AA Amyloid Deposition Research Articles

#2698 Regression of amyloid deposits after treatment with tocilizumab

Abstract Background and Aims AA amyloidosis is a multisystem disease characterized by the deposition of serum amyloid A protein, which is secondary to chronic inflammation. Tocilizumab (an interleukin-6 inhibitor monoclonal antibody) is effective in suppressing inflammation, normalizing serum amyloid A protein levels and inducing remission in patients with amyloidosis. Recently, tocilizumab treatment has been associated with the disappearance of amyloid deposits. Results We report a case of AA amyloidosis secondary to chronic arthritis in a 61-year-old woman referred to our hospital in 2011 due to oligoarthritis of the knees and elevation of acute-phase reactants. Corticosteroids and methotrexate were prescribed, without clinical response. Two years later, the patient presented with foamy urine, nocturia, sweating and dizziness. An elevated C-reactive protein (CRP), erythrocyte sedimentation rate and nephrotic-range proteinuria were found. Rectal and oral mucosa biopsies were performed and amyloid AA deposits were detected in both (Fig. 1A, B). Magnetic resonance imaging (MRI) of the right knee showed arthropathy due to amyloid deposition (Fig. 2). Intravenous monthly tocilizumab was prescribed with rapid improvement of CRP, proteinuria (Fig. 3) and nephrotic syndrome symptoms. Arthritis also improved significantly. Two years later, a new biopsy of the rectal mucosa did not show amyloid deposits (Fig. 1C, D) and right knee MRI was normal, without evidence of amyloid synovitis (Fig. 4). Eight years later, the patient continues treatment with tocilizumab and remains clinically stable, with no evidence of recurrence. Literature review: The efficacy of tocilizumab has been described mainly in patients with rheumatoid arthritis, but also in AA amyloidosis secondary to systemic juvenile idiopathic arthritis, familial Mediterranean fever, psoriatic arthritis, ankylosing spondylitis, Still's disease, Muckle-Wells syndrome, Behçet syndrome, polyarteritis nodosa and Takayasu arteritis. Some of the studies report long-term effectiveness of up to 9 years. In 11 case reports of patients with AA amyloidosis treated with tocilizumab, a follow-up biopsy was performed and a reduction or disappearance of the deposits was also observed. Lane et al. analyzed pre- and on-treatment serial scintigraphy scans in 20 patients with AA amyloidosis, showing that AA amyloid deposits either regressed or did not increase whilst on tocilizumab. We have not identified any study demonstrating the disappearance of amyloid arthropathy in MR images. Conclusion Tocilizumab treatment controls chronic inflammatory disease and improves symptoms of AA amyloidosis. Long-term treatment with tocilizumab may remove amyloid deposits from tissues, leading to a definitive cure of this disease.

Early Development and Pre-Clinical Evaluation of a Fluorine-18 Labeled Peptide p5+14 for PET/CT Imaging of Cardiac Amyloidosis

Background:Systemic amyloidosis is a rare protein misfolding disorder, where patients can present with varied symptoms due to the diverse organ involvement. This is particularly true of patients with light chain associated (AL) amyloidosis, which makes early and accurate diagnosis challenging. Currently there are no FDA-approved methods that allow visualization of amyloidosis in patients. Nuclear imaging is a promising method for early detection of amyloid. We have developed a novel amyloid-reactive peptide, designated p5+14, capable of binding AL, as well as other types of amyloid, via multivalent electrostatic interactions. Peptide p5+14 has been successfully radiolabeled with radioiodine and technetium-99m and evaluated clinically, labeled with iodine-124, in a PET/CT imaging study of patients with amyloidosis (NCT03678259). While there are numerous advantages to using I-124 as the radionuclide for amyloid imaging, fluorine is a viable alternative for detecting cardiac amyloidosis. Fluorine-18 has a shorter half-life (108 min as compared to 4.2 days) thus reducing the internal radiation dose to patients. Moreover, F-18 is the most common nuclide used in PET imaging. We have previously generated a 18F-labeled variant of p5+14; however, the reaction was inefficient and not translatable. Here we present a novel development strategy for generating 18F labeled p5+14 using a commercially available precursor that can bind AL amyloid and perform initial characterization of the reagent in a murine model of inflammation-associated systemic AA amyloidosis. Methods: Isotopic exchange chemistry using a silicon-fluoride-acceptor (SiFA) method was used to label peptide p5+14 with F-18. The peptide precursor was purchased from Almac Life Sciences (Penicuik, UK). 18F was purchased from PetNet (Siemens Healthineers, Knoxville, TN) and prepared for reaction according to standard methods. After drying, F-18 (1000 - 1900 MBq ) was dissolved in anhydrous acetonitrile and the pH neutralized before the addition of peptide precursor. Radiolabeling was performed at room temperature for 5 min. After standard purification of the product, radiochemical purity studies demonstrated that it was stable, with no significant loss of F-18 for at least 5 hours. Radiofluorinated p5+14 was assessed in bioactivity “pulldown” assays to ensure binding to synthetic AL amyloid-like fibrils and human AL amyloid extracts. The radiolabeled peptide was also diluted in PBS and injected IV in the lateral tail vein of mice with severe systemic AA amyloidosis. After 1 h, mice were euthanized small animal PET/CT imaging performed and tissue biodistribution measurements were conducted using an automated Wizard 3 gamma counter (1480 Wallac Gamma Counter, Perkin-Elmer). Results: Using optimized synthesis conditions, the non-decay corrected radiochemical yield was 55±4.5%. Radiochemical purity was 99±1% at end of synthesis. Peptide purity was shown to be 93.7±4.9% by assessed using HPLC. Radiochemical stability was similarly evaluated using an HLPC method and remained >97.5% radiochemical purity at 5 hours after synthesis. The binding of 18F-p5+14 to synthetic AL amyloid like fibrils composed of a l6 variable domain was 96.2%, mimicking data using the radioiodinated peptide, and 87.2% to human AL amyloid extracts. Background binding to control beads was 17.4%. In mice, accumulation of 18F-peptide in the liver and spleen, the organs with most AA amyloid deposits in this mouse model, was readily evident in PET images taken 1 h post injection. There was also evidence of hepatic clearance of the peptide, manifest as a prominent gall bladder in the images. There was no accumulation of F-18 in bone, indicating positive in vivo stability. Imaging of amyloid-free wild type mice showed rapid clearance with radioactivity in the urinary bladder, gall bladder and gastrointestinal tract with little or no hepatosplenic radiotracer retention. Conclusion: Radiofluorination of peptides, such as p5+14, has been made more efficient through the use of novel precursors amenable to isotopic exchange. 18F-peptide binds amyloid effectively and may serve as a next generation radiotracer for the detection of cardiac amyloid by PET/CT imaging. Acknowledgments: EW is a doctoral student in the Comparative and Experimental Medicine Program. This study was supported by the Amyloidosis and Cancer Theranostics Program and the UTGSM.

Histological evaluation of the distribution of systemic AA-amyloidosis in nine domestic shorthair cats.

Amyloidosis is a group of protein-misfolding disorders characterized by the accumulation of amyloid in organs, both in humans and animals. AA-amyloidosis is considered a reactive type of amyloidosis and in humans is characterized by the deposition of AA-amyloid fibrils in one or more organs. In domestic shorthair cats, AA-amyloidosis was recently reported to be frequent in shelters. To better characterize this pathology, we report the distribution of amyloid deposits and associated histological lesions in the organs of shelter cats with systemic AA-amyloidosis. AA-amyloid deposits were identified with Congo Red staining and immunofluorescence. AA-amyloid deposits were then described and scored, and associated histological lesions were reported. Based on Congo Red staining and immunofluorescence nine shelter cats presented systemic AA-amyloidosis. The kidney (9/9), the spleen (8/8), the adrenal glands (8/8), the small intestine (7/7) and the liver (8/9) were the organs most involved by amyloid deposits, with multifocal to diffuse and from moderate to severe deposits, both in the organ parenchyma and/or in the vascular compartment. The lung (2/9) and the skin (1/8) were the least frequently involved organs and deposits were mainly focal to multifocal, mild, vascular and perivascular. Interestingly, among the organs with fibril deposition, the stomach (7/9), the gallbladder (6/6), the urinary bladder (3/9), and the heart (6/7) were reported for the first time in cats. All eye, brain and skeletal muscle samples had no amyloid deposits. An inflammatory condition was identified in 8/9 cats, with chronic enteritis and chronic nephritis being the most common. Except for secondary cell compression, other lesions were not associated to amyloid deposits. To conclude, this study gives new insights into the distribution of AA-amyloid deposits in cats. A concurrent chronic inflammation was present in almost all cases, possibly suggesting a relationship with AA-amyloidosis.

Renal failure and pleural effusion; a diagnostic challenge

Sjögren’s syndrome is a chronic inflammatory disorder mostly involving the exocrine glands. Extraglandular disease may occur in up to one quarter of patients. Kidney involvement is rare, more often manifested by tubular dysfunction secondary to tubulointerstitial nephritis. Primary glomerular disease is uncommon. The authors present the case of a 73-year-old woman with xerostomia and positivity for anti-Ro and anti-La antibodies admitted for acute kidney injury and exudative pleural effusion. Biopsy of salivary glands was compatible with Sjögren’s syndrome. Extraglandular involvement was also confirmed by renal and pleural deposition of AA-amyloid. The patient was started on prednisolone followed by azathioprine with rapid improvement of lung disease. However, due to progressing renal disease and clinical deterioration, prognosis was guarded and the patient died. We describe a case of secondary amyloidosis with systemic involvement and infrequent clinical manifestations, briefly reviewing the key aspects of Sjögren’s syndrome and AA-amyloidosis.

Rapid Clinical Improvement of Multicentric Castleman Disease (MCD) with Renal Involvement Following Treatment with Tocilizumab: AA Amyloidosis as a Possible Renal Involvement of MCD.

Castleman disease (CD) is a lymphoproliferative disorder that manifests as hypergammaglobulinemia and severe inflammation with multiorgan involvement. However, renal involvement has been infrequently described in CD. We present a case of a 63-year-old Japanese male patient with multicentric CD (MCD) in whom kidney involvement, including impaired renal function and massive proteinuria, is present. He had a 2-year history of inflammatory arthritis and was referred to our clinic with newly developed proteinuria, renal dysfunction, and elevated levels of acute-phase proteins. Abdominal computed tomography scan revealed hepatosplenomegaly, including mesenteric and inguinal lymph node enlargements. The patient underwent inguinal lymph node resection. Excisional biopsy of the inguinal lymph node showed multiple lymphoid follicles and expansion of interfollicular areas by marked plasmacytosis consistent with mixed type CD. The patient was diagnosed with human herpes virus 8-negative MCD according to the international diagnostic criteria for CD. Diagnostic renal biopsy was not performed following the medical viewpoint. Tocilizumab (TCZ) treatment was highly effective in reducing proteinuria and stabilizing renal function, as well as improving other clinical symptoms. The patient responded to TCZ treatment, and the renal involvement was rapidly improved. Our preliminary immunohistochemical analysis indicated AA amyloid deposits in urinary epithelial cells suggesting a possible renal involvement of AA amyloidosis. TCZ could potentially be one of the therapeutic options in patients with MCD with renal involvement.

Gastrointestinal AA amyloidosis secondary to chronic pyelonephritis presenting with refractory diarrhea and severe hypoalbuminemia

Secondary amyloidosis is a rare complication of chronic inflammatory diseases, such as collagen diseases, and is often difficult to treat. In addition, the gastrointestinal tract is frequently involved in amyloid deposition that often results in various disorders and symptoms. A 70-year-old woman was admitted to our hospital with refractory diarrhea and hypoalbuminemia. Abdominal computed tomography demonstrated extensive edematous wall thickening of the small intestine and colon. Video capsule endoscopy revealed multiple ulcerations with a white mossy appearance of the ileum. Double-balloon endoscopy showed severe circumferential ulcers in the entire ileum. Histological examination of ileum biopsy samples revealed severe amyloid deposition in the lamina propria and perivascular areas of the submucosa. The patient was diagnosed with gastrointestinal AA amyloidosis. The cause of AA amyloid deposition was presumed to be chronic pyelonephritis due to ureteral stones that had been left untreated for 35years. After treatment with ureteral drainage and antibiotics, the patient's symptoms and serological abnormalities improved dramatically. Here, we describe a case of severe gastrointestinal AA amyloidosis secondary to chronic pyelonephritis. Clinicians should thoroughly investigate the entire gastrointestinal tract in patients with refractory diarrhea and severe hypoalbuminemia considering the possibility of gastrointestinal amyloidosis.

Characterization of G‐quadruplex Structures in Serum Amyloid A Gene as a Novel Approach for Systemic Amyloidosis Therapy

Transcriptional initiation is an important step in the regulation of transcription. When transcriptional initiation is dysfunctional, it will lead to abnormal gene expression. Overexpression of Serum Amyloid A (SAA) and self-assembly into fibrils have been associated with chronic inflammatory conditions and certain neoplasms, which lead to the deposition of AA amyloid in organs such as the liver, spleen, and kidney (systemic amyloidosis). For this reason, SAA is a highly significant molecular target. Insight into the structural biology of the promoter element that determines the combinatorial control of gene expression by different transcriptional factors is essential for understanding the dysfunction of SAA gene expression. The highly GC-rich region of the human SAA promoter is crucial for basal promoter activity and likely to assume a DNA secondary structure, such as G-quadruplex (GQ). GQs often serve as transcriptional silencer elements. Stabilization of GQ is possible with small molecule therapeutics to modulate gene expression. In the present study, G-quadruplex formation has been isolated from the GC-rich region of the 5’-untranslated region (5’UTR) of SAA2. An electrophoretic mobility shift and thioflavin T fluorescence assays were used to confirm the formation of a biologically relevant intramolecular structure. The structure of the G-quadruplex is currently under investigation by circular dichroism and DMS footprinting. These data characterizing the formation of a unique secondary structure in SAA gene are promising to develop novel anti-amyloid therapy for the treatment of systemic amyloidosis.

AA Amyloid Deposition in the Central and Peripheral Nervous Systems in Flamingos.

AA amyloidosis is characterized by amyloid deposition in systemic organs, but amyloid deposition in the central nervous system (CNS) or peripheral nervous system (PNS) is rare. In this study, AA amyloidosis was observed in 31 of 48 flamingos that died at a Japanese zoo. Almost all cases developed AA amyloidosis secondary to inflammatory diseases such as enteritis. Affected flamingos had AA amyloid deposition around blood vessels in periventricular white matter of the brain and in peripheral nerves. In addition, cerebral Aβ amyloidosis was observed in one of the 31 cases with AA amyloidosis. In conclusion, flamingos in the zoo commonly developed systemic amyloidosis with frequent amyloid deposition in the CNS and PNS, which seems to be a unique distribution in this avian species. Comparative pathological analyses in flamingos may help elucidate the pathogenesis of amyloid neuropathy.

Description of rare clinical case of AA-amyloidosis with involvement in pathological process of heart and lungs

Amyloidosis is a unique group of disorders caused by the insoluble protein fibers accumulation known as amyloid fibrils in extracellular tissue and organ spaces. The involvement of different organs and tissues in amyloidosis is often the cause of missed or delayed diagnosis, and amyloidosis remains a major clinical problem as it is associated with 1/1,000 deaths in developed countries. We present a case of a 59-year-old female patient with complaints of breath shortness while talking, a sense of air lack in the horizontal position, swelling of the lower limbs, reduction of blood pressure to a minimum of 70/50 mm Hg, weight reduction by 7 kg in 6 months, dizziness. The patient was hospitalized to the Cardiology Department of Scientific Research Institute – Ochapovsky Regional Clinical Hospital #1 with heart failure. The electrocardiogram revealed left ventricular hypertrophy. Echocardiography showed biventricular myocardial hypertrophy with a maximum interventricular septum thickness of 16 mm, nonuniform ventricular myocardial structure and reduction of global left ventricular comparability to 38%. Computer tomography of chest organs demostrated interstitial swelling of parenchyma of both lungs. The infection during the further examination. For the final morphological verification of the diagnosis, it was necessary to perform peripheral transbronchial biopsy S 3, 4, 5 of the left lung and myocardial biopsy with specific staining on amyloid-congo – red. In the lung and myocardial biopsy, the colour of the congo red is positive. An immunohistochemical study of the lung tissue and myocardial sample revealed Amyloid AA expression. This case represents a rare cause of heart failure in a woman. A feature of this observation is the rare involvement in the pathological process of both pulmonary tissue and myocardium with AA-amyloid deposition.

Clinical Profile of Patients with Head and Neck Amyloidosis: A Single-Institution Retrospective Chart Review.

Introduction Isolated amyloidosis involving the head and neck is a rare entity. The pathophysiology of the localized disease appears to be distinct from that of the systemic counterpart. Systemic progression of the localized disease is unusual, and the prognosis of the localized form is excellent. Objective To describe the demographic and clinicopathological characteristics of patients presenting with localized head and neck subsite amyloidosis. Methods A retrospective chart review of the patients with head and neck amyloidosis identified by the electronic search of the electronic database of the Departments of Pathology and Otorhinolaryngology was performed. The various demographic and clinical data were tabulated. Results In total, seven patients (four females, three males) with localized head and neck amyloidosis (three supraglottic, three lingual and one sinonasal) were identified. Six patients had AL-amyloid deposits, and one patient had AA-amyloid deposits. Supraglottic involvement and that of the base of the tongue were treated surgically using CO2 laser, and these patients were disease-free at the last follow-up. The patient with sinonasal amyloidosis experienced symptom recurrence after six months of the functional endoscopic sinus surgery. All of the patients were screened for systemic amyloidosis with abdominal fat pad biopsy, and were found to be free of systemic spread. Conclusion Isolated head and neck amyloidosis, as opposed to systemic amyloidosis, has an excellent prognosis in terms of survival. Therefore, systemic amyloidosis should be excluded in all cases. The treatment of choice remains surgical excision; however, watchful waiting may be a suitable strategy for mild symptoms or for cases in which the disease was discovered incidentally.

Synchronous Unicentric Castleman Disease and Inflammatory Hepatocellular Adenoma: a Case Report

Systemic symptoms such as fever and fatigue are non-specific manifestations spanning from inflammation to neoplasia. Here we report the case of a 34 year-old man who presented with systemic symptoms for four months. CT-scan and MRI revealed a 3.4 cm arterialized hepatic lesion and a 7 cm paraduodenal mass. Surgical resection of both lesions and histological examination revealed an inflammatory hepatocellular adenoma and a unicentric plasma cell type of Castleman disease. Moreover, a diffuse AA amyloid deposition in the liver was observed. Resection of both lesions was associated with an improvement of the symptoms. To our knowledge, this is the first report of a synchronous presentation of a unicentric plasma cell type of Castleman disease, inflammatory hepatocellular adenoma and AA amyloidosis.

Apolipoprotein A-II induces acute-phase response associated AA amyloidosis in mice through conformational changes of plasma lipoprotein structure

During acute-phase response (APR), there is a dramatic increase in serum amyloid A (SAA) in plasma high density lipoproteins (HDL). Elevated SAA leads to reactive AA amyloidosis in animals and humans. Herein, we employed apolipoprotein A-II (ApoA-II) deficient (Apoa2−/−) and transgenic (Apoa2Tg) mice to investigate the potential roles of ApoA-II in lipoprotein particle formation and progression of AA amyloidosis during APR. AA amyloid deposition was suppressed in Apoa2−/− mice compared with wild type (WT) mice. During APR, Apoa2−/− mice exhibited significant suppression of serum SAA levels and hepatic Saa1 and Saa2 mRNA levels. Pathological investigation showed Apoa2−/− mice had less tissue damage and less inflammatory cell infiltration during APR. Total lipoproteins were markedly decreased in Apoa2−/− mice, while the ratio of HDL to low density lipoprotein (LDL) was also decreased. Both WT and Apoa2−/− mice showed increases in LDL and very large HDL during APR. SAA was distributed more widely in lipoprotein particles ranging from chylomicrons to very small HDL in Apoa2−/− mice. Our observations uncovered the critical roles of ApoA-II in inflammation, serum lipoprotein stability and AA amyloidosis morbidity, and prompt consideration of therapies for AA and other amyloidoses, whose precursor proteins are associated with circulating HDL particles.

A Peptide-Fc Opsonin with Pan-Amyloid Reactivity.

There is a continuing need for therapeutic interventions for patients with the protein misfolding disorders that result in systemic amyloidosis. Recently, specific antibodies have been employed to treat AL amyloidosis by opsonizing tissue amyloid deposits thereby inducing cell-mediated dissolution and organ improvement. To develop a pan-amyloid therapeutic agent, we have produced an Fc-fusion product incorporating a peptide, p5, which binds many if not all forms of amyloid. This protein, designated Fcp5, expressed in mammalian cells, forms the desired bivalent dimer structure and retains pan-amyloid reactivity similar to the p5 peptide as measured by immunosorbent assays, immunohistochemistry, surface plasmon resonance, and pulldown assays using radioiodinated Fcp5. Additionally, Fcp5 was capable of opsonizing amyloid fibrils in vitro using a pH-sensitive fluorescence assay of phagocytosis. In mice,125 I-labeled Fcp5 exhibited an extended serum circulation time, relative to the p5 peptide. It specifically bound AA amyloid deposits in diseased mice, as evidenced by biodistribution and microautoradiographic methods, which coincided with an increase in active, Iba-1-positive macrophages in the liver at 48 h postinjection of Fcp5. In healthy mice, no specific tissue accumulation was observed. The data indicate that polybasic, pan-amyloid-targeting peptides, in the context of an Fc fusion, can yield amyloid reactive, opsonizing reagents that may serve as next-generation immunotherapeutics.

The pattern recognition reagents RAGE VC1 and peptide p5 share common binding sites and exhibit specific reactivity with AA amyloid in mice

In the US, there remains a need to develop a clinical method for imaging amyloid load in patients with systemic, visceral amyloidosis. The receptor for advanced glycation end products (RAGE), which exists as a transmembrane receptor and soluble variant, is found associated with a number of amyloid deposits in man. It is unclear whether amyloid-associated RAGE is the membrane or soluble form; however, given the affinity of RAGE for amyloid, we have examined the ability of soluble RAGE VC1 to specifically localize with systemic AA amyloid in mice. We further compared the reactivity of RAGE VC1 with that of the synthetic, amyloid-reactive peptide p5.Methods: Binding of radiolabeled RAGE VC1 and p5 to synthetic amyloid fibrils was evaluated using in vitro “pulldown” assays in the presence or absence of RAGE ligands. Radioiodinated RAGE VC1 and technetium-99 m-labeled p5 were studied in mice with systemic AA amyloidosis using dual-energy SPECT/CT imaging, biodistribution and microautoradiography.Results: Soluble RAGE VC1 competed with radioiodinated peptide p5 for binding to rVλ6Wil, Aβ (1–40) and IAPP fibrils but not with the higher affinity peptide, p5R. Pre-incubation with AGE-BSA abrogated binding of VC1 and p5 to rVλ6Wil fibrils. Dual-energy SPECT/CT images and quantitative tissue biodistribution data showed that soluble RAGE VC1 specifically bound AA amyloid-laden organs in mice as effectively as peptide p5. Furthermore, microautoradiography confirmed that RAGE VC1 bound specifically to areas of Congo red-positive amyloid in mouse tissues but not in comparable tissues from control WT mice.Conclusion: Soluble RAGE VC1 and peptide p5 have similar ligand binding properties and specifically localize with visceral AA amyloid deposits in mice.

Experimental transmission of AA amyloidosis by injecting the AA amyloid protein into interleukin-1 receptor antagonist knockout (IL-1raKO) mice.

The incidence of AA amyloidosis is high in humans with rheumatoid arthritis and several animal species, including cats and cattle with prolonged inflammation. AA amyloidosis can be experimentally induced in mice using severe inflammatory stimuli and a coinjection of AA amyloid; however, difficulties have been associated with transmitting AA amyloidosis to a different animal species, and this has been attributed to the "species barrier." The interleukin-1 receptor antagonist knockout (IL-1raKO) mouse, a rodent model of human rheumatoid arthritis, has been used in the transmission of AA amyloid. When IL-1raKO and BALB/c mice were intraperitoneally injected with mouse AA amyloid together with a subcutaneous pretreatment of 2% AgNO3, all mice from both strains that were injected with crude or purified murine AA amyloid developed AA amyloidosis. However, the amyloid index, which was determined by the intensity of AA amyloid deposition, was significantly higher in IL-1raKO mice than in BALB/c mice. When IL-1raKO and BALB/c mice were injected with crude or purified bovine AA amyloid together with the pretreatment, 83% (5/6 cases) and 38% (3/8 cases) of IL-1raKO mice and 17% (1/6 cases) and 0% (0/6 cases) of BALB/c mice, respectively, developed AA amyloidosis. Similarly, when IL-1raKO and BALB/c mice were injected with crude or purified feline AA amyloid, 33% (2/6 cases) and 88% (7/8 cases) of IL-1raKO mice and 0% (0/6 cases) and 29% (2/6 cases) of BALB/c mice, respectively, developed AA amyloidosis. These results indicated that IL-1raKO mice are a useful animal model for investigating AA amyloidogenesis.

Failure of heterogeneous amyloid-enhancing factor in geriatric squirrel monkeys (Saimiri boliviensis).

Cross-species transmission of AA amyloidosis between primates and other animals has not been previously reported. Eight geriatric squirrel monkeys were intravenously administered chimpanzee, bovine, or chicken amyloid fibrils and simultaneously received inflammatory stimulation. AA amyloid deposition was not detected in any of the monkeys histopathologically or immunohistochemically. These results suggest that heterogeneous AA amyloidosis may not be easily transmitted into primates.

Renal involvement in secondary amyloidosis of Muckle-Wells syndrome: marked improvement of renal function and reduction of proteinuria after therapy with human anti-interleukin-1β monoclonal antibody canakinumab

Muckle-Wells syndrome (MWS) is a rare hereditary autoinflammatory disorder characterized by recurrent urticaria-like skin rashes, arthralgias, conjunctivitis, hypoacusia, and risk of reactive AA amyloidosis due to the progressive accumulation of amyloid fibrils in different organs. Its genetic defect lies in mutations in the NLRP3 gene, encoding the cryopyrin protein, and resulting in interleukin (IL)-1β oversecretion. Renal involvement, in terms of proteinuria or renal insufficiency, can be observed in up to 25% of patients. Herein, we describe our experience with two Caucasian patients, father and son, aged 52 and 26 years, respectively, heterozygous for both V198M and R260W NLRP3 mutations who had AA amyloid deposits on renal biopsy. The fully human monoclonal antibody canakinumab, providing selective and prolonged IL-1β blockade, was administered in both patients every 60 days over a period of 18 months. This treatment allowed to obtain amazing results: a rapid disappearance of any clinical symptoms, the stable normalization of serum amyloid-A and, furthermore, a marked improvement of glomerular filtration rate and proteinuria with no adverse events. Our data, though limited to only two patients, emphasize that therapeutic intervention with canakinumab, suppressing both inflammation and IL-1β-mediated manifestations, can contribute to improve kidney function in MWS with overt renal amyloidosis.

Therapeutic Benefits of Tocilizumab Vary in Different Organs of a Patient with AA Amyloidosis.

Systemic reactive AA amyloidosis is a life-threatening complication of chronic inflammatory diseases. Anti-interleukin-6 receptor, tocilizumab (TCZ), has been shown to improve clinical symptoms of patients with AA amyloidosis, accompanied with regression of the amyloid deposition. We report a case of AA amyloidosis evaluated by histology of multiple organs before and after TCZ treatment. A woman in her 60s with rheumatoid arthritis was referred to our hospital because of cardiac and renal dysfunction. A gastric and renal biopsy revealed the deposition of AA amyloid, and echocardiography revealed concentric left ventricular hypertrophy. Her estimated glomerular filtration rate was decreased to 8.6 mL/min/1.73 m2, and B-type natriuretic peptide, C-reactive protein, and serum amyloid A protein were significantly elevated. TCZ treatments markedly decreased her serum amyloid A protein and C-reactive protein levels, but hemodialysis was required 1 year later. Endoscopic gastric rebiopsy 3 years after initiation of TCZ treatments revealed the regression of amyloid deposition and echocardiography revealed improvement of her left ventricular hypertrophy. However, a renal rebiopsy revealed that the amyloid deposition had not regressed. In conclusion, these observations suggest that the therapeutic effects of TCZ can vary among organs in patients with AA amyloidosis.

Graft pyelonephritis causing graft failure from de novo AA amyloid

A 59-year-old man with end-stage renal failure secondary to autosomal dominant polycystic kidney disease received a renal transplant in 1994. Between 2008 and 2010 he developed recurrent, microbiologically proven episodes of urosepsis associated with a ureteric stricture, which required balloon ureteroplasty, insertion of a JJ stent, and finally a doubleended Memokath. Despite this, graft function continued to decline with nephrotic-range proteinuria, and in 2011 he recommenced hemodialysis. Ongoing episodes of urosepsis necessitated graft nephrectomy. The septic episodes subsequently abated and inflammatory markers normalized. Histology of the kidney revealed scarring and an accumulation of eosinophilic material in the glomeruli and vessel walls, which stained positive for Congo red (Figure 1a and b). Immunohistochemisty for AA amyloid was positive. It appears that AA amyloid deposition resulting from chronic graft pyelonephritis was the cause of this patient’s nephrotic-range proteinuria and, ultimately, graft failure. There have been very few case reports of de novo AA amyloid in renal allografts, and in these cases it has occurred in patients with chronic infective or inflammatory conditions that were present before transplantation. To our knowledge, this is the first case of de novo AA amyloid in a transplanted kidney not associated with a pre-existing chronic inflammatory or immune disorder. http://www.kidney-international.org n e p h r o l o g y i m a g e

Serum amyloid A renal amyloidosis in a chronic subcutaneous ("skin popping") heroin user.

Systemic AA amyloidosis is a long-term complication of several chronic inflammatory disorders. Organ damage results from the extracellular deposition of proteolytic fragments of the acute-phase reactant serum amyloid A (SAA) as amyloid fibrils. Drug users that inject drug by a subcutaneous route ("skin popping") have a higher chance of developing secondary amyloidosis. The kidneys, liver, and spleen are the main target organs of AA amyloid deposits. More than 90% of patients with renal amyloidosis will present with proteinuria, nephrotic syndrome, or renal function. A 37 year-old female presented to the hospital with a one-week history of pain and redness in her right axilla. Her relevant medical history included multiple skin abscesses secondary to "skin popping", heroin abuse for 18 years, and hepatitis C. The physical examination revealed "skin popping" lesions, bilateral costovertebral angle tenderness, and bilateral knee swelling. The laboratory workup was significant for renal insufficiency with a serum creatinine of 5 mg/dL and 14.8 grams of urine protein per 1 gram of urine creatinine. The renal biopsy findings were consistent with a diagnosis of renal amyloidosis due to serum amyloid A deposition and acute tubulointerstitial nephritis. AA renal amyloidosis among heroin addicts seems to be associated with chronic suppurative skin infection secondary to "skin popping". It is postulated that the chronic immunologic stimulation by one or more exogenous antigens or multiple acute inflammatory episodes is an important factor in the pathogenesis of amyloidosis in these patients. Therefore, AA renal amyloidosis should always be considered in chronic heroin users presenting with proteinuria and renal impairment.