Franck Bridoux

Adult Faconi Syndrome Secondary to Light Chain Gammopathy: Clinicopathologic Heterogeneity and Unnsual Features in 11 Patients

Fifty-seven cases of Ig light chain-associated Fanconi syndrome (FS) have been reported so far, mostly as isolated reports. The pioneering work by Maldonado and associates (35), who reviewed the first 17 cases in 1975, led to the unifying concept that patients with FS and Bence Jones proteinuria have a special form of plasma cell dyscrasia characterized by slow progression of the tumor and by prominent crystal formation in proximal tubule cells, in the absence of myeloma casts in the distal tubule. We carefully reappraised these characteristics in a series of 11 patients. Ten renal biopsy specimens were available for electron microscopy, adding to the 15 previously reported cases with ultrastructural studies. Moreover, 10 of the kappa light chains could be entirely or partially sequenced and tested for their resistance to cathepsin B, a lysosomal protease present in proximal tubule cells. Our series showed an unexpected clinicopathologic heterogeneity. Seven patients presented with the typical clinical and pathologic features of FS and low-mass myeloma or monoclonal gammopathy of undetermined significance (MGUS), in keeping with Maldonado et als description. Crystals in bone marrow cells were detected in patients of this group, only. Three patients who presented with full-blown FS exhibited, however, the characteristic features of myeloma cast nephropathy in the setting of high-mass myeloma. One patient of this group also had numerous crystals in proximal tubule cells. The eleventh patient had complete FS with MGUS, but no crystals in proximal tubule cells even after electron microscopy. Contrasting with the clinicopathologic heterogeneity, genetic and biochemical analyses of the light chains showed a striking homogeneity. First, they all were of the kappa type. Second, 8 of 9 belonged to the V kappa I variability subgroup, which indicates that FS light chains are related by the sequence of their variable regions. Third, the 8 V kappa I light chain sequences most likely originated from only 2 germline genes, LCO2/012 and LCO8/018. Fourth, all 5 LCO2/012-derived sequences presented an unusual hydrophobic or nonpolar residue at position 30. These sequence peculiarities may account for unusual physicochemical properties of the light chains including the resistance of their variable domain V kappa to proteolysis by cathepsin B, observed in 7 of 9 patients in our series, while light chains isolated from patients with myeloma cast nephropathy are completely digested. Resistance of V kappa to proteolysis in FS patients can explain the accumulation of the light chain in the endocytotic compartment of the proximal tubule cells, leading to impairment of proximal tubule functions.

Management of noninfectious mixed cryoglobulinemia vasculitis: data from 242 cases included in the CryoVas survey

Data on the clinical spectrum and therapeutic management of noninfectious mixed cryoglobulinemia vasculitis (CryoVas) in the era of hepatitis C virus screening are lacking. We analyzed data from 242 patients with noninfectious mixed CryoVas included in the French multicenter CryoVas survey. Baseline manifestations were purpura (75%), peripheral neuropathy (52%), arthralgia or arthritis (44%), glomerulonephritis (35%), cutaneous ulcers (16%), and cutaneous necrosis (14%). A connective tissue disease was diagnosed in 30% and B-cell non-Hodgkin lymphoma in 22%, whereas the CryoVas was considered to be essential in 48%. With the use of Cox-marginal structural models, rituximab plus corticosteroids showed the greater therapeutic efficacy compared with corticosteroids alone and alkylating agents plus corticosteroids to achieve complete clinical, renal, and immunologic responses and a prednisone dosage < 10 mg/d at 6 months. However, this regimen was also associated with severe infections, particularly when high doses of corticosteroids were used, whereas death rates did not differ between the therapeutic regimens. The role of each of these strategies remains to be defined in well-designed randomized controlled trials.

Lenalidomide in combination with melphalan and dexamethasone in patients with newly-diagnosed AL amyloidosis: a multicenter phase 1/2 dose escalation study.

New treatment options are required for primary systemic amyloid light chain (AL) amyloidosis. This phase 1/2 dose-escalation study aimed to determine the maximum tolerated dose (MTD) of lenalidomide in combination with melphalan and dexamethasone (M-dex), and assess the efficacy and tolerability of this therapy for patients with de novo AL amyloidosis. Twenty-six patients were enrolled across 4 cohorts: M-dex + lenalidomide 5, 10, 15, and 20 mg once daily on days 1 to 21 in a 28-day cycle. No dose limiting toxicity (DLT) was observed in cohorts 1, 2, and 3. 4. Seven patients in cohort 4, M-dex + lenalidomide 20 mg/day, experienced DLT. MTD was defined as 15 mg of lenalidomide. A complete hematologic response was achieved in 42% at the dose of 15 mg of lenalidomide per day. After a median follow-up of 19 months, estimated 2-year overall survival (OS) and event-free survival (EFS) were 80.8% and 53.8%, respectively. Hematologic and organ responses were both associated with superior EFS rates (P = .0001). A higher EFS was also observed in patients whose free light chains decreased by more than 50% during therapy (P = .019). Lenalidomide 15 mg/d + M-dex is a new effective combination therapy in patients with newly diagnosed AL amyloidosis. This study is registered at www.clinicaltrials.gov as NCT00621400.

Serial measurements of antineutrophil cytoplasmic autoantibodies in patients with systemic vasculitis

PURPOSE To assess the value of serial determinations of antineutrophil cytoplasmic autoantibodies (ANCA) for monitoring disease activity in patients with systemic vasculitis. PATIENTS AND METHODS Forty-three patients with histologically proven vasculitis (21 with Wegeners granulomatosis, 17 with microscopic polyangiitis, and 5 with renal-limited vasculitis) were studied for a median follow-up of 22 months. Disease activity was prospectively assessed and quantified by the Birmingham Vasculitis Activity Score. A total of 347 sera were analyzed for ANCA determination. RESULTS Relapses occurred in 23 (54%) of 43 patients. Diagnostic category (Wegeners granulomatosis vs micropolyangiitis and renal-limited vasculitis), severity of initial symptoms (mean vasculitis activity score, mean number of organs involved), and ANCA pattern [cytoplasmic-ANCA (c-ANCA) vs perinuclear-ANCA (p-ANCA)] did not significantly differ between relapsers and nonrelapsers. Lung involvement was more frequent at onset among relapsers [16 of 23 (70%) vs 6 of 20 (30%); P = 0.02]. Relapses were slightly, but not significantly, more frequent in patients with Wegeners granulomatosis or a c-ANCA pattern. The percentage of relapsers was greater in patients with persistently positive ANCA than in patients with negative or decreasing ANCA titers (86% vs 20%, P = 0.0001). However, the predictive value of an increase in ANCA titers for the occurrence of a subsequent relapse was only 28% (4 of 14) for c-ANCA, 12% (2 of 17) for anti-proteinase 3-ANCA, and 43% (6 of 14) for anti-myeloperoxidase-ANCA. An increase in ANCA occurred before or during relapse in 33% (10 of 30) of cases for c-ANCA/anti-proteinase 3 antibodies, and 73% (11 of 15) of cases for anti-myeloperoxidase antibodies. CONCLUSION The persistence of ANCA positivity is strongly associated with relapses. However, an increase in ANCA titers has a poor value for the early prediction of a subsequent relapse and should not be used as a sole parameter for therapeutic intervention. In addition, our results suggest that serial anti-myeloperoxidase determination may be useful as a prognostic marker in patients who are p-ANCA positive.

Hereditary systemic amyloidosis due to Asp76Asn variant β2-microglobulin.

We describe a kindred with slowly progressive gastrointestinal symptoms and autonomic neuropathy caused by autosomal dominant, hereditary systemic amyloidosis. The amyloid consists of Asp76Asn variant β(2)-microglobulin. Unlike patients with dialysis-related amyloidosis caused by sustained high plasma concentrations of wild-type β(2)-microglobulin, the affected members of this kindred had normal renal function and normal circulating β(2)-microglobulin values. The Asp76Asn β(2)-microglobulin variant was thermodynamically unstable and remarkably fibrillogenic in vitro under physiological conditions. Previous studies of β(2)-microglobulin aggregation have not shown such amyloidogenicity for single-residue substitutions. Comprehensive biophysical characterization of the β(2)-microglobulin variant, including its 1.40-Å, three-dimensional structure, should allow further elucidation of fibrillogenesis and protein misfolding.

Glomerulonephritis With Isolated C3 Deposits and Monoclonal Gammopathy: A Fortuitous Association?

BACKGROUND AND OBJECTIVES Glomerular deposition of monoclonal Ig has been exceptionally described as the cause of membranoproliferative glomerulonephritis, through activation of the complement alternative pathway (CAP). DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS We retrospectively studied six adults with monoclonal gammopathy and glomerulonephritis (GN) characterized by isolated C3 deposits. RESULTS All patients presented with hematuria, associated with chronic renal failure and proteinuria in five patients, three of whom had nephrotic syndrome. Five patients had monoclonal gammopathy of undetermined significance and one had smoldering myeloma. The serum monoclonal IgG (κ four of six, λ two of six) was associated with light chain (LC) proteinuria in five patients. Four patients had low serum C3 and/or factor B levels. C4, factor H (CFH), and I protein levels were normal in five of five patients; none had detectable C3NeF. IgG anti-CFH activity was positive in one case. No mutations in CFH, CFI, and MCP genes were identified in four of four patients. Deposits were intramembranous, subepithelial, and mesangial by electron microscopy, and stained positive for C3 (six of six), properdin, and CFH (two of two) but negative for Ig LC and heavy chains, C4, and C1q (6/6) by immunofluorescence. Five patients progressed to end-stage renal disease over a median period of 47 months, despite chemotherapy in four patients. In one patient, monoclonal λLC deposits were observed on a follow-up kidney biopsy after 4 years. CONCLUSIONS GN with isolated glomerular C3 deposits might represent an unusual complication of plasma cell dyscrasia, related to complement activation through an autoantibody activity of the monoclonal Ig against a CAP regulator protein.

Prognostic factors of survival in patients with non-infectious mixed cryoglobulinaemia vasculitis: data from 242 cases included in the CryoVas survey

Background Data on the prognosis of non-infectious mixed cryoglobulinaemia vasculitis (CryoVas) in the era of hepatitis C virus screening are lacking. Methods The French multicentre and retrospective CryoVas survey included 242 patients with non-infectious mixed CryoVas. Causes of death and prognostic factors of survival were assessed and a prognostic score was determined to predict survival at 5 years. Results After a median follow-up of 35 months, 42 patients (17%) died. Causes of death were mainly serious infections (50%) and vasculitis flare (19%). One-, 2-, 5- and 10-year overall survival rates were 91%, 89%, 79% and 65%, respectively. A prognostic score, the CryoVas score (CVS), for the prediction of survival at 5 years was devised. Pulmonary and gastrointestinal involvement, glomerular filtration rate <60 ml/min and age >65 years were independently associated with death. At 5 years the death rates were 2.6%, 13.1%, 29.6% and 38.5% for a CVS of 0, 1, 2 and ≥3, respectively. At 1 year the death rates were 0%, 3.2%, 18.5% and 30.8% for a CVS of 0, 1, 2 and ≥3, respectively. The CVS was strongly correlated with the Five Factor Score (FFS) 2009, another prognostic score validated in primary necrotising vasculitis (r=0.82; p<0.0001). The area under the curve for the CVS was 0.74 compared with 0.67 for the FFS, indicating a better performance of the CVS (p=0.052). Conclusions In patients with non-infectious mixed CryoVas, the main prognostic factors are age >65 years, pulmonary and gastrointestinal involvement and renal failure. A score including these variables is significantly associated with the prognosis.

Long-term Kidney Disease Outcomes in Fibrillary Glomerulonephritis: A Case Series of 27 Patients

BACKGROUND Fibrillary glomerulonephritis (GN) is a rare disorder with poor renal prognosis. Therapeutic strategies, particularly the use of immunosuppressive drugs, are debated. STUDY DESIGN Case series. SETTING & PARTICIPANTS 27 adults with fibrillary GN referred to 15 nephrology departments in France between 1990 and 2011 were included. All patients were given renin-angiotensin system blockers and 13 received immunosuppressive therapy, including rituximab (7 patients) and cyclophosphamide (3 patients). OUTCOMES & MEASUREMENTS Clinical and histologic features of patients and kidney disease outcome. Renal response was defined as a >50% decrease in 24-hour proteinuria with <15% decline in estimated glomerular filtration rate (eGFR). RESULTS All patients presented with proteinuria, associated with nephrotic syndrome (41%), hematuria (73%), and hypertension (70%). Baseline median eGFR was 49 mL/min/1.73 m(2). Eight patients had a history of autoimmune disease and none had evidence of hematologic malignancy during follow-up. Light microscopic studies showed mesangial GN (70%), predominant pattern of membranous GN (19%), or membranoproliferative GN (11%). By immunofluorescence, immunoglobulin G (IgG) deposits (IgG4, 15/15; IgG1, 9/15) were polyclonal in 25 cases. Serum IgG subclass distribution was normal in the 6 patients tested. After a median 46-month follow-up, renal response occurred in 6 of 13 patients who received immunosuppressive therapy with rituximab (5 patients) or cyclophosphamide (1 patient). Of these, 5 had a mesangial or membranous light microscopic pattern, and median eGFR before therapy was 76 mL/min/1.73 m(2). In contrast, chronic kidney disease progressed in 12 of 14 patients who were not given immunosuppressive therapy, 10 of whom reached end-stage renal disease. LIMITATIONS Number of patients, retrospective study, use of multiple immunosuppressive regimens. CONCLUSIONS The therapeutic approach in fibrillary GN remains challenging. The place of immunosuppressive therapy, particularly anti-B-cell agents, needs to be assessed in larger collaborative studies.

The Alarmin Concept Applied to Human Renal Transplantation: Evidence for a Differential Implication of HMGB1 and IL-33

The endogenous molecules high mobility group box 1 (HMGB1) and interleukin-33 (IL-33) have been identified as alarmins, capable of mediating danger signals during tissue damage. Here, we address their possible role as innate-immune mediators in ischemia-reperfusion injury (IRI) following human kidney transplantation. We analysed serum and urinary HMGB1 and IL-33 levels, all determined by enzyme-linked immunosorbent assay, in a cohort of 26 deceased renal transplant recipients. Urinary HMGB1 and IL-33 levels were significantly increased as soon as 30 min after reperfusion, as compared to those before treatment. Moreover, both serum and urinary IL-33 (but not HMGB1) increase was positively correlated with cold ischemia time, from 30 min to 3 days post-transplantation. In vitro, human umbilical vein endothelial cells subjected to hypoxia conditions released both HMGB-1 and IL-33, while only the latter was further increased upon subsequent re-oxygenation. Finally, we postulate that leukocytes from renal recipient patients are targeted by both HMGB1 and IL-33, as suggested by increased transcription of their respective receptors (TLR2/4 and ST2L) shortly after transplantation. Consistent with this view, we found that iNKT cells, an innate-like T cell subset involved in IRI and targeted by IL-33 but not by HMGB1 was activated 1 hour post-transplantation. Altogether, these results are in keeping with a potential role of IL-33 as an innate-immune mediator during kidney IRI in humans.

Heart transplantation in systemic (AL) amyloidosis: a retrospective study of eight French patients.

BACKGROUND Immunoglobulinic (AL) amyloidosis is a complication of plasma cell dyscrasia, characterized by widespread deposition of amyloid fibrils derived from monoclonal light chains. Cardiac amyloid is the main prognostic factor, with a median survival of six months. Cardiac transplantation in AL amyloidosis is associated with high mortality, due to disease recurrence in the allograft and systemic progression. Suppression of light chain (LC) production with chemotherapy by melphalan plus dexamethasone (MD) or high dose melphalan followed by autologous stem cell transplantation (HDM/ASCT) improves survival. However, both the indications and results of chemotherapy in patients transplanted for cardiac AL amyloidosis remain unclear. AIMS To assess the outcome of cardiac transplantation and haematological therapy in patients with cardiac AL amyloidosis. METHODS Eight French patients, who underwent heart transplantation for cardiac AL amyloidosis between 2001 and 2006 were studied retrospectively. RESULTS Before transplantation, six patients received MD (n=5) or HDM/ASCT (n=1). Haematological remission was obtained in three patients treated with MD. In the three remaining patients, postoperative HDM/ASCT (n=2) or allogeneic bone marrow transplantation (n=1) resulted in haematological remission in one patient. In 2 patients not treated before transplantation, post-operative treatment with MD resulted in complete hematological remission in one. After a median follow-up of 26 months from cardiac transplantation, six patients were alive and four had sustained haematological remission, as indicated by normal serum free LC levels. CONCLUSION Appropriate haematological therapy, including MD, may result in a survival benefit in AL amyloidosis patients with advanced heart failure requiring transplantation.