Nasr, Samih H.

Significance Statement Approximately 20% of patients with lupus nephritis, the most common renal manifestation of systemic lupus erythematosus, show membranous lupus nephritis on kidney biopsy, and nearly 10% eventually develop ESKD. Recently, two proteins, Exostosin 1 and Exostosin 2 (EXT1/EXT2), were shown to be present in a subset of membranous lupus nephritis kidney biopsy specimens. In an examination of 374 membranous lupus nephritis kidney biopsy specimens, the authors found 32.6% to be EXT1/EXT2-positive. Kidney biopsy specimens from patients with EXT1/EXT2-positive membranous lupus nephritis showed less chronicity features (glomerulosclerosis, interstitial fibrosis, and tubular atrophy) compared with those from EXT1/EXT2-negative patients. EXT1/EXT2-negative patients were also more likely to reach ESKD than EXT1/EXT2-positive patients. These findings suggest that the presence of EXT1/EXT2 is favorable, and that EXT1/EXT2-positive patients have better renal outcomes compared with EXT1/EXT2-negative patients. Background In patients with secondary (autoimmune) membranous nephropathy, two novel proteins, Exostosin 1 and Exostosin 2 (EXT1/EXT2), are potential disease antigens, biomarkers, or both. In this study, we validate the EXT1/EXT2 findings in a large cohort of membranous lupus nephritis. Methods We conducted a retrospective cohort study of patients with membranous lupus nephritis, and performed immunohistochemistry studies on the kidney biopsy specimens against EXT1 and EXT2. Clinicopathologic features and outcomes of EXT1/EXT2-positive versus EXT1/EXT2-negative patients were compared. Results Our study cohort included 374 biopsy-proven membranous lupus nephritis cases, of which 122 (32.6%) were EXT1/EXT2-positive and 252 (67.4%) were EXT1/EXT2-negative. EXT1/EXT2-positive patients were significantly younger ( P =0.01), had significantly lower serum creatinine levels ( P =0.02), were significantly more likely to present with proteinuria ≥3.5 g/24 h ( P =0.009), and had significantly less chronicity features (glomerulosclerosis, P =0.001 or interstitial fibrosis and tubular atrophy, P <0.001) on kidney biopsy. Clinical follow-up data were available for 160 patients, of which 64 (40%) biopsy results were EXT1/EXT2-positive and 96 (60%) were EXT1/EXT2-negative. The proportion of patients with class 3/4 lupus nephritis coexisting with membranous lupus nephritis was not different between the EXT1/EXT2-positive and EXT1/EXT2-negative groups (25.0% versus 32.3%; P= 0.32). The patients who were EXT1/EXT2-negative evolved to ESKD faster and more frequently compared with EXT1/EXT2-positive patients (18.8% versus 3.1%; P =0.003). Conclusions The prevalence of EXT1/EXT2 positivity was 32.6% in our cohort of membranous lupus nephritis. Compared with EXT1/EXT2-negative membranous lupus nephritis, EXT1/EXT2-positive disease appears to represent a subgroup with favorable kidney biopsy findings with respect to chronicity indices. Cases of membranous lupus nephritis that are EXT1/EXT2-negative are more likely to progress to ESKD compared with those that are EXT1/EXT2-positive.

AimsTo characterise the clinicopathological features of amyloidosis due to EGF‐containing fibulin‐like extracellular matrix protein 1 (EFEMP1), a newly described amyloid type.Methods and resultsWe identified cases by searching the Mayo Clinic amyloid liquid chromatography and tandem mass spectrometry typing database for specimens with the universal amyloid signature proteins, abundant EFEMP1 spectra and absence of other specific amyloid precursor proteins. We also developed an immunohistochemical stain for EFEMP1 applicable to formalin‐fixed tissue sections and performed electron microscopy in one case. We identified 33 specimens from 32 patients with EFEMP1 amyloid. Most patients were female (91%) with a mean age of 75 years, and most specimens (94%) were from the bowel. EFEMP1 amyloid was incidentally identified in specimens biopsied/resected for a variety of clinical indications. In bowel specimens, EFEMP1 amyloid involved blood vessels and interstitium of the lamina propria, submucosa and/or muscularis propria. Although the EFEMP1 deposits were weakly to moderately Congo red‐positive with absent to weak birefringence, they were strongly positive for EFEMP1 by immunohistochemistry, had the characteristic fibrillar ultrastructure of amyloid and were readily identified by mass spectrometry.ConclusionsEFEMP1 amyloid is a recently described novel amyloid type that predominantly affects the bowel of elderly females. Because EFEMP1 amyloid is only weakly Congo red‐positive, it may be overlooked without a high index of suspicion. However, its characteristic microanatomical distribution is highlighted by immunohistochemistry and its identity is readily confirmed by mass spectrometry. Based on its distinctive features, we propose that EFEMP1 amyloidosis be considered a new amyloid type.

Abstract Background Coexistence of fibrillary glomerulonephritis (FGN) and immunoglobulin A (IgA) nephropathy (IgAN) in the same kidney biopsy (FGN–IgAN) is rare, and the clinicopathologic characteristics and outcome of this dual glomerulopathy are unknown. Methods In this study, 20 patients with FGN–IgAN were studied and their characteristics were compared with 40 FGN and 40 IgAN control patients. Results Concurrent IgAN was present in 1.8% of 847 consecutive FGN cases and was the second most common concurrent glomerulopathy after diabetic nephropathy. FGN–IgAN patients were overwhelmingly White (94%) and contrary to FGN patients were predominantly (60%) males. Compared with IgAN patients, FGN–IgAN patients were older, had higher proteinuria, a higher incidence of renal insufficiency, and a lower incidence of microhematuria and gross hematuria at diagnosis. Six (30%) patients had malignancy, autoimmune disease or hepatitis C infection, but none had a secondary cause of IgAN or clinical features of Henoch–Schonlein purpura. Histologically, all cases exhibited smudgy glomerular staining for immunoglobulin G and DnaJ homolog subfamily B member 9 (DNAJB9) with corresponding fibrillary deposits and granular mesangial staining for IgA with corresponding mesangial granular electron-dense deposits. On follow-up (median 27 months), 10 of 18 (56%) FGN–IgAN patients progressed to end-stage kidney disease (ESKD), including 5 who subsequently died. Serum creatinine at diagnosis was a poor predictor of renal survival. The proportion of patients reaching ESKD or died was higher in FGN–IgAN than in IgAN. The median Kaplan–Meier ESKD-free survival time was 44 months for FGN–IgAN, which was shorter than IgAN (unable to compute, P = 0.013) and FGN (107 months, P = 0.048). Conclusions FGN–IgAN is very rare, with clinical presentation and demographics closer to FGN than IgAN. Prognosis is guarded with a median renal survival of 3.6 years. The diagnosis of this dual glomerulopathy requires careful evaluation of immunofluorescence findings, and electron microscopy or DNAJB9 immunohistochemistry.

Abstract Light chain cast nephropathy (LCCN) in multiple myeloma often leads to severe and poorly reversible acute kidney injury. Severe renal impairment influences the allocation of chemotherapy and its tolerability; it also affects patient survival. Whether renal biopsy findings add to the clinical assessment in predicting renal and patient outcomes in LCCN is uncertain. We retrospectively reviewed clinical presentation, chemotherapy regimens, hematologic response, and renal and patient outcomes in 178 patients with biopsy-proven LCCN from 10 centers in Europe and North America. A detailed pathology review, including assessment of the extent of cast formation, was performed to study correlations with initial presentation and outcomes. Patients presented with a mean estimated glomerular filtration rate (eGFR) of 13 ± 11 mL/min/1.73 m2, and 82% had stage 3 acute kidney injury. The mean number of casts was 3.2/mm2 in the cortex. Tubulointerstitial lesions were frequent: acute tubular injury (94%), tubulitis (82%), tubular rupture (62%), giant cell reaction (60%), and cortical and medullary inflammation (95% and 75%, respectively). Medullary inflammation, giant cell reaction, and the extent of cast formation correlated with eGFR value at LCCN diagnosis. During a median follow-up of 22 months, mean eGFR increased to 43 ± 30 mL/min/1.73 m2. Age, β2-microglobulin, best hematologic response, number of cortical casts per square millimeter, and degree of interstitial fibrosis/tubular atrophy (IFTA) were independently associated with a higher eGFR during follow-up. This eGFR value correlated with overall survival, independently of the hematologic response. This study shows that extent of cast formation and IFTA in LCCN predicts the quality of renal response, which, in turn, is associated with overall survival.

Abstract Background Fibrillary glomerulonephritis (FGN) is a rare type of glomerulonephritis with poor prognosis, with no known effective therapies available for treatment. The objective of the study was to evaluate the efficacy and safety of rituximab in treatment of patients with FGN and to investigate the effect of rituximab on DNAJB9 levels. Methods This was a pilot prospective clinical trial in which patients with idiopathic FGN were treated with two courses of rituximab (1 g each) 2 weeks apart at the beginning and then again at 6 months. Primary outcome was defined as preservation of kidney function at 12 months with stable or increased creatinine clearance. Secondary outcome was defined as achieving complete remission (CR) defined as proteinuria &lt;300 mg/24 h or partial remission (PR) with proteinuria &lt;3 g/24 h and at least 50% reduction in the proteinuria. DNAJB9 levels were also measured in the serum at baseline, 6 and 12 months. Results The creatinine clearance did not change significantly during this time, from 47.7 mL/min/1.73 m2 at baseline to 43.7 mL/min/1.73 m2 during follow-up (P = 0.15). Proteinuria declined from 4.43 (1.6–5.53) g/24 h at baseline to 1.9 (0.46–5.26) g/24 h at 12 months but did not reach significance (P = 0.06). None of the patients reached CR, and 3 of the 11 achieved PR. There was no change in the DNAJB9 levels following treatment with rituximab. The most common adverse event was nasal congestion, fatigue and muscle cramps. Conclusions Treatment of patients with two courses of rituximab over a span of 6 months was associated with stabilization of renal function but did not result in a significant change in proteinuria and with no change in the DNAJB9 levels.

Background: Seventy percent of patients with light chain (AL) amyloidosis present with renal involvement. The phases of the disease include asymptomatic seeding, increasing proteinuria, and progression to end stage renal disease. In an attempt to identify genes relevant to renal reprogramming due to persistent disease,renal biopsies from treated AL patients were obtained for systematic histologic evaluation and transcriptional profiling. Correlates were sought between these two approaches. Methods: Renal biopsies from 10 patients with persistent proteinuria (>500mg/day) following hematologic responses to anti-plasma cell therapy were scored independently by 2 expert renal pathologists employing a novel histologic tool that assessed scarring, fibrosis and the distribution of amyloid, and were successfully evaluated by transcriptional profiling in the Michigan Kidney Translational Medicine Core lab. Clinical data and histologic scores (CSIC = composite scarring injury score, AS = amyloid score) were correlated to the expression profiles of specific tubular and glomerular gene sets. Results: Baseline characteristics and histologic scores are in Table 1. Using a false discovery rate corrected P-value of < 0.10, numerous genes of interest were identified (Table 2). Transcriptional profiling revealed 2 distinct patient clusters (G1 and G2) within the tubular and glomerular gene expression sets. The histopathologic features were different between G1 and G2; the amyloid score was significantly higher in G2 in both the tubular (7.0 vs. 4.25; p=0.03) and the glomerular (6.92 vs. 4.38; p= 0.04) compartments. The differential expression for the genes of interest between G1 and G2 were also determined (Table 2). Conclusion: This effort has generated multiple genes of interest. ICQD and PODXL, in particular, correlated with the distribution of amyloid in the capillaries and mesangium. We are currently comparing these expression profiles to those of other nephropathies to identify genes whose expression levels may be specific to AL nephropathy, hopefully leading to further novel histologic and protein-based investigations. Disclosures Comenzo: Takeda: Research Funding; Prothena Biosciences: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi-Aventis: Membership on an entity's Board of Directors or advisory committees; Caelum: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Karyopharm: Research Funding; Unum: Membership on an entity's Board of Directors or advisory committees, Research Funding; Myself: Patents & Royalties: Patent 9593332, Pending 20170008966.

Abstract Background Chronic lymphocytic leukemia (CLL) can effect renal function in a variety of ways including direct infiltration of the kidney, ureteral obstruction by lymphadenopathy, and treatment related tumor lysis syndrome (uric acid nephropathy). Rarely, CLL has also been reported to be associated with light chain nephropathy, renal amyloidosis, membranoproliferative glomerulonephritis (MPGN), granulomatous interstitial nephritis (GIN), and minimal change disease (MCD). Nearly all the data on the effects of CLL on renal function is at the case report level. We systematically evaluated the prevalence of renal insufficiency at diagnosis as well the incidence of acquired renal insufficiency during follow-up in a large cohort of patients with newly diagnosed CLL to more accurately define the effects of CLL on the kidney and its impact on clinical outcomes. Methods Between January 1995 -February 2013, previously untreated CLL patients seen in the Division of Hematology at Mayo Clinic at diagnosis (<12 months) and who had baseline assessment of serum creatinine were included in this analysis. Patients with serum creatinine (Cr) ≥1.5 mg/dL at baseline were classified as having renal insufficiency at diagnosis. Patients who initially had baseline creatinine <1.5 mg/dL but who developed a Cr≥1.5 mg/dL during the course of their disease were considered to have acquired renal insufficiency. Results Existing renal insufficiency at the time of CLL diagnosis: Of 2047 patients who met the eligibility criteria, 153 (7.5%) patients had renal insufficiency (Cr≥1.5 mg/dL) at the time of CLL diagnosis including 15 (0.7%) with a Cr≥3 mg/dL. Renal insufficiency was also more common among men (9.3% vs. 3.9%; p<0.00001), those with advanced stage disease (Rai 0=7.0%; Rai I-II=6.4%, Rai III-IV=20.2%; p<0.0001), and CD49d positive patients (6.8% vs. 3.8%; p<0.038). Patients with renal insufficiency at diagnosis were also older (median age 72.2 vs. 63.9; p<0.0001). No difference in the prevalence of renal insufficiency at diagnosis was observed based on cytogenetic abnormalities detected by FISH or CD38, ZAP-70 or IGHV gene mutation status. Although renal insufficiency at diagnosis was strongly associated with OS on univariate analysis (p<0.001), no association was observed between renal insufficiency and TTT or OS on multi-variate analysis adjusting for age, sex, and Rai stage. Acquired renal insufficiency during CLL disease course: Among the 1894 patients with normal renal function at diagnosis, 304 (16.1%) acquired renal insufficiency (Cr≥1.5 mg/dL) during the course of their CLL disease course including 43 (2.3%) with peak Cr≥3 mg/dL. In addition to age (older) and male sex, a number of CLL disease characteristics were associated with a higher likelihood of acquired renal insufficiency including: IGHV UM (OR=2.0; p=0.0001), unfavorable FISH (del17p- or 11q-; OR=2.0; p=0.001), and being CD49d+ (OR=1.8; p=0.002), ZAP-70+ (OR=1.6; p=0.004), or CD38+ (OR=1.4; p=0.0.032),. Shorter TTT (p<0.001) and OS (P<0.001) was observed among patients with initially normal creatinine who acquired renal insufficiency (Figure 1A and 1B). On MV analysis adjusting for age, sex, and stage at diagnosis, acquired renal insufficiency remained an independent predictor of TTT (OR=1.77; p=0.001) and OS (OR=2.67; p<0.001). Renal insufficiency and therapy selection After median follow-up of 4.5 years (range 0-18.0), 620 of 2047 (30.3%) patients have progressed to require treatment. Patients with renal insufficiency prior to treatment were less likely to receive purine nucleoside analogue based therapy and more likely to receive single agent alkylator based treatment. Conclusions Approximately 1 in every 13 patients (7.5%) with CLL has renal insufficiency at the time of diagnosis and an additional 16.1% acquire renal insufficiency during the course of the disease. The risk of developing renal insufficiency is associated with a variety of CLL B-cell characteristics and is associated with TTT and OS. Data on causes of acquired renal insufficiency is being abstracted and will be presented at the meeting. Disclosures: Shanafelt: Genentech: Research Funding; Glaxo-Smith-Kline: Research Funding; Cephalon: Research Funding; Hospira: Research Funding; Celgene: Research Funding; Polyphenon E International: Research Funding. Off Label Use: MK2206 in a phase 1 trial of CLL.