Clinical and therapeutic aspects of AA amyloidosis

Case report: Rapid development of amyloid A amyloidosis in temporal arteritis with SAA1.3 allele; An unusual case of intestinal amyloidosis secondary to temporal arteritis

Temporal arteritis (TA) is a large-vessel vasculitis mostly seen in older patients. Amyloid A (AA) amyloidosis secondary to a chronic inflammation induces multiple organ dysfunctions, including a dysfunction of the gastrointestinal tract. Herein, we present a case of TA complicated by AA amyloidosis that was resistant to oral and intravenous steroids. An 80-year-old man with a history of new-onset headache, jaw claudication, and distended temporal arteries was referred to our department. On admission, the patient presented with tenderness and a subcutaneous temporal nodule in both temple arteries. Ultrasonography of the nodule revealed an anechoic perivascular halo surrounding the right temporal artery. Following the diagnosis of TA, high-dose prednisolone therapy was initiated. However, the patient presented with recurrent abdominal pain and refractory diarrhea. Due to the unclear origin of refractory diarrhea, an extensive workup, including biopsy of the duodenal mucosa, was performed. Endoscopy revealed chronic inflammation in the duodenum. Immunohistochemical analysis of duodenal mucosal biopsy samples revealed AA amyloid deposition resulting in the diagnosis of AA amyloidosis. After tocilizumab (TCZ) administration, refractory diarrhea reduced; however, the patient died of intestinal perforation 1 month after the start of TCZ administration. Gastrointestinal involvement was the main clinical manifestation of AA amyloidosis in the present case. This case highlights the importance of bowel biopsy screening for amyloid deposition in patients with unexplained gastrointestinal tract symptoms, even in a recent onset of large-vessel vasculitis. In the present case, the carriage of the SAA1.3 allele likely contributed to the rare association of AA amyloidosis with TA.

[What is confirmed in the treatment of autoinflammatory fever diseases?]

In den letzten 20 Jahren hat die Aufklärung von monogenetisch verursachten periodischen Fiebererkrankungen zum eigenständigen Konzept der Autoinflammation geführt. In diese heterogene Gruppe werden inzwischen auch polygenetisch verursachte, komplexe Erkrankungen eingruppiert. Das Spektrum der Krankheitsbilder wächst kontinuierlich. Hauptunterschied zur Autoimmunität ist eine übermäßige Aktivierung des angeborenen Immunsystems ohne Autoantikörperbildung oder antigenspezifische T‑Zellen. Als Kardinalsymptom treten rezidivierende Fieberschübe, begleitet von Entzündungszeichen, auf; diese wechseln sich bei den periodischen Krankheitsbildern mit Intervallen allgemeinen Wohlbefindens ab. Die klassischen monogenetischen Erkrankungen werden auch als hereditäres rezidivierendes Fieber (HRF) bezeichnet. Beispiele sind das familiäre Mittelmeerfieber (FMF), das Cryopyrin-assoziierte periodische Syndrom (CAPS), das Tumor-Nekrose-Faktor-Rezeptor-1-assoziierte periodische Syndrom (TRAPS), die Adenosindesaminase(ADA2)-Defizienz und die Mevalonatkinasedefizienz (MKD; Hyper-IgD-Syndrom). Die polygenetischen Erkrankungen werden auch als nichthereditäre Fiebersyndrome bezeichnet. Hierzu zählen die adulte Form der Still-Erkrankung („adult-onset Still’s disease“, AoSD), die Adamantiades-Behçet-Erkrankung, das PFAPA-Syndrom (periodisches Fieber, aphthöse Stomatitis, Pharyngitis und zervikale Adenitis) und die Gichtarthritis. Alle autoinflammatorischen Fiebersyndrome gehen mit einem von individuellem Schweregrad und Therapieerfolg abhängigen Langzeitrisiko für die Entwicklung einer Amyloid-A-Amyloidose einher. Bei einigen Erkrankungen können z. T. schwere Komplikationen auftreten.

Amyloid storm: acute kidney injury and massive proteinuria, rapidly progressing to end-stage kidney disease in AA amyloidosis of familial Mediterranean fever

OBJECTIVE

Amyloid A nephropathy of FMF usually progresses over many years to end-stage renal disease (ESRD). We aim to describe an acute condition, termed here 'amyloid storm', typically manifesting with a rapid (≤2 weeks) increase in serum creatinine and urine protein, that has never been characterized in FMF amyloidosis.

METHODS

This retrospective analysis features amyloid storm by comparing between FMF amyloidosis patients who have experienced an episode of amyloid storm (study group) and matched patients who have not (control group). The primary outcome was ESRD or death within 1 year from study entry. Featured data were retrieved from hospital files.

RESULTS

The study and control groups, each comprising 20 patients, shared most baseline characteristics. However, they differed on the time from FMF onset to reaching serum creatinine of 1.2 mg/dl [26.5 years (s.d. 15.15) vs 41.55 (10.98), P = 0.001] and the time from the onset of proteinuria to study entry [8.8 years (s.d. 6.83) vs 15.75 (13.05), P = 0.04], culminating in younger age at study entry [39.95 years (s.d. 16.81) vs 48.9 (9.98), respectively, P = 0.05] and suggesting an accelerated progression of kidney disease in the study group. Within 1 year from study entry, 16 patients in the study and 3 in the control groups reached the primary endpoint (P = 0.000). The major triggers of amyloid storm were infections, occurring in 17 of 20 patients.

CONCLUSION

Amyloid storm is a complication of FMF amyloidosis, induced by infection and associated with poor prognosis and death.

Naturally occurring antibodies against serum amyloid A reduce IL-6 release from peripheral blood mononuclear cells

Serum amyloid A (SAA) is a sensitive inflammatory marker rapidly increased in response to infection, injury or trauma during the acute phase. Resolution of the acute phase and SAA reduction are well documented, however the exact mechanism remains elusive. Two inducible SAA proteins, SAA1 and SAA2, with their variants could contribute to systemic inflammation. While unconjugated human variant SAA1α is already commercially available, the variants of SAA2 are not. Antibodies against SAA have been identified in apparently healthy blood donors (HBDs) in smaller, preliminary studies. So, our objective was to detect anti-SAA and anti-SAA1α autoantibodies in the sera of 300 HBDs using ELISA, characterize their specificity and avidity. Additionally, we aimed to determine the presence of anti-SAA and anti-SAA1α autoantibodies in intravenous immunoglobulin (IVIg) preparations and examine their effects on released IL-6 from SAA/SAA1α-treated peripheral blood mononuclear cells (PBMCs). Autoantibodies against SAA and SAA1α had a median (IQR) absorbance OD (A₄₅₀) of 0.655 (0.262–1.293) and 0.493 (0.284–0.713), respectively. Both anti-SAA and anti-SAA1α exhibited heterogeneous to high avidity and reached peak levels between 41–50 years, then diminished with age in the oldest group (51–67 years). Women consistently exhibited significantly higher levels than men. Good positive correlation was observed between anti-SAA and anti-SAA1α. Both anti-SAA and anti-SAA1α were detected in IVIg, their fractions subsequently isolated, and shown to decrease IL-6 protein levels released from SAA/SAA1α-treated PBMCs. In conclusion, naturally occurring antibodies against SAA and anti-SAA1α could play a physiological role in down-regulating their antigen and proinflammatory cytokines leading to the resolution of the acute phase and could be an important therapeutic option in patients with chronic inflammatory diseases.

Pulmonary, renal and neurological comorbidities in patients with ankylosing spondylitis; implications for clinical practice

Ankylosing spondylitis (AS) is associated with several comorbidities which contribute significantly to morbidity and mortality and add to the complexity of management. In addition to the well known extra-articular manifestations and increased cardiovascular risk, several pulmonary, renal, and neurological complications which have been associated with AS deserve equal attention. Whereas a clear link has been established for some manifestations, the evidence for other associations is less clear. Interstitial lung disease, apical fibrosis, secondary infection, and ventilatory restriction from reduced chest wall movement are well known pulmonary complications; more recently an association with sleep apnoea has been suggested. Renal amyloidosis and IgA nephropathy remain a treatment challenge which may respond to anti-TNF therapy. Atlanto axial subluxation and vertebral fractures can result in serious neurological complications and are notoriously difficult to diagnose unless a high level of suspicion is maintained. Despite several reports linking AS with demyelination a true link remains to be proved. This review discusses the prevalence, pathophysiology, and management of pulmonary, renal, and neurological complications, and implications for clinical practice.

Amyloid A amyloidosis: frequently neglected renal disease in injecting drug users

Implication for health policy/practice/research/medical education: Amyloid A (AA) amyloidosis is a systemic form of amyloidosis secondary to chronic infections and inflammatory disorders such as recurrent suppurative skin infections secondaryto subcutaneous administration of drugs (skinpopping).The diagnosis of AA amyloidosis is frequently overlooked due to the insidious nature of the disease. The renal manifestations of AA amyloidosis include proteinuria, tubular dysfunction, and progressive loss of renal function. Urinalysis and quantification of urinary protein excretion are important screening tests. Early diagnosis and treatment of AA amyloidosis can reverse end-organ damage.

Familial Mediterranean fever (FMF) with proteinuria: clinical features, histology, predictors, and prognosis in a cohort of 25 patients

OBJECTIVE

Reactive (AA) amyloidosis may complicate familial Mediterranean fever (FMF), the prototype of autoinflammatory diseases. Thus, proteinuria in FMF is commonly viewed as resulting from amyloidosis, and kidney biopsy is deemed superfluous. However, nephropathy other than amyloidosis has been described in FMF, but its rate and distinctive characteristics are unknown. Our aim was to determine the rate and underlying pathology of FMF-related nonamyloidotic proteinuria and compare its clinical course, demographic, and genetic features to those of FMF-amyloid nephropathy.

METHODS

This study is a retrospective analysis of data from patients with FMF undergoing kidney biopsy for proteinuria above 0.5 g/24 h, over 10 years (2001-2011). Clinical, laboratory, genetic, and pathology data were abstracted from patient files. Biopsies were viewed by an experienced pathologist, as necessary.

RESULTS

Of the 25 patients referred for kidney biopsy, only 15 (60%) were diagnosed with amyloid kidney disease (AKD), and 10 were diagnosed with another nephropathy. The AKD and nonamyloid kidney disease (NAKD) groups were comparable on most variables, but showed distinct characteristics with regard to the degree of proteinuria (6.45 ± 4.3 g vs 2.14 ± 1.6 g, p = 0.006), rate of severe FMF (14 vs 5 patients, p = 0.022), and rate of development of end stage renal disease (73.3% vs 20%, p = 0.015), respectively.

CONCLUSION

NAKD is common in FMF and, compared to amyloidosis, it is featured with milder course and better prognosis. Contrary to common practice, it is highly recommended to obtain a kidney biopsy from patients with FMF and proteinuria more than 0.5 g/24 h.

Amyloidosis: a clinical overview

Amyloidosis is the name for protein-folding diseases characterized by extracellular deposition of a specific soluble precursor protein that aggregates in the form of insoluble fibrils. The classification of amyloidosis is based on the chemical characterization of the precursor protein. Deposition of amyloid is localized or systemic. The 4 main types of systemic amyloidosis are AL, AA, ATTR, and Aβ2M type. A schematic approach is proposed for the clinical management of systemic amyloidosis. The importance of typing amyloid with confidence, the usefulness of imaging techniques, the principles of treatment, and the need for well-planned treatment monitoring during follow-up are discussed.

Review of eprodisate for the treatment of renal disease in AA amyloidosis

Secondary (AA) amyloidosis is a multisystem disorder complicating chronic infections or inflammatory diseases. It is characterized by extracellular deposit of fibrils composed of fragments of serum amyloid A (SAA), an acute phase reactant protein. The kidney is the most frequent organ involved, manifesting as progressive proteinuria and renal impairment. Attenuation of the level of circulating SAA protein by treating the underlying inflammatory condition remains the primary strategy in treating AA amyloidosis. However, at times, achieving adequate control of protein production can prove difficult. In addition, relapse of renal function often occurs rapidly following any subsequent inflammatory stimulus in patients with existing amyloidosis. Recently there has been an interest in finding other potential strategies targeting amyloid deposits themselves. Eprodisate is a sulfonated molecule with a structure similar to heparan sulfate. It competitively binds to the glycosaminoglycan-binding sites on SAA and inhibits fibril polymerization and amyloid deposition. Recent randomized clinical trial showed that it may slow down progressive renal failure in patients with AA amyloidosis. However confirmatory studies are needed and results of a second Phase III study are eagerly awaited to clarify whether or not eprodisate has a place in treating renal amyloid disease.

A case of systemic amyloidosis associated with cyclic neutropenia

Reactive AA amyloidosis is caused by the accumulation of the acute phase reactant, serum amyloid A (SAA), as a complication of chronic inflammatory conditions. Cyclic neutropenia is a rare hereditary disorder characterized by repeated episodes of neutropenia at regular intervals, with or without concurrent infection, and is known to be a rare cause of AA amyloidosis. Here, we report a case of a patient who developed systemic AA amyloidosis following a prolonged course of undiagnosed cyclic neutropenia. The patient had a history of recurrent infections since infancy and developed goiter, proteinuria, and azotemia at age 14 years. Her SAA level was markedly increased (601.8 μg/mL, normal range <8 μg/mL), and a thyroid and kidney biopsy revealed typical lesions of AA amyloidosis. Amyloid deposits were also detected in the myocardium, colon, and gallbladder. She had repeated episodes of neutropenia regularly at 3-week intervals and a pathogenic mutation in the ELA2 gene. After 10 months of treatment with recombinant human granulocyte colony-stimulating factor, her SAA level normalized (<2.5 μg/mL), but her renal function did not recover. This case clearly shows that cyclic neutropenia can be complicated by AA amyloidosis unless it is detected early and treated adequately.

Treatment strategies for amyloid A amyloidosis

BACKGROUND

Amyloid A (AA) amyloidosis is a serious complication of a wide range of chronic inflammatory, infectious and neoplastic diseases. A longstanding overproduction of the liver-synthesised cytokine-induced acute phase serum amyloid A (SAA) protein is a key event in the pathogenetic cascade leading to the deposition of AA amyloid in tissues and organs.

OBJECTIVE

The aim of the study was to critically review treatment strategies in AA amyloidosis.

METHODS

A systematic literature review was conducted based on PubMed (January 1980 - April 2008) and selected conference abstracts.

RESULTS/CONCLUSIONS

The current strategy for the treatment of AA amyloidosis is firmly based on the knowledge of the underlying pathogenetic mechanism and aims at reducing the amyloid precursor (SAA) load by intensive anti-inflammatory/immunosuppressive therapy and, in selected instances, anticytokine (TNF-alpha, IL-1beta or IL-6 blockade) therapy, or, when applicable, the eradication of an existing infectious focus (surgery, antimicrobial drugs). Emerging strategies focus on the dissolution of the amyloid deposits using small molecules that either interact with the glycosaminoglycans or the fibril component of the deposits, or deplete amyloid P component.

Spontaneous perirenal hematoma with AA amyloidosis in a hemodialysis patient after unilateral nephrectomy

Secondary amyloidosis presents with a variety of systemic symptoms or signs. Amyloid diseases can be associated with potentially life-threatening hemorrhage. Although bleeding manifestations are common in amyloidosis, renal bleeding is rare and generally due to trauma, cyst and malignancy. For the first time we present a ureamic patient who was diagnosed with AA amyloidosis after unilateral nephrectomy because of spontaneous perirenal hematoma.

Analysis of SAA1 gene polymorphisms in the Greek population: rheumatoid arthritis and FMF patients relative to normal controls. Homogeneous distribution and low incidence of AA amyloidosis

OBJECTIVE

To address whether or not the rarity of amyloidosis in Greek patients with rheumatoid arthritis (RA) is related to specific alleles of single nucleotide polymorphisms (SNPs) in the 5'-flanking region and the exon 3 of the SSA1 gene.

METHODS

The genotypes of the -13T/C SNP in the 5'-flanking region of the SAA1 gene and the two SNPs within exon 3 of SAA1 (2995C/T and 3010C/T polymorphisms) were determined in 88 Greek patients with RA, 14 patients with familial Mediterranean fever (FMF) and 110 healthy controls. Linkage disequilibrium and haplotype frequencies involving -13T/C, 2995C/T and 3010C/T in these populations were tested and estimated, respectively.

RESULTS

The genotypic distribution and allelic frequencies were similar in all groups tested. SNPs 2995 and 3010 were in linkage disequilibrium for all study populations (p < 0.05), whereas SNP -13 was not in linkage disequilibrium with either 2995 or 3010 (p > or = 0.05). Two major haplotypes presented in all patients with RA and FMF and controls: -13C; 2995T; 3010C (-13C; alpha) and -13C; 2995C; 3010T (-13C; beta). The -13T allele was linked with the gamma haplotype in Greek patients with RA and controls. The frequency of the -13T allele was found to be very rare in all groups tested.

CONCLUSIONS

In conclusion, the rarity of the putative amyloidogenic -13T allele in Greek populations may be related to low prevalence of AA amyloidosis development in Greek RA patients.

[Amyloid diagnostics in rheumatic diseases]

Amyloid is a pathological protein deposit in tissue which has a red eosin color when the slice preparation is stained with traditional hematoxylin and eosin and after Congo red staining under polarized light exhibits a characteristic apple-green polarization color. Over 26 different autologous physiological proteins have been described that can form amyloid. In surgical pathology, immunoglobulin light chain-associated AL amyloidosis is the most frequent generally occurring amyloidosis, followed by hereditary and nonhereditary ATTR amyloidosis and AA amyloidosis. AA amyloidosis mostly develops subsequent to chronic infectious or inflammatory underlying disease and can represent a potentially life threatening complication. The spectrum of causes for AA amyloidosis has changed in the past few decades and is now determined by chronic rheumatic diseases and hereditary periodic fever syndromes. Early diagnosis of an amyloidosis and its correct classification continue to pose a great challenge. Precise classification of the amyloid and amyloidosis is essential for prognosis assessment and treatment planning. In addition to anti-inflammatory management of AA amyloidosis, specific treatment strategies may possibly become available in the future.

Clinical and histological characteristics of renal AA amyloidosis: a retrospective study of 68 cases with a special interest to amyloid-associated inflammatory response

We retrospectively reviewed the clinicopathological features of a series of 68 renal AA amyloidosis observations collected between 1990 and 2005. The amyloidogenic disease was a chronic infection (40.8%), a chronic inflammation (38%), a tumor (9.9%), a hereditary disease (9.9%), or was undetermined in 1.4% of cases. Nephrotic syndrome and renal insufficiency were noted in 63.1% and 75% of patients, respectively. The distribution pattern of glomerular amyloid deposits was mesangial segmental (14.7%), mesangial nodular (26.5%), mesangiocapillary (32.3%), and hilar (26.5%). Glomerular form was observed in 80.9% of cases and vascular form in 19.1%. AA amyloidosis-related inflammation was noted in 30 patients (44.1%) and appeared as a multinucleated giant cell reaction (27.9%) or a glomerular inflammatory infiltrate (25%), including glomerular crescents (17.6%). At the end of follow-up, 26 patients (38.2%) showed end-stage renal disease. The clinical presentation of glomerular and vascular forms was distinct with a clear predominance of proteinuria in glomerular form. Inflammatory reaction was preferentially observed in biopsies with a codeposition of immunoglobulin chains and/or complement factors in AA amyloid deposits. The distribution pattern of glomerular amyloid deposits and glomerular inflammatory reaction were independent factors influencing proteinuria level. Tubular atrophy, abundance, and distribution pattern of glomerular amyloid deposits at the time of biopsy were independent predictors of renal outcome. In conclusion, the glomerular involvement appeared as the determining histological factor for clinical manifestations and outcome of renal AA amyloidosis. AA amyloidosis-related inflammation could partly result from an immune response directed against AA fibrils and could induce amyloid resolution and crescents.

Ankylosing spondylitis-related secondary amyloidosis responded well to etanercept: a report of three patients

Secondary (AA) amyloidosis is one of the most significant complications of ankylosing spondylitis (AS) that frequently leads to proteinuria and renal dysfunction. Anti-tumor necrosis factor alpha (anti-TNF) agents are promising in inducing clinical remission by suppressing systemic inflammation in AA amyloidosis. We report three cases with AS-related AA amyloidosis that responded well to etanercept therapy. Despite treatment with disease modifying anti-rheumatic drugs, all three patients had active AS, marked proteinuria, impaired renal function, and low serum albumin level. During 1-year treatment with etanercept, all patients experienced gradual improvement in all of these parameters.

Prognosis of clinical renal disease and incidence of new renal findings in patients with rheumatoid arthritis: follow-up of a population-based study

The objective of this study was to assess the long-term prognosis of nephropathy findings and the incidence of new abnormal clinical renal findings in patients with rheumatoid arthritis (RA). The original population-based cross-sectional study of 604 RA patients was carried out in 1988, 103 nephropathy patients being found. Controls matched for age, sex, and duration of RA were selected from among RA patients with normal renal function and urinalysis in 1988. In 2003, a follow-up study was made of the 103 nephropathy patients and 102 controls, and the median follow-up time was 13 years. In the original nephropathy group, serum creatinine exceeded 200 mumol/l in 8% of the original isolated hematuria patients, in 30% of the isolated proteinuria patients, in 57% of the combined hematuria and proteinuria patients, but in none of the isolated chronic renal failure (CRF) patients (p = 0.001 for the difference). Probable or definitive renal amyloidosis was diagnosed in 19% of the nephropathy patients. Dialysis therapy was given to 10 out of the 103 nephropathy patients, nine of them belonging to the original isolated proteinuria or combined hematuria and proteinuria groups. There were six renal deaths among the nephropathy patients, and none in the controls. In the control group, new abnormal renal findings, in most cases mild, were detected in 28%. Serum creatinine exceeded 200 mumol/l in 4% of the controls, and dialysis therapy was given to 2% of the controls. Probable or definitive renal amyloidosis was diagnosed in 4% of this group. With regards to the development or progression of chronic renal failure, the long-term clinical prognosis of isolated hematuria and isolated CRF was found to be favorable. Proteinuria alone or combined with hematuria or CRF was related to evidently poorer prognosis.

Prevalence of amyloid deposition in long standing rheumatoid arthritis in Iranian patients by abdominal subcutaneous fat biopsy and assessment of clinical and laboratory characteristics

Background

The study was aimed at determining the prevalence of secondary amyloidosis in a group of Iranian patients with Rheumatoid Arthritis (RA), and the assessment of its correlation with the clinical and laboratory findings and data.

Method

A total number of 220 patients (167 female and 53 male) with a minimum five-year history of RA were selected. Congo red staining method was used for staining the specimens obtained by abdominal subcutaneous fat biopsy (ASFB) method. All of the specimens were examined for apple-green birefringence under polarized light microscope. Clinical and laboratory characteristics of the patients were assessed. Chi-square test and unpaired student's t-test were run for intergroup comparisons.

Results

Amyloid deposition test yielded positive results in 15 out of the 220 cases (6.8%) examined by the ASFB technique. Thirteen patients were found to have minimal amyloid deposits. Of all the clinically significant cases, 8 (53%) presented with proteinuria, and 7 cases (46.6%) had severe constipation.

Conclusion

The prevalence of fat amyloid deposits in Iranian patients with RA is low. In up to half of the study group the deposits were subclinical. Follow up studies are required to determine whether this subclinical amyloidosis can develop into full-blown clinically significant amyloidosis.

Successful use of a humanized anti–interleukin-6 receptor antibody, tocilizumab, to treat amyloid A amyloidosis complicating juvenile idiopathic arthritis

We report an excellent clinical response to treatment with a humanized anti-interleukin-6 receptor antibody, tocilizumab, in a patient with progressive amyloid A (AA) amyloidosis complicating very active juvenile idiopathic arthritis. Treatment with tocilizumab immediately normalized the serum AA (SAA) level, and subsequently all of the clinical symptoms of AA amyloidosis disappeared. Serial gastrointestinal biopsy specimens showed marked lasting regression of AA protein deposits. The patient's functional ability score improved dramatically, she maintains her mobility, and she has regained her previous quality of life. Tocilizumab appears to have an excellent ability to suppress SAA levels and could therefore be an important therapeutic strategy in AA amyloidosis secondary to rheumatic diseases.

Clinical aspects of systemic amyloid diseases

Amyloidosis is a protein misfolding disorder in which soluble proteins aggregate as insoluble amyloid fibrils. Protein aggregates and amyloid fibrils cause functional and structural organ damage respectively. To date, at least 24 different proteins have been recognized as causative agents of amyloid diseases, localized or systemic. The two most common forms of systemic amyloidosis are light-chain (AL) amyloidosis and reactive AA amyloidosis due to chronic inflammatory diseases. beta(2)-microglobulin amyloidosis is a common complication associated with long-term hemodialysis. Hereditary systemic amyloidoses are a group of autosomal dominant disorders caused by mutations in the genes of several plasma proteins. Heterogeneity in clinical presentation, pattern of amyloid-related organ toxicity and rate of disease progression is observed among systemic amyloidoses. In particular, beta(2)-microglobulin presents unique clinical features compared to the other systemic forms. The phenotypic features of hereditary systemic amyloidoses may instead overlap those of the two more common forms of acquired amyloidoses mentioned above and therefore a correct diagnosis can not rely only on clinical grounds. Unequivocal identification of the deposited protein is essential in order to avoid misdiagnosis and inappropriate treatment. Amyloid deposits can be reabsorbed and organ dysfunction reversed if the concentration of the amyloidogenic protein is reduced or zeroed. At present, the most effective approach to treatment of the systemic amyloidoses involves shutting down, or substantially reducing the synthesis of the amyloid precursor, or, as in the case of beta(2)-microglobulin, promoting its clearance.

The systemic amyloidoses: clearer understanding of the molecular mechanisms offers hope for more effective therapies

Knowledge about the systemic amyloidoses has increased considerably during the last few years. This group of diseases is characterized by great biochemical variability, including at least 11 different amyloid fibril proteins and a remarkable range of clinical manifestations. With the understanding that the pathogenesis is different in the various forms of amyloidosis, it is now being increasingly accepted that an early and accurate diagnosis, including that of the underlying biochemical nature, is crucial for a successful treatment. The elucidation of the molecular mechanisms involved in amyloidogenesis is at the basis of the recent blossoming of new, innovative and more effective therapeutic approaches.

Amyloid load and clinical outcome in AA amyloidosis in relation to circulating concentration of serum amyloid A protein

BACKGROUND

Reactive systemic (AA, secondary) amyloidosis occurs in chronic inflammatory diseases, and most patients present with nephropathy. The amyloid fibrils are derived from the circulating acute-phase reactant serum amyloid A protein (SAA), but the relation between production of fibril precursor protein, amyloid load, and clinical outcome in AA and other types of amyloidosis is unclear.

METHODS

We studied amyloidotic organ function and survival prospectively for 12-117 months in 80 patients with systemic AA amyloidosis in whom serum SAA concentration was measured monthly and visceral amyloid deposits were assessed annually by serum amyloid P component scintigraphy. Underlying inflammatory diseases were treated as vigorously as possible.

FINDINGS

Amyloid deposits regressed in 25 of 42 patients whose median SAA values were within the reference range (<10 mg/L) throughout follow-up, and amyloidotic organ function stabilised or improved in 39 of these cases. Outcome varied substantially among patients whose median SAA concentration exceeded 10 mg/L, but amyloid load increased and organ function deteriorated in most of those whose SAA was persistently above 50 mg/L. Estimated survival at 10 years was 90% in patients whose median SAA was under 10 mg/L, and 40% among those whose median SAA exceeded this value (p=0.0009).

INTERPRETATION

Although isolated amyloid fibrils are stable in vitro, AA amyloid deposits exist in a state of dynamic turnover, and outcome is favourable in AA amyloidosis when the SAA concentration is maintained below 10 mg/L. The potential for amyloid to regress and for the function of amyloidotic organs to recover support therapeutic strategies to decrease the supply of amyloid fibril precursor proteins in amyloidosis generally.

The clinical significance of amyloid fat deposits in rheumatoid arthritis: a systematic long-term followup study using abdominal fat aspiration

OBJECTIVE

To analyze the prevalence of subclinical amyloid fat deposits in patients with rheumatoid arthritis (RA) and to evaluate its clinical significance.

METHODS

A cohort of 313 adult RA patients were included in this prospective observational study. Systematic abdominal subcutaneous fat aspiration (ASFA) was performed on all patients at study entry. The prevalence of visceral amyloidosis at study entry and at the end of followup was analyzed for patients with a positive ASFA test result. Followup ranged from 1 to 14 years (mean +/- SD 6.7 +/- 4.1 years). Patients with clinical and subclinical amyloidosis were compared with regard to clinical characteristics and the degree of amyloid deposits in abdominal fat.

RESULTS

The first ASFA test found amyloid in the abdominal fat of 51 patients (16.3%), and subsequent ASFA tests found amyloid in the abdominal fat of 10 additional patients. At the time of the ASFA test, amyloidosis was subclinical in 45 of these 61 patients, 41 of whom were followed up. During followup, 11 of these 41 patients developed renal involvement, 5 due to amyloid nephropathy. Thus, amyloidosis remained subclinical in at least 30 of 41 patients (73%) throughout followup. Marked amyloid fat deposits were found more frequently in patients with clinical amyloidosis than in those whose amyloidosis remained subclinical at the end of followup (57% versus 22%; P = 0.04).

CONCLUSION

Amyloid fat deposits are not uncommon in adult RA. In the majority of patients, the deposits do not indicate clinically evident organic dysfunction, even after several years of followup. Patients with more extensive fat deposits may have a higher risk of developing clinical amyloidosis.

Amyloid precursors and amyloidosis in inflammatory arthritis

Recent data demonstrating the multifunctional role of serum amyloid A (SAA) in the pathogenesis of amyloidosis have yielded important insights into this potentially fatal consequence of chronic inflammation. SAA has been shown to participate in chemotaxis, cellular adhesion, cytokine production, and metalloproteinase secretion and is thus integrally involved in the disease process. In addition to its production by the liver as part of the acute phase response, SAA is also expressed by several pathologic tissues such atherosclerotic plaques, rheumatoid synovitis and in the brains of patients with Alzheimer disease. Its constitutive production in normal tissue suggests a role for SAA in host defense and tissue turnover. Many pathways are involved in the regulation of SAA, and as more becomes known about these, potential therapeutic targets may be identified. However, the prevention of secondary amyloidosis is best achieved by early and adequate treatment of patients with chronic inflammatory disorders. Suppression of the acute phase response and normalization of SAA levels are likely to significantly impact on the incidence of amyloidosis in inflammatory arthritis.

Amyloid precursors and amyloidosis in rheumatoid arthritis

Amyloidosis refers to the extracellular accumulation of amyloid fibrils, derived from a circulating precursor, in various tissue and organs. The most common form of amyloidosis worldwide is that which occurs secondary to chronic inflammatory disease, particularly rheumatoid arthritis. The precursor molecule is serum amyloid A (SAA), an acute phase reactant, which can be used as a surrogate marker of inflammation in many diseases. SAA has a number of immunomodulatory roles, can induce chemotaxis and adhesion molecule expression, has cytokine-like properties and can promote the upregulation of metalloproteinases. It enhances the binding of high density lipoprotein to macrophages and thus helps in the delivery of lipids to sites of injury for use in tissue repair. It is thus thought to be an integral part of the disease process. Moreover, elevated levels of SAA over time predispose to secondary amyloidosis. Pathogenic factors underlying this disease are outlined along with guidelines for diagnosis and management.

Intractable diarrhoea associated with secondary amyloidosis in rheumatoid arthritis

OBJECTIVE

To examine the clinical characteristics of intractable diarrhoea associated with secondary amyloidosis in rheumatoid arthritis (RA).

METHODS

Of 179 RA patients with biopsy confirmed secondary amyloidosis, 24 cases (23 women and one man) with intractable diarrhoea lasting for more than one month were retrospectively evaluated.

RESULTS

The mean (SD) duration of diarrhoea was 87 (64) days. Prodromal symptoms of gastrointestinal dysfunction (n = 21) and impaired peristalsis (n = 16) were observed. Laboratory data showed hypoproteinaemia (4.7 (0.85) g/dl) caused by malabsorption or protein loss and high values of C reactive protein (17.0 (9.3) mg/dl). Recurrence of intractable diarrhoea (n = 4) and transition from intractable diarrhoea to other gastrointestinal problems of amyloidosis (ischaemic colitis (n = 2) and intestinal pseudo-obstruction (n = 4)) were observed. In 19 patients (25 episodes) the duration of intravenous hyperalimentation at remission (18 episodes) was 68 (52) days. Corticosteroid pulse therapy was administered to 10 patients (11 times) and the time elapsed from the end of corticosteroid pulse therapy to the end of diarrhoea was 18 (14) days. One and five year survival rates after the onset of intractable diarrhoea were 73.4% and 38.9%. Seven of 13 patients (54%) had died as a result of infectious diseases.

CONCLUSION

Intractable diarrhoea associated with secondary amyloidosis in RA is a serious clinical entity and the prognosis is poor. Although it is assumed that intravenous hyperalimentation treatment and corticosteroid pulse therapy are favourable regimens for intractable diarrhoea, the patients should be monitored for possible infectious complications.

99mTc-HSA-D scintigraphy in the diagnosis of protein-losing gastroenteropathy due to secondary amyloidosis

Secondary amyloidosis frequently involves the gastrointestinal tract and may result in ulceration, hemorrhage, and protein-losing enteropathy. We report a patient with severe hypoalbuminemia in whom endoscopy revealed widespread ulceration of the small intestine. The protein-losing site was detected by 99mTc-diethylene triamine pentaacetic acid human serum albumin (99mTc HSA-D) scintigraphy. This evidence suggests that the ulcers and mucosal lesions associated with amyloidosis contribute to abnormal protein loss from the gastrointestinal tract.