Deep phenotyping of p.(V142I)-associated variant transthyretin amyloid cardiomyopathy: Distinct from wild-type transthyretin amyloidosis?

AIMS

Transthyretin amyloid cardiomyopathy (ATTR-CM) is an increasingly recognized cause of heart failure. A total of 3-4% of individuals of African descent carry a TTR gene mutation encoding the p.(V142I) variant, a powerful risk factor for development of variant ATTR-CM (ATTRv-CM); this equates to 1.6 million carriers in the United States. We undertook deep phenotyping of p.(V142I)-ATTRv-CM and comparison with wild-type ATTR-CM (ATTRwt-CM).

METHODS AND RESULTS

A retrospective study of 413 patients with p.(V142I) ATTRv-CM who attended the UK National Amyloidosis Centre (NAC) was conducted. Patients underwent evaluation at time of diagnosis, including clinical, echocardiography, and biomarker analysis; a subgroup had cardiac magnetic resonance (CMR) imaging. A total of 413 patients with ATTRwt-CM, matched for independent predictors of prognosis (age, NAC Stage, decade of first presentation), were used as a comparator group. At time of diagnosis, patients with ATTRv-CM had significant functional impairment by New York Heart Association classification (NHYA class ≥ III; 38%) and 6-min walk test distance (median 276 m). Median 5-year survival in ATTRv-CM patients was 31 versus 59 months in matched patients with ATTRwt-CM (p < 0.001). Patients with ATTRv-CM had significant impairment of functional parameters by echocardiography including biventricular impairment, high burden of regurgitant valvular disease and low cardiac output. Multivariable analysis revealed the prognostic importance of right ventricular dysfunction. CMR and histological analysis revealed myocyte atrophy and widespread myocardial infiltration in ATTRv-CM.

CONCLUSION

p.(V142I)-ATTRv-CM has an aggressive phenotype characterized by myocyte loss and widespread myocardial infiltration which may account for frequent biventricular failure and poor prognosis in this ATTR-CM genotypic subgroup.

Size matters - redefining sex differences among patients with transthyretin amyloid cardiomyopathy – have we been wrong all along?

Background

Transthyretin amyloid cardiomyopathy (ATTR-CM) is most often diagnosed in men (1–5). The few available studies suggest affected women have a more favourable cardiac phenotype (5–8), but remain unclear regarding differences in outcomes.

Objectives and methods

To characterise sex differences among consecutive patients with non-hereditary and two prevalent forms of hereditary ATTR-CM diagnosed over a 20-year period at our specialist centre through analysis of deep phenotyping at presentation, changes on serial echocardiography and overall prognosis.

Results

In total, 1732 patients were studied, comprising: 1095 with wild-type (wt)ATTR-CM; 206 with T60A-hATTR-CM; and 431 with V122I-hATTR-CM. Female prevalence was greater in T60A-hATTR-CM (29.6%) and V122I-hATTR-CM (27.8%) compared to wtATTR-CM (6%). At presentation, females were 3.3 years older than males (81.9 vs 77.8 years for wtATTR-CM; 68.7 vs 65.1 years for T60A-hATTR-CM; 77.1 vs 74.9 years for V122I-hATTR-CM). At diagnosis, non-indexed measures of wall thickness were significantly greater in males (interventricular septum in diastole (IVSd) of 17.13mm in males & 16.15mm in females; p&lt;0.001). When indexed for body surface area (BSA), we observed that the mean indexed IVSd was fairly constant in males throughout the study period, but in females, had a tendency to decrease over the same study period. Furthermore, BSA significantly influenced measures of disease severity. When indexed for BSA, overall structural and functional phenotype was similar between sexes; the few observed significant differences including indexed IVSd (9.62mm/m2 in females & 8.88mm/m2 in males; p&lt;0.001), indexed left ventricular (LV) end-diastolic volume (35.07ml/m2 in females & 41.05ml/m2 in males; p&lt;0.001) and indexed LV end-systolic volume (17.95ml/m2 in females & 21.74ml/m2 in males; p&lt;0.001) suggested a mildly worse phenotype in females. No significant differences were observed in disease progression on serial echocardiography and mortality across the overall population (p=0.459) and when divided by genotype (p=0.730 for wtATTR-CM; p=0.161 for T60A-hATTR-CM; p=0.056 for V122I-hATTR-CM).

Conclusion

This study of a well-characterized large cohort of ATTR-CM patients, contrary to previous dogmas, did not demonstrate overall differences between sexes in either clinical phenotype, when indexed, or with respect to disease progression and prognosis. The analysis highlighted the deficiencies in using non-indexed values which can not only lead to the inaccurate perception of a milder clinical phenotype in women compared to men, but has been shown to result in female patients presenting at an older age and with a worse phenotype compared to men. These findings indicate the need for revision of existing clinical guidelines regarding awareness and diagnosis of ATTR-CM in women, and modification of clinical trials which currently use single non-indexed threshold for wall thickness as key inclusion criterion.

Funding Acknowledgement

Type of funding sources: Foundation.

Cardiac transplantation in transthyretin amyloid cardiomyopathy: outcomes from three decades of tertiary centre experience

Background

Transthyretin cardiac amyloidosis (ATTR-CM) is a progressive and fatal cardiomyopathy. Treatment options in patients with advanced heart failure are limited to cardiac transplantation (CT). Despite small case series demonstrating comparable outcomes with CT between patients with ATTR-CM and non-amyloid cardiomyopathies, ATTR-CM is considered to be an absolute contraindication to CT in some centres. This is in part due to a perceived risk of amyloid recurrence in the cardiac allograft. We report outcomes of patients with ATTR-CM assessed at our centre whom underwent CT over the past thirty years.

Methods

We retrospectively evaluated all ATTR-CM patients assessed at the UK National Amyloidosis Centre between 1990 and 2020 who underwent CT. Pre-transplantation disease and patient characteristics were determined and outcomes were compared with our large cohort of non-transplanted ATTR-CM patients. Censor date was 11th January 2022.

Results

Eleven (9 male, 2 female) patients with ATTR-CM underwent CT including 8 with wild-type ATTR-CM and 3 with variant ATTR-CM (ATTRv). Median age at CT was 60.3 years and median follow up post-CT was 65.7 months. Median (range) NT-proBNP concentration pre-transplant was 4478ng/L (1057–8778ng/L), median (range) left ventricular ejection fraction (LVEF) was 39% (27–56%) and mean (IQR) interventricular septal (IVSD) was 18 mm (15.9–20.1 mm). 8 patients were NYHA functional class III, the 3 remaining patients were class II.

One, three, and five-year survival was 100%, 89% and 86%, respectively and the longest surviving patient was censored &gt;19 years post CT. Survival is at least comparable to UK and US CT outcome registry data for all non-amyloid patients undergoing CT. No patients had recurrence of amyloid in the cardiac allograft as assessed by endomyocardial biopsy and/or Tc-DPD scintigraphy. Two patients were commenced on Patisiran for amyloid polyneuropathy at 211 and 5 months post-CT. Graft rejection requiring treatment was observed in 2 patients, and successfully treated with intravenous steroids. Renal impairment was common, with 6 patients being left with chronic kidney disease.

Three patients died, including one with ATTRv-CM from complications of leptomeningeal amyloidosis. Survival among the cohort of patients who underwent CT was significantly longer than UK patients with ATTR-CM generally (P≤0.006), regardless of NAC ATTR disease stage and including those diagnosed under 65 years of age (P=0.028). (Figure 1) All surviving patients were NYHA functional class I at time of censor.

Conclusion

Our data indicates that cardiac transplantation is well tolerated, restores functional capacity, and prolongs survival in ATTR-CM with little risk of recurrence of amyloid in the cardiac allograft. We believe that our data argues strongly for ATTR-CM to be routinely included in the list of indications for cardiac transplantation.

Funding Acknowledgement

Type of funding sources: None.

Progression, regression and redefining the treatment response – cardiac magnetic resonance with T1 and extracellular volume mapping in cardiac light-chain amyloidosis

Background

The presence and severity of cardiac involvement in AL amyloidosis is the main driver of prognosis [1]; patients with symptomatic heart failure frequently die within 6 months [1] but median survival has nearly doubled over the past decade, mainly due to significant improvements in chemotherapy. The haematological response to chemotherapy is principally evaluated with serial measurements of serum-free light-chains (FLC) [2]. The cardiac response to chemotherapy is assessed through changes in serum concentrations of brain natriuretic peptides (including NT-proBNP) and echocardiographic parameters [3–5]. Neither are able to directly measure cardiac amyloid burden. Cardiovascular magnetic resonance (CMR) with extra-cellular volume (ECV) mapping can measure the extent cardiac amyloid infiltration [6].

Aims

We investigated the ability of CMR to: 1) measure changes in response to chemotherapy; 2) assess the correlation between haematological response (HMR) and changes in cardiac amyloid; 3) assess the association between changes in cardiac amyloid and prognosis over and above existing predictors.

Methods

In total, 176 patients with cardiac light-chain amyloidosis treated with chemotherapy were assessed with FLC, NT-proBNP and CMR with ECV mapping at baseline (before chemotherapy), 6-months, 12-months & 24-months after commencing chemotherapy. Haematological response was categorized by reductions in FLC as: complete response (CR), very good partial response (VGPR), partial response (PR) or no response (NR). CMR response was categorized by changes in ECV as: progression (≥0.05 increase), stable (&lt;0.05 change) or regression (≥0.05 decrease).

Results

A progressive increase in patients achieving either CR or VGPR was observed at each time point (61% of patients at 6-months, 71% at 12-months and 80% at 24-months). At 6-months, CMR regression was observed in 3% (all had either CR or VGPR) and progression in 32% (61% had either PR or NR; 39% had either CR or VGPR). At 1-year, CMR regression was observed in 22% (all had either CR or VGPR); progression in 22% (63% had either PR or NR; 37% had either CR or VGPR). At 2-years, CMR regression was observed in 38% (all had CR/VGPR); progression in 14% (80% had either PR or NR; 20% had either CR or VGPR). During follow-up (40±15 months), 36 (25%) patients died. CMR response at 6-months predicted death (progression HR 3.821; 95% CI 1.950–7.487; p&lt;0.001) and remained independently associated with prognosis after adjusting for haematological response, NT-proBNP and longitudinal strain on echocardiography (p&lt;0.01).

Conclusions

CMR demonstrates that cardiac amyloid deposits frequently regress following chemotherapy, but only in patients who achieve CR or VGPR, highlighting the need for deep haematological response. Changes in amyloid burden (ECV) predict outcomes after adjusting for known predictors, showing the crucial role of CMR in redefining treatment response.

Funding Acknowledgement

Type of funding sources: Foundation.

ARFs get the BioID treatment: what have we been missing?

Li et al present the results of a proximity-interaction screen in mammalian cells for the effector proteins of 25 members of the Arf family of small GTPases. This study has generated an important resource for those working in several areas of cell biology and provided an initial characterisation of two new cellular roles for some of the least well studied members of this family, the regulation of PLD1 by ARL11/14 in phagocytosis, and the regulation of PI4KB by ARL5A/5B in the Golgi.

Clinical importance of left atrial infiltration in cardiac transthyretin amyloidosis

Funding Acknowledgements

Type of funding sources: None.

INTRODUCTION

 The clinical significance of left atrial (LA) involvement in ATTR amyloidosis cardiomyopathy (ATTR-CM) has not been characterized. The aims of this study were to characterize: (1)LA pathology in explanted ATTR-CM hearts; (2)LA mechanics using echocardiographic speckle-tracking in a large cohort of ATTR-CM patients; (3)to study the association with mortality.

METHODS AND RESULTS

Congo red staining and immunohistochemistry was performed to assess the presence, type and extent of amyloid and associated changes in 5 explanted ATTR-CM atria. Echo speckle-tracking was used to assess LA reservoir, conduit, contractile function and stiffness in 906 ATTR-CM patients (551 wt-ATTR-CM;93 T60A-ATTR-CM;241 V122I-ATTR-CM;21 other).

There was extensive ATTR amyloid infiltration in the 5 atria with loss of normal architecture, vessels remodelling, capillary disruption and subendocardial fibrosis. Echo speckle-tracking in 906 ATTR-CM patients demonstrated increased atrial stiffness [median(25th-75th quartile) 1.83(1.15-2.92)] that remained independently associated with prognosis, after adjusting for known predictors (lnLA stiff:HR = 1.26,CI 1.07-1.57;p = 0.009). There was substantial impairment of the three phasic functional atrial components [reservoir 8.86(5.94-12.97)%; conduit 6.5(4.53-9.28)%; contraction function 4.0(2.29-6.56)%]. Atrial contraction was absent in 21.6% of patients whose ECG showed sinus rhythm (SR)-"atrial electro-mechanical dissociation"(AEMD). AEMD was associated with poorer prognosis compared to SR patients with effective mechanical contraction (p &lt; 0.0001). AEMD conferred a similar prognosis to patients in AF.

CONCLUSION

The phenotype of ATTR-CM includes significant infiltration of the atrial walls with progressive loss of atrial function and increased stiffness, which is a strong independent predictor of mortality. AEMD emerged as a distinctive phenotype identifying patients in SR with poor prognosis.

Abstract Figure.

Class IA PI3Ks regulate subcellular and functional dynamics of IDO1

Knowledge of a protein's spatial dynamics at the subcellular level is key to understanding its function(s), interactions, and associated intracellular events. Indoleamine 2,3-dioxygenase 1 (IDO1) is a cytosolic enzyme that controls immune responses via tryptophan metabolism, mainly through its enzymic activity. When phosphorylated, however, IDO1 acts as a signaling molecule in plasmacytoid dendritic cells (pDCs), thus activating genomic effects, ultimately leading to long-lasting immunosuppression. Whether the two activities-namely, the catalytic and signaling functions-are spatially segregated has been unclear. We found that, under conditions favoring signaling rather than catabolic events, IDO1 shifts from the cytosol to early endosomes. The event requires interaction with class IA phosphoinositide 3-kinases (PI3Ks), which become activated, resulting in full expression of the immunoregulatory phenotype in vivo in pDCs as resulting from IDO1-dependent signaling events. Thus, IDO1's spatial dynamics meet the needs for short-acting as well as durable mechanisms of immune suppression, both under acute and chronic inflammatory conditions. These data expand the theoretical basis for an IDO1-centered therapy in inflammation and autoimmunity.

Regression of cardiac amyloid deposits with novel therapeutics: reaching new frontiers in cardiac ATTR amyloidosis

Background

Cardiac involvement is the main driver of outcome in ATTR amyloidosis. Advances in therapeutics hold potential in transforming the course of the disease but the impact on cardiac amyloid load is unknown. The aim of this study was to evaluate the impact of patisiran, a new double stranded RNA based gene silencing therapy and a stabilizer, diflunisal, on cardiac amyloid load as measured by CMR and T1 mapping, in patients with ATTR amyloidosis.

Methods and results

Thirty-two patients with hereditary cardiac amyloidosis were studied. Sixteen patients received treatment with patisiran, and sixteen control subjects did not receive any disease modifying treatment. Patients were assessed with echocardiogram, CMR, NT-proBNP and six-minute walk time measurements at baseline and at 1 year (Mean interval 11.45±3.08 months in treatment group, mean interval 12.82±5.06 months in the control group). CMR analysis comprised LV volumes, T1 mapping to measure the extracellular volume (ECV) occupied by amyloid, T2 mapping and late gadolinium enhancement imaging. At 1-year follow-up, there was a substantial reduction in cardiac amyloid burden, in keeping with cardiac amyloid regression in 45% of patients on treatment. Overall the treatment group showed a reduction in ECV at 1 year follow up compared to an increase in ECV at 1 year in the control group (−1.37%, 95% CI: −3.43 to 0.68% versus 5.02%, 95% CI: 2.86% to 7.18% respectively, p&lt;0.001). The treatment group also showed an improvement in change in 6MWT at 1 year follow up compared to 6MWT at 1 year in the control group (−8.12 meters, 95% CI: −50.8 to 34.6 meters in the treatment group versus −132.27 meters, 95% CI: −216 to −48.6 meters in the control group, p=0.002). The treatment group showed a reduction in BNP at 1 year follow up compared to an increase in the control group (−567.87, 95% CI: −1288.90 to 153.15 in the treatment group versus 2004, 95% CI: 12.82 to 3995.45 in the control group, p&lt;0.001). There was no significant difference from baseline and 1-year data between the control and treatment groups for the difference in echocardiographic parameters, native T1, T2. There was a significant reduction in the percentage of injected dose by 99Tc-DPD scintigraphy in treated patients at 1 year compared to baseline.

Conclusions

These findings provide the first compelling evidence of substantial cardiac amyloid regression in ATTR amyloidosis, as well as the potential for CMR to be used to track response in treated patients with ATTR cardiac amyloidosis. Combination therapy with transthyretin knock down and stabilizing agents may well be synergistic given enhanced stoichiometry of stabilizers in the face of much reduced plasma transthyretin concentration.

Funding Acknowledgement

Type of funding source: None

Global longitudinal strain predicts survival and response in patients with systemic AL amyloidosis. analysis of 915 patients from the ALchemy prospective trial

Background

Cardiac involvement determines prognosis in systemic AL amyloidosis. The extent is assessed by biomarker-based staging systems. This a prospective report of a large cohort of patients assessing the utility of changes in longitudinal function by 2D strain (GLS%), impairment - a hallmark of amyloidosis.

Purpose

To evaluate the prognostic role of GLS% and other echocardiographic parameters in systemic AL amyloidosis.

Methods

915 newly diagnosed patients seen at the UK National Amyloidosis Centre (February 2010–August 2017) were included. All patients underwent 6-monthly comprehensive assessments inclusive of echocardiogram. The European modification of the Mayo 2004 staging was used with Mayo stage III patients stratified into IIIa (NT-proBNP &lt;8500ng/L) and IIIb (NT-proBNP ≥8500ng/L).

Results

653/915 (71.4%) patients had cardiac involvement. Mayo stage 1, 2, 3a and 3b in 144 (15.7%), 302 (33.0%) 344 (37.6%) and 125 (13.7%) respectively. The median NT-proBNP was 2228ng/L and TNT was 0.54ng/ml. The GLS% significantly worsened with increasing Mayo stage (p&lt;0.0001 between GLS% for each Mayo stage). Poorer baseline GLS% associated with significantly worse OS and stratified patients into three groups: GLS% &lt;−12.8%: OS 69.1 months; GLS% −12.8% to −9%: OS 54.5 months; GLS% &gt;−9%: OS 45.3 months (p&lt;0.0001). On univariate analysis, 11/14 parameters predicted survival (LV wall thickness, LV ejection fraction, systolic velocities of the septal (s'sep) and lateral mitral annulus (s' lat), mitral annulus movement at the lateral corner (e' lat), transmitral early peak flow velocity (E) divided by tissue Doppler mitral annular motion velocity (e') – E/e' and mitral annular plane systolic excursion (MAPSE)). Baseline GLS% &gt;−17% was independent of Mayo stage in predicting survival [Mayo II: Hazard ratio (HR) 2.10 (95% CI: 1.12–3.92) p=0.02, Mayo III: HR 3.94 (95% CI: 2.13–7.32) p&lt;0.0001, Mayo IV: HR 7.49 (95% CI: 3.94–14.21) p&lt;0.0001, GLS &lt;17%: HR 2.14 (95% CI: 1.59–2.88) p&lt;0.0001]. At 12 months, only patients in a haematological complete response (CR) had significant improvement in overall GLS% (p=0.02) as well as baso-lateral (p=0.0004) and baso-septal (p=0.0001) GLS% and MAPSE (p=0.002). The OS was significantly better in patients who achieved a minimum absolute improvement in GLS% of 1.5% improvement (not reached in those with improved GLS% vs. 72 mo in those without) (p=0.034)).

Conclusion

These data show that baseline GLS% is an independent predictor of survival in AL amyloidosis. GLS% is the first functional marker that is independent of the Mayo staging in predicting outcomes and should be incorporated in prognostic staging for patients with AL amyloidosis. GLS% shows improvement in patients who achieve a complete haematologic response to treatment and improvement in GLS% of 1.5% is associated with improved outcomes. An absolute improvement in GLS% should be considered as a criterion for cardiac response in AL amyloidosis.

Funding Acknowledgement

Type of funding source: None

Diffusion Tensor Cardiovascular Magnetic Resonance in Cardiac Amyloidosis

Background Cardiac amyloidosis (CA) is a disease of interstitial myocardial infiltration, usually by light chains or transthyretin. We used diffusion tensor cardiovascular magnetic resonance (DT-CMR) to noninvasively assess the effects of amyloid infiltration on the cardiac microstructure. Methods DT-CMR was performed at diastole and systole in 20 CA, 11 hypertrophic cardiomyopathy, and 10 control subjects with calculation of mean diffusivity, fractional anisotropy, and sheetlet orientation (secondary eigenvector angle). Results Mean diffusivity was elevated and fractional anisotropy reduced in CA compared with both controls and hypertrophic cardiomyopathy (P<0.001). In CA, mean diffusivity was correlated with extracellular volume (r=0.68, P=0.004), and fractional anisotropy was inversely correlated with circumferential strain (r=-0.65, P=0.02). In CA, diastolic secondary eigenvector angle was elevated, and secondary eigenvector angle mobility was reduced compared with controls (both P<0.001). Diastolic secondary eigenvector angle was correlated with amyloid burden measured by extracellular volume in transthyretin, but not light chain amyloidosis. Conclusions DT-CMR can characterize the microstructural effects of amyloid infiltration and is a contrast-free method to identify the location and extent of the expanded disorganized myocardium. The diffusion biomarkers mean diffusivity and fractional anisotropy effectively discriminate CA from hypertrophic cardiomyopathy. DT-CMR demonstrated that failure of sheetlet relaxation in diastole correlated with extracellular volume in transthyretin, but not light chain amyloidosis. This indicates that different mechanisms may be responsible for impaired contractility in CA, with an amyloid burden effect in transthyretin, but an idiosyncratic effect in light chain amyloidosis. Consequently, DT-CMR offers a contrast-free tool to identify novel pathophysiology, improve diagnostics, and monitor disease through noninvasive microstructural assessment.

1171Myocardial perfusion mapping in cardiac amyloidosis - exploring the spectrum from infiltration to ischaemia

Background

Cardiac involvement is the main driver of outcome in systemic amyloidosis, but the relationship between amyloid deposits and outcomes is not well understood. The simple explanation of physical, mechanical replacement of the interstitium by amyloid seems insufficient. Preliminary studies support the hypothesis that myocardial ischaemia could contribute to cell damage.

Purpose

(1) To assess myocardial ischaemia in cardiac amyloidosis. (2) To compare patients with cardiac amyloidosis to patients assessed on invasive coronary angiography (ICA) to have normal coronary physiology (NCP), microvascular dysfunction (MVD) and triple vessel coronary disease (3VD). (3) To assess correlation of perfusion mapping to markers of disease severity and prognosis.

Methods

86 patients and 20 healthy volunteers (HV) underwent CMR at 1.5T (Siemens) with standard cine, PSIR-LGE, T1, T2, Extracellular Volume (ECV) mapping and adenosine stress with myocardial blood flow (MBF) mapping. Thirty-eight patients also underwent ICA with 3 vessel assessment of Index of Microcirculatory Resistance and Fractional Flow Reserve: 7 had cardiac amyloidosis, 8 had NCP, 15 had MVD and 8 had 3VD.

Results

Cardiac amyloidosis patients had severe reduction in stress MBF and myocardial perfusion reserve (MPR) (1.22ml/g/min±0.70 and 1.62±0.63) compared to HV (3.21ml/g/min±0.64, p<0.001 and 4.17±0.78, p<0.001), NCP (2.66±0.56, p<0.001 and 2.51±0.43, p=0.036) and MVD (2.10±0.31, p<0.001 and 2.29±0.87, p=0.014) with the degree of reduction being similar only to patients with 3VD (1.44±0.54, p=1.000 and 1.64±0.68, p=1.000) (Figure 1). Rest MBF was also lower in amyloidosis than HV. Cardiac amyloidosis stress MBF and MPR inversely correlated with amyloid burden (ECV, r=−0.715, p<0.001, transmurality of LGE, p<0.01), systolic dysfunction (EF, r=0.405, p<0.01), and blood biomarkers (NT-proBNP (r=−0.678, p<0.001) and Troponin T (r=−0.628, p<0.001)). There was a correlation between stress MBF and native T1 (r=−0.588, p<0.001) but not T2 (p=0.591). Stress MBF and MPR were early disease markers, being elevated in patients with early cardiac amyloid infiltration (raised ECV, no LGE, P<0.01 vs HV).

Conclusion

Myocardial ischaemia is common in cardiac amyloidosis – with stress MBF and MPR similar to that of patients with 3VD. The reduction correlates with the degree of amyloid infiltration and markers of adverse prognosis, highlighting the potential role of myocardial ischaemia as a key mechanism in the pathophysiology of cardiac amyloidosis.

9. Successful use of IL-6 pathway blockade to treat autoinflammation occurring in the context of a novel TNFRS1A gene mutation

Introduction

Autoinflammatory fever syndromes are rare and present significant diagnostic and treatment challenges. We present a case which illustrates some key concepts regarding the diagnosis and treatment of a patient with an autoinflammatory disorder, and also touches on the management of active autoinflammation in pregnancy.

Case description

A 29-year-old woman with a recently identified autoinflammatory disorder was referred to the local rheumatology service in September 2018. She reported having been symptomatic of fever, rashes and arthralgia since the age of 10, and TNF receptor 1 associated periodic syndrome (TRAPS) was suspected on the basis of an N71 deletion on axon 2 of the TNFRS1A gene when tested by a national reference centre 9 months previously.

At the time of presentation she was 25 weeks into her sixth pregnancy, the first with a new partner. She reported significant pregnancy morbidity having given birth to a daughter with multiple congenital abnormalities who unfortunately died two days after birth. She suffered 4 subsequent miscarriages at 5-7 weeks gestation with the same partner and underwent extensive genetic testing. At her initial review in the obstetric clinic, she was already receiving low-molecular-weight heparin with aspirin. Colchicine 1 mg tds, did not confer significant symptomatic benefit.

One month later, with careful counselling about pregnancy exposure to this biological treatment, IL-1 receptor antagonist (anakinra) therapy was instituted but discontinued after three weeks for generalised rash, as well as lack of efficacy manifesting in raised inflammatory markers. Infection was excluded during a subsequent hospital admission, and prednisolone treatment resulted in significant improvement in clinical course and acute phase response. The patient gave birth to a healthy infant at 37 weeks’ gestation.

In the postpartum period, a recurrence of symptoms was observed. IL-6 receptor antagonist (tocilizumab) treatment was commenced at 12 weeks postpartum but discontinued owing to reports of sore throat, cough, headache and fever on the day of the injection. The patient had also discontinued prednisolone on the day of the injection and tocilizumab was rechallenged with good symptomatic response, normalisation of inflammatory markers, and successful reduction in prednisolone dose.

Discussion

This case highlights some interesting points with relation to the treatment of autoinflammatory disorders refractory to IL-1 pathway blockade, and also, of the management of flares of autoinflammation during pregnancy.

Firstly, this lady failed to respond to IL-1 receptor antagonist anakinra which has been associated with efficacy in several reports for individuals with TRAPS, and has supplanted TNF blockade with agents such as etanercept for this condition. Only a handful of case reports describe successful IL-6 inhibitor administration for this condition, and this merits further study. This patient’s flare of autoinflammation was treated in the post-partum period, but the demographic characteristics of the autoinflammatory diseases are such that people of child-bearing age may be required to receive treatment in order to prevent pregnancy morbidity as a result of uncontrolled inflammation. IL-6 blockade has not to date been associated with adverse pregnancy outcomes, although this data requires extension and validation. 2 cases of renal agenesis have been reported in children born to mothers with anakinra, but the very small numbers of exposed parents warrants further examination of this observation and the careful study of ongoing pharmacovigilance data to explore this observation.

Secondly, success with IL-6 inhibition has been reported in a series of patients with familial Mediterranean fever, the most common autoinflammatory disorder, but this treatment does not feature in the most recent European guidelines for this condition. IL-6 inhibition is well-established in the treatment of adult-onset Still’s disease (AoSD) however, and this lady’s presentation shares important features with that condition. The existence of TNF-receptor 1 mutations has been reported in patients with AoSD, and it may be that this patient’s presentation is more akin to adult-onset Still’s disease and that her TNF receptor mutation is an incidental finding.

Key learning points

This report adds to the handful cases in which IL-6 blockade has been used successfully to treat the autoinflammatory manifestations of suspected TNF receptor 1 associated periodic syndrome (TRAPS) after the failure of IL-1 receptor blockade with anakinra.

Careful history and examination are required to differentiate between potentially overlapping symptoms of drug reaction, autoinflammation, and infection in patients with systemic autoinflammatory disorders (SAIDs). Once a history consistent with autoinflammatory flare was established, cautiously rechallenging with an IL-6 pathway inhibitor ensured this effective treatment was not discounted due to concerns over a drug reaction.

With a degree of commonality between the more common conditions in the SAID family, a detailed examination of the clinical phenotype is essential to the interpretation of genetic tests used for the diagnosis of TRAPS and related disorders.

Uncontrolled inflammatory disease is associated with pregnancy morbidity and very limited information is available about the short and long-term safety of treatments for autoinflammatory diseases in general. Current guidelines do not recommend the use of IL-6 inhibitor therapy in pregnancy.

Conflict of interest

The authors declare no conflicts of interest.

Genome organization and chromatin analysis identify transcriptional downregulation of insulin-like growth factor signaling as a hallmark of aging in developing B cells

BACKGROUND

Aging is characterized by loss of function of the adaptive immune system, but the underlying causes are poorly understood. To assess the molecular effects of aging on B cell development, we profiled gene expression and chromatin features genome-wide, including histone modifications and chromosome conformation, in bone marrow pro-B and pre-B cells from young and aged mice.

RESULTS

Our analysis reveals that the expression levels of most genes are generally preserved in B cell precursors isolated from aged compared with young mice. Nonetheless, age-specific expression changes are observed at numerous genes, including microRNA encoding genes. Importantly, these changes are underpinned by multi-layered alterations in chromatin structure, including chromatin accessibility, histone modifications, long-range promoter interactions, and nuclear compartmentalization. Previous work has shown that differentiation is linked to changes in promoter-regulatory element interactions. We find that aging in B cell precursors is accompanied by rewiring of such interactions. We identify transcriptional downregulation of components of the insulin-like growth factor signaling pathway, in particular downregulation of Irs1 and upregulation of Let-7 microRNA expression, as a signature of the aged phenotype. These changes in expression are associated with specific alterations in H3K27me3 occupancy, suggesting that Polycomb-mediated repression plays a role in precursor B cell aging.

CONCLUSIONS

Changes in chromatin and 3D genome organization play an important role in shaping the altered gene expression profile of aged precursor B cells. Components of the insulin-like growth factor signaling pathways are key targets of epigenetic regulation in aging in bone marrow B cell precursors.

Real world outcomes of pomalidomide for treatment of relapsed light chain amyloidosis

Pomalidomide is a next-generation immunomodulatory agent with activity in relapsed light chain (AL) amyloidosis, but real world outcomes are lacking. We report the experience of the UK National Amyloidosis Centre. All patients with AL amyloidosis treated with pomalidomide between 2009 and 2017 were included. Data was collected on treatment toxicity and clonal response. Survival was calculated by the Kaplan-Meier method and outcomes reported on an intent-to-treat (ITT) basis. A total of 29 patients treated with pomalidomide were identified. Haematological responses at 3 months were: complete response (CR) nil, very good partial response (VGPR) 10 (35%), partial response (PR) 9 (31%), stable or progressive disease 7 (24%), unevaluable 3 (10%). On an ITT basis (n = 28), responses at 6 months were: CR- nil, VGPR-11 (39%), PR-2 (7%) and the remaining patients were non-responders 15 (53%). Median overall survival was 27 months (95% confidence interval 15·7-38·1 months). Median progression free survival (PFS) was 15 months (95% confidence interval 6·24-23·77). In conclusion, pomalidomide has activity in patients with relapsed AL amyloidosis. Responses are rapid and early responses may be predictive of a sustained overall response. Deep responses (VGPR or better) are seen in only a third of all patients and combination therapy needs to be explored.

Multicentric Evaluation of a New PT Reagent Based on Recombinant Human Tissue Factor and Synthetic Phospholipids

A new PT reagent based on recombinant human tissue factor and synthetic phospholipids (phosphatidyl choline and phosphatidyl serine) with defined fatty acid side chains was calibrated against BCT/253 and CRM 149R. A small but consistent bias in the International Sensitivity Index (ISI) value was obtained using either the human or rabbit brain reference material. ISI values were around 1.0 or slightly lower depending on the respective instrument. Mixing studies with factor deficient plasmas showed a high factor sensitivity especially for factor VII as compared to commercial rabbit brain or human placenta thromboplastin. In an international field trial the reagent was tested using fully or semi automated Electra™ coagulometers in 4 different laboratories. Results with normal samples were in excellent agreement among the different laboratories. Mean values were 10.9, 10.9, 11.0, 11,7 s with a range of 9.5 to 12.5 s. Results of males and females were not different. In patients with liver disease very similar PT activities were found as compared to sensitive rabbit brain or human placental thromboplastins. In normals and patients with oral anticoagulation INR values correlated very well against BCT (r = 0.98, regression line y =-0.07 + 0.9 x). The distribution of samples was linear over the whole range. In the comparison against sensitive rabbit brain thromboplastin or human placental thromboplastin similar correlations were found. In a few cases higher INR values were observed for the recombinant reagent especially in patients with intensive treatment. Factor assays in those patients showed at least the strong reduction of one vitamin Independent coagulation factor. Over all the linearity was better against the rabbit brain reagent than against the human placental reagent which is slightly less factor VII sensitive as shown in mixing studies with normal and factor VII deficient plasma. Precision studies in the 4 laboratories showed excellent reproducibility of lyophilised controls or local patient plasma pools for all reagents with a better performance of the recombinant reagent. C. V. values from day to day ranged from 1.3% to 5% for normal and abnormal controls.

These results show that the recombinant PT reagent, especially in conjunction with a precise automated instrument, may improve the results of PT testing and thus may lead to better patient care.

Femtosecond Laser Mass Spectrometry and High Harmonic Spectroscopy of Xylene Isomers

Structural isomers, molecules having the same chemical formula but with atoms bonded in different order, are hard to identify using conventional spectroscopy and mass spectrometry. They exhibit virtually indistinguishable mass spectra when ionized by electrons. Laser mass spectrometry based on photoionization of the isomers has emerged as a promising alternative but requires shaped ultrafast laser pulses. Here we use transform limited femtosecond pulses to distinguish the isomers using two methods. First, we probe doubly charged parent ions with circularly polarized light. We show that the yield of doubly charged ortho-xylene decreases while para-xylene increases over a range of laser intensities when the laser polarization is changed from linear to circular. Second, we probe high harmonic generation from randomly oriented isomer molecules subjected to an intense laser field. We show that the yield of high-order harmonics varies with the positioning of the methyl group in xylene isomers (ortho-, para- and meta-) and is due to differences in the strength of tunnel ionization and the overlap between the angular peaks of ionization and photo-recombination.

SGK1 Is a Critical Component of an AKT-Independent Pathway Essential for PI3K-Mediated Tumor Development and Maintenance

Activation of the PI3K-AKT signaling cascade is a common critical event during malignant transformation. In this study, we used thyroid gland epithelial cells and a series of genetically engineered mouse strains as model systems to demonstrate that, although necessary, AKT activation is not sufficient for PI3K-driven transformation. Instead, transformation requires the activity of the PDK1-regulated AGC family of protein kinases. In particular, SGK1 was found to be essential for proliferation and survival of thyroid cancer cells harboring PI3K-activating mutations. Notably, cotargeting SGK1 and AKT resulted in significantly higher growth suppression than inhibiting either PI3K or AKT alone. Overall, these findings underscore the clinical relevance of AKT-independent pathways in tumors driven by genetic lesions targeting the PI3K cascade. Cancer Res; 77(24); 6914-26. ©2017 AACR.

Alpha-1-antitrypsin deficiency-related panniculitis: two cases with diverse clinical courses

Alpha-1-antitrypsin deficiency (AATD)-related panniculitis is an extremely rare and underdiagnosed entity, and there is a paucity of data on its treatment. We report two cases of AATD-related panniculitis. The first was a 24-year-old woman with known AATD who presented with painful leg ulcers refractory to treatment with corticosteroids and colchicine. She had a good response to α1-antitrypsin infusions but required dose adjustment due to flares in disease activity. The second case was a 38-year-old woman who presented with painful nodules on the legs refractory to corticosteroid therapy. Laboratory investigations revealed severe AATD. She had an excellent response to colchicine therapy. In both these cases of AATD, panniculitis was the first clinical manifestation of the disease. AATD-related panniculitis may have none of the typical clinical clues for AATD, such as a family history, cirrhosis or emphysema. Early identification may help prevent these complications from developing.

Genome-wide association study of immunoglobulin light chain amyloidosis in three patient cohorts: comparison with myeloma

Immunoglobulin light chain (AL) amyloidosis is characterized by tissue deposition of amyloid fibers derived from immunoglobulin light chain. AL amyloidosis and multiple myeloma (MM) originate from monoclonal gammopathy of undetermined significance. We wanted to characterize germline susceptibility to AL amyloidosis using a genome-wide association study (GWAS) on 1229 AL amyloidosis patients from Germany, UK and Italy, and 7526 healthy local controls. For comparison with MM, recent GWAS data on 3790 cases were used. For AL amyloidosis, single nucleotide polymorphisms (SNPs) at 10 loci showed evidence of an association at P<10^-5 with homogeneity of results from the 3 sample sets; some of these were previously documented to influence MM risk, including the SNP at the IRF4 binding site. In AL amyloidosis, rs9344 at the splice site of cyclin D1, promoting translocation (11;14), reached the highest significance, P=7.80 × 10^-11; the SNP was only marginally significant in MM. SNP rs79419269 close to gene SMARCD3 involved in chromatin remodeling was also significant (P=5.2 × 10^-8). These data provide evidence for common genetic susceptibility to AL amyloidosis and MM. Cyclin D1 is a more prominent driver in AL amyloidosis than in MM, but the links to aggregation of light chains need to be demonstrated.

The Inositol-3-Phosphate Synthase Biosynthetic Enzyme Has Distinct Catalytic and Metabolic Roles

Inositol levels, maintained by the biosynthetic enzyme inositol-3-phosphate synthase (Ino1), are altered in a range of disorders, including bipolar disorder and Alzheimer's disease. To date, most inositol studies have focused on the molecular and cellular effects of inositol depletion without considering Ino1 levels. Here we employ a simple eukaryote, Dictyostelium discoideum, to demonstrate distinct effects of loss of Ino1 and inositol depletion. We show that loss of Ino1 results in an inositol auxotrophy that can be rescued only partially by exogenous inositol. Removal of inositol supplementation from the ino1(-) mutant resulted in a rapid 56% reduction in inositol levels, triggering the induction of autophagy, reduced cytokinesis, and substrate adhesion. Inositol depletion also caused a dramatic generalized decrease in phosphoinositide levels that was rescued by inositol supplementation. However, loss of Ino1 triggered broad metabolic changes consistent with the induction of a catabolic state that was not rescued by inositol supplementation. These data suggest a metabolic role for Ino1 that is independent of inositol biosynthesis. To characterize this role, an Ino1 binding partner containing SEL1L1 domains (Q54IX5) and having homology to mammalian macromolecular complex adaptor proteins was identified. Our findings therefore identify a new role for Ino1, independent of inositol biosynthesis, with broad effects on cell metabolism.

Perturbations of PIP3 signalling trigger a global remodelling of mRNA landscape and reveal a transcriptional feedback loop

PIP3 is synthesized by the Class I PI3Ks and regulates complex cell responses, such as growth and migration. Signals that drive long-term reshaping of cell phenotypes are difficult to resolve because of complex feedback networks that operate over extended times. PIP3-dependent modulation of mRNA accumulation is clearly important in this process but is poorly understood. We have quantified the genome-wide mRNA-landscape of non-transformed, breast epithelium-derived MCF10a cells and its response to acute regulation by EGF, in the presence or absence of a PI3Kα inhibitor, compare it to chronic activation of PI3K signalling by cancer-relevant mutations (isogenic cells expressing an oncomutant PI3Kα allele or lacking the PIP3-phosphatase/tumour-suppressor, PTEN). Our results show that whilst many mRNAs are changed by long-term genetic perturbation of PIP3 signalling ('butterfly effect'), a much smaller number do so in a coherent fashion with the different PIP3 perturbations. This suggests a subset of more directly regulated mRNAs. We show that mRNAs respond differently to given aspects of PIP3 regulation. Some PIP3-sensitive mRNAs encode PI3K pathway components, thus suggesting a transcriptional feedback loop. We identify the transcription factor binding motifs SRF and PRDM1 as important regulators of PIP3-sensitive mRNAs involved in cell movement.

Phosphoinositide 3-kinase δ gene mutation predisposes to respiratory infection and airway damage

Genetic mutations cause primary immunodeficiencies (PIDs) that predispose to infections. Here, we describe activated PI3K-δ syndrome (APDS), a PID associated with a dominant gain-of-function mutation in which lysine replaced glutamic acid at residue 1021 (E1021K) in the p110δ protein, the catalytic subunit of phosphoinositide 3-kinase δ (PI3Kδ), encoded by the PIK3CD gene. We found E1021K in 17 patients from seven unrelated families, but not among 3346 healthy subjects. APDS was characterized by recurrent respiratory infections, progressive airway damage, lymphopenia, increased circulating transitional B cells, increased immunoglobulin M, and reduced immunoglobulin G2 levels in serum and impaired vaccine responses. The E1021K mutation enhanced membrane association and kinase activity of p110δ. Patient-derived lymphocytes had increased levels of phosphatidylinositol 3,4,5-trisphosphate and phosphorylated AKT protein and were prone to activation-induced cell death. Selective p110δ inhibitors IC87114 and GS-1101 reduced the activity of the mutant enzyme in vitro, which suggested a therapeutic approach for patients with APDS.

A novel oxygen and/or carbon dioxide-sensitive optical transducer

A novel oxygen (O(2)) and/or carbon dioxide (CO(2))-sensitive transducer for the measurement of both gaseous O(2) and CO(2) over the concentration ranges of O(2), 0-100% and CO(2), 0-10% has been described employing a solution of 10.6 muM fluorescein (FL) and 190 muM potassium hydroxide in a solvent mixtures of 1:1 (v/v) N,N'-diethylaniline (DEA) and N,N-dimethylformamide. Increasing O(2) concentrations cause the absorbance of the solution at a wavelength of 400 nm to increase owing to a contact charge transfer reaction existing between O(2) and DEA molecules, and increasing CO(2) concentrations produce a non-linear fall in absorbance at 520 nm as the colour of FL changes from its orange dianion form to the colourless neutral, lactonic form. Both processes are independent of each other and reversible. The response to changes in O(2) concentrations is in good agreement with Beer-Lambert's law and the response to changes in CO(2) concentrations in non-linear. A fibre optic sensing system based on this solvent-dye solution has been set up for continuous and reversible determination of both gaseous O(2) and CO(2). Possible applications include environmental and physiological monitoring of O(2) over the ranges of 0-100% and CO(2), 0-10%.