Soft tissue, joint, and bone manifestations of AL amyloidosis: clinical presentation, molecular features, and survival

Oxidative Post-Translational Modifications of an Amyloidogenic Immunoglobulin Light Chain Protein

Immunoglobulin light chain amyloidosis (AL) is a plasma cell disorder characterized by overproduction and deposition of monoclonal immunoglobulin (Ig) light chains (LC) or variable region fragments as amyloid fibrils in various organs and tissues. Much clinical evidence indicates that patients with AL amyloidosis sustain cardiomyocyte impairment and suffer from oxidative stress. We seek to understand the underlying biochemical pathways whose disruption or amplification during sporadic or sustained disease states leads to harmful physiological consequences and to determine the detailed structures of intermediates and products that serve as signposts for the biochemical changes and represent potential biomarkers. In this study, matrix-assisted laser desorption/ionization mass spectrometry provided extensive evidence for oxidative post-translational modifications (PTMs) of an amyloidogenic Ig LC protein from a patient with AL amyloidosis. Some of the tyrosine residues were heavily mono- or di-chlorinated. In addition, a novel oxidative conversion to a nitrile moiety was observed for many of the terminal aminomethyl groups on lysine side chains. In vitro experiments using model peptides, in-solution oxidation, and click chemistry demonstrated that hypochlorous acid produced by the myeloperoxidase - hydrogen peroxide - chloride system could be responsible for these and other, more commonly observed modifications.

Light chain amyloidosis: Where are the light chains from and how they play their pathogenic role?

Amyloid light-chain (AL) amyloidosis is a plasma-cell dyscrasia, as well as the most common type of systematic amyloidosis. Pathogenic plasma cells that have distinct cytogenetic and molecular properties secrete an excess amount of amyloidogenic light chains. Assisted by post-translational modifications, matrix components, and other environmental factors, these light chains undergo a conformational change that triggers the formation of amyloid fibrils that overrides the extracellular protein quality control system. Moreover, the amyloidogenic light-chain itself is cytotoxic. As a consequence, organ dysfunction is caused by both organ architecture disruption and the direct cytotoxic effect of amyloidogenic light chains. Here, we reviewed the molecular mechanisms underlying this sequence of events that ultimately leads to AL amyloidosis and also discuss current in vitro and in vivo models, as well as relevant novel therapeutic approaches.

Immunoglobulin heavy light chain test quantifies clonal disease in patients with AL amyloidosis and normal serum free light chain ratio

BACKGROUND

Serum and urine immunofixation electrophoreses (SIFE/UIFE) are used for clonal detection in plasma cell dyscrasias, while serum free light chain (sFLC) testing provides quantitation of clonal disease. Up to 20% of patients with light chain (AL) amyloidosis may present with normal FLC ratio (FLCr).

METHODS

We assessed the diagnostic, quantitative and prognostic potential of serum heavy light chain ratio (HLCr) in 199 untreated patients at initial evaluation.

RESULTS

An abnormal HLCr was found in 37.2%, abnormal FLCr in 81.9% and positivity by SIFE/UIFE in 94% of patients. HLCr together with SIFE/UIFE identified clonality in 94% patients; the combination with FLCr yielded 100% sensitivity. An HLCr abnormality was significantly over-represented in normal compared to abnormal FLCr group (63.9% versus 31.3%). HLCr did not predict overall survival (OS) (log rank, p = 0.09), while an abnormal FLCr was associated with decreased OS (log rank, p = 0.03). The combined use of both ratios trended toward increased OS in the abnormal HLCr/normal FLCr group (log rank, p = 0.11; Wilcoxon, p = 0.04). On multivariate analysis, HLCr was not predictive of OS, whereas an abnormal FLCr was associated with shorter OS (HR = 1.7, p = 0.04).

CONCLUSIONS

The HLC assay has potential as a supplemental test to quantify monoclonal protein in patients with normal FLCr results.

Clarifying immunoglobulin gene usage in systemic and localized immunoglobulin light-chain amyloidosis by mass spectrometry

The goal of this study was to investigate the frequency of use of light-chain variable region (IGVL) genes among patients with systemic (AL_S) and localized (AL_L) amyloidosis and to assess for associations between IGVL gene usage and organ tropism. We evaluated clinic charts from 821 AL patients seen at the Mayo Clinic who had bone marrow, fat pad, and solid organ tissue samples typed by liquid chromatography tandem mass spectrometry (LC-MS). We identified 701 patients with AL_S and 120 with AL_L Overall, we were able to identify an IGVL gene in 87 (72%) patients with AL_L and 573 (82%) patients with AL_S When compared with AL_L, LV6-57 was more common, whereas KV3-20 and heavy-chain codeposition were less common in AL_S In this large series of AL_S, characteristics particular to specific genotypes became apparent. LV6-57 patients were more likely to have renal involvement and to harbor a translocation 11;14. LV3-01 patients were less likely to have advanced cardiac disease and renal involvement. LV2-14 patients were more likely to have peripheral nerve involvement, an intact circulating immunoglobulin, and lower circulating dFLC. LV1-44 patients were more likely to have cardiac involvement. KV1-33 patients had more liver involvement and higher circulating dFLC. Finally, KV1-05 was associated with inferior overall survival but not independently of cardiac stage. IGVL gene usage appears to provide clues about disease pathophysiology and tissue tropism. LC-MS is a high-throughput and low-resource technique that can be used to identify IGVL gene from clinical tissue specimens.

Amyloidosis of the gastrointestinal tract and the liver: clinical context, diagnosis and management

Amyloidosis is a group of disorders that can manifest in virtually any organ system in the body and is thought to be secondary to misfolding of extracellular proteins with subsequent deposition in tissues. The precursor protein that is produced in excess defines the specific amyloid type. This requires histopathological confirmation using Congo red dye with its characteristic demonstration of green birefringence under cross-polarized light. Gastrointestinal (GI) manifestations are common and the degree of organ involvement dictates the symptoms that a patient will experience. The small intestine usually has the most amyloid deposition within the GI tract. Patients generally have nonspecific findings such as abdominal pain, nausea, diarrhea, and dysphagia that can often delay the proper diagnosis. Liver involvement is seen in a majority of patients, although symptoms typically are not appreciated unless there is significant hepatic amyloid deposition. Pancreatic involvement is usually from local amyloid deposition that can lead to type 2 diabetes mellitus. In addition, patients may undergo either endoscopic or radiological evaluation; however, these findings are usually nonspecific. Management of GI amyloidosis primarily aims to treat the underlying amyloid type with supportive measures to alleviate specific GI symptoms. Liver transplant is found to have positive outcomes, especially in patients with specific variants of hereditary amyloidosis.

Atypical immunoglobulin light chain amyloidosis: Spontaneous vertebral compression fracture, liver involvement, and bone marrow involvement report of 3 cases and review of the literature

BACKGROUND

Primary immunoglobulin light chain amyloidosis (AL amyloidosis) is a plasma cell disorder which mainly affects heart, kidneys, liver, and peripheral nervous system. Cases of atypical AL amyloidosis presented as spontaneous vertebral compression fractures have been rarely reported, and data about the management and clinical outcomes of the patients are scarce.

METHODS

Herein, we present 3 new cases of AL amyloidosis with spontaneous vertebral compression fracture and review 13 cases retrieved from the literature.

RESULTS

Moreover, we observed overrepresentations of liver involvement and bone marrow involvement in AL amyloidosis with spontaneous vertebral compression fracture.

CONCLUSION

We believe that better awareness of the rare clinical presentation as spontaneous vertebral compression fracture of AL amyloidosis can facilitate earlier diagnosis and earlier treatment.

Immunoglobulin Light Chain Systemic Amyloidosis

Immunoglobulin light chain amyloidosis (AL) is a rare, complex disease caused by misfolded free light chains produced by a usually small, indolent plasma cell clone. Effective treatments exist that can alter the natural history, provided that they are started before irreversible organ damage has occurred. The cornerstones of the management of AL amyloidosis are early diagnosis, accurate typing, appropriate risk-adapted therapy, tight follow-up, and effective supportive treatment. The suppression of the amyloidogenic light chains using the cardiac biomarkers as guide to choose chemotherapy is still the mainstay of therapy. There are exciting possibilities ahead, including the study of oral proteasome inhibitors, antibodies directed at plasma cell clone, and finally antibodies attacking the amyloid deposits are entering the clinic, offering unprecedented opportunities for radically improving the care of this disease.

[Optimization of the immunohistochemical diagnosis of AL amyloidosis using novel antibodies]

OBJECTIVE

to improve the immunohistochemical diagnosis of AL amyloidosis, by generating novel peptide antibodies against the variable and constant regions of the κ-light chains.

MATERIAL AND METHODS

All amyloidogenic κ-light chains were sought in the scientific literature and the database of the National Center for Biotechnology Information. On the basis of the findings, a chain was formed from the most common amino acid residues that were used to choose peptide regions for immunization. Four antibodies were generalized via immunization of rabbits with two peptides that corresponded to the variant or constant regions of κ-light chains.

RESULTS

The specificity of the obtained antibodies was confirmed using a series of 222 biopsy specimens from 193 patients with AL, AA, transthyretin, or insulin amyloidosis. All the novel polyclonal peptide antibodies produced positive staining in cases of ALκ amyloidosis.

CONCLUSION

The generated polyclonal peptide antibodies against the variable and constant regions of κ-light chains are able to improve the immunohistochemical diagnosis of amyloidosis.

Osteoprotegerin is a significant prognostic factor for overall survival in patients with primary systemic amyloidosis independent of the Mayo staging

Bone metabolism has not been systematically studied in primary (AL) amyloidosis. Thus we prospectively evaluated bone remodeling indices in 102 patients with newly diagnosed AL amyloidosis, 35 healthy controls, 35 newly diagnosed myeloma and 40 monoclonal gammopathy of undetermined significance patients. Bone resorption markers (C-telopeptide of type-1 collagen, N-telopeptide of type-1 collagen) and osteoclast regulators (soluble receptor activator of nuclear factor-κB ligand (sRANKL), osteoprotegerin (OPG)) were increased in AL patients compared with controls (P<0.01), but bone formation was unaffected. Myeloma patients had increased bone resorption and decreased bone formation compared with AL patients, while sRANKL/OPG ratio was markedly decreased in AL, due to elevated OPG in AL (P<0.001). OPG correlated with N-terminal pro-brain natriuretic peptide (P<0.001) and was higher in patients with cardiac involvement (P=0.028) and advanced Mayo stage (P=0.001). OPG levels above the upper value of healthy controls was associated with shorter survival (34 versus 91 months; P=0.026), while AL patients with OPG levels in the top quartile had very short survival (12 versus 58 months; P=0.024). In Mayo stage 1 disease, OPG identified patients with poor survival (12 versus >60 months; P=0.012). We conclude that increased OPG in AL is not only a compensation to osteoclast activation but may also reflect early cardiac damage and may identify patients at increased risk of death within those with earlier Mayo stage.

Vertebral compression fractures as the initial presentation of AL amyloidosis: case series and review of literature

The clinical presentation of AL amyloidosis is highly variable. In this series, we describe five cases of AL amyloidosis with vertebral compression fractures as initial presentation. All five patients had evidence of bone marrow replacement on magnetic resonance imaging and bone marrow biopsies demonstrating diffuse interstitial amyloid deposition. Hepatomegaly and elevated liver enzymes, consistent with liver involvement with amyloidosis, were also seen in each case. All five patients responded well to anti-plasma cell chemotherapy, with normalization of serum free light chain levels, reduction in alkaline phosphatase and improvement in pain and functional status. Although rare, AL amyloidosis should be considered in the differential diagnosis of selected patients with spontaneous vertebral compression fractures. Moreover, there seems to be an association of vertebral compression fractures with liver involvement in AL amyloidosis.

Lymphadenopathy as a manifestation of amyloidosis: a case series

Lymphadenopathy as a manifestation of amyloidosis is rare. Of 3008 new patients with amyloidosis evaluated from 1994 to 2013 at a single center, 47 (1.6%) presented with lymph node enlargement leading to a biopsy and the diagnosis. We conducted a retrospective review of the initial presentation, time to progression, and treatment outcomes for these patients. Upon initial evaluation, 14 (30%) had isolated lymphadenopathy while 33 (70%) had evidence of vital organ involvement. Thirty-nine patients (83%) had systemic AL amyloidosis at initial evaluation or developed it on follow up; there was a single case each of AA, wtTTR and V122ITTR and one untyped amyloidosis. Eleven patients (23%) had IgM monoclonal gammopathy and 3 (6%) had histology consistent with lymphoplasmacytic lymphoma. Of the 14 patients with isolated lymphadenopathy, 10 (71%) eventually progressed to other organ disease requiring treatment at a median time of 10 months (range 4-71). This series demonstrates that patients presenting with amyloid lymphadenopathy usually have AL amyloidosis, and should have a thorough evaluation for other organ involvement at diagnosis. If present, treatment should be similar to that of other patients with systemic AL amyloidosis, but if not, patients should be monitored regularly for development of other organ disease over time.

[A 48-year-old patient with oligoarthritis of the knees, having excluded spondyloarthritis and rheumathoid arthritis]

We report the case of a patient with amyloid light-chain (AL) amyloidosis, presenting for more than 1.5 years with oligoarthritis as the only clinical symptom of the underlying disease. Developing further organ symptoms (heart and gastrointestinal tract) led to the definitive diagnosis. Joint involvement due to AL amyloidosis is extremely rare and may mimic rheumatoid arthritis. Arthritis might be the first symptom of the AL amyloidosis. The combination of arthritis and other organ disorders (e.g., proteinuria, heart failure, or diarrhea) should initiate further diagnostic efforts considering AL amyloidosis as a differential diagnosis. The diagnosis will be confirmed by the typical histology of synovia or involved organs including immunohistochemistry for typing amyloid and performing immunoelectrophoresis.

Amyloidoma, an unusual cause of fracture

We report a case of a spontaneous hip fracture in a context of dysglobulinemia. The bone histologic examination found amyloidoma. Amyloidoma is an overload pathology and an unusual cause of fracture. In most of the cases, it is associated with myeloma and the difference between bone invasion of myeloma and amyloidoma in an osteolytic radiographic picture is not easy but is of importance because prognosis and treatment may be totally different. Thus, in the context of dysglobulinemia, one must keep in mind that spontaneous bone fracture may be due to amyloidoma with another prognosis.

Immunoglobulin light chain amyloidosis

Primary light chain amyloidosis is the most common form of systemic amyloidosis and is caused by misfolded light chains that cause proteotoxicity and rapid decline of vital organ function. Early diagnosis is essential in order to deliver effective therapy and prevent irreversible organ damage. Accurate diagnosis requires clinical skills and advanced technologies. The disease can be halted and the function of target organs preserved by the prompt reduction and elimination of the plasma cell clone producing the toxic light chains in the bone marrow. Heart damage is the major determinant of survival, and staging with cardiac biomarkers guides treatment. Two-thirds of patients can benefit from treatment with improved quality of life and extended survival. Future efforts should be directed at early diagnosis, improving the tolerability and efficacy of anti-plasma cell therapy, accelerating recovery of organ function via promoting resorption of amyloid deposits, and developing novel approaches to counter light chain proteotoxicity.

[Skin manifestations of monoclonal gammopathies]

Whatever their aetiology, monoclonal gammopathies can be associated to several clinical features. Mechanisms are various and sometimes unknown. Skin is frequently involved and may represent a challenging diagnosis. Indeed, skin manifestations are either the presenting features and isolated, or at the background of a systemic syndrome. Our objective was to review the various skin manifestations that have been associated with monoclonal gammopathies.

Amyloid formation in light chain amyloidosis

Light chain amyloidosis is one of the unique examples within amyloid diseases where the amyloidogenic precursor is a protein that escapes the quality control machinery and is secreted from the cells to be circulated in the bloodstream. The immunoglobulin light chains are produced by an abnormally proliferative monoclonal population of plasma cells that under normal conditions produce immunoglobulin molecules such as IgG, IgM or IgA. Once the light chains are in circulation, the proteins misfold and deposit as amyloid fibrils in numerous tissues and organs, causing organ failure and death. While there is a correlation between the thermodynamic stability of the protein and the kinetics of amyloid formation, we have recently found that this correlation applies within a thermodynamic range, and it is only a helpful correlation when comparing mutants from the same protein. Light chain amyloidosis poses unique challenges because each patient has a unique protein sequence as a result of the selection of a germline gene and the incorporation of somatic mutations. The exact location of the misfolding process is unknown as well as the full characterization of all of the toxic species populated during the amyloid formation process in light chain amyloidosis.

Systemic amyloidoses

The amyloidoses are a group of protein misfolding diseases in which the precursor protein undergoes a conformational change that triggers the formation of amyloid fibrils in different tissues and organs, causing cell death and organ failure. Amyloidoses can be either localized or systemic. In localized amyloidosis, amyloid deposits form at the site of precursor protein synthesis, whereas in systemic amyloidosis, amyloid deposition occurs distant from the site of precursor protein secretion. We review the type of proteins and cells involved and what is known about the complex pathophysiology of these diseases. We focus on light chain amyloidosis to illustrate how biochemical and biophysical studies have led to a deeper understanding of the pathogenesis of this devastating disease. We also review current cellular, tissue, and animal models and discuss the challenges and opportunities for future studies of the systemic amyloidoses.

How to deal with laryngeal amyloidosis? Experience based on 16 cases

INTRODUCTION

Amyloidosis is characterized by the deposition of amorphous fibrillar protein (amyloid) in the intercellular or intracellular space. Localized amyloidosis is rare in the head and neck area. In Polish literature of the last decade it has been the subject of case studies.

AIM

The goal of the study was to carry out a retrospective analysis of patients treated for amyloidosis in the Department of Otolaryngology and Head and Neck Surgery of the Poznań University of Medical Sciences in the period from 2000 to 2009. Based on the collected clinical material, the authors made an attempt to determine the most frequent anatomical location of amyloid deposits and the most frequently affected organs, the type and duration of symptoms, the therapeutic approach, further diagnostic measures taken and the final outcome of the treatment. The next goal was to assess the number of microlaryngoscopies performed in patients with amyloidosis affecting the larynx as compared to the overall number of such procedures.

MATERIAL

The detailed analysis included 16 patients with laryngeal amyloidosis.

RESULTS

Amyloidosis of the larynx was found in only 0.52% of patients undergoing microlaryngoscopies in the period from 2000 to 2009. In the vast majority of patients (11 of 16), there was no suspicion of amyloidosis in the initial diagnosis. Only the histopathological assessment definitely confirmed the nature of pathological changes in the larynx. Glottis was the most common location of amyloid deposits in the study group. In all cases, additional studies and long-term monitoring of the postoperative course excluded generalized amyloidosis.

CONCLUSIONS

Laryngeal amyloidosis is very rare, however it should be considered in the differential diagnosis in patients with laryngeal dysfunction. Surgery remains the treatment of choice in most patients, although the attempts of radiotherapy are undertaken. Preserving the normal function of the organ remains the priority.

Hereditary lysozyme amyloidosis -- phenotypic heterogeneity and the role of solid organ transplantation

OBJECTIVES

Lysozyme amyloidosis (ALys) is a form of hereditary systemic non-neuropathic amyloidosis, which is inherited in an autosomal dominant fashion. Lysozyme, which is the amyloidogenic precursor protein in ALys, is a ubiquitous bacteriolytic enzyme synthesized by hepatocytes, polymorphs and macrophages. The aim of this study is to describe the phenotype and outcome of patients with ALys including the role of solid organ transplantation.

DESIGN

Retrospective evaluation of patients with ALys.

SETTING

UK National Amyloidosis Centre.

PATIENTS

All 16 patients with ALys followed at the centre.

RESULTS

A family history of amyloidosis was present in every affected individual. Although the phenotype was broadly similar amongst those from the same kindred, there were marked phenotypic differences between kindreds who possessed the same amyloidogenic mutation. Symptomatic gastrointestinal (GI) amyloid was prevalent, and macroscopically visible amyloidotic lesions were present in nine of 10 patients who underwent GI endoscopy. All symptomatic ALys individuals had hepatic amyloid. Four patients received orthotopic liver transplants (OLT), three for spontaneous hepatic rupture and one case, who had extensive hepatic amyloid and a strong family history of hepatic rupture, pre-emptively. All of the liver grafts were functioning at censor 1.7, 5.8, 9.0 and 11.0 years after OLT. Five patients had progressive amyloidotic renal dysfunction culminating in end-stage renal failure, three of whom underwent renal transplantation (RTx). There was no evidence of renal allograft dysfunction at censor 6.6, 1.8 and 0.8 years after RTx.

CONCLUSIONS

Lysozyme amyloidosis is a disease of the GI tract, liver and kidneys, which has a slow natural history. There was a clear family history in all cases within this cohort, demonstrating a high clinical penetrance in the presence of an amyloidogenic lysozyme mutation. There is currently no amyloid-specific therapy for the condition which is managed symptomatically. OLT and RTx appear to be successful treatments for patients with liver rupture or end-stage renal disease, respectively, with excellent outcomes in terms of medium-term graft function and patient survival.

Immunoglobulin light chain, Blimp-1 and cytochrome P4501B1 peptides as potential vaccines for AL amyloidosis

Amyloid light chain (AL) amyloidosis is a lethal disorder characterized by the pathologic deposition of clonal plasma cell-derived, fibrillogenic immunoglobulin light chains in vital organs. Current chemotherapeutic regimens are problematic in patients with compromised organ function and are not effective for all patients. Here, a platform of computer-based prediction and preclinical mouse modeling was used to begin development of a complementary, immunotherapeutic approach for AL amyloidosis. Three peptide/MHC I-binding algorithms identified immunogenic peptides from three AL plasma cell-associated proteins: (1) amyloidogenic λ6 light chains, (2) CYP1B1, a universal tumor antigen hyper-expressed in AL plasma cells and (3) B lymphocyte-induced maturation protein 1 (Blimp-1), a transcription factor required for plasma cell differentiation. The algorithms correctly predicted HLA-A(*)0201-binding native and heteroclitic peptides. In HLA-A2 transgenic mice, these peptides, given individually or in combination, induced potent CTL which kill peptide-loaded human lymphoma cells and/or lymphoma cells producing target protein. Blimp-1 peptide-immunized mice exhibited a reduced percentage of splenic, lymph node and bone marrow plasma cells and a decrease in the absolute number of splenic plasma cells demonstrating (1) presentation of target peptide by endogenous plasma cells and (2) appropriate CTL homing to lymphoid organs followed by killing of target plasma cells. These studies suggest that AL amyloidosis, with its relatively low tumor cell burden, may be an attractive target for peptide-based multivalent vaccines.

What do I need to know about immunoglobulin light chain (AL) amyloidosis?

Immunoglobulin light chain (AL) amyloidosis is the most common acquired systemic amyloidoses. Its presentation is often insidious and progressive, which may delay diagnosis. The interval between first symptoms and actual diagnosis along the intrinsic heterogeneity of tissue tropism create a wide spectrum of presentations, both in terms of scope and depth of symptoms and signs and functional status of patients. In this review, the authors review the pathogenesis, diagnosis and differential diagnosis of AL amyloidosis along with the prognosis and state-of-the-art management for patients with this affliction.

The repertoire of λ light chains causing predominant amyloid heart involvement and identification of a preferentially involved germline gene, IGLV1-44

Monoclonal Ig light chains (LC) can be responsible for pathologic conditions in humans, as in systemic amyloid light amyloidosis. Protean clinical manifestations characterize this disorder with the most varied combination of symptoms generated by different degrees of diverse organ involvement. Kidney and heart are most frequently interested, with major heart involvement as the most relevant prognostic factor. The identification of the underlying mechanism involved in organ targeting is of major relevance for the pathobiology of this disorder. To this aim, we characterized the repertoire of variable region germline genes of λ LC preferentially targeting the heart and compared it with the repertoire of LC that do not in a case-control study. We found that the repertoires were highly restricted, showing preferential use of the same few germline genes but with a different frequency pattern. A single gene, IGVL1-44, was found associated with a 5-fold increase in the odds of dominant heart involvement (after adjusting for confounders in a multivariable logistic model). These results support an involvement of LC genetics in the determination of organ targeting. Study of the characteristics of IGVL1-44-LC with, and of the minority without, heart involvement might lead to identification of LC/tissue interactions.

Macroglossia due to Systemic Amyloidosis: Is There a Role for Radiotherapy?

Background

Macroglossia due to amyloid depositions can cause cosmetic problems and functional disability, and can lead to life-threatening airway obstruction. Management of macroglossia in systemic amyloidosis is controversial, and the role of surgery is unclear.

Case Description

We present a case of a 66-year-old woman affected by macroglossia due to light chain amyloidosis who presented with eating and breathing difficulties. Because of prior successful results of radiotherapy for localized amyloid disease, our patient was treated with external beam radiation therapy (20 Gy in 10 fractions). The treatment was well tolerated by the patient. However, her systemic amyloidosis progressed, with a subclinical increase in tongue width.

Conclusions

This is the first reported use of radiotherapy for amyloidosis of the tongue. There was no evidence of benefit using a total dose of 20 Gy. This therapeutic modality is not recommended for the routine management of macroglossia.

Amyloidosis: pathogenesis and new therapeutic options

The systemic amyloidoses are a group of complex diseases caused by tissue deposition of misfolded proteins that results in progressive organ damage. The most common type, immunoglobulin light chain amyloidosis (AL), is caused by clonal plasma cells that produce misfolded light chains. The purpose of this review is to provide up-to-date information on diagnosis and treatment options for AL amyloidosis. Early, accurate diagnosis is the key to effective therapy, and unequivocal identification of the amyloidogenic protein may require advanced technologies and expertise. Prognosis is dominated by the extent of cardiac involvement, and cardiac staging directs the choice of therapy. Treatment for AL amyloidosis is highly individualized, determined on the basis of age, organ dysfunction, and regimen toxicities, and should be guided by biomarkers of hematologic and cardiac response. Alkylator-based chemotherapy is effective in almost two thirds of patients. Novel agents are also active, and trials are ongoing to establish their optimal use. Treatment algorithms will continue to be refined through controlled trials. Advances in basic research have led to the identification of new drug targets and therapeutic approaches, which will be integrated with chemotherapy in the future.

Role of glycosaminoglycan sulfation in the formation of immunoglobulin light chain amyloid oligomers and fibrils

Primary amyloidosis (AL) results from overproduction of unstable monoclonal immunoglobulin light chains (LCs) and the deposition of insoluble fibrils in tissues, leading to fatal organ disease. Glycosaminoglycans (GAGs) are associated with AL fibrils and have been successfully targeted in the treatment of other forms of amyloidosis. We investigated the role of GAGs in LC fibrillogenesis. Ex vivo tissue amyloid fibrils were extracted and examined for structure and associated GAGs. The GAGs were detected along the length of the fibril strand, and the periodicity of heparan sulfate (HS) along the LC fibrils generated in vitro was similar to that of the ex vivo fibrils. To examine the role of sulfated GAGs on AL oligomer and fibril formation in vitro, a κ1 LC purified from urine of a patient with AL amyloidosis was incubated in the presence or absence of GAGs. The fibrils generated in vitro at physiologic concentration, temperature, and pH shared morphologic characteristics with the ex vivo κ1 amyloid fibrils. The presence of HS and over-O-sulfated-heparin enhanced the formation of oligomers and fibrils with HS promoting the most rapid transition. In contrast, GAGs did not enhance fibril formation of a non-amyloidogenic κ1 LC purified from urine of a patient with multiple myeloma. The data indicate that the characteristics of the full-length κ1 amyloidogenic LC, containing post-translational modifications, possess key elements that influence interactions of the LC with HS. These findings highlight the importance of the variable and constant LC regions in GAG interaction and suggest potential therapeutic targets for treatment.

Comparison of amyloid fibril formation by two closely related immunoglobulin light chain variable domains

Light chain amyloidosis (AL amyloidosis) is a haematological disorder in which a clonal population of B cells expands and secretes enormous amounts of the immunoglobulin light chain protein. These light chains misfold and aggregate into amyloid fibrils, leading to organ dysfunction and death. We have studied the in vitro fibril formation kinetics of two patient-derived immunoglobulin light chain variable domain proteins, designated AL-09 and AL-103, in response to changes in solution conditions. Both proteins are members of the κI O18:O8 germline and therefore are highly similar in sequence, but they presented with different clinical phenotypes. We find that AL-09 forms fibrils more readily and more rapidly than AL-103 in vitro, mirroring the clinical phenotypes of the patients and suggesting a possible connection between the fibril kinetics of the disease protein and the disease progression.

Systemic amyloidosis: a challenge for the rheumatologist

Amyloidosis comprises a group of diseases characterized by the extracellular deposition of insoluble fibrillar proteins. This mechanism generates different clinical syndromes depending on the site and extent of organ involvement. Amyloidosis is classified into categories of systemic and localized disease. Systemic amyloidosis is further subdivided into a hereditary familial form (for example, ATTR amyloidosis), a reactive form (AA amyloidosis), dialysis-related (Abeta(2)M) amyloidosis and immunoglobulin light chain (AL) amyloidosis. Treatment can be symptomatic, directed at the affected organ, or can be directed at reducing the production of the abnormal proteins with different strategies. Despite advances in treatment, the prognosis is still poor and depends on the underlying disease as well as the type and degree of dysfunction in involved organs. Early diagnosis is essential because patients with advanced disease are generally unable to undergo intensive therapy. Patients with systemic amyloidosis often present to a rheumatologist not only because the disease can include musculoskeletal and articular symptoms but also because it can be associated with chronic rheumatic diseases. This Review discusses the clinical features of amyloidosis and its rheumatic manifestations. The various types of amyloidosis, as well their prognosis and treatment, are also presented.

Exceptional oral manifestations of amyloid light chain protein (AL) systemic amyloidosis

Oral amyloidosis is usually presented in the tongue and is often associated with multiple myeloma. We present three patients with unusual oral manifestations of primary amyloidosis, which to the best of our knowledge have not been previously published. In two cases the oral manifestation was overt at the time of diagnosis and all cases ended in patient mortality. Since these oral manifestations can contribute to the diagnosis of systemic amyloidosis, clinicians should be made aware of them. Future research should assess the significance of oral manifestation as a prognostic indicator.

Amyloid and the GI tract

Amyloidosis is characterized by the extracellular deposition of an abnormal fibrillar protein, which disrupts tissue structure and function. Amyloid may be localized to a single organ, such as the GI tract, or be systemic where the amyloid type is defined by the respective fibril precursor protein. Among patients with systemic amyloidosis, histological involvement of the gastrointestinal (GI) tract is very common but often subclinical. The presence and pattern of GI symptoms varies substantially, not only between the different amyloid types but also within them. GI presentations are frequently nonspecific and include macroglossia, dyspepsia, hemorrhage, a change in bowel habit and malabsorption. Endoscopic and radiological features of amyloidosis are also nonspecific, with the small intestine most commonly affected. In the absence of specific treatments for GI amyloidosis, therapy is aimed at reducing or eliminating the supply of the respective fibril precursor protein. Supportive measures such as nutritional support and antidiarrheal agents should be instigated while awaiting the clinical improvement associated with a successful reduction in the abundance of the fibril precursor protein. GI tract surgery should be performed only if the benefits clearly outweigh the risks, as there is a risk of decompensation of organs affected by amyloid.

Systemic amyloidosis and the gastrointestinal tract

Systemic amyloidosis is characterized by the extracellular deposition of protein in an abnormal fibrillar form. Several different types of amyloidosis exist, each defined by the identity of their respective fibril precursor protein. Among patients with systemic amyloidosis, histological involvement of the gastrointestinal tract is very common but is often subclinical. Conversely, primary diseases of the gastrointestinal tract can cause systemic amyloidosis; for example, AA amyloidosis can occur secondary to IBD. The presence and pattern of gastrointestinal symptoms varies substantially, not only between the different types of amyloidosis but also within them. Typical clinical presentations, most of which are nonspecific, include macroglossia, hemorrhage, motility disorders, disturbance of bowel habit and malabsorption. Endoscopic and radiological features are also nonspecific, with the small intestine most commonly affected. Currently, the aim of therapy for amyloidosis is to slow amyloid formation by reducing the abundance of the fibril precursor protein. No specific treatments for the gastrointestinal symptoms of systemic amyloidosis are available; however, case reports and small published series encourage nutritional support for patients with motility disorders and pharmacological agents for treatment of diarrhea. Surgical procedures should be contemplated only in an emergency setting because of the risk of decompensation of organs affected by amyloid deposition.

Hepatic response after high-dose melphalan and stem cell transplantation in patients with AL amyloidosis associated liver disease

High-dose melphalan chemotherapy and autologous peripheral blood stem cell transplantation has been shown to result in durable hematologic response and prolonged overall survival in systemic AL amyloidosis. In this retrospective study, we evaluated clinical and hematologic responses in 69 patients with predominant liver involvement who were treated with high-dose intravenous melphalan and autologous stem cell transplantation from 1998 to 2006. Nine patients (13%) died from treatment-related mortality, similar to patients without hepatic involvement. The overall survival was 81% at one year and 61% at five years, by Kaplan-Meier estimates. A hematologic complete response was achieved by 53% (31/58) of patients at one year. A hepatic response occurred in 57% (33/58) at one year after high-dose intravenous melphalan and autologous stem cell transplantation and 63% (19/30) at two years after high-dose intravenous melphalan and autologous stem cell transplantation. In conclusion, hepatic disease improves in almost 2/3 patients treated with high-dose intravenous melphalan and autologous stem cell transplantation who have a complete or partial hematologic response to treatment.

Mutations in specific structural regions of immunoglobulin light chains are associated with free light chain levels in patients with AL amyloidosis

Background

The amyloidoses are protein misfolding diseases characterized by the deposition of amyloid that leads to cell death and tissue degeneration. In immunoglobulin light chain amyloidosis (AL), each patient has a unique monoclonal immunoglobulin light chain (LC) that forms amyloid deposits. Somatic mutations in AL LCs make these proteins less thermodynamically stable than their non-amyloidogenic counterparts, leading to misfolding and ultimately the formation of amyloid fibrils. We hypothesize that location rather than number of non-conservative mutations determines the amyloidogenicity of light chains.

Methodology/Principal Findings

We performed sequence alignments on the variable domain of 50 κ and 91 λ AL light chains and calculated the number of non-conservative mutations over total number of patients for each secondary structure element in order to identify regions that accumulate non-conservative mutations. Among patients with AL, the levels of circulating immunoglobulin free light chain varies greatly, but even patients with very low levels can have very advanced amyloid deposition.

Conclusions

Our results show that in specific secondary structure elements, there are significant differences in the number of non-conservative mutations between normal and AL sequences. AL sequences from patients with different levels of secreted light chain have distinct differences in the location of non-conservative mutations, suggesting that for patients with very low levels of light chains and advanced amyloid deposition, the location of non-conservative mutations rather than the amount of free light chain in circulation may determine the amyloidogenic propensity of light chains.

Systemic light chain amyloidosis and Sjogren syndrome: an uncommon association

Sjogren syndrome is associated with lymphoproliferative disease in 7% of cases; however, association with AL amyloidosis is uncommon. We present a patient who presented simultaneously with Sjogren syndrome (supported by dry mouth, positive Schirmer's test, anti-Ro/SSA antibodies, and a lower lip salivary gland biopsy) and AL amyloidosis revealed by heart failure without myeloma. Although is it know that amyloidosis can masquerade as Sjogren syndrome, the occurrence of simultaneous AL amyloidosis and primary Sjogren syndrome has been reported rarely.

Heterogeneity in primary structure, post-translational modifications, and germline gene usage of nine full-length amyloidogenic kappa1 immunoglobulin light chains

Immunoglobulin light chain amyloidosis is a protein misfolding disease in which a monoclonal immunoglobulin (Ig) light chain (LC) with a critically folded beta-conformation self-aggregates to form highly ordered, nonbranching amyloid fibrils. The insoluble nature of amyloid fibrils ultimately results in the extracellular deposition of the LC in tissues and organs throughout the body. Structural features that confer amyloidogenic properties on an Ig LC likely include amino acid sequence variations and post-translational modifications, but the specific natures of these changes remain to be defined. As part of an exploration of the effective range of amyloidogenic modifications, this study details the structural and genetic analyses of nine kappa1 LC proteins. Urinary LCs were purified by size exclusion chromatography using FPLC, and structural analyses were performed by electrospray ionization, matrix-assisted laser desorption/ionization, and tandem mass spectrometry. RT-PCR amplification, cloning, and sequencing of the monoclonal LC genes were accomplished using bone marrow-derived mRNA. Clinical data were reviewed retrospectively. Characterization of the urinary kappa1 LCs revealed extensive post-translational modification in all proteins, in addition to somatic mutations expected on the basis of results from genetic analyses. Post-translational modifications included disulfide-linked dimerization, S-cysteinylation, glycosylation, fragmentation, S-sulfonation, and 3-chlorotyrosine formation. Genetic analyses showed that several LC variable region germline gene donors were represented including O18/O8, O12/O2, L15, and L5. Clinical features included soft tissue, cardiac, renal, and hepatic involvement. This study demonstrated the extensive heterogeneity in primary structure, post-translational modifications, and germline gene usage that occurred in nine amyloidogenic kappa1 LC proteins.