Eculizumab improves posttransplant thrombotic microangiopathy due to antiphospholipid syndrome recurrence but fails to prevent chronic vascular changes.

Thrombotic microangiopathy (TMA) is one of the hallmark vascular lesions of antiphospholipid syndrome nephropathy (APSN). These lesions are at high risk of recurrence after kidney transplantation. The complement pathway is thought to be active in this process. We used eculizumab to treat three consecutive kidney transplant recipients with posttransplant TMA due to APSN recurrence that was resistant to plasmapheresis and explored the complement deposition and apoptotic and vascular cell markers on the sequential transplant biopsies. Treatment with eculizumab resulted in a rapid and dramatic improvement of the graft function in all three patients and in improvement of the TMA lesions within the graft. None of these patients had TMA flares after eculizumab was withdrawn. At the time of TMA diagnosis, immunofluorescence studies revealed intense C5b-9 and C4d depositions at the endothelial cell surface of the injured vessels. Moreover, C5b-9 colocalized with vessels exhibiting a high rate of apoptotic cells. Examination of sequential biopsies during eculizumab therapy showed that TMA lesions, C4d and apoptotic markers were rapidly cleared but the C5b-9 deposits persisted for several months as a footprint of the TMA. Finally, we noticed that complement inhibition did not prevent the development of the chronic vascular changes associated with APSN. Eculizumab seems to be an efficient method for treating severe forms of posttransplant TMA due to APSN recurrence. Terminal complement inhibition does not prevent the development of chronic APSN.

Eculizumab for atypical hemolytic uremic syndrome recurrence in renal transplantation.

Eculizumab (anti-C5) has been sporadically reported as an efficient therapy for atypical hemolytic uremic syndrome (aHUS). However, the lack of series precludes any firm conclusion about the optimal use of anti-C5 for preventing or treating aHUS posttransplant aHUS recurrence. We thoroughly studied 22 renal transplant recipients with aHUS who received off-label therapy with anti-C5, including 12 cases, which have not been reported yet. Nine patients, all carrying a complement genetic abnormality associated with a high risk of aHUS recurrence, received prophylactic anti-C5 therapy to prevent posttransplant recurrence. Eight of them had a successful recurrence-free posttransplant course and achieved a satisfactory graft function, while the remaining patient experienced early arterial thrombosis of the graft. Thirteen renal transplant recipients were given anti-C5 for posttransplant aHUS recurrence. A complete reversal of aHUS activity was obtained in all of them. Importantly, the delay of anti-C5 initiation after the onset of the aHUS episode inversely correlated with the degree of renal function improvement. Three patients in whom anti-C5 was subsequently stopped experienced a relapse. Altogether these data suggest that long-term eculizumab is highly effective for preventing and treating posttransplant aHUS recurrence. Our study also indicates that anti-C5 should be promptly started if a recurrence occurs.

Comparison of C4d detection on erythrocytes and PTC-C4d to histological signs of antibody-mediated rejection in kidney transplantation.

C4d on erythrocytes (EC4d), C4d peritubular capillary deposition (PTC-C4d) staining and histology were compared in a cross-sectional cohort of 146 renal allograft biopsies (132 patients). EC4d levels paralleled PTC-C4d staining, but were more predictive of peritubular capillaritis (PTC). Donor-specific antibodies (DSA), PTC-C4d, EC4d and PTC were analyzed in an independent longitudinal follow-up cohort (96 biopsies, 76 patients). Seventy-six samples were PTC and EC4d concordant, 11 positive and 65 negative, 7 PTC-EC4d+ and 13 PTC+EC4d-. EC4d levels were related to DSA occurrence. With ABMR defined by PTC and DSA, all apparently discordant patients, EC4d negative, were correctly reassigned comparing EC4d level curves with rejection kinetics, with positive EC4d samples predating biopsy or late biopsies compared with ABMR flare-ups. All EC4d-positive patients without PTC or DSA had permanent high EC4d levels unrelated to rejection. EC4d was more abundant in PTC-positive (mean = 108.5%± 3.4; n = 50) than PTC-negative samples (mean = 88.1%± 1.3; n= 96; p < 0.0001). Sensitivity, specificity, positive predictive value and negative predictive value of PTC-C4d and EC4d for PTC were, respectively, 75%, 79%; 64%, 76% (p < 0.05); 28%, 46% (p < 0.05) and 93%, 94%. Values were similar for DSA. A noninvasive blood test, EC4d, and particularly longitudinally monitoring EC4d levels, may increase surrogate ABMR testing options.

Long-term impact of subclinical inflammation diagnosed by protocol biopsy one year after renal transplantation.

The long-term impact of subclinical acute rejection (SCAR) on renal graft function remains poorly understood. Furthermore, the interpretation of borderline lesions is difficult and their incidence is variable. The aim of this study was to analyze the characteristics of subclinical inflammation (SCI) in protocol biopsies performed 1-year after renal transplantation. SCI was defined as the presence of borderline lesions or SCAR according to the Banff 2005 classification. The patients included were a subpopulation of the CONCEPT study in which patients were randomized 3 months after transplantation to receive either sirolimus (SRL) or cyclosporine A (CsA) in combination with mycophenolate mofetil. At 1 year, we observed SCI in 37 of the 121 patients observed with an evaluable biopsy. The incidence was more frequent in the SRL group (SRL 45.2% vs. CsA 15.3%). At 30 months , SCI was associated with a significantly lower level of estimated glomerular filtration rate (mean MDRD 50.8 [±13.3] vs. 57.7 [±16.3] mL/min/1.73 m(2) , p = 0.035). In conclusion, SCI at 1-year posttransplantation is associated with worsening renal function and is more frequent in SRL-treated patients. Therefore, evaluation of SCI may be a valuable tool to allow the optimization of immunosuppressive regimens.

Specificity of histological markers of long-term CNI nephrotoxicity in kidney-transplant recipients under low-dose cyclosporine therapy.

The specificity of chronic histological lesions induced by calcineurin inhibitors (CNI) is often questioned, but few studies have directly compared long-term lesions in renal-transplant patients who received this treatment and those who did not. We therefore conducted a retrospective study of 141 kidney-transplant recipients treated with (n = 48) or without (n = 93) cyclosporine (CsA) to compare the histological lesions observed at 3-month, 24-month and 10-year protocol biopsies. All of the chronic elementary lesions (glomerulosclerosis, interstitial fibrosis, tubular atrophy, arteriolar hyalinosis, fibrointimal thickening) progressed in frequency and severity in both groups, although significantly more in the CsA group. Ten-year biopsy results showed that 92% of patients in the CsA-treated group and 65% in the control group had arteriolar hyalinosis lesions. When we focused on muscular arteriolar hyaline deposits more specific to CsA arteriolopathy, we observed these lesions in 68% of CsA patients and 28% of patients who had never received CsA. CsA was not the sole factor involved in the development of arteriolar hyalinosis and was independently associated with an increased risk of graft loss. In summary, we observed that histological lesions commonly attributed to CsA nephrotoxicity were not sufficiently specific to definitively diagnose CNI nephrotoxicity.

Interstitial fibrosis evolution on early sequential screening renal allograft biopsies using quantitative image analysis.

Screening renal biopsies (RB) may assess early changes of interstitial fibrosis (IF) after transplantation. The aim of this study was to quantify IF by automatic color image analysis on sequential RB. We analyzed RB performed at day (D) 0, month (M) 3 and M12 from 140 renal transplant recipients with a program of color segmentation imaging. The mean IF score was 19 ± 9% at D0, 27 ± 11% at M3 and 32 ± 11% at M12 with a 8% progression during the first 3 months and 5% between M3 and M12. IF at M3 was correlated with estimated glomerular rate (eGFR) at M3, 12 and 24 (p < 0.02) and IF at M12 with eGFR at M12 and 48 (p < 0.05). Furthermore, IF evolution between D0 and M3 (ΔIFM3-D0) was correlated with eGFR at M24, 36 and 48 (p < 0.03). IF at M12 was significantly associated with male donor gender and tacrolimus dose (p = 0.03). ΔIFM3-D0 was significantly associated with male donor gender, acute rejection episodes (p = 0.04) and diabetes mellitus (p = 0.02). Thus, significant IF is already present before transplantation. IF evolution is more important during the first 3 months and has some predictive ability for change in GFR. Intervention to decrease IF should be applied early, i.e. before 3 months, after transplantation.

Severe vascular lesions and poor functional outcome in kidney transplant recipients with lupus anticoagulant antibodies.

The impact of antiphospholipid antibodies (APA) on clinical outcome and graft histology following renal transplantation remains poorly known and controversial. We retrospectively explored the functional and histological significance of APA, primarily lupus anticoagulant (LA), in kidney transplant recipients using a systematic evaluation of 3- and 12-month posttransplant screening biopsies and glomerular filtration rate measurements (mGFR). During the study period, 37 patients had APA (2.7%), primarily LA, and 12 fulfilled antiphospholipid syndrome (APS) diagnostic criteria (0.8%) at the time of transplantation. Early after transplantation, 4 of the 12 APS patients died. Early thrombosis of graft vessels and deep venous thrombosis occurred more frequently in APA+ patients than in controls (27% vs. 7%, p < 0.05 and 35% vs. 14%, p < 0.05, respectively). The survival rate was significantly lower in patients with APS. Strikingly, the hallmark lesions of APS-associated nephropathy (APSN) were found in most of screening graft biopsies in APA+ patients but not in the controls. Accordingly, APA+ patients had a dramatic increase in chronic vascular scores and a faster decline in mGFR at 1 year. In conclusion, renal transplantation may be life-threatening in APS patients, and the presence of LA at the time of transplantation is associated with a high rate of allograft APSN and poor transplantation outcomes.

Kidney transplantation at Necker Hospital: the most recent 5-year period (2004-2009).

The results of our last 5 years activity in kidney transplantation clearly show that it is possible to perform high-risk transplantations with very acceptable results: ECD kidneys, dual transplantation, recipients with DSAs. In depth statistical analysis of these data should allow a clearer definition of the best strategies to use in these situations.

Anti-Factor H autoantibodies in a fifth renal transplant recipient with atypical hemolytic and uremic syndrome.

Hemolytic uremic syndrome (HUS) associated with anti-Factor H (anti-FH) autoantibodies is a recently described pathophysiological entity. Monitoring of anti-FH IgG titer may be a sensitive marker of disease activity and guide treatment to eliminate circulating anti-FH antibodies. We report here a case of atypical HUS (aHUS) in which anti-FH autoantibodies were detected during the course of a fifth kidney transplant, 30 years after the first flare of aHUS. This exceptional case suggests that early, specific management based on immunosuppressive therapy and plasma exchanges monitored by anti-FH IgG titer may result in long-term graft survival.

Evaluation of the effect of autologous mesenchymal stem cell injection in a large-animal model of bilateral kidney ischaemia reperfusion injury.

OBJECTIVES: Adult mesenchymal stem cells (MSC) have been proven to be of benefit to the kidney in different experimental models of renal injuries. All studies have been performed in valuable rodent models, but the relevance of these results to large mammals and ultimately, to humans remains unknown. Therefore, the aim of this study was to investigate the effect of MSC transplantation in an alternative ovine large-animal model of bilateral kidney ischaemia reperfusion injury. MATERIAL AND METHODS: Sheep were divided into three groups: one sham-operated group and two groups submitted to renal bilateral ischaemia for 60 min. Animals with ischaemia reperfusion injury were treated with injection of autologous MSCs or with vehicle medium. RESULTS: The model sheep presented with renal histological manefestations that closely resembled lesions seen in patients. Transplanted MSCs were found in glomeruli but not in tubules and did not express glomerular cell markers (podocin, von Willebrand factor), but functional evaluation showed no beneficial effect of MSC infusion. Morphological and molecular analyses corroborated the functional results. MSCs did not repair kidney parenchyma and failed to modulate cell death and proliferation or cytokine release (tumour necrosis factor-alpha, vascular endothelial growth factor alpha (VEGF-alpha), Bcl-2, caspase). CONCLUSION: In this unique autologous large-animal model, MSCs did not exhibit reparative or paracrine protective properties.

Intensive and prolonged treatment of focal and segmental glomerulosclerosis recurrence in adult kidney transplant recipients: a pilot study.

No treatment has consistently induced long-term remission of proteinuria in adult patients with focal segmental glomerulosclerosis (FSGS) recurrence after kidney transplantation. We undertook an open-label, nonrandomized pilot trial of intensive and prolonged treatment of FSGS recurrence. Over an 18-month period, 10 adult kidney transplant recipients with FSGS recurrence received concomitantly high-dose steroids, intravenous cyclosporine for 14 days followed by oral cyclosporine therapy, and an intensive and prolonged course of plasma exchanges (PE). We compared this treatment with those of a control group of 19 patients with a FSGS recurrence transplanted between 1997 and 2005. Complete, rapid (mean 23 +/- 7 days) and sustained remission was obtained in 9/10 patients (90%) as opposed to 27% in the control group. At month 3 and month 12, proteinuria was 0.16 g/day (range 0.05-0.3 g/day) and 0.19 g/day (range 0.05-1 g/day) respectively. Only one patient remained in partial remission at month 12 but he had already lost two previous grafts due to FSGS recurrence. PEs were stopped at month 9 in all patients except for the patient with a partial remission who remains PE-dependent. This small pilot study provides very encouraging results demonstrating that this treatment rapidly achieves complete and sustained remission in a high proportion of patients.

[Nephrotoxicity of calcineurin inhibitors: presentation, diagnostic problems and risk factors]. / Néphrotoxicité des inhibiteurs de la calcineurine: présentation, problèmes diagnostiques et facteurs de risques.

Nephrotoxicity of calcineurin inhibitors (CNIs) is an acute, reversible and chronic, irreversible pathology. Histologically, acute nephrotoxicity manifests as hemodynamic modifications caused by vasoconstriction of the essentially afferent arterioles resulting in a drop in the glomerular filtration rate. Chronic nephrotoxicity is characterized by arteriolar hyalinosis resulting in a variety of tubulointerstitial and glomerular lesions with an essentially ischemic mechanism. However, these histological lesions, whether chronic or acute, are not specific of CNI toxicity and can be seen in the course of many pathological circumstances in kidney transplantation. This absence of specificity makes the histological diagnosis of CNI nephrotoxicity difficult. In addition, the individual risk of developing CNI nephrotoxicity, difficult to predict based solely on the pharmacokinetic parameters of systemic CNI exposure, also involves local exposure (CNI concentrations in the graft) modulated by several, notably pharmacogenetic factors. The difficulty of diagnosing CNI nephrotoxicity and the interindividual variability of its risk require development of new diagnostic tools so that the patients at highest risk of developing severe CNI nephrotoxicity lesions, in whom minimization protocols would produce the best risk-benefit ratio, can be identified.

[Interest of screening biopsies in renal transplantation]. / Intérêt des biopsies systématiques du greffon rénal?

Renal biopsy is an invaluable tool used for the monitoring of grafts and the management of their survival. Since 1993, thanks to research on biopsy tissues that enabled to distinguish the different types of rejection and to find markers of reversible or irreversible rejection, a classification of renal lesions has been established to achieve the regularly updated Banff classification. The last in date (2005) has defined the antibody-mediated chronic rejection, forsaken the term "chronic allograft nephropathy" and described a new class with interstitial fibrosis and tubular atrophy (IF/TA). Systematic or screening biopsies allow revealing infraclinical rejection lesions before any renal function degradation, better understanding of allograft nephropathy pathophysiology, confirming the diagnostic, but also displaying other more specific lesions that could benefit from a treatment. However, the interest of biopsies is limited by interpretation problems and risks for the patient.

A simple clinico-histopathological composite scoring system is highly predictive of graft outcomes in marginal donors.

The predictive value of pre-implantation biopsies versus clinical scores has not been studied extensively in marginal donors. Pre-implantation biopsies were performed in 313 kidneys from donors that were > or = 50 years of age (training set, n = 191; validation set, n = 122). The value of the donor clinical parameters and histological results in predicting 1-year estimated glomerular filtration rate (eGFR) <25 mL/min/1.73 m(2) was retrospectively evaluated. In multivariate analysis, the only clinical parameters associated with low eGFR were donor hypertension and a serum creatinine level > or =150 micromol/L before organ recovery. Clinical scores (Nyberg and Pessione) were not significantly associated with graft function. Regarding histological parameters, univariate analysis showed that glomerulosclerosis (GS) (p = 0.02), arteriolar hyalinosis (p = 0.03) and the Pirani (p = 0.02) and chronic allograft damage index (CADI) (p = 0.04) histological scores were associated with low eGFR. The highest performance in predicting low eGFR was achieved using a composite score that included donor serum creatinine (> or =150 micromol/L or <150 micromol/L), donor hypertension and GS (> or =10% or <10%). The validation set confirmed the critical importance of taking into account biopsy and clinical parameters during marginal donor evaluation. In conclusion, clinical scores are weak predictors of graft outcomes with marginal donors. Instead, a simple and convenient composite score strongly predicts graft function and survival and may facilitate optimal allocation of marginal donors.

Osteomalacia revealing celiac disease and primary biliary cirrhosis-related Fanconi syndrome in a patient with systemic sclerosis.

Systemic sclerosis (SSc) may affect the gastrointestinal tract and cause very rarely malabsorption syndrome related to bacterial overgrowth. Malabsorption syndrome may be responsible for weight loss, diarrhea, osteomalacia, and iron and vitamins deficiency. We report the case of a SSc patient who developed osteomalacia caused by the combination of two exceptional conditions in the setting of SSc: celiac disease (CD) and primary biliary cirrhosis (PBC)-related Fanconi syndrome. Oral prednisone with angiotensin-converting enzyme inhibitors, was initiated because of active lesions of tubulitis, and led to the complete regression of bone pains, and by the improvement of renal function and regression of the features of proximal tubulopathy. Thus, in the presence of vitamin deficiencies in a patient with SSc, together with a search for malabsorption syndrome secondary to bacterial overgrowth, CD and/or PBC-associated Fanconi syndrome should be investigated.

Mortality and risk factors of scleroderma renal crisis: a French retrospective study of 50 patients.

OBJECTIVES: To describe presentation and outcome of patients with scleroderma renal crisis (SRC). METHODS: SRC was defined as rapidly progressive oliguric renal insufficiency and/or rapidly progressive arterial hypertension occurring during the course of systemic sclerosis (SSc). Chronic dialysis-free survival was analysed using multivariate Cox proportional hazards regression models. The risk for developing SRC associated with corticosteroid (CS) exposure during the preceding 1- or 3-month periods was analysed according to a case-crossover design. RESULTS: A total of 50 SSc patients aged 53.3 (14.5) (mean (SD)) years were included in the study. SRC occurred between 1979 and 2003, after a mean (SD) disease duration of 27.7 (49.1) months. A total of 43 (86%) patients had diffuse SSc, 5 (10%) had limited cutaneous SSc and 2 (4%) had SSc sine scleroderma. At the time of SRC, 10 (20%) patients were taking angiotensin converting enzyme inhibitors, and mean creatininaemia was 468 (293) micromol/l. A total of 28 (56%) patients required haemodialysis. In all, 11 patients underwent a renal biopsy, all of them had specific vascular lesions of SRC. Multivariate analyses retained age >53 years and normal blood pressure as independent predictors of decreased dialysis-free survival. Exposure to CS prior to SRC was identified in 30 (60%) patients. The odds ratios for developing SRC associated with CS exposure during the preceding 1- or 3-month periods were 24.1 (95% CI 3.0-193.8) and 17.4 (95% CI 2.1-144.0), respectively. CONCLUSION: SRC remains associated with severe morbidity and mortality. CS might increase the risk of developing SRC. Further studies are needed to confirm these results.

Collagen alpha5 and alpha2(IV) chain coexpression: analysis of skin biopsies of Alport patients.

Alport syndrome is a collagen type IV disease caused by mutations in the COL4A5 gene with the X-linked form being most prevalent. The resultant alpha5(IV) collagen chain is a component of the glomerular and skin basement membranes (SBMs). Immunofluorescent determination of the alpha5(IV) chain in skin biopsies is the procedure of choice to identify patients. In 30% of patients, however, the mutant protein is still found in the SBM resulting in a normal staining pattern. In order to minimize or eliminate false results, we compared the distribution of the alpha2(IV) chain (another SBM component) and the alpha5(IV) chain by standard double label immunofluorescence (IF) and by confocal laser scanning microscopy. The study was performed on 55 skin biopsies of patients suspected of Alports and five normal control specimens. In normal skin, IF showed the classical linear pattern for both collagens along the basement membrane. Additionally, decreased alpha5(IV) was found in the bottom of the dermal papillary basement membrane. Confocal analysis confirmed the results and show alpha5(IV) focal interruptions. In suspected patients, both techniques showed the same rate of abnormal alpha5(IV) expression: segmental in women and absent in men. Our results show a physiological variation of alpha5(IV) location with focal interruptions and decreased expression in the bottom of the dermal basement membrane. Comparison of alpha5(IV) with alpha2(IV) expression is simple and eliminates technical artifacts.

Posttransplant prophylactic intravenous immunoglobulin in kidney transplant patients at high immunological risk: a pilot study.

The effects of posttransplant prophylactic intravenous immunoglobulin (IVIg) were investigated in renal transplant recipients at high immunological risk. Thirty-eight deceased-donor kidney transplant recipients with previous positive complement-dependent cytotoxicity crossmatch (n=30), and/or donor-specific anti-HLA antibodies (n=14) were recruited. IVIg (2 g/kg) was administrated on days 0, 21, 42 and 63 with quadruple immunosuppression. Biopsy-proven acute cellular and humoral rejection rates at month 12 were 18% and 10%, respectively. Glomerulitis was observed in 31% and 60% of patients at months 3 and 12, respectively, while allograft glomerulopathy rose from 3% at month 3 to 28% at 12 months. Interstitial fibrosis/tubular atrophy increased from 18% at day 0 to 51% and 72% at months 3 and 12 (p<0.0001). GFR was 50 +/- 17 mL/min/1.73 m(2) and 48 +/- 17 mL/min/1.73 m(2) at 3 and 12 months. PRA decreased significantly after IVIg (class I: from 18 +/- 27% to 5 +/- 12%, p<0.01; class II: from 25 +/- 30% to 7 +/- 16%, p<0.001). Patient and graft survival were 97% and 95%, respectively and no graft was lost due to rejection (mean follow-up 25 months). In conclusion, prophylactic IVIg in high-immunological risk patients is associated with good one-year outcomes, with adequate GFR and a profound decrease in PRA level, but a significant increase in allograft nephropathy.