Unveiling renal pathology's potential: exploring a rare subtype of amyloid - apolipoprotein CII amyloidosis in the youngest patient: a case report and literature review

In this clinical case report, we present a rare subtype of amyloidosis, apolipoprotein CII (apo CII), which was diagnosed through a renal biopsy and subsequently confirmed by identifying the p.K41T mutation via germline DNA sequencing. Upon reviewing the literature, five patients exhibiting identical mutation were identified via renal biopsy, while an additional patient was diagnosed through biopsies of the fat pad and bone marrow. Notably, our patient is the youngest recorded case. We pioneered the application of immunofluorescence and immunogold electron microscopy techniques for apo CII evaluation. Our report provides a detailed description of this case, supplemented by an extensive review encompassing apo CII, documented instances of apo CII amyloidosis with renal or systemic involvement, and potential underlying mechanisms.

Secondary renal amyloidosis due to primary Sjogren's syndrome: a case report

Amyloidosis is a rare disorder characterized by the deposition of abnormal proteins in extracellular tissues, resulting in the dysfunction of vital organs and, eventually, death. The occurrence of amyloidosis due to primary Sjogren's syndrome (pSS) is a rare finding. This study describes a rare case of pSS complicated by amyloid-associated amyloidosis.

Case presentation

A 35-year-old male was diagnosed with nephrotic syndrome and secondary amyloidosis caused by pSS. He had microscopic hematuria, a creatinine level of 6.59 mg/dl, and an elevated erythrocyte sedimentation rate of 107 mm/hrs. Furthermore, investigations of antinuclear antibodies, antimitochondrial antibodies, SSA, SSA native, and Ro-52 recombinant as well as rheumatoid factor showed positive results. After establishing the diagnosis of pSS through clinical, physical, and laboratory assessments, a renal biopsy was performed, which revealed the occurrence of secondary amyloidosis.

Clinical discussion

The risk of developing secondary amyloidosis depends on the extent of elevated serum amyloid levels as well as persistent subclinical inflammation. The definitive diagnosis of amyloidosis requires histological confirmation of amyloid fibril deposition in tissue.

Conclusion

Secondary renal amyloidosis is an unusual condition in patients with pSS. Still, it should be regarded in the differential diagnosis of patients with proteinuria and/or renal failure, and a renal biopsy should be performed.

Non-Perturbative Identification and Subtyping of Amyloidosis in Human Kidney Tissue with Raman Spectroscopy and Machine Learning

Amyloids are proteins with characteristic beta-sheet secondary structures that display fibrillary ultrastructural configurations. They can result in pathologic lesions when deposited in human organs. Various types of amyloid protein can be routinely identified in human tissue specimens by special stains, immunolabeling, and electron microscopy, and, for certain forms of amyloidosis, mass spectrometry is required. In this study, we applied Raman spectroscopy to identify immunoglobulin light chain and amyloid A amyloidosis in human renal tissue biopsies and compared the results with a normal kidney biopsy as a control case. Raman spectra of amyloid fibrils within unstained, frozen, human kidney tissue demonstrated changes in conformation of protein secondary structures. By using t-distributed stochastic neighbor embedding (t-SNE) and density-based spatial clustering of applications with noise (DBSCAN), Raman spectroscopic data were accurately classified with respect to each amyloid type and deposition site. To the best of our knowledge, this is the first time Raman spectroscopy has been used for amyloid characterization of ex vivo human kidney tissue samples. Our approach, using Raman spectroscopy with machine learning algorithms, shows the potential for the identification of amyloid in pathologic lesions.

Long-term results of kidney transplantation in patients with familial mediterranean fever

INTRODUCTION

Long-term kidney transplantation (KT) results in patients with familial Mediterranean fever (FMF)-related amyloidosis are not well studied. This study reviewed the long-term survival outcomes of FMF patients who underwent KT.

METHODS

We compared the outcomes of 31 patients who underwent (KT) for biopsy-proven amyloidosis secondary to FMF with 31 control patients (five with diabetes mellitus and 26 with nondiabetic kidney disease) undergoing KT between 1994 and 2021 at Başkent University Hospital. All data were recorded retrospectively from patients' files.

RESULTS

THE MEDIAN AGE (QUARTILE DEVIATION: QD) at the time of KT in the FMF and control group were 31 (6.7) and 33 (11), respectively. The median follow-up period (QD) after KT was 108 (57) months in the FMF and 132 (72) months in the control group. In the FMF group, graft and patient survivals were 71% and 84% at 5 years and 45% and 48% at 10 years, respectively. In the control group, graft and patient survivals were 79% and 100% at 5 years and 63% and 71% at 10 years, respectively. Patient survival in the FMF group at 5 years was significantly lower than in the control group (p = .045). There was no statistically significant difference between the FMF and control groups in terms of graft and patient survival, and serum creatinine levels at 10 years. All patients were given triple immunosuppressive treatment with cyclosporine, mycophenolate mofetil, and prednisolone. Three patients received anakinra and one received canakinumab in addition to colchicine treatment. One FMF patient also underwent heart transplantation due to AA amyloidosis. Of the FMF patients, 11 died during follow-up.

CONCLUSION

We have found that the long-term outcome of KT in patients with FMF amyloidosis is numerically worse but not statistically different from the control group. However, short- and long-term complications still need to be resolved.

Clinicopathological Profile of Paraprotein-Associated Kidney Disease in Monoclonal Gammopathies: An Observational Study

Background Renal involvement in monoclonal gammopathies presents with different clinico-morphological patterns and can manifest at the onset or the late phase of hematological disease, or after chemotherapy. The spectrum is ever-expanding with advancements in diagnostic methods. Renal biopsy is needed for accurate diagnosis, as each of these patterns carries therapeutic and prognostic implications. Methods A total of 41 cases of monoclonal gammopathies were included in the study. Clinical, biochemical, and hematological details were obtained, and pathological variables were observed. Patients were followed till the maximum possible period, and treatment history and follow-up creatinine details were collected. Results The spectrum of renal biopsy lesions observed included light chain cast nephropathy (LCCN) n=19, amyloidosis n=11, monoclonal immunoglobulin deposition disease (MIDD) n=6, and proliferative glomerulonephritis with monoclonal immunoglobulin deposition (PGNMID) n=5; 10 of these cases can be categorized as monoclonal gammopathy of renal significance (MGRS). Acute kidney injury (AKI) (41%) is the predominant clinical presentation in general whereas the majority of amyloidosis cases presented with nephrotic and sub-nephrotic proteinuria. LCCN cases had high serum creatinine and calcium, positivity for M-spike, as well as a high FLC ratio, compared to the other types. Around 100% of LCCN and MIDD patients had myeloma and 100% of PGNMID cases had normal marrow. Conclusion More than three-fourths of patients were diagnosed with monoclonal gammopathies with biochemical and hematological workups after an initial kidney biopsy. The clinicopathological profile of these patients had a broad spectrum but there were still some consistent findings within the different types. A subgroup of patients (MGRS) had undetectable serum paraproteins but had monoclonal immunoglobulin deposition in the kidney.

Renal amyloidosis: a new time for a complete diagnosis

Amyloidoses are a group of disorders in which soluble proteins aggregate and deposit extracellularly in tissues as insoluble fibrils, causing organ dysfunction. Clinical management depends on the subtype of the protein deposited and the affected organs. Systemic amyloidosis may stem from anomalous proteins, such as immunoglobulin light chains or serum amyloid proteins in chronic inflammation or may arise from hereditary disorders. Hereditary amyloidosis consists of a group of rare conditions that do not respond to chemotherapy, hence the identification of the amyloid subtype is essential for diagnosis, prognosis, and treatment. The kidney is the organ most frequently involved in systemic amyloidosis. Renal amyloidosis is characterized by acellular pathologic Congo red-positive deposition of amyloid fibrils in glomeruli, vessels, and/or interstitium. This disease manifests with heavy proteinuria, nephrotic syndrome, and progression to end-stage kidney failure. In some situations, it is not possible to identify the amyloid subtype using immunodetection methods, so the diagnosis remains indeterminate. In cases where hereditary amyloidosis is suspected or cannot be excluded, genetic testing should be considered. Of note, laser microdissection/mass spectrometry is currently the gold standard for accurate diagnosis of amyloidosis, especially in inconclusive cases. This article reviews the clinical manifestations and the current diagnostic landscape of renal amyloidosis.

A multicenter study of the clinical, laboratory characteristics, and potential prognostic factors in patients with amyloid A amyloidosis on hemodialysis

INTRODUCTION

While light chain (AL) amyloidosis is more common in western countries, the most common type of amyloidosis is amyloid A (AA) amyloidosis in Eastern Mediterranean Region, including Turkey. Although worse prognosis has been attributed to the AL amyloidosis, AA amyloidosis can be related to higher mortality under renal replacement therapies. However, there are no sufficient data regarding etiology, clinical presentation, and prognostic factors of AA amyloidosis. The objective of our study is to evaluate the clinical, laboratory characteristics, and possible predictive factors related to mortality in patients with AA amyloidosis undergoing hemodialysis (HD).

METHODS

This multicenter, cross-sectional study was a retrospective analysis of 2100 patients on HD. It was carried out in 14 selected HD centers throughout Turkey. Thirty-two patients with biopsy-proven AA amyloidosis and thirty-two control patients without AA amyloidosis undergoing HD were included between October 2018 and October 2019. There was no significant difference between the groups in terms of age and dialysis vintage. Causes of AA amyloidosis, treatment (colchicine and/or anti-interleukin 1 [IL] treatment), and the number of familial Mediterranean fever (FMF) attacks in the last year in case of FMF, systolic and diastolic blood pressures, biochemical values such as mean CRP, hemoglobin, serum albumin, phosphorus, calcium, PTH, ferritin, transferrin saturation, total cholesterol levels, EPO dose, erythropoietin-stimulating agents resistance index, interdialytic fluid intake, body mass indexes, heparin dosage, UF volume, and Kt/V data in the last year were collected by retrospective review of medical records.

FINDINGS

Prevalence of AA amyloidosis was found to be 1.87% in HD centers. In amyloidosis and control groups, 56% and 53% were male, mean age was 54 ± 11 and 53 ± 11 years, and mean dialysis vintage was 104 ± 94 and 107 ± 95 months, respectively. FMF was the most common cause of AA amyloidosis (59.5%). All FMF patients received colchicine and the mean colchicine dose was 0.70 ± 0.30 mg/day. 26.3% of FMF patients were unresponsive to colchicine and anti-IL-1 treatment was used in these patients. In AA amyloid and control groups, erythropoietin-stimulating agents resistance index were 7.88 ± 3.78 and 5.41 ± 3.06 IU/kg/week/g/dl, respectively (p = 0.008). Additionally, higher CRP values (18.78 ± 18.74 and 10.61 ± 10.47 mg/L, p = 0.037), lower phosphorus (4.68 ± 0.73 vs. 5.25 ± 1.04 mg/dl, p = 0.014), total cholesterol (135 ± 42 vs. 174 ± 39 mg/dl, p < 0.01), and serum albumin (3.67 ± 0.49 mg/dl, 4.03 ± 0.22, p < 0.01) were observed in patients with AA amyloidosis compared to the control group.

DISCUSSION

In this study, we found that long-term prognostic factors including higher inflammation, malnutritional parameters, and higher erythropoietin-stimulating agents resistance index were more frequent in AA amyloidosis patients under HD treatment.

A Pilot Study of Rare Renal Amyloidosis Based on FFPE Proteomics

Renal amyloidosis typically manifests albuminuria, nephrotic-range proteinuria, and ultimately progresses to end-stage renal failure if diagnosed late. Different types of renal amyloidosis have completely different treatments and outcomes. Therefore, amyloidosis typing is essential for disease prognosis, genetic counseling and treatment. Thirty-six distinct proteins currently known to cause amyloidosis that have been described as amyloidogenic precursors, immunohistochemistry (IHC) or immunofluorescence (IF), can be challenging for amyloidosis typing especially in rare or hereditary amyloidosis in clinical practice. We made a pilot study that optimized the proteomics pre-processing procedures for trace renal amyloidosis formalin-fixed paraffin-embedded (FFPE) tissue samples, combined with statistical and bioinformatics analysis to screen out the amyloidosis-related proteins to accurately type or subtype renal amyloidosis in order to achieve individual treatment. A sensitive, specific and reliable FFPE-based proteomics analysis for trace sample manipulation was developed for amyloidosis typing. Our results not only underlined the great promise of traditional proteomics and bioinformatics analysis using FFPE tissues for amyloidosis typing, but also proved that retrospective diagnosis and analysis of previous cases laid a solid foundation for personalized treatment.

Hyperechoic kidneys in a patient with bronchiectasis

Introduction

Hyperechoic renal cortex in a normal-sized kidney has a range of causes, some of which irreparably damage the kidney and should initiate further investigations.

Case Report

We present a 72-year-old woman with longstanding bronchiectasis, noticed to have worsening renal function. Renal tract ultrasonography showed hyperechoic normal-sized kidneys. Renal biopsy confirmed amyloidosis.

Discussion

Imaging findings in renal amyloidosis tend to be non-specific and are not always present. However, ultrasonography findings of hyperechoic cortex in normal-sized kidneys should not be ignored.

Conclusion

Renal impairment from blood chemistry in addition to hyperechoic kidneys may be the key to diagnosing secondary amyloidosis in a patient with bronchiectasis, a rare association but important to recognise.

Kidney-limited AL amyloidosis: a case report and review of the literature

Amyloidosis involves the deposition of abnormal proteins in various tissues and results in progressive organ dysfunction, commonly affecting multiple organs. Two types of systemic amyloidosis are AA and AL; the former is associated with acute phase reactions and the latter is composed of light chain immunoglobulins. This disease commonly affects the kidneys and is evidenced by massive proteinuria. A biopsy is the gold standard of diagnosis, with Congo Red staining revealing an apple-green birefringence under polarized light. Although the kidneys are frequently affected in this disease, it is rare that amyloidosis is limited to the kidneys without involvement of other organs. We present an 83-year-old female with bilateral lower extremity swelling for several months who was found to have 12.374 grams of protein in a 24-hour urine sample and a large amount of free lambda chains. A renal biopsy demonstrated renal amyloidosis of the AL type. Serum immunofixation and flow cytometry were unremarkable for any plasma dyscrasia; a bone marrow biopsy did not reveal systemic amyloidosis and imaging with PET/CT scan did not show evidence of other organ involvement. She was diagnosed with renal-limited amyloidosis and started on bortezomib, melphalan, and steroids. Clinicians should be aware of the signs and symptoms of amyloidosis, specifically its ability to present with unusual involvement of individual organs.

Occult Adrenal Insufficiency in Renal Amyloidosis Patients

Objective

Systemic amyloidosis may affect many organs, and may cause endocrinologic problems which may result in adrenal insufficiency. However, assessment of adrenocortical reserve is challenging in amyloidosis patients with renal involvement. We aimed to evaluate adrenocortical reserve with various methods of cortisol measurement to determine any occult clinical condition.

Methods

Patients with renal amyloidosis and healthy subjects were evaluated in this cross-sectional study. Basal cortisol, corticosteroid-binding globulin (CBG), and albumin levels were measured. Serum free cortisol (cFC) level was calculated. Cortisol response tests performed after ACTH stimulation test (250 μg, intravenously) were evaluated, and free cortisol index (FCI) was calculated.

Results

Twenty renal amyloidosis patients, and 25 healthy control subjects were included in the study. Patients and control subjects had similar median serum baseline cortisol levels [258 (126-423) vs 350 (314-391) nmol/L, p=0.169)] whereas patients’ stimulated cortisol levels at the 60^th minute were lower [624 (497-685) vs 743 (674-781) nmol/L, p=0.011)]. The 60^th-minute total cortisol levels of 8 of the 20 (40%) amyloidosis patients were <500 nmol/L, but only three of these 8 patients had stimulated FCI <12 nmol/mg suggesting an adrenal insufficiency (15%).

Conclusion

ACTH stimulation test and cortisol measurements should be considered in renal amyloidosis patients with severe proteinuria to avoid false positive results if only ACTH stimulation test is used. It will be appropriate to evaluate this group of patients together with estimated measurements as FCI.

Differential expression of MAP3K7 and TROPONIN C proteins and related perturbations in renal amyloidosis

OBJECTIVES

Renal amyloidosis (RA) is a rare protein misfolding disorder that prompts progressive renal insufficiency. This study aimed to decipher proteomic changes in human sera to understand the pathophysiology and molecular mechanisms underlying the disease development, hence assisting in the diagnosis of RA.

METHODS

Serum proteomic analysis was performed using a gel-based approach followed by MALDI-TOF MS. RA patients with age and sex matched healthy volunteers were recruited from Max Super Speciality Hospital, New Delhi, India.

RESULTS

Proteome profiles of serum revealed eight differentially expressed proteins namely, Zinc finger protein 624, Protein FAM183A, Calcium-binding mitochondrial carrier protein Scamc-3, V-type proton ATPase 116 kDa subunit A isoforms 2, Protein TXNRD3NB, ATP - dependent RNA helicase, Troponin C and Mitogen-activated protein kinase kinase kinase 7. These proteins were reported first time in RA. The increased levels of MAP3K7 and TROPONIN C were validated by bio-layer interferometry and their diagnostic accuracy was evaluated by ROC curve analysis. The differentially expressed proteins were predominantly associated with vesicular trafficking, transcriptional regulation, metabolic processes, apoptotic process and mitochondrial metabolism.

CONCLUSION

The results indicate that these proteomic signatures may be considered as potential molecular targets for RA diagnostics and therapeutics subject to validation on large sample size. Abbreviations: AβP= Amyloid-beta protein, Aβ=Amyloid-beta, AL= Light chain amyloidosis, AA= Amyloid A, ALECT2= LECT2 amyloidosis, APS= Ammonium persulfate CKD= Chronic Kidney Diseases, EBRT= external beam radiation therapy, ESRD= End-Stage Kidney Disease, Glis2= Gli-similar 2, JNK= c-Jun NH 2-terminal kinase, MAPK= Mitogen-Activated Protein Kinase, MM=Multiple Myeloma, PHD= Prolyl hydroxylase, RA = Renal Amyloidosis, SAA= Serum Amyloid A, SD= Standard Deviation, Sepp= Selenoprotein, SCC= Squamous cell carcinoma, SDS= Sodium dodecyl sulfate, TEMED = tetramethyl ethylenediamine, TGF-Beta-1=Transforming growth factor- Beta-1, Trx = Thioredoxin, TrxR= Thioredoxin reductase.

The utility of repeat kidney biopsy in systemic immunoglobulin light chain amyloidosis

Background: The diagnostic utility of repeat kidney biopsy in AL amyloidosis patients in complete (CR) or very good partial hematologic response (VGPR) but with renal organ relapse is not clear.Methods: We present eight patients with AL amyloidosis who had a repeat kidney biopsy performed.Results: AL amyloidosis was initially diagnosed by a kidney biopsy. All patients had a favorable response to treatment (CR/VGPR) and five of them also had initially a renal organ response. A repeat kidney biopsy was done due to gradual deterioration of kidney function and/or proteinuria while maintaining a hematologic response. Repeat kidney biopsies showed findings consistent with amyloid deposits in all patients. Seven patients had renal progression with four of them requiring dialysis initiation. Only one patient had a favorable renal outcome. This patient had subacute kidney injury with decreasing proteinuria and was found to have granulomatous interstitial nephritis in addition to amyloid deposits and responded well to steroid treatment with rapid improvement in renal function.Conclusions: In AL amyloidosis patients who achieve a favorable hematologic response to treatment (CR/VGPR) but subsequently develop worsening renal insufficiency or proteinuria, a repeat kidney biopsy should generally not be performed. Amyloid deposits persist in the kidneys even after successful hematologic treatment and it is impossible to differentiate between new versus old amyloid deposits, which makes performing a repeat kidney biopsy unnecessary in most cases. Demonstration of amyloid deposits on repeat kidney biopsy would not aid in the decision making regarding re-initiation of hematologic treatment. A kidney biopsy should be considered only in cases when a specific alternative diagnosis is suspected.

Primary thymic mucosa-associated lymphoid tissue lymphoma complicated with renal amyloidosis: A first case report

INTRODUCTION

Primary mucosa-associated lymphoid tissue (MALT) lymphomas originating in thymus is rare. And, there have been few reports of patients with MALT coexisting with amyloidosis. As far as we know, this was the first case report on MALT lymphoma associated with renal amyloidosis.

PATIENT CONCERNS

A 57-year-old man presented with nephrotic syndrome. Further workup revealed IgM-Lambda type monoclonal gammopathy. Bone marrow biopsy showed 8% clonal plasma cells. Renal biopsy confirmed the diagnosis of Lambda light chain AL amyloidosis. positron emission tomography/computed tomography showed thymic lesions which upon biopsy were diagnosed as MALT lymphoma of the thymus.

DIAGNOSIS

Primary thymic MALT lymphoma complicated with renal amyloidosis.

INTERVENTIONS

The patient underwent surgical resection of the thymus mass and 2 courses of chemotherapy.

OUTCOMES

Follow-up data showed that the patient survived 18 months after surgical excision and chemotherapy.

CONCLUSION

The case highlights the importance of screening for malignancy in patients with renal amyloidosis.

Revisiting renal amyloidosis with clinicopathological characteristics, grading, and scoring: A single-institutional experience

INTRODUCTION:

Kidney involvement is a major cause of mortality in systemic amyloidosis. Glomerulus is the most common site of deposition in renal amyloidosis, and nephrotic syndrome is the most common presentation. Distinction between AA and AL is done using immunofluorescence (IF) and immunohistochemistry (IHC). Renal biopsy helps in diagnosis and also predicting the clinical course by applying scoring and grading to the biopsy findings.

MATERIALS AND METHODS:

The study includes all cases of biopsy-proven renal amyloidosis from January 2008 to May 2017. Light microscopic analysis; Congo red with polarization; IF; IHC for Amyloid A, kappa, and lambda; and bone marrow evaluation were done. Classification of glomerular amyloid deposition and scoring and grading are done as per the guidelines of Sen S et al.

RESULTS:

There are 40 cases of biopsy-proven renal amyloidosis with 12 primary and 23 secondary cases. Mean age at presentation was 42.5 years. Edema was the most common presenting feature. Secondary amyloidosis cases were predominant. Tuberculosis was the most common secondary cause. Multiple myeloma was detected in four primary cases. Grading of renal biopsy features showed a good correlation with the class of glomerular involvement.

CONCLUSION:

Clinical history, IF, and IHC are essential in amyloid typing. Grading helps provide a subtle guide regarding the severity of disease in the background of a wide range of morphological features and biochemical values. Typing of amyloid is also essential for choosing the appropriate treatment.

A Rare Case of Renal AA Amyloidosis Secondary to Sjogren's Syndrome

AA amyloidosis is a rare complication of chronic inflammatory disorders and has been associated with rheumatoid arthritis and ankylosing spondylitis.

We present a case of AA amyloidosis secondary to Sjogren’s syndrome (SS). A 79-year-old woman presented with rapidly progressive renal failure and complaints of asthenia, anorexia and generalized oedema. She had severe renal failure (creatinine 6.0 mg/dl), with microscopic haematuria, nephrotic proteinuria and low serum albumin levels, and an increased erythrocyte sedimentation rate. Serum protein electrophoresis revealed a peak in the gamma globulin zone. The patient was started on haemodialysis and corticosteroids. Clinical results showed the patient met the diagnostic criteria for primary SS, and neoplastic haematological disease was excluded. Renal biopsy revealed a diagnosis of AA amyloidosis.

Renal AA amyloidosis is a rare condition in patients with primary SS. However, in patients with proteinuria and/or renal failure, it should be included in the differential diagnosis and a renal biopsy should be performed.

[Renal amyloidosis complicating adult onset Still's disease: about three cases]

L’amylose rénale est une complication rare au cours de la maladie de Still de l’adulte. Nous rapportons 3 observations d’amylose rénale parmi une série de 33 cas de maladie de Still de l’adulte. Il s’agit de 3 patientes d’âge moyen de 43 ans (extrême: 33 et 58 ans). Le diagnostic de maladie de Still a été retenu devant une polyarthrite fébrile (3 cas) associée à une éruption cutanée fugace (1 cas), un syndrome inflammatoire biologique en l’absence de toute cause infectieuse, inflammatoire ou néoplasique. Toutes ont été traitées par une corticothérapie associée secondairement au méthotrexate devant une polyarthrite destructrice (2 cas) et devant une récidive (1 cas). Une amylose rénale était survenue 4,9 ans après la maladie de Still (extrême: 33 mois et 7ans). L’amylose était révélée par un syndrome néphrotique (3 cas), associé à une insuffisance rénale (1 cas). Le diagnostic a été posé par une ponction biopsie rénale (3 cas) concluant à une amylose AA (2 cas) et non typée (1 cas). Tous les malades ont reçu la colchicine. L’évolution était favorable chez une patiente alors que les deux autres ont évolué vers l’insuffisance rénale chronique. L’amylose rénale est une atteinte inhabituelle de la maladie de Still de l’adulte. Une fois installée, elle peut engager le pronostic vital.

Fibrinogen αC domain: Its importance in physiopathology

ABSTRACT

Fibrinogen, involved in coagulation, is a soluble protein composed of two sets of disulfide-bridged Aα, Bβ, and γ-chains. In this review, we present the clinical implications of the αC domain of the molecule in Alzheimer's disease, hereditary renal amyloidosis and a number of thrombotic and hemorrhagic disorders. In Alzheimer's disease, amyloid beta peptide (Aβ) is increased and binds to the αC domain of normal fibrinogen, triggering increased fibrin(ogen) deposition in patients' brain parenchyma. In hereditary renal amyloidosis, fibrinogen is abnormal, with mutations located in the fibrinogen αC domain. The mutant αC domain derived from fibrinogen degradation folds incorrectly so that, in time, aggregates form, leading to amyloid deposits in the kidneys. In these patients, no thrombotic tendency has been observed. Abnormal fibrinogens with either a point mutation in the αC domain or a frameshift mutation resulting in absence of a part of the αC domain are often associated with either thrombotic events or bleeding. Mutation of an amino acid into cysteine (as in fibrinogens Dusart and Caracas V) or a frameshift mutation yielding an unpaired cysteine in the αC domain is often responsible for thrombotic events. Covalent binding of albumin to the unpaired cysteine via a disulphide bridge leads to decreased accessibility to the fibrinolytic enzymes, hence formation of poorly degradable fibrin clots, which explains the high incidence of thrombosis. In contrast, anomalies due to a frameshift mutation in the αC connector of the molecule, provoking deletion of a great part of the αC domain, are associated with bleeding.

Primary Vesical Amyloidosis Masquerading as Vesical Calculus in a Retroviral Positive Patient

The common causes of irritative voiding symptoms in women include cystitis, vesical calculi, carcinoma bladder and neurologic disorders. Isolated primary vesical amyloidosis (VA) is a rare cause of irritative voiding symptoms.

A 50-year-old female, a known case of retroviral disease but not on anti-retroviral therapy, presented with right flank and suprapubic pain for six months, worsening over the past 15 days with dysuria. She also presented with increased frequency of micturition with nocturia and urgency for the same duration. She had no hematuria, other lower urinary tract symptoms or fever. Clinical examination revealed suprapubic tenderness. Ultrasonogram (USG) revealed 1.7 cm vesical calculus. Cystoscopy revealed three spiky vesical calculi. There was a fluffy lesion with mucosal edema over the right lateral wall in the region of the right ureteric orifice, which was biopsied. Biopsy showed fragments of urothelial mucosa with focal areas of ulceration. The underlying stroma was edematous with amorphous pale eosinophilic acellular deposits. Congo red stain showed apple-green birefringence under polarized microscopy suggestive of amyloid. Sections were negative for dysplasia, granulomas or malignancies.

VA presents with intermittent gross hematuria in up to 77% patients and irritative voiding symptoms in 23% patients. VA is an uncommon differential diagnosis of cancer urinary bladder, with less than 200 cases reported in the literature. Hence we report this case to highlight that primary VA should also be considered in the evaluation of irritative voiding symptoms.

Profile of renal AA amyloidosis in older and younger individuals: a single-centre experience

OBJECTIVE

In epidemiological studies of amyloid A (AA) amyloidosis from Turkey, the most frequently cause was familial Mediterranean fever (FMF) and it occurs generally in young age population. However, there are no sufficient data regarding aetiology, clinical presentation and prognosis of renal AA amyloidosis in advanced age patients. In this study, we aimed to investigate demographic, clinical presentation, aetiology and outcomes of adults aged 60 years or older patients with biopsy-proven renal AA amyloidosis.

METHODS

This is a retrospective study involving 53 patients who were diagnosed with AA amyloidosis by kidney biopsy from 2006 to 2016. In all patients, kidney biopsies were performed due to asymptomatic proteinuria, nephrotic syndrome and/or renal insufficiency. The patients were separated into two groups on the basis of age (group I: ≥60 years and group II: <60 years). Outcomes of patients in terms of the requirement of renal replacement therapy and mortality were recorded.

RESULTS

In patients with group I, the causes of AA amyloidosis were as follows: FMF 16 (50%), bronchiectasis 7 (23%), chronic osteomyelitis 2 (6%), inflammatory bowel disease 2 (6%), rheumatoid arthritis 2 (6%), ankylosing spondylitis 1 (3%) and unknown aetiology 2 (6%). The underlying disorders of AA amyloidosis in group II patients were as follows: FMF 17 (81%), Behcet's disease 1 (5%) and unknown aetiology 3 (14%). No statistically significant differences were detected between two groups with regard to systolic and diastolic blood pressures, albumin, proteinuria and lipids. The combination of chronic kidney disease and nephrotic syndrome was the most common clinical presentation in group I (73%) and group II (43%) (p = .05). Compared to the group II, estimated glomerular filtration rate was significantly lower in group I at the time of kidney biopsy (p = .003). At 12-month follow-up, 61% of the group I and 33% of the group II developed end-stage kidney disease requiring dialysis, while 11% of the group I died.

CONCLUSION

Our results indicated that renal AA amyloidosis is a rare disease in advanced age patients. At baseline and follow-up period, advanced age patients had worse kidney disease and outcomes.

Systemic amyloidosis: novel therapies and role of biomarkers

Systemic amyloidosis is caused by misfolding and extracellular deposition of one of an ever-growing list of circulating proteins, resulting in vital organ dysfunction and eventually death. Despite different predisposing conditions, including plasma cell dyscrasias [immunoglobulin light chain (AL) amyloidosis], long-lasting inflammation [reactive (AA) amyloidosis] or mutations (hereditary amyloidoses), clinical manifestations are conspicuously overlapping and mimic more prevalent conditions, significantly complicating and often delaying the recognition of these rare, complex diseases. However, refined diagnostic and imaging approaches and the increasing role of biomarkers, which help in establishing the diagnosis, assessing the prognosis and evaluating the response to therapy, have considerably improved the management of these conditions. The pillar of anti-amyloid therapy remains the prompt reduction or elimination of the amyloidogenic precursor. This is accomplished by targeting the underlying condition, and recent improvements in the treatment of plasma cell disorders and chronic inflammatory conditions have positively reverberated onto the management of AL and AA amyloidosis, respectively. Moreover, recent, substantial improvements in the understanding of the molecular underpinnings of systemic amyloidosis have unveiled different key steps in the amyloidogenic cascade which can be valid therapeutic targets. These include stabilizers of the native conformation of the amyloidogenic precursor, inhibitors of fibrillogenesis, amyloid fibril disruptors and promoters of amyloid clearance. Innovative pharmacological strategies, including rational, structure-based drug design, gene knockdown and immunotherapy, but also repurposing of old, safe drugs with newly recognized anti-amyloid properties, are currently being pursued already in the clinical setting, holding the promise of dramatically improving the outcome of these dismal conditions in the near future.

An interesting case of renal amyloidosis

In amyloidosis, there is an extracellular deposition of beta-sheet fibrils. Over 25 proteins have been demonstrated to form amyloid. One of them is Ig amyloid light (AL) chains. We are presenting a 40-year-old female who presented with progressive kyphoscoliosis for last 2 years following a minor trauma and bilateral pedal edema for last 3 months. On further investigation, we found that she had a biclonal variety of MM with amyloidosis of kidney leading to massive proteinuria. Very few case reports are available where patient with biclonal variety of MM develop renal amyloidosis.

Rare and unusual clinicopathologic presentation of renal AL amyloidosis

Rarely, renal light chain (AL) amyloidosis may present without significant proteinuria owing to glomerular sparing and amyloid deposition confined to the vasculature and tubulointerstitium.

Leukocyte Cell-Derived Chemotaxin 2-Associated Amyloidosis: A Recently Recognized Disease with Distinct Clinicopathologic Characteristics

Amyloidosis derived from leukocyte cell-derived chemotaxin 2 is a recently recognized form of amyloidosis, and it has already been established as a frequent form of systemic amyloidosis in the United States, with predominant involvement of kidney and liver. The disease has a strong ethnic bias, affecting mainly Hispanics (particularly Mexicans). Additional ethnic groups prone to develop amyloidosis derived from leukocyte cell-derived chemotaxin 2 include Punjabis, First Nations people in British Columbia, and Native Americans. Most patients are elderly who present with chronic renal insufficiency and bland urinary sediment. Proteinuria is variable, being absent altogether in about one third of patients. Liver involvement is frequently an incidental finding. Amyloidosis derived from leukocyte cell-derived chemotaxin 2 deposits shows a characteristic distribution: in the kidney, there is consistent involvement of cortical interstitium, whereas in the liver, there is a preferential involvement of periportal and pericentral vein regions. Concurrent renal disease is frequent, with diabetic nephropathy and IgA nephropathy being the most common. Patient survival is excellent, likely because of the rarity of cardiac involvement, whereas renal survival is guarded, with a median renal survival of 62 months in those without concurrent renal disease. There is currently no efficacious therapy for amyloidosis derived from leukocyte cell-derived chemotaxin 2 amyloidosis. Renal transplantation seems to be a reasonable treatment for patients with advanced renal failure, although the disease may recur in the allograft. The pathogenesis of amyloidosis derived from leukocyte cell-derived chemotaxin 2 amyloidosis has not yet been elucidated. It could be a result of leukocyte cell-derived chemotaxin 2 overexpression by hepatocytes either constitutively (controlled by yet-uncharacterized genetic defects) or secondary to hepatocellular damage. It is critical not to misdiagnose amyloidosis derived from leukocyte cell-derived chemotaxin 2 amyloidosis as Ig light chain-derived amyloidosis to avoid harmful chemotherapy.

Renal amyloidosis in children

Renal amyloidosis is a detrimental disease caused by the deposition of amyloid fibrils. A child with renal amyloidosis may present with proteinuria or nephrotic syndrome. Chronic renal failure may follow. Amyloid fibrils may deposit in other organs as well. The diagnosis is through the typical appearance on histopathology. Although chronic infections and chronic inflammatory diseases used to be the causes of secondary amyloidosis in children, the most frequent cause is now autoinflammatory diseases. Among this group of diseases, the most frequent one throughout the world is familial Mediterranean fever (FMF). FMF is typically characterized by attacks of clinical inflammation in the form of fever and serositis and high acute-phase reactants. Persisting inflammation in inadequately treated disease is associated with the development of secondary amyloidosis. The main treatment is colchicine. A number of other monogenic autoinflammatory diseases have also been identified. Among them cryopyrin-associated periodic syndrome (CAPS) is outstanding with its clinical features and the predilection to develop secondary amyloidosis in untreated cases. The treatment of secondary amyloidosis mainly depends on the treatment of the disease. However, a number of new treatments for amyloid per se are in the pipeline.