Philip N. Hawkins

Native T1 Mapping in Transthyretin Amyloidosis

OBJECTIVESnThe aims of the study were to explore the ability of native myocardial T1 mapping by cardiac magnetic resonance to: 1) detect cardiac involvement in patients with transthyretin amyloidosis (ATTR amyloidosis); 2) track the cardiac amyloid burden; and 3) detect early disease.nnnBACKGROUNDnATTR amyloidosis is an underdiagnosed cause of heart failure, with no truly quantitative test. In cardiac immunoglobulin light-chain amyloidosis (AL amyloidosis), T1 has high diagnostic accuracy and tracks disease. Here, the diagnostic role of native T1 mapping in the other key type of cardiac amyloid, ATTR amyloidosis, is assessed.nnnMETHODSnA total of 3 groups were studied: ATTR amyloid patients (n = 85; 70 males, age 73 ± 10 years); healthy individuals with transthyretin mutations in whom standard cardiac investigations were normal (n = 8; 3 males, age 47 ± 6 years); and AL amyloid patients (n = 79; 55 males, age 62 ± 10 years). These were compared with 52 healthy volunteers and 46 patients with hypertrophic cardiomyopathy (HCM). All underwent T1 mapping (shortened modified look-locker inversion recovery); ATTR patients and mutation carriers also underwent cardiac 3,3-diphosphono-1,2-propanodicarboxylicacid (DPD) scintigraphy.nnnRESULTSnT1 was elevated in ATTR patients compared with HCM and normal subjects (1,097 ± 43 ms vs. 1,026 ± 64 ms vs. 967 ± 34 ms, respectively; both p < 0.0001). In established cardiac ATTR amyloidosis, T1 elevation was not as high as in AL amyloidosis (AL 1,130 ± 68 ms; p = 0.01). Diagnostic performance was similar for AL and ATTR amyloid (vs. HCM: AL area under the curve 0.84 [95% confidence interval: 0.76 to 0.92]; ATTR area under the curve 0.85 [95% confidence interval: 0.77 to 0.92]; p < 0.0001). T1 tracked cardiac amyloid burden as determined semiquantitatively by DPD scintigraphy (p < 0.0001). T1 was not elevated in mutation carriers (952 ± 35 ms) but was in isolated DPD grade 1 (n = 9, 1,037 ± 60 ms; p = 0.001).nnnCONCLUSIONSnNative myocardial T1 mapping detects cardiac ATTR amyloid with similar diagnostic performance and disease tracking to AL amyloid, but with lower maximal T1 elevation, and appears to be an early disease marker.

Therapeutic Clearance of Amyloid by Antibodies to Serum Amyloid P Component

BACKGROUNDnThe amyloid fibril deposits that cause systemic amyloidosis always contain the nonfibrillar normal plasma protein, serum amyloid P component (SAP). The drug (R)-1-[6-[(R)-2-carboxy-pyrrolidin-1-yl]-6-oxo-hexanoyl]pyrrolidine-2-carboxylic acid (CPHPC) efficiently depletes SAP from the plasma but leaves some SAP in amyloid deposits that can be specifically targeted by therapeutic IgG anti-SAP antibodies. In murine amyloid A type amyloidosis, the binding of these antibodies to the residual SAP in amyloid deposits activates complement and triggers the rapid clearance of amyloid by macrophage-derived multinucleated giant cells.nnnMETHODSnWe conducted an open-label, single-dose-escalation, phase 1 trial involving 15 patients with systemic amyloidosis. After first using CPHPC to deplete circulating SAP, we infused a fully humanized monoclonal IgG1 anti-SAP antibody. Patients with clinical evidence of cardiac involvement were not included for safety reasons. Organ function, inflammatory markers, and amyloid load were monitored.nnnRESULTSnThere were no serious adverse events. Infusion reactions occurred in some of the initial recipients of larger doses of antibody; reactions were reduced by slowing the infusion rate for later patients. At 6 weeks, patients who had received a sufficient dose of antibody in relation to their amyloid load had decreased liver stiffness, as measured with the use of transient elastography. These patients also had improvements in liver function in association with a substantial reduction in hepatic amyloid load, as shown by means of SAP scintigraphy and measurement of extracellular volume by magnetic resonance imaging. A reduction in kidney amyloid load and shrinkage of an amyloid-laden lymph node were also observed.nnnCONCLUSIONSnTreatment with CPHPC followed by an anti-SAP antibody safely triggered clearance of amyloid deposits from the liver and some other tissues. (Funded by GlaxoSmithKline; ClinicalTrials.gov number, NCT01777243.).

CMR-based differentiation of AL and ATTR cardiac amyloidosis.

OBJECTIVESnThis study was devised to describe the different cardiac magnetic resonance (CMR) appearances in light chain amyloid (AL) and transthyretin-related amyloidosis (ATTR).nnnBACKGROUNDnCMR is increasingly used to investigate patients with suspected amyloidosis. Global subendocardial late gadolinium enhancement (LGE) has been reported as typical of AL amyloidosis, whereas different patterns have been noted in ATTR amyloidosis.nnnMETHODSnWe performed de novo analyses on original DICOM magnetic resonance imaging in 46 patients with cardiac AL amyloidosis and 51 patients with ATTR type who had been referred to a specialist amyloidosis center between 2007 and 2012 after CMR. Histological examination was performed in all cases, with immunohistochemistry, to confirm systemic amyloidosis.nnnRESULTSnPatients median age was 68 ± 10 years, and 74% were male. Left ventricular mass was markedly increased in ATTR amyloidosis (228 g [202 to 267 g]) compared with AL type (167 g [137 to 191 g]) (p < 0.001). LGE was detected in all but 1 cardiac amyloidosis patient (AL type) and was substantially more extensive in ATTR compared with AL amyloidosis. Ninety percent of ATTR patients demonstrated transmural LGE compared with 37% of AL patients (p < 0.001). Right ventricular LGE was apparent in all ATTR patients but in only 33 AL patients (72%) (p < 0.001). Despite these findings, survival was significantly better in cardiac ATTR amyloidosis compared with AL type. We derived an LGE scoring system (Query Amyloid Late Enhancement) that independently differentiated ATTR from AL amyloidosis and, when incorporated into a logistic regression model with age and wall thickness, detected ATTR type with 87% sensitivity and 96% specificity.nnnCONCLUSIONSnTransmural patterns of LGE distinguished ATTR from AL cardiac amyloidosis with high accuracy in this real-world analysis of CMR. Precise diagnosis of cardiac amyloidosis is crucial given the role of chemotherapy in AL type and with novel therapies for ATTR type currently in development.

Amyloidogenicity and Clinical Phenotype Associated with Five Novel Mutations in Apolipoprotein A-I

The phenotype of hereditary apolipoprotein A-I amyloidosis is heterogeneous with some patients developing extensive visceral amyloid deposits and end-stage renal failure as young adults and others having only laryngeal and/or skin amyloid, which may be of little clinical consequence. Clinical management and prognosis of patients with systemic amyloidosis depend entirely on correct identification of the fibril protein, such that light chain amyloidosis (AL, previously referred to as primary), the most frequently diagnosed type, is treated with chemotherapy, which has absolutely no role in hereditary apolipoprotein A-I amyloidosis. We report five novel apolipoprotein A-I variants, four of which were amyloidogenic and one of which was incidental in a patient with systemic AL amyloidosis. Interestingly, only one of four patients with apolipoprotein A-I amyloidosis had a family history of similar disease. Laser microdissection and tandem mass spectrometry-based proteomics were used to confirm the amyloid fibril protein and, for the first time in apolipoprotein A-I amyloidosis, demonstrated that only mutated protein as opposed to wild-type apolipoprotein A-I was deposited as amyloid. The clinical spectrum and outcome of hereditary apolipoprotein A-I amyloidosis are reviewed in detail and support the need for sequencing of the apolipoprotein A-I gene among patients with apparent localized amyloidosis in whom IHC is nondiagnostic of the fibril protein, even in the absence of a family history of disease.

Brief Report: Whole‐Exome Sequencing Revealing Somatic NLRP3 Mosaicism in a Patient With Chronic Infantile Neurologic, Cutaneous, Articular Syndrome

To identify the genetic cause of chronic infantile neurologic, cutaneous, articular syndrome (CINCA syndrome) using whole‐exome sequencing in a child who had typical clinical features but who was NLRP3 mutation negative based on conventional Sanger sequencing.

Brief Report: AA Amyloidosis Complicating the Hereditary Periodic Fever Syndromes

OBJECTIVEnAA amyloidosis is a life-threatening complication of the hereditary periodic fever syndromes (HPFS), which are otherwise often compatible with normal life expectancy. This study was undertaken to determine the characteristics, presentation, natural history, and response to treatment in 46 patients who had been referred for evaluation at the UK National Amyloidosis Centre.nnnMETHODSnDisease activity was monitored by serial measurement of serum amyloid A. Renal function was assessed by measurement of serum creatinine and albumin levels, the estimated glomerular filtration rate, and proteinuria from 24-hour urine collections. The amyloid load was measured by serum amyloid P scintigraphy.nnnRESULTSnTwenty-four patients had familial Mediterranean fever, 12 patients had tumor necrosis factor receptor-associated periodic syndrome, 6 patients had cryopyrin-associated periodic syndromes, and 4 patients had mevalonate kinase deficiency. The median age at onset of HPFS was 5 years; median age at presentation with AA amyloidosis was 38 years. Diagnosis of an HPFS had not been considered prior to presentation with AA amyloidosis in 23 patients (50%). Eleven patients (24%) had end-stage renal failure (ESRF) at presentation; of these, 3 had received transplants prior to referral. A further 13 patients developed ESRF over the followup period, with 10 undergoing renal transplantation. The median time to progression to ESRF from onset of AA amyloidosis was 3.3 years (interquartile range [IQR] 2-8), with a median time to transplant of 4 years (IQR 3-6). Eleven patients (24%) died. The median survival in the entire cohort was 19 years from diagnosis of AA amyloidosis. Of the 37 patients who were treated successfully, or in whom at least partial suppression of the underlying HPFS was achieved, 17 (46%) showed amyloid regression, 14 (38%) showed a stable amyloid load, and 2 (5%) showed increased amyloid deposition over the followup period.nnnCONCLUSIONnAA amyloidosis remains a challenging and serious late complication of HPFS; however, outcomes are excellent when HPFS is diagnosed early enough to allow effective treatment, thus preventing or retarding further amyloid deposition and organ damage.

Natural history and outcomes in localised immunoglobulin light-chain amyloidosis: a long-term observational study

BACKGROUNDnLocalised immunoglobulin light-chain amyloidosis, involving one type of tissue, is rare. Little systematic data exists regarding clinical presentations, course or outcomes, or risk of progression to systemic amyloidosis. We aimed to report clinical features and outcomes of a large series of patients with localised light-chain amyloidosis.nnnMETHODSnWe examined data for all patients with localised amyloidosis who were diagnosed, assessed, and followed at the UK National Amyloidosis Centre (NAC) between Jan 2, 1980, and Dec 15, 2011, from the NAC database and written records. The inclusion criteria was the presence of biopsy sample proven localised amyloidosis classified as biopsy proven amyloid deposition confined to one site or tissue proven by histology of the tissue examined), without any evidence of vital organ involvement, which was defined as cardiac, renal, or liver involvement or peripheral or autonomic neuropathy and treatment naive.nnnFINDINGSnWe identified 606 patients with biopsy proven localised amyloidosis (likely light-chain type in 98%) from 5050 newly diagnosed patients with all types of amyloidosis. Median age was 59·5 years (IQR 50·2-74·5). The most common sites included bladder (95; 16%), laryngeal or tonsillar (92; 15%), cutaneous (84; 14%), and pulmonary nodular (47; 8%). 121 (20%) had a monoclonal immunoglobulin or abnormal circulating free light chains. At median follow-up of 74·4 months (IQR 37·2-132·0), seven (1%) patients progressed to systemic immunoglobin light-chain amyloidosis. 270 (51%) patients had one repeated treatment intervention and 112 (21%) had more than one repeated treatment interventions (predominantly localised debulking). The estimated 5-year overall survival was 90·6% (95% CI 87·7-92·9) and 10-year overall survival was 80·3% (75·1-84·1). In patients aged 70 years or older, median overall survival was 12·1 years (95% CI 10·5-13·7).nnnINTERPRETATIONnLocalised immunoglobulin light-chain amyloidosis has an excellent prognosis with no apparent effect on life expectancy. Evolution into systemic immunoglobulin light chain amyloidosis is very rare.nnnFUNDINGnNone.

Magnetic Resonance in Transthyretin Cardiac Amyloidosis

BACKGROUNDnCardiac transthyretin amyloidosis (ATTR) is an increasingly recognized cause of heart failure. Cardiac magnetic resonance (CMR), with late gadolinium enhancement (LGE) and T1 mapping, is emerging as a reference standard for diagnosis and characterization of cardiac amyloidosis.nnnOBJECTIVESnThe authors used CMR with extracellular volume fraction (ECV) measurement to characterize cardiac involvement in relation to outcome in ATTR.nnnMETHODSnSubjects comprised 263 patients with cardiac ATTR corroborated by grade 2 to 3 99mTc-DPD (99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid) cardiac uptake, 17 with suspected cardiac ATTR (grade 1 99mTc-DPD), and 12xa0asymptomatic individuals with amyloidogenic transthyretin (TTR) mutations. Fifty patients with cardiac light-chain (AL) amyloidosis acted as disease comparators.nnnRESULTSnUnlike cardiac AL amyloidosis, asymmetrical septal left ventricular hypertrophy (LVH) was present in 79% of patients with ATTR (70% sigmoid septum and 30% reverse septal contour), whereas symmetrical LVH was present in 18%, and 3% had no LVH. In patients with cardiac amyloidosis, the pattern of LGE was always typical forxa0amyloidosis (29% subendocardial, 71% transmural), including right ventricular LGE (96%). During follow-up (19xa0±xa014xa0months), 65 patients died. ECV independently correlated with mortality and remained independent after adjustment for age, N-terminalxa0pro-B-type natriuretic peptide, ejection fraction, E/E, and left ventricular mass (hazard ratio: 1.164; 95% confidence interval: 1.066 to 1.271; pxa0< 0.01).nnnCONCLUSIONSnAsymmetrical hypertrophy, traditionally associated with hypertrophic cardiomyopathy, was the commonest pattern of ventricular remodeling in ATTR. LGE imaging was typical in all patients with cardiac ATTR. ECVxa0correlated with amyloid burden and was an independent prognostic factor for survival in this cohort of patients.

European Collaborative Study Defining Clinical Profile Outcomes and Novel Prognostic Criteria in Monoclonal Immunoglobulin M–Related Light Chain Amyloidosis

PURPOSEnImmunoglobulin M (IgM)-related light chain (AL) amyloidosis, which accounts for 6% to 10% of all AL amyloidosis cases, is a rare and poorly studied clinical entity. Its natural history and management is not clearly defined. Prognostic and response criteria for AL amyloidosis in general have not been validated in this population.nnnPATIENTS AND METHODSnWe retrospectively gathered data for 250 patients diagnosed with IgM AL amyloidosis from three European amyloidosis centers. Clinical features, hematologic response, and overall survival (OS) were analyzed. The current staging and response criteria in non-IgM AL amyloidosis was applied to this series to assess its utility in this patient cohort.nnnRESULTSnPatients with IgM AL amyloidosis have a significant IgM paraprotein (median, 10 g/L), less frequent lambda light chain isotype, and evaluable difference between involved and uninvolved free light chains (dFLCs; > 50 mg/L) in only two thirds of patients. Bone marrow showed clear non-Hodgkin lymphoma as the underlying disorder in 54% of patients. Cardiac involvement (45%) is less common but there is more frequent lymph node (20%) and neuropathic (28%) involvement compared with non-IgM AL. Fifty-seven percent of patients achieved a hematologic response (14% very good partial response/complete response [VGPR/CR]), with median OS not reached for patients achieving VGPR/CR, 64 months for PR, and 28 months for nonresponders (P < .001). On multivariate analysis, cardiac involvement, advanced Mayo disease stage, neuropathic involvement, and liver involvement were independent factors that had an impact on survival. Combining abnormal N-terminal pro-brain natriuretic peptide (NT-proBNP) and troponin T with liver involvement and the presence of neuropathy gives a better risk model: median OS of patients with none, one, or two or more abnormal factors was 90, 33, and 16 months, respectively.nnnCONCLUSIONnIgM AL amyloidosis is a distinct clinical entity. Low-risk disease can be defined by combining cardiac involvement with novel prognostic markers. Deeper hematologic responses translate into improved outcomes, yet deep responses remain dismally poor, which highlights the urgent need for novel therapies.

Brief Report: Association of Tumor Necrosis Factor Receptor-Associated Periodic Syndrome With Gonosomal Mosaicism of a Novel 24-Nucleotide TNFRSF1A Deletion.

To investigate the molecular cause of persistent fevers in a patient returning from working overseas, in whom investigations for tropical diseases yielded negative results.