (t1/2) were correlated with the incidence of diabetic complications, levels of HbA1, and circulating immune complexes (CIC). Two patterns of abnormal clearance were observed: first, an isolated defect of IgG-coated cell clearance in 7 patients (3 had the HLA B8/DR3 haplotype) and second, abnormal removal of both types of cell in a further 7 patients (3 had B8/DR3). There was no correlation between half-lives as measured by the two methods, although exclusion of the patients with a defect of IgG-coated cell clearance alone yielded a highly significant correlation for the remaining 15 Rh-positive patients (P less than 0.01). Abnormalities of IgG-coated cell clearance were more frequent in patients with HbA1 greater than 9% (P less than 0.02), while t1/2 of NEM-altered cells was significantly greater in patients with CIC (P less than 0.05). There was no correlation between t1/2 and the incidence of peripheral complications.(ABSTRACT TRUNCATED AT 250 WORDS)

Association of complement allotype C4B2 with anterior uveitis.

We have studied allotypes of the fourth component of complement (C4) in 44 patients with inflammatory eye disease in order to define genetic susceptibility factors further. Twenty-six patients had uveitis (18 had anterior uveitis) and 18 patients had retinal vasculitis. There was an increased incidence of the C4B2 allotype in patients with anterior uveitis (pc less than 0.002), especially in HLA B27 positive males. In contrast, there was no increased incidence of specific allotypes in patients with posterior uveitis or retinal vasculitis. This genetic association may form part of a disease susceptibility supratype in patients with anterior uveitis.

Post-streptococcal glomerulonephritis: studies on the interaction between nephritis strain-associated protein (NSAP), complement and the glomerulus.

Nephritis strain-associated protein (NSAP), a streptokinase produced by strains of streptococci isolated from patients with acute glomerulonephritis, is believed to be a specific antigen which participates in the production of glomerular injury. In order to investigate the mechanisms by which NSAP induces damage we have examined its potential to activate complement in vitro and to bind to isolated human glomeruli. NSAP, both alone and in combination with specific antibody, caused depletion of complement in normal human serum as measured by total haemolytic complement activity and generation of the complement breakdown products. C3a and C4a. Furthermore, Scatchard analysis showed that NSAP bound tightly to human glomeruli (Ka of 400 +/- 240 x 10(6) M) when compared to non-nephritic streptokinase (Ka of 7.3 +/- 4.1 x 10(6) M) and fully cationized human serum albumin (Ka of 0.6 +/- 0.04 x 10(6) M). These findings are consistent with the hypothesis that the deposition of streptococcal antigens within the glomerulus may precede the fixation of complement and specific antibody.

Renal granulomatous angiitis--a case report.

A case of non-necrotizing granulomatous angiitis without significant glomerular pathology is described in a 61 yr-old female. The characteristic lesion consists of periarterial inflammation comprising a mixed population of mononuclear cells with prominent giant cell formation. There is no evidence of immunoglobulin, complement or fibrin deposition. It is concluded that this represents an unusual variant of polyarteritis nodosa which is apparently controlled by steroid therapy.

Mesangial IgA nephropathy: detection of defective reticulophagocytic function in vivo.

The splenic component of the reticulophagocytic system (RPS) was studied in 20 patients with primary mesangial IgA nephropathy and 15 healthy controls. Eight patients were hypertensive, seven had renal failure and six had significant proteinuria. RPS function was assessed by the measurement of T1/2 clearance of altered, radio-labelled autologous erythrocytes. Three different methods were used to alter the red cells - thermal stress, sulfhydryl inhibition with N-ethylmaleimide (NEM) and antibody-coating - and in 12 patients two of these methods were used simultaneously in double-isotope-labelled studies. Impaired clearance was demonstrated in 16 of the 20 patients. T1/2 of NEM-altered cells was abnormal in 12 of 19 studies in 17 patients (i.e. T1/2 greater than 22.5 mins) while T1/2 of IgG-coated cells was abnormal in 8 of 10 patients (i.e. T1/2 greater than 62 mins). The clearance of thermally-damaged cells was not significantly different from that observed in controls (normal range: 10.5-17 mins). In the double-isotope studies, the clearance of NEM-altered cells correlated with the clearance of IgG-coated cells (P less than 0.05). There was no correlation between T1/2 clearance times and circulating immune complexes. These abnormalities of splenic function suggest there is a primary reticulophagocytic defect in patients with mesangial IgA nephropathy. This finding could bear relevance to the pathogenesis of the disease.

Verapamil prevents post-transplant oliguric renal failure.

Verapamil has proven effective in preventing acute renal failure in animal models if given prior to the insult and hence possibly has a role in the preservation of cadaveric renal tissue for transplantation. Twenty renal donors were randomly assigned to treatment (receiving verapamil 20 mg intravenously) and control groups. Recipients were monitored for renal failure by urine output and serum creatinines on days 1 and 7 and dialysis requirement to one week. Early urine outputs and serum creatinines (day 1) were significantly better in the treated than control group (p greater than 0.01, 0.05 respectively). We conclude therefore that verapamil may prevent post-transplant acute renal failure, but its optimal dosage and route of administration remain to be determined.

Reduced and standard target concentration tacrolimus with sirolimus in renal allograft recipients.

We report 6-month results of renal allograft recipients enrolled in seven Australian centers as part of a worldwide, multicenter, randomized, open-label, concentration-controlled trial comparing standard tacrolimus (sTAC) with reduced tacrolimus (rTAC) both with sirolimus (SRL) and steroids. Patients were randomized 1:1 to either rTAC (n = 33) with a target maintenance concentration of SRL of 8 to 15 ng/mL and TAC of 3 to 7 ng/mL, or sTAC (n = 31) with SRL target of 5 to 10 ng/mL and TAC of 8 to 12 ng/mL. Antibody induction was prohibited. Adult recipients of a first or second cadaveric or non-HLA-identical living donor renal graft were eligible for enrollment. Recipients with a panel-reactive antibody level of >50% and recipients of regrafts who had lost their first graft from rejection within the first 6 months were ineligible. The groups were compared for graft function, incidence of rejection, and patient and graft survival at 6 months. There were no differences in demographics. There were 30% and 29% discontinuations in the rTAC and sTAC groups mainly due to adverse events in the first month. The 6-month patient and graft survival by intention-to-treat analysis was 94% and 91% for rTAC and 100% and 97% for sTAC (P = NS), respectively. Incidence and severity of biopsy-proven acute rejection was not different between the two groups, being 21% for rTAC and 19% for sTAC. The mean serum creatinine was 121 micromol/L and 148 micromol/L for rTAC and sTAC groups (P =.09), respectively. Glomerular filtration rate (GFR) was 68 mL/min and 62 mL/min (P =.23), respectively. Adverse events, infections, and antihypertensive and antilipidemic agent usage were similar. Of interest is that the overall incidence of thrombotic microangiopathy was 14%. These results support the safety and efficacy of SRL + TAC. Reduced TAC is associated with a trend toward improved renal function.

Sensory nerve excitability and neuropathy in end stage kidney disease.

BACKGROUND: Peripheral neuropathy is present in 65% of patients with end stage kidney disease (ESKD) starting dialysis. Studies of membrane potential and axonal ion channel function may help explain the pathophysiology. OBJECTIVES: To follow changes in median sensory axon excitability in patients with ESKD treated with haemodialysis, and correlate them with clinical rating scales and serum levels of potential neurotoxins. METHODS: Sensory nerve action potentials were recorded from the second digit following stimulation of the median nerve in 12 ESKD patients. Stimulus-response behaviour using two stimulus durations, threshold electrotonus to 100 ms polarising currents, a current-threshold relation, and recovery of excitability following supramaximal stimulation were recorded before, during, and after haemodialysis. Serum concentrations of potential neurotoxins were measured. RESULTS: Before dialysis, there were changes in nerve excitability consistent with axonal depolarisation: refractoriness was increased; superexcitability and depolarising threshold electrotonus were reduced. Following dialysis there were improvements in all indices, with correlations between excitability abnormalities and serum potassium measurements. Neuropathic symptoms correlated with excitability changes. CONCLUSIONS: Nerves are depolarised before haemodialysis in ESKD patients. The correlation of excitability abnormalities with potassium indicates that the achievement of normokalaemia should be a priority in treating such patients.

Activation of rabbit C3: studies of the generation of cleavage products in vitro and of their metabolism in vivo.

The cleavage of purified, functionally active rabbit C3 by cobra venom factor and trypsin was analysed by reducing and non-reducing sodium dodecyl sulphate electrophoresis and autoradiography. The specific aim of the study was to compare these reactions to those that occur with human C3. Analysis showed that the pattern of breakdown was very similar to that for the human protein: while the beta-chain remained intact, there was step-wise degradation of the alpha-chain to form C3a, C3b, iC3b and C3c, all of which could be identified by gel analysis. The metabolic behaviour of three of these cleavage products, C3a, C3b and iC3b, was then examined in vivo using dual isotope techniques. Rabbits were studied simultaneously with 131I-C3 and 125I-labelled C3 breakdown products. Analysis of plasma and urine radioactivity for the subsequent 72 h showed that all three breakdown proteins had rapid rates of catabolism in vivo compared to the native molecule. Specifically, 93 and 98% of C3b and iC3b, respectively, were eliminated from the plasma compartment within 10 h of injection. C3a was completely eliminated within 10 h. By comparison, native C3 showed a half-life of 29 +/- 3 h (mean +/- SD) and a fractional catabolic rate of 4.30 +/- 0.75%/h. The data support the use of this species in studies of complement behaviour in models of human immune disease and further clarify the basis for changes in plasma C3 concentration that accompany active immune complex- and antibody-mediated activity, in vivo.

Failure to detect brain reactivity of lymphocytotoxins in cerebral lupus.

Lymphocytotoxic activity (LCA) was examined in the sera of 29 patients with systemic lupus erythematosus (SLE), including eight with cerebral involvement. LCA was elevated in 80% of samples and was significantly higher in the group with cerebral disease (P less than 0.001). No correlations were observed between LCA and immune complexes or complement components. Sera from 10 patients (six with cerebral SLE) were absorbed with homogenates of normal human frontal cortex and liver using protein standards to control for dilutional effects. No serum sample showed selective depletion of LCA following incubation with brain homogenate. It is concluded that no single parameter, including brain absorption of LCA, is effective in monitoring disease activity in cerebral lupus.

Normal human serum inhibits the lymphocytotoxicity of sera from patients with infectious mononucleosis.

The inhibitory effects of normal human serum (NHS) on the lymphocytotoxic activity (LCA) of sera from patients with infectious mononucleosis (IM) were investigated. Dilution of IM serum with complement fixation diluent (CFD) caused a significant rise in LCA at 1/10 dilution (P less than 0.001) followed by a steady decline at higher dilutions. In contrast, 1/10 dilution with pooled NHS caused a gross reduction in lymphocyte killing (P less than 0.01). This reduction occurred irrespective of the order of incubation of NHS and IM serum with target lymphocytes. Pre-dilution of the NHS showed this inhibitory effect to be dose-responsive. Further characterization of the inhibitor(s) showed it to reside in the exclusion peak of Sephadex G-200, to be abolished by treatment with the sulphydryl inhibitors, 2-mercaptoethanol and iodoacetamide and to be depleted selectively by incubation with monospecific anti-IgM (but not anti-C1q or anti-alpha 2-macroglobulin). The site of the inhibitory reaction was examined by indirect immunoperoxidase staining of the lymphocyte surface with monospecific anti-IgM and peroxidase conjugated swine anti-rabbit immunoglobulin. This showed that pre-incubation of IM serum with NHS caused a significant reduction in IgM positive cells compared to that observed with IM serum diluted in CFD alone. It is concluded that certain IgM molecules, present in NHS, inhibit the complement-mediated LCA of IM sera. This inhibition occurs by fluid phase interference with surface deposition of cytotoxic IgM rather than by competitive surface binding. The presence of such serum-serum interactions emphasises the complexity of the lymphocytotoxin reaction and the need for caution in attributing abnormalities in vivo to cytotoxic phenomena measured in vitro.

Inhibition of reticuloendothelial function by gold and its relation to postinjection reactions.

A patient with rheumatoid arthritis developed severe exacerbation of symptoms 18 hours after an injection of gold thiomalate (sodium aurothiomalate). Immune complexes were present in his serum and synovial fluid; in the synovial fluid they were associated with intense complement activation. The effect of gold salts on splenic reticuloendothelial function was determined by measuring the clearance of heat-damaged erythrocytes from the circulation. Gold thiomalate (50 mg) substantially delayed clearance in the patient but had no effect in four other patients with rheumatoid arthritis who had not had a postinjection reaction. Severely impaired clearance also occurred in three out of four healthy people given 100 mg gold but they remained asymptomatic. The postinjection reaction may be an immune-complex disease that is triggered in certain patients because gold transiently inhibits reticuloendothelial function.

The inhibitory effect of rosmarinic acid on complement involves the C5 convertase.

Rosmarinic acid (RA), a naturally occurring extract from Melissa officinalis, inhibits several complement-dependent inflammatory processes and may have potential as a therapeutic agent for the control of complement activation in disease. Rosmarinic acid has been reported to have effects on both the classical pathway C3-convertase and on the cobra venom factor-induced, alternative pathway convertase. In order to define the mechanism of inhibition, the effect of RA on classical and alternative pathway lysis, C1q binding, the classical pathway convertase, the alternative pathway convertase, membrane attack pathway lysis and the generation of fragments of C3 and C5 during activation, was tested in vitro. The results showed that RA inhibited lysis by the classical pathway more than by the alternative pathway. This effect was dose-dependent with maximum inhibition of classical pathway lysis observed at 2.6 mmoles of RA. There was little effect on C1q binding or on the classical and alternative pathway convertases. However, there was highly significant inhibition of lysis of pre-formed EA43b cells by dilutions of human or rabbit serum in the presence of RA (1 mM); this was accompanied by inhibition of C5a generation. We conclude that the inhibitory effect of RA involves the C5 convertase. Such inhibition could be advantageous to the host in disorders where the terminal attack sequence plays a role in pathogenesis.

Differences in the metabolism of C4 isotypes in patients with complement activation.

The metabolism of the C4 allotypes C4A3,B1 and C4A3,BO was studied in five healthy control subjects and six patients with active immunological disease (five with systemic lupus erythematosus and one with rheumatoid arthritis). The specific aim was to identify any differences in the metabolism of C4A and C4B gene products that may be linked to their documented functional differences in vitro. The fractional catabolic rate of C4A3,B1 in patients was significantly greater than that of C4A3,BO (3.98 +/- 1.37 versus 3.31 +/- 0.85%/h; mean +/- s.d.; P less than 0.05) but there was no difference in control subjects (1.95 versus 1.99%/h). The extravascular:intravascular (EV:IV) distribution ratio of C4A3,B1 was also greater in both patients (1.19 +/- 0.36 versus 0.97 +/- 0.35; P less than 0.01) and controls (0.43 +/- 0.11 versus 0.31 +/- 0.13; P = 0.01). We conclude that C4B1 was catabolized more rapidly than C4A3 in patients with pathological complement activation but not in control subjects. This difference could reflect the relatively greater extravascular distribution (i.e. EV:IV ratio) of C4B at sites of immune complex deposition or, alternatively, different rates of catabolism of inactive C4 isotypes (iC4b).