Retinitis pigmentosa associated with systemic light chain amyloidosis (AL amyloidosis)

Retinitis pigmentosa (RP) or hereditary retinal dystrophy is a rare disease that can be isolated (non-syndromic RP) or associated with other systemic signs (syndromic RP). Kidney damage is exceptionally reported in patients with RP, particularly in syndromic forms. Association with renal amyloidosis remains unusual with only one reported case of RP and hereditary gelsolin amyloidosis due to a G654A gelsolin mutation defining the new syndrome of Ardalan-Shoja-Kiuru. Apart from this publication, no case associating RP and AL amyloidosis has been found. We report an original case of renal damage revealing kappa-type systemic light chains amyloidosis (AL amyloidosis) in 35-year-old man with sporadic RP. Our observation is, to our knowledge, the first to report this association.

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Retinal Transplantation, Stem Cell and Gene Therapy in Retinitis Pigmentosa

Güncel Retina Dergisi (Current Retina Journal) ◽

10.37783/crj-0251 ◽

2021 ◽

pp. 131-139

Keyword(s):

Gene Therapy ◽

Stem Cell ◽

Retinitis Pigmentosa ◽

Retinal Dystrophy ◽

Gene Replacement ◽

Disease Genes ◽

Functional Roles ◽

Tunnel Vision ◽

Hereditary Retinal Dystrophy ◽

Cell And Gene Therapy

Retinitis pigmentosa is the most common hereditary retinal dystrophy which has marked clinical and genetic heterogeneity. Common presentations among this disorder include night blindness, tunnel vision, and subsequent progression to complete blindness respectively. The known causative disease genes have a variety of developmental and functional roles, with mutations in more than 120 genes shown to be responsible for the phenotypes. In addition, mutations within the same gene have been shown to cause different disease phenotypes, even within the same family, highlighting further levels of complexity. In recent years significant advancements have been made in the understanding of the pathogenesis of the disease and stem cell and gene replacement treatments have been proposed as potentially efficacious therapies. This review summarizes the clinical development of retinal stem cell and gene therapy.

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Quantitative Immunoprecipitation Free Light Chain Mass Spectrometry (QIP-FLC-MS) Simplifies Monoclonal Protein Assessment and Provides Added Clinical Value in Systemic AL Amyloidosis

Blood ◽

10.1182/blood-2019-128175 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 4375-4375 ◽

Cited By ~ 1

Author(s):

Faye Amelia Sharpley ◽

Hannah Victoria Giles ◽

Richa Manwani ◽

Shameem Mahmood ◽

Sajitha Sachchithanantham ◽

...

Keyword(s):

Mass Spectrometry ◽

Light Chain ◽

Residual Disease ◽

Renal Involvement ◽

Light Chains ◽

Al Amyloidosis ◽

Free Light Chains ◽

Accurate Identification ◽

Monoclonal Protein ◽

Serum And Urine

Introduction Early diagnosis, effective therapy and precise monitoring are central for improving clinical outcomes in systemic light chain (AL) amyloidosis. Diagnosis and disease response assessment is primarily based on the presence of monoclonal immunoglobulins and free light chains (FLC). The ideal goal of therapy associated with best outcomes is a complete responses (CR), defined by the absence of serological clonal markers. In both instances, detection of the monoclonal component (M-component) is based on serum FLC assessment together with traditional serum and urine electrophoretic approaches, which present inherent limitations and lack sensitivity particularly in AL where the levels are typically low. Novel mass spectrometry methods provide sensitive, accurate identification of the M-component and may prove instrumental in the timely management of patients with low-level amyloidogenic light chain production. Here we assess the performance of quantitative immunoprecipitation FLC mass spectrometry (QIP-FLC-MS) at diagnosis and during monitoring of AL amyloidosis patients treated with bortezomib-based regimens. Methods We included 46 serial patients with systemic AL amyloidosis diagnosed and treated at the UK National Amyloidosis Centre (UK-NAC). All patients had detailed baseline assessments of organ function and serum FLC measurements. Baseline, +6- and +12-month serum samples were retrospectively analysed by QIP-FLC-MS. Briefly, magnetic microparticles were covalently coated with modified polyclonal sheep antibodies monospecific for free kappa light chains (anti-free κ) and free lambda light chains (anti-free λ). The microparticles were incubated with patient sera, washed and treated with acetic acid (5% v/v) containing TCEP (20 mM) in order to elute FLC in monomeric form. Mass spectra were acquired on a MALDI-TOF-MS system (Bruker, GmbH). Results were compared to serum FLC measurements (Freelite®, The Binding Site Group Ltd), as well as electrophoretic assessment of serum and urine proteins (SPE, sIFE, UPE and uIFE). Results Cardiac (37(80%) patients) and renal (31(67%) patients) involvement were most common; 25(54%) patients presented with both. Other organs involved included liver (n=12), soft tissue (n=4), gastrointestinal tract (n=3) and peripheral nervous system (n=2). Baseline Freelite, SPE, sIFE and uIFE measurements identified a monoclonal protein in 42(91%), 22(48%), 34(74%) and 21(46%) patients, respectively. A panel consisting of Freelite + sIFE identified the M-component in 100% of the samples. QIP-FLC-MS alone also identified an M-component in 100% of the samples and was 100% concordant with Freelite for typing the monoclonal FLC (8 kappa, 34 lambda). In 4 patients, QIP-FLC-MS identified an additional M-protein that was not detected by the other techniques. In addition, 4/8(50%) kappa and 4/38(11%) lambda patients showed a glycosylation pattern of monoclonal FLCs at baseline by mass spectrometry. Interestingly, the frequency of renal involvement was significantly lower for patients with non-glycosylated forms (25% vs 76%, p=0.01), while no similar relationship was found for any other organs. During the 1-year follow-up period, 17 patients achieved a CR; QIP-FLC-MS identified serum residual disease in 13(76%) of these patients. Conclusion In our series, QIP-FLC-MS was concordant with current serum methods for identifying the amyloidogenic light chain type and provided, against all other individual tests, improved sensitivity for the detection of the monoclonal protein at diagnosis and during monitoring. The ability to measure the unique molecular mass of each monoclonal protein offers clone-specific tracking over time. Glycosylation of free light chains is over-represented in AL patients which may allow earlier diagnosis and better risk-assessment of organ involvement. Persistence of QIP-FLC-MS positive M component in patients otherwise in CR may allow targeted therapy. Overall, QIP-FLC-MS demonstrates potential to be exploited as a single serum test for precise serial assessment of monoclonal proteins in patients with AL amyloidosis. Disclosures Wechalekar: GSK: Honoraria; Janssen-Cilag: Honoraria; Amgen: Research Funding; Takeda: Honoraria; Celgene: Honoraria.

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Immunoglobulin Light Chain Amyloidosis Presenting as Inferior Vena Cava Thrombosis

The American Surgeon ◽

10.1177/00031348211050834 ◽

2021 ◽

pp. 000313482110508

Author(s):

Anna Axentiev ◽

Marina Rozik ◽

Eliza Slama ◽

Viney Setya

Keyword(s):

Inferior Vena Cava ◽

Rare Disease ◽

Light Chain ◽

Inferior Vena ◽

Vena Cava ◽

Abdominal Fat ◽

Al Amyloidosis ◽

Fat Pad ◽

Renal Veins ◽

Immunoglobulin Light Chain

Immunoglobulin light chain (AL) amyloidosis is a rare disease characterized by the deposition of misfolded extracellular proteins within various body tissues resulting in dysfunction of the cardiac, renal, gastrointestinal, hematologic, and nervous systems, among others. Systemic AL amyloidosis often presents with a constellation of vague symptoms such as fatigue, dyspnea, and abdominal pain. Untreated AL amyloidosis with cardiac involvement is rapidly fatal with a median survival of 6 months. In this report, we will highlight the case of a 43-year-old female who presented with generalized abdominal symptoms and fatigue. She was found to have extensive inferior vena cava (IVC) thrombosis extending into the renal veins bilaterally in the setting of nephrotic range proteinuria, new onset arrhythmia, diastolic heart failure, gastrointestinal, and autonomic dysfunction. She received systemic thrombolytic therapy for the IVC and renal vein thrombosis. The multiorgan involvement led us to consider the possibility of amyloidosis. Abdominal fat pad biopsy was performed as part of the diagnostic effort. The abdominal fat pad biopsy did not reveal AL amyloidosis. Ultimately, the diagnosis of systemic AL amyloidosis was made on the basis of pathology from luminal biopsies obtained during outpatient esophagogastroduodenoscopy that was performed days prior to her admission. Unique to our case is the patient presentation with extensive thrombotic disease of the IVC and renal veins. It is important to understand the disease process, presenting signs and symptoms as well as diagnostic essentials based on current literature in order to minimize the morbidity and mortality of this rare disease.

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Al amyloidosis with cardiac involvement: cardiotoxicity of aggregation prone peptides deriving from variable domains of immunoglobulin light chains

European Heart Journal ◽

10.1093/ehjci/ehaa946.0886 ◽

2020 ◽

Vol 41 (Supplement_2) ◽

Author(s):

P.E Nikolaou ◽

G.I Nasi ◽

I Sulaiman ◽

P Spatharas ◽

S Kikionis ◽

...

Keyword(s):

Electron Microscopy ◽

Cell Death ◽

Light Chain ◽

Hot Spots ◽

Cytotoxic Effect ◽

Light Chains ◽

Al Amyloidosis ◽

H9c2 Cells ◽

Variable Domains

Abstract Background/Introduction Light chain (AL) amyloidosis is an uncommon malignancy manifested by systemic extracellular deposition of immunoglobulin light chain fibrils. The cardiac phenotype is characterised by ventricular wall thickening and stands as the most prominent cause of morbidity and mortality. Although, it has been established that the circulating light chains directly impair cardiomyocyte function, the cytotoxic effect of specific amyloidogenic peptides that may appear due to excessive cleavage of light chains remains unspecified. Purpose In the present work, we aimed to detect amyloidogenic “hot-spots” on the variable domains of light chains associated with cardiac AL amyloidosis (IGLV1-44 and IGLV3-01) or inferior outcomes (IGLV6-57) and define their cytotoxic effect in vitro. Methods At first, we used the curated database ALBase and we performed a multiple sequence alignment of the IGLV1-44, IGLV3-01 and IGLV6-57 inputs that derived only from patients with AL amyloidosis. “Aggregation-prone” hot-spots in the conserved amino acid sequences were identified with the aid of AMYLPRED2, a tool which combines 11 independent computational methods and provides a consensus result of potent amyloidogenic regions. Five peptides were rationally selected and synthetically produced in order to be tested in vitro. The amyloidogenic properties of the peptides were evaluated with Transmission Electron Microscopy and Congo red staining, while the rate of fibril formation at lower concentrations was monitored with Thioflavin T and confirmed with Scanning Electron Microscopy. In order to assess the cytotoxic effect of the non-polymerized peptides, H9C2 cells were incubated with the peptides for 24 hours at 200μg/mL and 100μg/mL and cell death was determined by lactate dehydrogenase release assay. Results Interestingly, sequence alignment on the variable domains of cardiac related light chains revealed the presence of several conserved domains in patients with AL amyloidosis. The chosen peptides were proven to be amyloidogenic suggesting that the variable domains share common amyloidogenic cores. Treatment of H9C2 cells with the peptides at 200μg/mL led to significant reduction in cell viability compared to vehicle treated cells (p<0.001). Two of the peptides deriving from the IGLV6-57 and IGLV3-01 significantly increased cell death at 100μg/mL (p<0.01 and p<0.001 respectively). During the 24h treatment the tested peptides comprised of soluble species and not amyloid fibrils suggesting that monomeric and oligomeric intermediates are highly toxic. Conclusion We discovered five novel amyloidogenic prone regions of cardiac related variable domains that are associated with cellular toxicity and could be exploited for targeted therapeutic interventions. Funding Acknowledgement Type of funding source: None

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Pathology and Proteomics-Based Diagnosis of Localized Light-Chain Amyloidosis in Dogs and Cats

Veterinary Pathology ◽

10.1177/0300985820934113 ◽

2020 ◽

Vol 57 (5) ◽

pp. 658-665

Author(s):

Ayumi Kadota ◽

Susumu Iwaide ◽

Shinya Miyazaki ◽

Ikki Mitsui ◽

Noboru Machida ◽

...

Keyword(s):

Potassium Permanganate ◽

Light Chain ◽

Congo Red ◽

Light Chains ◽

Al Amyloidosis ◽

Specificity And Sensitivity ◽

Amyloid Deposits ◽

Liquid Chromatography Tandem Mass ◽

Congo Red Staining ◽

Amyloid Light Chain

Amyloidosis is classified according to the amyloid precursor protein, and accurate diagnosis of the amyloidosis type may guide appropriate treatment. Immunohistochemistry and Congo red staining are the most frequently used methods used to distinguish types of amyloidosis, but problems with specificity and sensitivity indicate the need for an alternative diagnostic method. In this study, we evaluated laser microdissection-liquid chromatography-tandem mass spectrometry (LMD-LC-MS/MS) for the diagnosis of amyloid light-chain (AL) amyloidosis in animals. Plasmacytomas with amyloid deposits from 15 dogs and 2 cats were subjected to Congo red staining with or without potassium permanganate pretreatment, immunohistochemistry for kappa and lambda light chains, and LMD-LC-MS/MS. Congo red staining was diagnostic in 12 of 17 cases based on resistance to potassium permanganate pretreatment, but in 5 of 17 cases the pretreatment unexpectedly reduced Congo red staining or abrogated the birefringence and a definitive diagnosis could not be reached. Immunohistochemistry detected kappa or lambda light chains in 6 of 17 cases. With LMD-LC-MS/MS, immunoglobulin lambda light chain was detected in all 17 cases. The amyloid signature proteins ApoA-I, ApoA-IV, and ApoE were detected in 9, 1, and 3 of the 15 canine cases by LMD-LC-MS/MS, but not in the feline cases. In conclusion, LMD-LC-MS/MS consistently determined the amyloid type in all examined specimens, while Congo red staining after potassium permanganate treatment and immunohistochemistry were less sensitive tests.

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A patient with AL amyloidosis with negative free light chain results

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm-2015-0847 ◽

2016 ◽

Vol 54 (6) ◽

Cited By ~ 3

Author(s):

Paolo Milani ◽

Veronica Valentini ◽

Giovanni Ferraro ◽

Marco Basset ◽

Francesca Russo ◽

...

Keyword(s):

Bone Marrow ◽

Bone Marrow Biopsy ◽

Light Chain ◽

Left Ventricular ◽

Free Light Chain ◽

Response To Treatment ◽

Light Chains ◽

Al Amyloidosis ◽

Light Chain Restriction ◽

Serum And Urine

AbstractThe detection and quantification of amyloidogenic monoclonal light chains are necessary for the diagnosis and evaluation of response to treatment in AL amyloidosis. However, the amyloid clone is often small and difficult to detect. We report the case of a 68-year-old man who was referred to our Center in April 2013 after syncope and the identification of left ventricular hypertrophy at echocardiography, suspected for amyloidosis. A commercial agarose gel electrophoresis immunofixation (IFE) did not reveal monoclonal components in serum and urine. The κ serum free light chain (FLC) concentration was 21.5 mg/L, λ 33 mg/L (κ/λ ratio 0.65), NT-proBNP 9074 ng/L (u.r.l. <332 ng/L) and an echocardiogram confirmed characteristic features of amyloidosis. The abdominal fat aspiration was positive and the amyloid typing by immune-electron microscopy revealed λ light chains deposits. A high-resolution (hr) IFE of serum and urine showed a faint monoclonal λ component in the urine. A bone marrow biopsy showed 8% plasma cells (BMPC) and a kappa/lambda light-chain restriction with λ light chain on immunofluorescence. The diagnosis of AL (λ) amyloidosis with cardiac involvement was made. In May 2013, patient was started on cyclophosphamide, bortezomib and dexamethasone. After six cycles, serum and urine hr-IFE were negative, the bone marrow biopsy showed 3% BMPC without light chain restriction by immunofluorescence, and a decrease of NT-proBNP was observed (5802 ng/L).Thus, treatment was discontinued. In this patient the amyloid clone could be detected only by in house hr-IFE of urine and bone marrow examination. The detection of the small dangerous amyloidogenic clone should be pursued with a combination of high-sensitivity techniques, including assessment of BMPC clonality. Studies of novel tools, such as mass spectrometry on serum and next-generation flow cytometry analysis of the bone marrow, for detecting plasma cell clones in AL amyloidosis and other monoclonal light chain-related disorders are warranted.

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Barriers to Small Molecule Drug Discovery for Systemic Amyloidosis

Molecules ◽

10.3390/molecules26123571 ◽

2021 ◽

Vol 26 (12) ◽

pp. 3571

Author(s):

Gareth J. Morgan

Keyword(s):

Small Molecules ◽

Light Chain ◽

Amyloid Fibrils ◽

Systemic Amyloidosis ◽

Light Chains ◽

Al Amyloidosis ◽

Amyloid Formation ◽

Amyloid Fibril Formation ◽

Amyloid Light Chain

Inhibition of amyloid fibril formation could benefit patients with systemic amyloidosis. In this group of diseases, deposition of amyloid fibrils derived from normally soluble proteins leads to progressive tissue damage and organ failure. Amyloid formation is a complex process, where several individual steps could be targeted. Several small molecules have been proposed as inhibitors of amyloid formation. However, the exact mechanism of action for a molecule is often not known, which impedes medicinal chemistry efforts to develop more potent molecules. Furthermore, commonly used assays are prone to artifacts that must be controlled for. Here, potential mechanisms by which small molecules could inhibit aggregation of immunoglobulin light-chain dimers, the precursor proteins for amyloid light-chain (AL) amyloidosis, are studied in assays that recapitulate different aspects of amyloidogenesis in vitro. One molecule reduced unfolding-coupled proteolysis of light chains, but no molecules inhibited aggregation of light chains or disrupted pre-formed amyloid fibrils. This work demonstrates the challenges associated with drug development for amyloidosis, but also highlights the potential to combine therapies that target different aspects of amyloidosis.

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A Phase I Trial of Pomalidomide, Bortezomib (Velcade), and Dexamethasone (PVD) As Initial Treatment of AL Amyloidosis and Light Chain Deposition Disease

Blood ◽

10.1182/blood.v124.21.4767.4767 ◽

2014 ◽

Vol 124 (21) ◽

pp. 4767-4767

Author(s):

Jeffrey Zonder ◽

Christiane Houde ◽

Sascha Tuchman ◽

Vishal Kukreti ◽

Vaishali Sanchorawala ◽

...

Keyword(s):

Plasma Cell ◽

Light Chain ◽

Research Funding ◽

Median Number ◽

Light Chains ◽

Al Amyloidosis ◽

Light Chain Deposition Disease ◽

Deposition Disease ◽

Plasma Cell Dyscrasias ◽

Light Chain Deposition

Abstract Introduction: AL amyloidosis (AL) and Light Chain Deposition Disease (LCDD) are plasma cell dyscrasias in which misfolded monoclonal light chains form insoluble extracellular protein deposits (fibrillar and amorphous, respectively). In AL particularly, toxic soluble light chain oligomers also play a role in disease pathogenesis. Treatment of AL and LCDD aims at eliminating the abnormal plasma cell clone. Typical agents used include corticosteroids, bortezomib (btz), alkylators, or immunomodulatory drugs (IMiDs) such as lenalidomide (len) or pomalidomide (pom). Len-btz-dexamethasone (dex) is a highly efficacious frontline regimen commonly used for multiple myeloma, a related plasma cell cancer. Despite this, prospective studies using btz-IMiD combos as initial therapy of AL or LCDD are lacking. Here we report our experience with pom-btz-dex(PVD) for pts with AL or LCDD. Methods: This is a prospective Phase I trial using a standard 3+3 dose escalation scheme (described in Table 1). The primary objective is to establish the maximally tolerated dosing (MTD), with assessment for dose limiting toxicity (DLT) extending through cycles 1 and 2 for each pt. Hematologic and organ responses (HR and OR) were assessed using recently updated guidelines. PVD was administered in repeating 28-day cycles until either DLT or progressive disease. Key inclusion/exclusion criteria: biopsy proven AL amyloidosis or LCDD; no more than 1 prior cycle of anti-plasma cell therapy; measurable disease defined as at least a 5 mg/dL difference between the involved (iFLC) and uninvolved (uFLC) serum free light chains, or a serum M-protein of 0.5 g/dL or greater (latter not permissible without measurable sFLCdifference after protocol amendment); ECOG PS of 2 or less; adequate renal, hepatic, and marrow function; no Grade 3 or higher peripheral neuropathy (PN; pts with painful grade 2 PN also excluded). Abnormal left ventricular ejection fraction or cardiac biomarkers allowed, but pts with NYHA class III/IV congestive heart failure or uncontrolled ventricular arrhythmias were excluded. Antithrombotic/antiviral prophylaxis was required for all pts. Results: Six pts have been enrolled thus far (3 each in cohorts 1 and 2, respectively). Three additional pts have already been identified for cohort 3. Five of 6 pts had AL, and 1 had LCDD. Median age was 65.5 yrs (range 49-74 yrs). 5 pts were female. Mayo cardiac stage I/II/III in 1, 2, and 3 pts, respectively. Three pts had one prior cycle of therapy (the others had none). The iFLC was lambda type in all 5 AL pts, and kappa for the pt with LCDD. Median number of organs involved by AL/LCDD was 2 (range, 2-4; 4 with both cardiac and renal, and 1 additional pt with cardiac). The median number of PVD cycles administered was 3 (range 1-6). Two pts are still on therapy. The reasons for stopping PVD in the other 4 pts were: sudden death due to underlying cardiac AL (during cycle 3 of PVD), pt preference after reaching maximal HR (after cycle 6), lack of HR (after cycle 3), and toxicity (after cycle 4). Baseline dex dose adjustment was required for protocol-specified reasons in all pts. One pt required further dex reduction during cycle 4 of PVD. No pts required baseline or subsequent modification of pom or btz. Table 2 summarizes reported adverse events (AEs). No DLTshave been observed. Two pts achieved HR (0 CR, 1 VGPR, 1 PR, 3 SD, 0 PD). Organ responses have not been observed, but the first protocol-specified OR assessment takes place after 4 cycles of PVD and some pts have yet to reach this time point. Conclusions: PVD was well tolerated in this group of pts with AL and LCDD. Importantly, no significant myelosuppression or PN was noted in the first 2 (out of a planned 4) dose cohorts. Most AEs have been related to the ptsÕ underlying AL/LCDD, though dex has posed difficulties for some pts. Hematologic responses have been seen, but organ responses are predictably lagging. Once the MTD is established, an 18-pt expansion cohort dosed at that level willfurther examine the efficacy of PVD as up-front treatment for AL and LCDD. Disclosures Zonder: Celgene: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy. Off Label Use: Pomalidomide and Bortezomib are approved drugs for multiple myeloma; they are used in this trial as treatment for the related plasma cell dyscrasias AL amyloidosis and light chain deposition disease. . Tuchman:Celgene: Honoraria, Research Funding, Speakers Bureau; Millennium: Honoraria, Research Funding, Speakers Bureau. Kukreti:Celgene: Honoraria. Burt:Celgene: Speakers Bureau. Matous:Takeda Pharmaceuticals International Co.: Speakers Bureau; Onyx: Speakers Bureau; Celgene: Consultancy, Speakers Bureau; Seattle Genetics, Inc.: Research Funding, Speakers Bureau.

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Early Serum Free Light Chain Response after High-Dose Melphalan and Stem Cell Transplantation Predicts Hematologic Response in AL Amyloidosis

Blood ◽

10.1182/blood-2020-138500 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 26-26

Author(s):

Vanessa Fiorini Furtado ◽

Dina Brauneis ◽

Shayna Sarosiek ◽

Karen Quillen ◽

Vaishali Sanchorawala

Keyword(s):

Light Chain ◽

Research Funding ◽

Amyloid Fibrils ◽

Advisory Board ◽

Free Light Chain ◽

Light Chains ◽

High Dose ◽

Al Amyloidosis ◽

Serum Free Light Chain ◽

High Dose Melphalan

Introduction Immunoglobulin light chain (AL) amyloidosis is a rare disease caused by a clonal plasma cell dyscrasia producing monoclonal light chains that misfold and form amyloid fibrils which can deposit in a variety of tissues and organs. This deposition of amyloid fibrils can lead to progressive organ impairment, multi-organ failure, and death if left untreated. High-dose melphalan and autologous stem cell transplantation (HDM/SCT) is known to improve patient outcomes with hematologic complete responses (CR) rates of 25-67%. Hematologic CR is currently defined as the absence of monoclonal protein in serum and urine by immunofixation electrophoreses and normal serum free light chain ratio (FLCR). Studies have shown that even among patients achieving a normal FLCR after initial therapy with HDM, persistent elevation of the involved FLC (hiFLC) predicts poor prognosis. Serum half-life of FLCs is approximately 2-6 hours, even with diminished glomerular filtration rates, and could be a tool for early treatment response evaluation. We sought to determine the extent to which early FLC responses after HDM/SCT predict hematologic complete response (CR) at 6 months. Methods We analyzed patients with AL amyloidosis who underwent HDM/SCT from 2012-2019 at Boston Medical Center. Exclusion criteria included death within 100 days, lack of FLC data at any time point, pre-SCT normal FLC concentrations and ratio, and chronic renal insufficiency (serum creatinine >1.3 mg/dL) with a normal FLC ratio. All subjects received a total of 140-200 mg/m2 melphalan IV in equally divided doses on days -3 and -2. Stem cells were infused on day 0. FLC measurements were obtained early in the peri-SCT period (< 1 month), at 6 months, and at 12 months after HDM/SCT. The patients were evaluated for response according to the consensus response criteria at 6 months. Statistical analysis to compare CR at 6 months and early post-SCT free light chain levels was performed by Chi-square with significance considered at p<0.05. Results Of the 113 patients with AL amyloidosis treated with HDM/SCT during the specified time period, 32 were excluded (4 died within 100 days of SCT, 15 had normal FLCs pre-SCT, 5 lacked data, and 8 had chronic renal insufficiency (Cr >1.3 mg/dL) with normal FLCR. A total of 81 subjects (females=30) were analyzed. Median follow-up from SCT was 27.6 months (range, 6-145). Median time of early post-SCT FLC measurement was 8 days (range, 7-30). Median age at diagnosis was 58 years (range 30-79) and the iFLC was lambda in 81.5% (n = 66) of patients. Median number of bone marrow plasma cells was 10% (range, 1-50). The mean absolute involved FLC was 196 mg/L ±221 prior to SCT, 60 mg/L ± 77 in the early post-SCT period, 92 mg/L ± 152 at 6 months post-SCT. In early post-SCT period, 39.5% (n=32) had iFLC <20 mg/L, 28% (n=16/57) had dFLC<10 mg/L, and 84% (n=48/57) had normal FLCR. Early post-SCT dFLC <10 mg/dL and early post-SCT iFLC <20 mg/L were statistically associated with prediction of hematologic CR at 6 months (p=0.025 and p=0.001, respectively). However, early post-SCT normal FLCR was not associated with predicting hematologic CR at 6 months. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of early post-SCT iFLC <20 mg/L, dFLC <10 mg/L and normal FLCR to predict hematologic CR at 6 months are presented in table 1. Conclusion This study concludes that achievement of dFLC <10 mg/L and iFLC <20 mg/L in the early post-SCT period is associated with prediction of hematologic CR at 6 months. Early post-SCT dFLC <10 mg/L could be considered a tool for early evaluation of treatment response following HDM/SCT in AL amyloidosis. Key words: immunoglobulin light chains; AL amyloidosis, HDM/SCT Disclosures Sarosiek: Spectrum: Research Funding. Sanchorawala:Caelum: Research Funding; Prothena: Research Funding; Celgene: Research Funding; Takeda: Research Funding; Proclara: Other: advisory board; Abbvie: Other: advisory board; UpToDate: Patents & Royalties; Oncopeptide: Research Funding; Regeneron: Other: advisory board; Caleum: Other: advisory board; Janssen: Research Funding.

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AL Amyloidosis — Pathogenesis and Prognosis Are Determined By the Amyloidogenic Potential of the Light Chain and the Molecular Characteristics of Malignant Plasma Cells

Blood ◽

10.1182/blood-2018-187 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 187-187

Author(s):

Anja Seckinger ◽

Ute Hegenbart ◽

Susanne Beck ◽

Martina Emde ◽

Tilmann Bochtler ◽

...

Keyword(s):

Gene Expression ◽

Plasma Cell ◽

Light Chain ◽

Research Funding ◽

Plasma Cells ◽

Memory B Cells ◽

Light Chains ◽

Molecular Characteristics ◽

Al Amyloidosis ◽

Malignant Plasma Cell

Abstract INTRODUCTION. Systemic light chain amyloidosis (AL) is caused by accumulation of plasma cells producing misfolded monoclonal light chains depositing as amyloid fibrils in different organs, most frequently heart and kidney. AIM of our study is first assessing the molecular characteristics of malignant plasma cells from AL-patients in relation to those from MGUS, asymptomatic, and symptomatic myeloma: Are these plasma cells different, does this difference explain amyloidogenicity? Does AL correspond to a certain developmental stage during evolution of symptomatic myeloma? Secondly, to what extent is prognosis determined by amyloid-deposition (organotropism, amount, amyloidogenicity) vs. number and molecular characteristics of malignant plasma cells? PATIENTS & METHODS . Consecutive patients (n=3023) with AL (n=582), MGUS (n=306), asymptomatic (n=444, AMM), or previously untreated, therapy-requiring multiple myeloma (n=1691, MM) were included. CD138-purified plasma cell samples were subjected to iFISH (n=582/306/444/1691), 1297 to gene expression profiling using Affymetrix U133 2.0 plus arrays (n=196/64/272/765), 712 to RNA- (n=124/52/38/489), and 258 to whole exome sequencing (n=115/53/39/51). Samples of normal bone marrow plasma cells, memory B-cells, and polyclonal plasmablasts were used as comparators. The CoMMpass-cohort (n=647) was used as comparator for the mutational spectrum of myeloma. RESULTS . Prognosis. By AL-factors. Expectedly, organ involvement, i.e. heart only vs. kidney only vs. heart+kidney vs. other (overall survival (OS), P=.001), the amount of free light chains (dFLC ≥18 mg/dL, HR=2.56, P=.01), and the cardiac European Mayo IIIB score (I/II/IIIA/IIIB, median OS 110/55/16/3 months, HR=1/1.94/3.73/7.90, P<.001) strongly determine prognosis (Fig. 1A). By malignant plasma cell factors. High proliferation rate (HR=3.58, P=.001) and expression-based risk factors for MM (GEP70 high, HR=2.38, P=.005; Rs-score high HR=4.63, P<.001) identify patients with very adverse prognosis (Fig. 1A). Tumor load, e.g. plasma cell infiltration >10%/>30% (HR=1.31/1.81, P=.01, P=.002) and M-protein ≥ 30g/l (HR=3.01, P=.005), are likewise prognostic (Fig. 1A). In multivariate analysis, all tested AL-specific (European Mayo IIIB score) and malignant plasma cell factors (proliferation or GEP70 and plasma cell infiltration) are independent. Molecular characteristics.iFISH. As MM (96.2%) and AMM (92.8%) AL-patients (93.1%) carry at least one recurrent myeloma typical aberration. The mean number of progression-associated aberrations in AL (n=0.98) fits between MGUS (n=0.85) and AMM (n=1.45) with significant difference compared to AMM (P<.001) unlike to MGUS. Main differences in frequency are found for t(11;14) and hyperdiploidy with a comparable pattern of non-etiologic aberrations. Gene expression (GEP and RNA-seq). Aberrant plasma cells in AL amyloidosis show the least difference with AMM, followed by MGUS and MM. In principal component analysis, AL overlaps with AMM and MGUS, independent of presence or absence of heart involvement (Fig. 1B). Pairwise assessment of similarity using a multivariate generalization of the squared Pearson correlation coefficient shows closest similarity to AMM and MM followed by MGUS, with comparable differences to normal plasma cells, polyclonal plasmablasts, and memory B-cells. Significantly more AL-patients present with higher proliferation rate vs MGUS (P<.001) and AMM (P<.02). AL and MM differ significantly regarding distinct molecular entities as determined by GEP (e.g. TC-classification; Fig. 1C). Mutation spectrum in AL amyloidosis vs. MM. From the 20 most frequently synonymously mutated non-Ig transcripts (CoMMpass-cohort), 16 could likewise be detected in AL amyloidosis, i.e. KRAS, NRAS, IGLL5, DIS3, FAM46C, MUC16, BRAF, TRAF3, PCLO, RYR2, FATA4, CSMD3, TP53, DNAH5, RYR2A, and FLG. CCND1 mutations were significantly more frequent in AL and AMM compared to MM (P=.02). DISCUSSION & CONCLUSION. Pathogenesis and prognosis of AL amyloidosis are explained both by AL-specific and malignant plasma cell characteristics. Aberrant plasma cells in AL amyloidosis show the same aberration- and expression pattern and a "molecular age" between MGUS and AMM, most closely resembling the latter. AL amyloidosis is thus mostly a rather early plasma cell dyscrasia with an unstable and toxic immunoglobulin light chain. Disclosures Seckinger: Celgene: Research Funding; EngMab: Research Funding; Sanofi: Research Funding. Hose:Celgene: Honoraria, Research Funding; Sanofi: Research Funding; EngMab: Research Funding.

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