Renal and vascular outcomes in patients with isolated antiphospholipid syndrome nephropathy

BACKGROUND

Antiphospholipid syndrome (APS) nephropathy (APSN) is a rare pattern with specific features resulting from microvascular lesions. The prognosis of APSN, outside of lupus nephritis, is unknown. The aim of this study was to describe the renal, vascular and overall outcomes of patients with APSN.

METHODS

Retrospective multicenter study of patients with antiphospholipid antibodies (aPL) associated with histological APSN lesions and no other nephropathy, identified through a national call for medical records. End-stage renal disease (ESRD)-free survival, thrombosis recurrence-free survival and overall survival were assessed.

RESULTS

Thirty patients were included (19 women) with a median age of 40 years (34-52 years). Fifteen patients had APS, 26/28 had lupus anticoagulant, and 15/26 had triple positivity for aPL. Median eGFR was 50 (31-60) mL/min/1.73 m². Glomerular thrombotic microangiopathy was found in 12/24 cases, fibrous intimal hyperplasia in 12/22 cases and focal cortical atrophy in 17/29 cases. Nineteen patients had moderate to severe interstitial fibrosis (>25%). Six patients developed ESRD at a median follow-up of 6.2 (1.8-9.1) years. The ESRD-free survival rates at 5 and 10 years were 80.0% (95% CI 57.6%-91.4%) and 72.7% (95% CI, 46.9%-87.4%) respectively. None of the histological factors considered was significantly associated with a decrease in eGFR at 12 months. Thrombosis recurrence-free survival was 77.8% (95% CI 48.2%-91.6%) at 10 years. Overall survival was 94% at 10 years (95% CI 65.0%-99.2%).

CONCLUSIONS

The renal prognosis of isolated APSN is poor. The severe fibrotic lesions observed are suggestive of late diagnosis.

Kidney Histopathology Can Predict Kidney Function in ANCA-Associated Vasculitides with Acute Kidney Injury Treated with Plasma Exchanges

BACKGROUND

Data from the PEXIVAS trial challenged the role of plasma exchange (PLEX) in ANCA-associated vasculitides (AAV). We aimed to describe kidney biopsy from patients with AAV treated with PLEX, evaluate whether histopathologic findings could predict kidney function, and identify which patients would most benefit from PLEX.

METHODS

We performed a multicenter, retrospective study on 188 patients with AAV and AKI treated with PLEX and 237 not treated with PLEX. The primary outcome was mortality or KRT at 12 months (M12).

RESULTS

No significant benefit of PLEX for the primary outcome was found. To identify patients benefitting from PLEX, we developed a model predicting the average treatment effect of PLEX for an individual depending on covariables. Using the prediction model, 223 patients had a better predicted outcome with PLEX than without PLEX, and 177 of them had >5% increased predicted probability with PLEX compared with without PLEX of being alive and free from KRT at M12, which defined the PLEX-recommended group. Risk difference for death or KRT at M12 was significantly lower with PLEX in the PLEX-recommended group (-15.9%; 95% CI, -29.4 to -2.5) compared with the PLEX not recommended group (-4.8%; 95% CI, 14.9 to 5.3). Microscopic polyangiitis, MPO-ANCA, higher serum creatinine, crescentic and sclerotic classes, and higher Brix score were more frequent in the PLEX-recommended group. An easy to use score identified patients who would benefit from PLEX. The average treatment effect of PLEX for those with recommended treatment corresponded to an absolute risk reduction for death or KRT at M12 of 24.6%.

CONCLUSIONS

PLEX was not associated with a better primary outcome in the whole study population, but we identified a subset of patients who could benefit from PLEX. However, these findings must be validated before utilized in clinical decision making.

Glomerular endothelial cell senescence drives age-related kidney disease through PAI-1

The mechanisms underlying the development of glomerular lesions during aging are largely unknown. It has been suggested that senescence might play a role, but the pathophysiological link between senescence and lesion development remains unexplained. Here, we uncovered an unexpected role for glomerular endothelial cells during aging. In fact, we discovered a detrimental cross-talk between senescent endothelial cells and podocytes, through PAI-1. In vivo, selective inactivation of PAI-1 in endothelial cells protected glomeruli from lesion development and podocyte loss in aged mice. In vitro, blocking PAI-1 in supernatants from senescent endothelial cells prevented podocyte apoptosis. Consistently, depletion of senescent cells prevented podocyte loss in old p16 INK-ATTAC transgenic mice. Importantly, these experimental findings are relevant to humans. We showed that glomerular PAI-1 expression was predictive of poor outcomes in transplanted kidneys from elderly donors. In addition, we observed that in elderly patients, urinary PAI-1 was associated with age-related chronic kidney disease. Altogether, these results uncover a novel mechanism of kidney disease and identify PAI-1 as a promising biomarker of kidney dysfunction in allografts from elderly donors.

Organ Transplantation in Hereditary Fibrinogen A α-Chain Amyloidosis: A Case Series of French Patients

RATIONALE & OBJECTIVE

Fibrinogen A α-chain amyloidosis (AFib amyloidosis) is a form of amyloidosis resulting from mutations in the fibrinogen A α-chain gene (FGA), causing progressive kidney disease leading to kidney failure. Treatment may include kidney transplantation (KT) or liver-kidney transplantation (LKT), but it is not clear what factors should guide this decision. The aim of this study was to characterize the natural history and long-term outcomes of this disease, with and without organ transplantation, among patients with AFib amyloidosis and various FGA variants.

STUDY DESIGN

Case series.

SETTING & PARTICIPANTS

32 patients with AFib amyloidosis diagnosed by genetic testing in France between 1983 and 2014, with a median follow-up of 93 (range, 4-192) months, were included.

RESULTS

Median age at diagnosis was 51.5 (range, 12-77) years. Clinical presentation consisted of proteinuria (93%), hypertension (83%), and kidney failure (68%). Manifestations of kidney disease appeared on average at age 57 (range, 36-77) years in patients with the E526V variant, at age 45 (range, 12-59) years in those with the R554L variant (P<0.001), and at age 24.5 (range, 12-31) years in those with frameshift variants (P<0.001). KT was performed in 15 patients and LKT was performed in 4. In KT patients with the E526V variant, recurrence of AFib amyloidosis in the kidney graft was less common than with a non-E526V (R554L or frameshift) variant (22% vs 83%; P=0.03) and led to graft loss less frequently (33% vs 100%). Amyloid recurrence was not observed in patients after LKT.

LIMITATIONS

Analyses were based on clinically available historical data. Small number of patients with non-E526V and frameshift variants.

CONCLUSIONS

Our study suggests phenotypic variability in the natural history of AFib amyloidosis, depending on the FGA mutation type. KT appears to be a viable option for patients with the most common E526V variant, whereas LKT may be a preferred option for patients with frameshift variants.

P0018GLOMERULAR ENDOTHELIAL CELL SENESCENCE DRIVES AGE-RELATED KIDNEY DISEASE THROUGH PAI-1

Background and Aims

In age-related chronic kidney disease (CKD), the most frequent histological lesion observed is glomerulosclerosis. The molecular mechanisms involved in this deterioration process are unclear, but cellular senescence might play a role.

Method

By combining several murine models of physiological and accelerated aging with transgenic animals and in vitro models, we discovered the role of endothelial senescence in the development of glomerular lesions.

Results

These senescent glomerular endothelial cells secreted several molecules, grouped under the senescence associated secretory phenotype (SASP) including the plasminogen activator inhibitor 1 (PAI-1). Specific deletion of PAI-1 in endothelial cells prevented the development of glomerulosclerosis during physiological and accelerated aging, by decreasing podocyte loss. In addition, we showed that PAI-1 mediates a detrimental endothelial-podocyte crosstalk, as incubation of podocytes by supernatant of senescent glomerular endothelial cells led to their detachment. Consistently, preincubation of the senescent supernatant with tiplaxtinin, a PAI-1 inhibitor, preserved podocytes. More importantly, we demonstrated that these data are relevant to humans. In fact, PAI-1 staining the day of the transplantation was predictive of kidney allograft dysfunction 12 months after transplantation from elderly donors.

Conclusion

In conclusion, our study uncovers the critical role played by endothelial senescence in the development of glomerulosclerosis during aging and identified PAI-1 as a novel promising biomarker for predicting kidney dysfunction in patients receiving a kidney from elderly donors.

P0204PREVALENCE AND PREDICTIVE FACTORS OF BIOPSY-PROVEN NEPHROPATHY RELATED TO MONOCLONAL GAMMOPATHY

Background and Aims

The prevalence of monoclonal gammopathy (MG) and kidney disease increases with age. When a patient present with both conditions, it is often necessary to perform a kidney biopsy in order to rule out a Monoclonal Immunoglobulin-Related Nephropathy (MIRN) that may require a specific therapy that targets either an overt hematological malignancy or a MG or Renal Significance (MGRS). The aim of our study was to identify factors that predict the presence of MIRN in this setting.

Method

This retrospective monocentric study included all patients who underwent a kidney biopsy between 2007 and 2018 with concurrent presence of GM, as defined by positive serum immuno-electrophoresis and/or Bence-Jones proteinuria.

Results

328 patients were included, representing 11.8% of all kidney biopsies performed in our center during this period. Indication of biopsy was renal failure (eGFR &lt;60ml/min/1.73m) in 77.4% of cases and/or proteinuria (urine protein-to-creatinine ratio &gt;0.5g/g) in 75.9% of them. Median (IQR) serum creatinine was 155 μmol/L (111-233), eGFR 37.5 (22-56) ml/min/1.73m, serum albumin 29.5 (24-35) g/l. Median age was 67 (57/75), the M/F ratio was 198/130, diabetes mellitus was present in 21.3% of cases, hypertension in 53.1%.

Kidney biopsy revealed that nephropathy was related to MG in 91/328 patients (27.7%). Myeloma cast nephropathy and AL amyloidosis were the most common histopathological subtypes (36 and 34% respectively), followed by monoclonal immunoglobulin deposition disease (15%) and cryoglobulinemic glomerulonephritis (8%). Patients with MIRN had more severe renal function impairment with median (IQR) serum creatinine of 176 (119-307) vs 149 (108-216) μmol/l (p=0.003) and heavier proteinuria, 3.9 (2.2-8.2) vs 2.0 (0.9-5.2) g/g (p&lt; 0.001), when compared to non-MIRN patients.

Hematological malignancy was diagnosed in 83 cases (25,3%) (Multiple Myeloma in 62, non-Hodgkin Lymphoma in 6, Waldenström Macroglobulinemia in 6, Chronic Lymphoid Leukemia in 6, Plasmocytoma in 3). Among them, MIRN was diagnosed in 51 (61%) cases but tumoral lympho-plasmocytic infiltration was observed in 9 (11%) cases. In this subgroup of patients, no laboratory test could predict the presence of a specific nephropathy.

Among patients with no hematological malignancy (n=245), MIRN was diagnosed in 40 cases (16%) to confirm MGRS diagnosis. The markers that were most commonly associated with the presence of MGRS were positive Bence-Jones proteinuria (OR 4.7; 95%CI 2.2-10.3; p&lt; 0.001), abnormal serum Free Light Chain (FLC) ratio (OR 4.2; 95%CI 1.7-10.7; p&lt; 0.001), and serum electrophoresis spike &gt;1.5 g/l (OR 5.9; 95%CI 2.6-13.5; p&lt; 0.001). However, none of those markers had sufficient power to formally predict the result of the biopsy, as positive (PPV) or negative (NPV) predictive values were 36/41/45 % and 89/86/88 % respectively.

Conclusion

Almost one-third of patients with MG and kidney disease referred to our Department have biopsy-proven related nephropathy. Although negativity of Bence-Jones proteinuria and a normal serum FLC ratio are frequently associated with the absence of MGRS, kidney biopsy, beyond its diagnostic and prognostic interest, remains the most discriminating test.

P0362ROLE OF REPEATED RENAL BIOPSY IN ANCA VASCULITIS

Background and Aims

Antineutrophil cytoplasmic antibody (ANCA) associated vasculitis (AAV) is a systemic disease characterized by inflammation of small vessels and presence of ANCA. Pauci-immune necrotizing crescentic glomerulonephritis is a severe renal complication of AAV. Despite immunosuppressive therapy, relapses are frequent during the course of the disease, affecting up to 50% of the patients.

Kidney biopsy is routinely used to diagnose AAV at initial presentation and to predict renal prognosis. Although the activity of renal AAV is not easily evaluated by plasma or urine biomarkers, kidney biopsy is rarely performed when relapse is suspected.

We herein analyze the clinical, laboratory and renal pathology data from patients who underwent repeated kidney biopsies during the course of AAV.

Method

We retrospectively reviewed data from 37 patients who underwent at least 2 kidney biopsies in our centre, between 2002 and 2018. The first renal biopsy (B1) was constantly performed at diagnosis. A follow-up biopsy (B2) was performed for purpose, either for suspicion of refractory disease or confirmation of renal relapse.

Modifications of renal pathology between B1 and B2 were studied, by comparing presence of active and chronic lesions. Active lesions were defined by the presence of cellular crescents and/or fibrinoid necrosis. Chronic lesions were quantified by the percentage of globally sclerotic glomeruli and the percentage of interstitial fibrosis / tubular atrophy (IF/TA).

Results

Median age at diagnosis was 57 years, M/F ratio was 21/16. ANCA specificity was anti-MPO in 65% of cases, anti-PR3 in 32%. The median delay between B1 and B2 was 3,3 [0,9-5,8] years. B2 was done for suspicion of refractory disease (n=8) or of renal relapse (n=29). Causes of B2 were : persistence or reappearance of haematuria in 78% of cases, increase of creatinine in 43%, increase of ANCA titer in 67%.

Systemic AAV activity was more important at B1 vs B2 (median BVAS 18 vs 9), as well as renal dysfunction (median sCreat 200 vs 156 μmol/l).

Active glomerulonephritis was constantly found at B1 but was present in only 35% of B2. Presence of cellular crescents decreased from 71,4 to 29,7% (p = 0,002), whereas fibrinoid necrosis decreased from 80,6 to 35,1% (p = 0.0003).

Five factors were significantly associated with the presence of active lesions : presence of at least one extra-renal AAV manifestation (p = 0.0006), increase of ANCA titer (p = 0.0022), CRP&gt;30mg/l (p = 0.001), absence of IF/TA (p=0,02) and high percentage of normal glomeruli (p=0,014) at B1. Interestingly, level of proteinuria and persistence of hematuria were not associated with histological activity at B2 (p =0,64 and 0,22 respectively).

In contrast, chronic lesions such as glomerulosclerosis and IF/TA were more severe at B2 compared to B1 (p &lt;0,0001 and 0,014 respectively). The worsening of fibrotic lesions was not associated with ANCA specificity (anti-MPO vs -PR3).

Conclusion

This is the largest cohort reporting on repeated renal biopsy in AAV. Despite several clinical and laboratory signs suggesting active renal AAV, B2 revealed no relapse in 2/3 of cases, allowing avoidance of a new immunosuppressive induction treatment. Our results suggest that rebiopsy is crucial when renal relapse is suspected, as proteinuria and hematuria do not predict active disease, suggesting that their persistence could be explained by glomerular scarring.

Clinicopathologic features of infection-related glomerulonephritis with IgA deposits: a French Nationwide study

Background

Infection-related glomerulonephritis with IgA deposits (IRGN-IgA) is a rare disease but it is increasingly reported in the literature. Data regarding epidemiology and outcome are lacking, especially in Europe. We aimed to assess the clinical, pathologic and outcome data of IRGN-IgA.

Methods

Clinical and outcome data from patients from 11 French centers over the 2007–2017 period were collected retrospectively. We reviewed pathologic patterns and immunofluorescence of renal biopsies and evaluated C4d expression in IRGN-IgA. We analyzed the correlation between histological presentation and outcome.

Results

Twenty-seven patients (23 men, mean age: 62 ± 15 years) were included. Twenty-one (78%) had Staphylococcus aureus infection and twelve (44%) were diabetic. At the time of biopsy, 95.2% had haematuria, 48.1% had a serum creatinine level of > 4 mg/dL, and 16% had hypocomplementemia. The most common pathologic presentation included mesangial (88.9%) and endocapillary proliferative glomerulonephritis (88.9%) with interstitial fibrosis and tubular atrophy (IF/TA) (85.1%). Diffuse and global glomerular C4d expression was found in 17.8%, mostly in biopsies with acute or subacute patterns, and was associated with a short delay between infection and renal biopsy compared to segmental and focal staining. After median follow-up of 13.2 months, 23.1% died, 46.2% had persistent renal dysfunction and 15.4% reached end-stage renal disease. Renal outcome was correlated to IF/TA severity.

Conclusions

Infection-related glomerulonephritis with IgA deposits is usually associated with Staphylococcus infections and mainly affects adult men. This entity has a poor prognosis which is correlated to interstitial fibrosis and tubular atrophy severity.

Ifosfamide nephrotoxicity in adult patients

Background

Ifosfamide, a widely prescribed antineoplasic agent, is frequently associated with kidney dysfunction. Its nephrotoxicity is well documented in children, but data are lacking in adult patients.

Methods

The aim of this retrospective study was to describe the clinical, biological and histological characteristics of ifosfamide nephrotoxicity.

Results

We report 34 patients (median age: 41 years) admitted in six French nephrology departments for kidney failure and/or tubular dysfunction. Fifteen patients (44.1%) received cisplatin as part of their chemotherapy. In 6 patients (17.7%), ifosfamide nephrotoxicity was revealed by a proximal tubular dysfunction (PTD), in 5 patients (14.4%) by an acute kidney injury (AKI), in 6 patients (17.7%) by a chronic kidney disease (CKD) and in 17 patients (49.7%) by an association of PTD and AKI. Fourteen renal biopsies (41.2%) were performed and revealed acute tubular necrosis (85.7%), vacuolation (78.6%) and nuclear atypias (71.4%) of renal epithelial cells, interstitial inflammation (71.4%) and fibrosis (57.1%). Electron microscopy showed mitochondrial enlargement and dysmorphic changes suggestive of mitochondrial toxicity. Ten patients (29.4%) progressed to Stage 5 CKD, six (17.6%) required haemodialysis and six patients died during a median follow-up period of 31 months. Risk factors for Stage 5 CKD were age and cisplatin co-administration.

The tetraspanin CD9 controls migration and proliferation of parietal epithelial cells and glomerular disease progression

The mechanisms driving the development of extracapillary lesions in focal segmental glomerulosclerosis (FSGS) and crescentic glomerulonephritis (CGN) remain poorly understood. A key question is how parietal epithelial cells (PECs) invade glomerular capillaries, thereby promoting injury and kidney failure. Here we show that expression of the tetraspanin CD9 increases markedly in PECs in mouse models of CGN and FSGS, and in kidneys from individuals diagnosed with these diseases. Cd9 gene targeting in PECs prevents glomerular damage in CGN and FSGS mouse models. Mechanistically, CD9 deficiency prevents the oriented migration of PECs into the glomerular tuft and their acquisition of CD44 and β1 integrin expression. These findings highlight a critical role for de novo expression of CD9 as a common pathogenic switch driving the PEC phenotype in CGN and FSGS, while offering a potential therapeutic avenue to treat these conditions.

In both focal segmental glomerulosclerosis (FSGS) and crescentic glomerulonephritis (CGN), kidney injury is characterised by the invasion of glomerular tufts by parietal epithelial cells (PECs). Here Lazareth et al. identify the tetraspanin CD9 as a key regulator of PEC migration, and find its upregulation in FSGS and CGN contributes to kidney injury in both diseases.

Genetic and pharmacological inhibition of microRNA-92a maintains podocyte cell cycle quiescence and limits crescentic glomerulonephritis

Crescentic rapidly progressive glomerulonephritis (RPGN) represents the most aggressive form of acquired glomerular disease. While most therapeutic approaches involve potentially toxic immunosuppressive strategies, the pathophysiology remains incompletely understood. Podocytes are glomerular epithelial cells that are normally growth-arrested because of the expression of cyclin-dependent kinase (CDK) inhibitors. An exception is in RPGN where podocytes undergo a deregulation of their differentiated phenotype and proliferate. Here we demonstrate that microRNA-92a (miR-92a) is enriched in podocytes of patients and mice with RPGN. The CDK inhibitor p57^Kip2 is a major target of miR-92a that constitutively safeguards podocyte cell cycle quiescence. Podocyte-specific deletion of miR-92a in mice de-repressed the expression of p57^Kip2 and prevented glomerular injury in RPGN. Administration of an anti-miR-92a after disease initiation prevented albuminuria and kidney failure, indicating miR-92a inhibition as a potential therapeutic strategy for RPGN. We demonstrate that miRNA induction in epithelial cells can break glomerular tolerance to immune injury.

Crescentic rapidly progressive glomerulonephritis is a severe form of glomerula disease characterized by podocyte proliferation and migration. Here Henique et al. demonstrate that inhibition of miRNA-92a prevents kidney failure by promoting the expression of CDK inhibitor p57^Kip2 that regulates podocyte cell cycle.

[Renal involvement during type 1 cryoglobulinemia]

Cryoglobulins are circulating immunoglobulins that precipitate with cold temperature and dissolve with rewarming. Type 1 cryoglobulinemia is composed of a single monoclonal immunoglobulin and is associated with renal involvement in up to 40% of cases. Type 1 cryoglobulinemia is related to an underlying B-cell haematological malignancy in 60% of patients. In the remaining cases, in the absence of criteria for malignancy, the diagnosis of monoclonal gammopathy of renal significance should be established. The clinical and biological setting and histological features of type 1 cryoglobulinemia are globally similar to those of mixed cryoglobulinemia. In case of haematological malignancy, the treatment is guided by the nature of the underlying disease, and aims at inducing haematological remission, which is necessary for the renal response. The management of monoclonal gammopathy of renal significance has been clarified by an international consensus group and is based on the nature of the underlying clone. In case of monoclonal cryoglobulinemia associated with a plasma-cell clone (IgG or IgA), the treatment is based on the combination of bortezomib, cyclophosphamide and dexamethasone. In case of IgM monoclonal cryoglobulinemia, the treatment is similar to that of Waldenström macroglobulinemia, and is based on rituximab. The clinical course of renal monoclonal cryoglobulinemia is intimately associated with the haematological response, and is usually favourable.

Nuclear Factor Erythroid 2-Related Factor 2 Drives Podocyte-Specific Expression of Peroxisome Proliferator-Activated Receptor γ Essential for Resistance to Crescentic GN

Necrotizing and crescentic rapidly progressive GN (RPGN) is a life-threatening syndrome characterized by a rapid loss of renal function. Evidence suggests that podocyte expression of the transcription factor peroxisome proliferator-activated receptor γ (PPARγ) may prevent podocyte injury, but the function of glomerular PPARγ in acute, severe inflammatory GN is unknown. Here, we observed marked loss of PPARγ abundance and transcriptional activity in glomerular podocytes in experimental RPGN. Blunted expression of PPARγ in podocyte nuclei was also found in kidneys from patients diagnosed with crescentic GN. Podocyte-specific Pparγ gene targeting accentuated glomerular damage, with increased urinary loss of albumin and severe kidney failure. Furthermore, a PPARγ gain-of-function approach achieved by systemic administration of thiazolidinedione (TZD) failed to prevent severe RPGN in mice with podocyte-specific Pparγ gene deficiency. In nuclear factor erythroid 2-related factor 2 (NRF2)-deficient mice, loss of podocyte PPARγ was observed at baseline. NRF2 deficiency markedly aggravated the course of RPGN, an effect that was partially prevented by TZD administration. Furthermore, delayed administration of TZD, initiated after the onset of RPGN, still alleviated the severity of experimental RPGN. These findings establish a requirement for the NRF2-PPARγ cascade in podocytes, and we suggest that these transcription factors have a role in augmenting the tolerance of glomeruli to severe immune-complex mediated injury. The NRF2-PPARγ pathway may be a therapeutic target for RPGN.

Sarcoidosis presenting as severe renin-dependent hypertension due to kidney vascular injury

Renal sarcoidosis embraces a wide variety of clinical patterns. Renal vascular involvement has seldom been reported and usually in the setting of systemic vasculitis. We report the case of a 22-year-old patient in whom inaugural manifestation of renal sarcoidosis consisted of severe hypertension associated with bilateral perfusion defects and tumour-like nodules. In the setting of renal sarcoidosis, our case suggests that renin-dependant hypertension may arise from renal ischaemia as a result of extrinsic compression of kidney blood vessels due to severe granulomatous inflammation.

Subclinical Rejection Phenotypes at 1 Year Post-Transplant and Outcome of Kidney Allografts

Kidney allograft rejection can occur in clinically stable patients, but long-term significance is unknown. We determined whether early recognition of subclinical rejection has long-term consequences for kidney allograft survival in an observational prospective cohort study of 1307 consecutive nonselected patients who underwent ABO-compatible, complement-dependent cytotoxicity-negative crossmatch kidney transplantation in Paris (2000-2010). Participants underwent prospective screening biopsies at 1 year post-transplant, with concurrent evaluations of graft complement deposition and circulating anti-HLA antibodies. The main analysis included 1001 patients. Three distinct groups of patients were identified at the 1-year screening: 727 (73%) patients without rejection, 132 (13%) patients with subclinical T cell-mediated rejection (TCMR), and 142 (14%) patients with subclinical antibody-mediated rejection (ABMR). Patients with subclinical ABMR had the poorest graft survival at 8 years post-transplant (56%) compared with subclinical TCMR (88%) and nonrejection (90%) groups (P<0.001). In a multivariate Cox model, subclinical ABMR at 1 year was independently associated with a 3.5-fold increase in graft loss (95% confidence interval, 2.1 to 5.7) along with eGFR and proteinuria (P<0.001). Subclinical ABMR was associated with more rapid progression to transplant glomerulopathy. Of patients with subclinical TCMR at 1 year, only those who further developed de novo donor-specific antibodies and transplant glomerulopathy showed higher risk of graft loss compared with patients without rejection. Our findings suggest that subclinical TCMR and subclinical ABMR have distinct effects on long-term graft loss. Subclinical ABMR detected at the 1-year screening biopsy carries a prognostic value independent of initial donor-specific antibody status, previous immunologic events, current eGFR, and proteinuria.

[Spectrum of renal manifestations in sickle cell disease]

Sickle cell disease (SCD), the most common hemoglobinopathy, is an increasing cause of chronic kidney disease. In the last decade, we have witnessed a better understanding in the characterization of clinical manifestations and pathogenesis of sickle cell nephropathy. The spectrum of renal diseases during SCD includes various renal manifestations such as impairment of urinary concentrating ability, defect in urine acidification, renal papillary necrosis and proteinuria related to glomerular injury leading to progressive end-stage renal disease. Endothelial dysfunction related to chronic hemolysis and the relative renal hypoxia caused by vaso-occlusive sickle red blood cells are probably two key factors for SCN development. Optimal therapeutic management (including the use of blockers of the renin-angiotensin system) of patients with proteinuria remains to be determined. Renal replacement therapy with dialysis is required in SCD patients with end-stage renal disease but these patients should probably undergo kidney transplantation that requires careful management.

[Cardiac amyloidosis: a case series of 14 patients, description and prognosis]

PURPOSE

Cardiac amyloidosis is rare. The objective of this study was to report on a case series of 14 patients with cardiac amyloidosis and to study the prognostic factors.

METHODS

Monocentric retrospective study of all adult patients who presented with cardiac amyloidosis, diagnosed at the Georges-Pompidou European hospital in Paris between 2003 and 2011.

RESULTS

Fourteen patients were identified (10 men and four women). Median age at diagnosis was 66.5 years. Twelve patients were diagnosed with AL amyloidosis, one with AA amyloidosis, and one with transthyretin amyloidosis. All patients presented cardiac manifestations: heart failure (n=9), rhythm disorders (n=6). Eight patients presented extra-cardiac manifestations of amyloidosis: renal (n=8), gastrointestinal (n=5). Troponin serum level was increased in eight patients and BNP level was superior to 400 pg/L in 12 patients. When performed, the cardiac magnetic resonance imaging (MRI) showed, in six patients out of seven, chamber dilatation, concentric hypertrophy or late enhancement. Among patients with cardiac failure at diagnosis (n=9), seven died with a median survival of 1 month duration. Factors of poor prognosis were, in our study, heart failure, elevated levels of troponin and BNP, and the AL amyloidosis subtype.

CONCLUSION

Cardiac amyloidosis, especially the AL type, has a very poor prognosis, essentially because of an underlying multiple myeloma and heart failure.

Complement-binding anti-HLA antibodies and kidney-allograft survival

BACKGROUND

Anti-HLA antibodies hamper successful transplantation, and activation of the complement cascade is involved in antibody-mediated rejection. We investigated whether the complement-binding capacity of anti-HLA antibodies plays a role in kidney-allograft failure.

METHODS

We enrolled patients who received kidney allografts at two transplantation centers in Paris between January 1, 2005, and January 1, 2011, in a population-based study. Patients were screened for the presence of circulating donor-specific anti-HLA antibodies and their complement-binding capacity. Graft injury phenotype and the time to kidney-allograft loss were assessed.

RESULTS

The primary analysis included 1016 patients. Patients with complement-binding donor-specific anti-HLA antibodies after transplantation had the lowest 5-year rate of graft survival (54%), as compared with patients with non-complement-binding donor-specific anti-HLA antibodies (93%) and patients without donor-specific anti-HLA antibodies (94%) (P<0.001 for both comparisons). The presence of complement-binding donor-specific anti-HLA antibodies after transplantation was associated with a risk of graft loss that was more than quadrupled (hazard ratio, 4.78; 95% confidence interval [CI], 2.69 to 8.49) when adjusted for clinical, functional, histologic, and immunologic factors. These antibodies were also associated with an increased rate of antibody-mediated rejection, a more severe graft injury phenotype with more extensive microvascular inflammation, and increased deposition of complement fraction C4d within graft capillaries. Adding complement-binding donor-specific anti-HLA antibodies to a traditional risk model improved the stratification of patients at risk for graft failure (continuous net reclassification improvement, 0.75; 95% CI, 0.54 to 0.97).

CONCLUSIONS

Assessment of the complement-binding capacity of donor-specific anti-HLA antibodies appears to be useful in identifying patients at high risk for kidney-allograft loss.