[Regulatory T cells in kidney transplant recipients]. / Cellule T-regolatorie nel trapianto di rene.

Immunosuppressive drugs are essential for the prevention of acute transplant rejection but some may not promote long-term tolerance. Tolerance to self-antigens is ensured naturally by several mechanisms; one major mechanism depends on the activity of regulatory T lymphocytes (Treg), particularly CD4+CD25+ T cells. The transcription factor forkhead box protein 3 (Foxp3) has been identified as a molecular marker for Treg cells. The direct effects of immunosuppressive drugs on CD4+CD25+ cells are uncertain. In the clinical setting, basiliximab used in the induction phase of immunosuppression effectively reduced the number of acute rejection episodes. We studied the effects of the most widely used immunosuppressive induction regimens including cyclosporine, mycophenolate mofetil, steroids, and anti-CD25 monoclonal antibody (basiliximab) on the capacity to regulate human Treg in vivo. Twenty first cadaveric kidney transplant recipients (14 men, 6 women) were enrolled in the study. Blood samples were collected before kidney transplant and after one month. Blood sampling was done immediately before the administration of immunosuppressive therapy after an overnight fast. None of the transplant recipients presented laboratory or clinical signs of infection or acute rejection. The number and percentage of CD4+CD25+ and Foxp3+ T cells were determined by fluorescence activated cell sorter (FACS) analysis. Our results showed absence of both CD4+CD25+ and CD4+CD25+ Foxp3+ T cells one month after transplant. Peripheral CD4+CD25-Foxp3+ T cells significantly decreased after transplant but did not disappear. These preliminary data suggest that immunosuppressive induction therapy with basiliximab completely suppresses CD4+CD25+ regulatory cells and significantly reduces the total number of Foxp3+ lymphocytes.

Influence of methylprednisolone on plasma homocysteine levels in cadaveric renal transplant recipients.

The aim of the present study was to investigate plasma homocysteine levels in renal transplant recipients in the course of steroid-based or steroid-free immunosuppression. Data from 32 patients were retrospectively analyzed according to the steroid immunosuppressive regimen. The 20 recipients on methylprednisolone (MP) plus cyclosporine (CyA) or tacrolimus (TRL) (n = 20) showed similar creatinine levels when compared with those on calcineurin inhibitors plus mycophenolate mofetil (MMF; n = 12), (1.6 +/- 1.5 vs 1.6 +/- 0.4 mg/dL; P = NS) but significantly higher total plasma homocysteine (tHcy) levels (28.5 +/- 12.5 vs 16.3 +/- 5.5 micromol/L; P < .05). No differences of tHcy levels have been observed when patients were analyzed according to CyA- or TRL-based immunosuppression regardless of MP or MMF associations. Our data suggest that recipients, particularly those on steroid-based immunosuppression, should receive homocysteine-lowering treatment early after transplantation.

Low-dose dopamine induces early recovery of recombinant interleukin-2--impaired renal function.

Recombinant interleukin-2 (rIL-2) can produce impairment of renal function with hypotension, fluid retention, elevated blood urea nitrogen, oliguria and low fractional sodium excretion; these side-effects are a common cause of reduction or interruption of rIL-2 infusion. The aim of this study was to investigate the control and treatment of renal toxicity induced by rIL-2 therapy. Here we show that dopamine, at a low dose of 2 micrograms/kg/min, completely prevented renal toxicity induced by rIL-2. While continuing rIL-2 therapy, 24-h continuous infusion of low-dose dopamine produced a rapid normalisation of urine output and a significant decrease in serum creatinine levels and body weight (P < 0.01), with an early and complete recovery of the rIL-2--impaired renal function: mean recovery time of renal function in patients treated with dopamine was significantly lower (P < 0.05) than in nontreated patients (4.8 days vs. 10 days, respectively).

Polarization of T-helper lymphocytes toward the Th2 phenotype in uremic patients.

T-helper (Th) lymphocytes consist of Th1 and Th2 subsets. Th1 cells are effectors of cell-mediated immunity and secrete interferon-gamma (IFN-gamma), which recruits new Th1 cells in cooperation with interleukin-12 (IL-12; produced by monocytes) and inhibits Th2 differentiation. Th2 cells produce IL-4 and IL-10, which inhibit IFN-gamma secretion and cell immunity. We investigated whether the impaired immune response in uremia is associated with an altered balance of Th1/Th2. Peripheral-blood mononuclear cells (PBMCs) were collected from patients with chronic renal failure (CRF) on conservative treatment (CRF patients), patients with end-stage renal disease (ESRD) on regular hemodialysis therapy (ESRD-HD patients), and healthy controls (CON). CD4(+) cells were isolated from PBMCs by negative selection using a magnetic labeling system. PBMCs and purified CD4(+) cells were cultured in Iscove's medium and Iscove's medium plus mitogens (phytohemagglutinin and lipopolysaccharide). IFN-gamma, IL-12, IL-4, and IL-10 were measured in supernatant. The constitutive release of IL-4 and IL-10 by PBMCs and CD4(+) cells of CRF and ESRD-HD patients was increased by five to eight times in comparison with CON (P < 0.001). Constitutive IFN-gamma release by PBMCs of ESRD-HD patients was undetectable, although they secreted an increased amount of IL-12. Mitogen-stimulated release of IFN-gamma by PBMCs and CD4(+) cells of CRF and ESRD-HD patients was blunted (average PBMCs: CON, 115.8 pg/2 x10(6) cells; CRF, 81.8 pg/2 x10(6) cells; ESRD-HD, 9.3 pg/2 x10(6) cells; CD4(+) cells: CON, 358.0 pg/5 x 10(5) cells; CRF, 165.4 pg/5 x 10(5) cells; ESRD-HD, 43.5 pg/5 x 10(5) cells). The ability of PBMCs of ESRD-HD patients to secrete IFN-gamma was recovered after IL-4 and IL-10 neutralization. Uremia is associated with a prevalence of Th1 over Th2 cells and a configuration of cytokine network that depresses cell-mediated immunity.

Hemodialysis related interleukin-2 receptor release by peripheral blood mononuclear cells.

To evaluate the effects of hemodialysis treatment on the spontaneous cell release of interleukin-2 receptor (IL-2R), we studied 19 hemodialyzed patients (HD), 9 non hemodialyzed patients with chronic uremia (UR, glomerular filtration rate: 8.4 +/- 1.8 ml/min), and 8 healthy control subjects (C). We measured the release of IL-2R in the supernatant of peripheral blood mononuclear cells (PBMC) cultured for 24 hrs in Iscove's medium as well as the plasma levels of IL-2R. A significant increase of IL-2R release was detected in the supernatant of PBMC harvested from HD patients (32.4 +/- 2.4 and 34.2 +/- 5.6 U/3 x 10(6) PBMC daily before and after HD, respectively) as compared with UR (16.6 +/- 5.2 U/3 x 10(6) PBMC daily) and C (21.4 +/- 3.8 U/3 x 10(6) PBMC daily). Similarly, IL-2R plasma levels were significantly higher in HD (378.5 +/- 164.6 U/ml) than in UR (189.5 +/- 89.3 U/ml) and C (11.2 +/- 2.68 U/ml). To summarize, the current study demonstrates: a) an enhancement of spontaneous IL-2R cell release in HD patients; b) an increase of sIL-2R plasma levels in UR patients possibly related to reduced metabolism and/or urinary excretion, because it was not associated with high IL-2R cell release; and c) a further increment of IL-2R systemic levels in HD likely secondary to the high cell release of IL-2R. Therefore, a chronic T cell activation with increased release of IL-2R secondary to the dialysis procedure is suggested.

The Oxfordshire Community Stroke Project classification in the early hours of ischemic stroke and relation to infarct site and size on cranial computed tomography.

BACKGROUND AND PURPOSE: The Oxfordshire Community Stroke Project (OCSP) classification clinically subdivides cerebral infarction into total anterior circulation (TACS), partial anterior circulation (PACS), posterior circulation (POCS) and lacunar (LACS) syndromes. We compared the OCSP classification in patients presenting within 12 hours of onset of stroke with infarct site and size on computed tomography (CT) brain scan at 5 to 7 days. METHODS: OCSP classification was prospectively assigned by 1 of 3 observers in 43 patients presenting within 12 hours of stroke. CT brain scan was performed on admission to exclude primary intracerebral hemorrhage. Repeat CT brain scan at 5 to 7 days was used to classify recent visible infarction as total anterior circulation infarction (TACI), partial anterior circulation infarction (PACI), lacunar circulation infarction (LACI), or posterior circulation infarction (POCI). For each OCSP subtype, sensitivity and specificity were calculated by using CT classification as a standard. RESULTS: Median (range) interval from onset of stroke symptoms to OCSP classification was 5.0 (1.5, 11.75) hours. Thirty-seven patients had ischemic stroke, with recent visible infarction in 34 (92%). Sensitivity and specificity of each OCSP subtype was TACS (0.80, 0.82), PACS (0.56, 0.79), LACS (0.33, 0.88), and POCS (1.00, 0.97). Overall, 65% of OCSP subtypes assigned were correct when compared to CT classification. CONCLUSIONS: In this small study, we have shown that the OCSP classification within 12 hours of ischemic stroke onset compares with CT classification at 5 to 7 days. Larger studies are required to evaluate the validity of the OCSP classification in the early hours of ischemic stroke in guiding appropriate patient selection for acute stroke therapy and interventions.

[Changes is Th1/Th2 balance in hemodialysis patients: effect of different membranes]. / Alterazione del bilancio Th1/Th2 nei pazienti in trattamento emodialitico: effetto di differenti membrane.

BACKGROUND: Hemodialysis (HD) patients present an immunodeficiency that is mainly related to the defect of cell-mediated immunity. We have previously shown the polarisation of T-helper cells toward the phenotype in HD treatment with cuprophan membrane. In the present study, we have examined the effect of a Vitamin E-coated dialyser (Excebrane, VE) on the activity of the two Th subsets. METHODS: We studied 8 healthy controls and 10 patients on RDT for at least 6 months with cellulose membrane (AC), then switched to HD-VE. Blood was collected from HD patients while on treatment with AC, and after 1 year of treatment with VE. CD4+ cells were isolated from peripheral blood mononuclear cells (PBMC) by negative selection, treating PBMC with a cocktail of anti-CD8, -CD16, -CD19, -CD36 and -CD56 antibodies labelled with magnetic beads, and passing them through a magnetic field. The collected Th cells were cultured for 48 h with and without phytohemagglutinin (PHA). IFNgamma and IL-4 were measured in the supernatant using the ELISA assay. RESULTS: The constitutive release of IL-4 by CD4+ cells was abated significantly by treatment with VE. IFNgamma released by mitogen-stimulated CD4+ recovered with VE. CONCLUSIONS: This study demonstrates that treatment with vitamin E-coated dialyser improves the defect of PBMC function associated with cellulose membrane dialyser consisting of altered spontaneous and mitogen-stimulated cytokine release. The effects of vitamin E-coated filter, in particular the recovery of reactive IFNgamma production by Th1 cells and the restriction of spontaneous IL-4 release by Th2 cells may have clinical importance.

[Micro RNA-155 expression in hemodialysis PBMC]. / Espressione del micro rna-155 nelle PBMC di pazienti in emodialisi cronica.

INTRODUCTION: MicroRNAs (miR) are fragments of non-coding RNA acting at post-transcriptional level, which modulate gene expression, and play a key role in several pathophysiological pathways. The aim of this study is to analyze the expression of miR-155 in basal Peripheral Blood Mononuclear Cells (PBMC) of chronic hemodialysis (HD) patients, before and after standard 4 -hour sessions, and after PHA stimulation compared with PBMC from healthy subjects. METHODS: miR-155 was isolated from chronic HD patients' PBMC and from PBMC derived from healthy subjects. Expression levels were quantified with Real-Time PCR; PCR reactions were performed using a specific thermocycler and cycle threshold levels were calculated using dedicated software. Blood samples were taken from HD patients after the long inter-dialytic interval. Data were expressed as MSE and statistical differences were calculated with t-test. RESULTS: Relative quantity (RQ) of pre-dialysis MiR-155 was 3.770.62 times higher than the control group (P=0,003). There was no significant difference before and after hemodialysis sessions. Pre-dialysis mir-155 RQ in PHA PBMC was 1.790.59 times higher than non stimulated PBMC (P=0.019). CONCLUSIONS: these preliminary data show a significant miR-155 up-regulation of HD PBMC when compared to PBMC from healthy individuals. An additional up-regulation was observed in HD PHA PBMC. Similar miR-155 expression was found in HD PBMC comparing pre and post-hemodialysis sessions.

Mycophenolate mofetil in primary glomerulopathies.

Mycophenolate mofetil is an immunosuppressive agent that blocks purine biosynthesis, inhibits T and B-lymphocyte and mesangial proliferation. Mycophenolate mofetil is not nephrotoxic like calcineurin inhibitors and is widely used in solid-organ transplantation. Recently, mycophenolate mofetil has been introduced in the treatment of autoimmune diseases and primary glomerulopathies. This review analyzes the literature currently available on the treatment of primary glomerulopathies with mycophenolate mofetil. Encouraging results have been obtained in minimal change nephropathy where it may help to reduce the use of steroids in these patients who are often very young. The results obtained in medium and high risk patients with focal segmental glomerulonephritis and idiopathic membranous nephropathy were less encouraging. Conflicting results have been reported on IgA nephropathy in controlled trials. None of these studies attained level A evidence, meaning that randomized control trials of sufficient statistical significance are necessary to estimate the real effectiveness of mycophenolate mofetil in primary glomerulopathies.

The effect of sirolimus- or cyclosporine-based immunosuppression effects on T-cell subsets in vivo.

While sirolimus (SRL) is thought to be a non-nephrotoxic agent, cyclosporine A (CsA) toxicity is a serious problem in kidney transplantation. We compared the effects of the two drugs on T-helper (Th) subsets in kidney transplant patients. We examined 24 first cadaver kidney recipients equally randomized to receive SRL/mycophenolate mofetil (MMF)/methylprednisolone (MP), or cyclosporine with either MMF or MP. The Th1 and Th2 subsets in peripheral blood were separated based on their production of interferon-gamma (INFgamma) or interleukin (IL)-4/IL-5. The lymphocytes were stimulated with phytohemoagglutinin or with allogenic CD3-depeted and irradiated antigen-presenting cells. Furthermore, the conversion potential of Th0 to Th1 was determined by measuring IL-12 and IL-18 levels after lipopolysaccharide challenge. When peripheral blood lymphocytes taken from SRL-treated patients were stimulated by phytohemoagglutinin, there were significantly lower INFgamma-producing cells compared with the lymphocytes taken from patients treated with CsA. The number of IL-4/IL-5-producing cells did not differ among the patient groups. Release of IL-12 but not IL-18 from peripheral lymphocytes following treatment with lipopolysaccharide was significantly lower in the SRL-treated patients. These results show that compared with CsA, SRL caused a significant decrease in the Th1 lymphocyte subset associated with a significant reduction of IL-12 release.

Diagnosis and management of transient ischaemic attacks in accident and emergency.

Stroke is an important cause of morbidity and mortality. Often the first presentation of cerebrovascular disease is a TIA which will present to the A&E department. Patients who have had a TIA are at increased risk of stroke, myocardial infarction, and vascular death. The risk of stroke after a TIA is greatest in the first year (approximately 11.6%) with a risk of approximately 5.9% per year over the first five years. As the risk is highest in the first months following a TIA it is important that the patients are diagnosed accurately, investigated promptly, and referred appropriately for treatment in order that valuable time is not lost. For this reason A&E physicians have a valuable role in the initial assessment and management of the patient. It has been advocated that patients should be seen by a neurologist or physician with an interest in cerebrovascular disease within days of their symptoms and be prepared for surgery within two weeks after a TIA. While it is usually not possible to achieve this ideal, improved cooperation between A&E physicians and these neurologists, general physicians, and geriatricians should lead to the implementation of speedy efficient referral procedures which can only improve patient care. When you next see a patient with a TIA in the A&E department remember what they have to lose. Three questions relating to this article are: (1) How are TIAs subdivided and what clinical features allow this differentation? (2) What are the initial investigations that should be performed in A&E? (3) When are the risks of completed stroke greatest after a TIA? Enumerate these risks. How effective is aspirin at reducting this risks?

Loop diuretics and renal vasodilators in acute renal failure.

Loop diuretics are powerful drugs able to increase urinary sodium and water excretion even in conditions of marked impairment of renal function. Loop diuretics are useful in preventing or ameliorating the course of acute renal failure. This effect may be obtained when they are used within 18 h after the ischaemic and/or toxic event. Loop diuretics reduce tubular work, providing resistance to cellular ischaemia. Other important beneficial effects include tubular wash-out of cellular debris and inhibition of tubuloglomerular feedback. Among vasodilators, dopamine, when used at 'dopaminergic dosage' is useful in preventing acute renal failure. Its efficacy is demonstrated in several situations of renal hypoperfusion, i.e. salt depletion, cyclosporin administration, and therapy with recombinant interleukin 2 in cancer patients. According to our studies it appears that dopamine should be used in the early phases of acute renal failure to improve renal perfusion, re-establish glomerular filtration rate, and increase tubular flow.

Validation of the Ottawa ankle rules in children.

OBJECTIVE: To assess whether the Ottawa ankle rules can be used to accurately predict which children with ankle and midfoot injuries need radiography. METHODS: Prospective study with historical control group of all children aged 1-15 years presenting to Sheffield Children's Hospital accident and emergency department with blunt ankle and/or midfoot injuries during two five month periods before and after implementation of the Ottawa ankle rules. RESULTS: In the study group 432 out of 761 (56.76%) patients received radiography compared with 500 out of 782 (63.93%) in the control group. This was a statistically significant reduction in radiography rate of 7.2% (95% confidence interval 2.3% to 12.1%, p <0.01). The sensitivity of the Ottawa ankle rules was 98.3% and the specificity 46.9%. There was no increase in the number of missed fractures (one in each group). CONCLUSION: The Ottawa ankle rules can be applied in children to determine the need for radiography in ankle and midfoot injuries. Their implementation leads to a reduction in the radiography rate without leading to an increase in the number of missed fractures.

Bicarbonate and calcium kinetics in postdilutional hemodiafiltration.

Hemodiafiltration (HDF) is a very effective blood treatment resulting from the coupling of dialysis and hemofiltration and leading to reduction of dialysis time. The aim of this study was to evaluate the balance of bicarbonate and calcium through the filter during postdilutional HDF (with an ultrafiltration flow rate of 70 ml/min) and to verify the effect of ultrafiltration on the kinetics of these two solutes. The study was performed by simultaneously collecting three blood samples (at filter inlet and outlet and after reinfusion) at different ultrafiltration flow rates (12.5-90 ml/min), to measure blood pH, pCO2, plasma total CO2(TCO2), total calcium, ionized calcium and plasma protein concentration. Plasma bicarbonate concentration was calculated by measuring plasma TCO2. The results showed an inverse linear relationship between bicarbonate (r: -0.7938; p less than 0.001) and calcium (r: -0.8731; p less than 0.001) balance and ultrafiltration flow rate. In particular, in postdilutional HDF both bicarbonate and calcium balances through the filter were negative at ultrafiltration flow rates greater than 40 and 55 ml/min, respectively. The negative bicarbonate balance, however, was corrected by reinfusing a substituting solution containing bicarbonate (40 mmol/l). By contrast, the negative calcium balance cannot be corrected by reinfusion and requires a greater calcium concentration in the dialysate and oral calcium supplements.

Effects of a two-month treatment with low oral doses of cyclosporin on renal function.

To test the effects of short-term therapy with low doses (LD) of cyclosporin A (CsA) in subjects with normal renal function, seven patients receiving CsA to treat psoriasis were studied. Clearances in maximal H2O diuresis were performed to evaluate changes in GFR (CIn), RPF (CPAH) and tubular function before starting CsA (BAS), after 2 days (S1) and 1 month (S2) of oral therapy with 5 mg/kg per day CsA. The study was repeated at the withdrawal of CsA after tapering (S3) and 2 months after the withdrawal (S4). The studies were performed 12 h after the evening dose of CsA. RPF was significantly less than in BAS throughout the therapy and returned almost to basal values in S4. GFR was significantly less than in BAS both in S2 and in S3. In S4, in spite of an increase, GFR was still significantly less than in BAS. Both in S2 and in S3 proximal tubular fractional sodium reabsorption was significantly less than in BAS and, consequently, both sodium delivery to diluting segments and sodium reabsorption in diluting segments increased. Moreover, both in S2 and in S3 fractional sodium reabsorption in diluting segments and free-water generation were greater than in BAS. In S4 tubular function returned almost to basal values. Our data suggest that short-term therapy with low dose CsA impairs renal function; this impairment is not completely reversed after drug withdrawal.