Internalisation of immunoglobulin light chains by cardiomyocytes in AL amyloidosis: what can biopsies tell us?

BACKGROUND: Cardiac involvement in systemic light chain amyloidosis (AL) leads to chronic heart failure and is a major prognosis factor. Severe cellular defects are provoked in cardiac cells by tissue-deposited amyloid fibrils of misfolded free immunoglobulin light chains (LCs) and their prefibrillar oligomeric precursors. OBJECTIVE: Understanding the molecular mechanisms behind cardiac cell cytotoxicity is necessary to progress in therapy and to improve patient management. One key question is how extracellularly deposited molecules exert their toxic action inside cardiac cells. Here we searched for direct evidence of amyloid LC uptake by cardiomyocytes in patient biopsies. METHODS: We immunolocalized LCs in cardiac biopsies from four AL cardiac amyloidosis patients and analysed histopathological images by high resolution confocal microscopy and 3D image reconstruction. RESULTS: We show, for the first time directly in patient tissue, the presence of LCs inside cardiomyocytes, and report their proximity to nuclei and to caveolin-3-rich areas. Our observations point to macropinocytosis as a probable mechanism of LC uptake. CONCLUSIONS: Internalisation of LCs occurs in patient cardiomyocytes. This event could have important consequences for the pathogenesis of the cardiac disease by enabling interactions between amyloid molecules and cellular organelles inducing specific signalling pathways, and might bring new insight regarding treatment.

Epstein-Barr Virus and immune status imprint the immunogenomics of non-Hodgkin lymphomas occurring in immune-suppressed environments.

Non-Hodgkin lymphomas (NHL) commonly occur in immune-deficient (ID) patients, both HIV-infected and transplanted, and are often EBV-driven with cerebral localization, raising the question of tumor immunogenicity, a critical issue for treatment responses. We investigated the immunogenomics of 68 lymphoproliferative disorders from 51 ID (34 posttransplant, 17 HIV+) and 17 immunocompetent patients. Overall, 72% were Large B Cells Lymphoma (LBCL) and 25% were primary central-nervous-system lymphoma (PCNSL) while 40% were EBV-positive. Tumor whole-exome and RNA sequencing, along with a bioinformatics pipeline allowed analysis of tumor mutational burden (TMB), tumor landscape and microenvironment (TME) and prediction of tumor neoepitopes. Both TMB (2.2 vs 3.4/Mb, p=0.001) and neoepitopes numbers (40 vs 200, p=0.00019) were lower in EBVpositive than in EBV-negative NHL, regardless of the immune status. In contrast both EBV and the immune status influenced the tumor mutational profile, with HNRNPF and STAT3 mutations exclusively observed in EBV-positive and ID NHL, respectively. Peripheral blood T-cell responses against tumor neoepitopes were detected in all EBV-negative cases but in only half EBV-positive ones, including responses against IgH-derived MHC-class-II restricted neoepitopes. The TME analysis showed higher CD8 T cell infiltrates in EBVpositive vs EBV-negative NHL, together with a more tolerogenic profile composed of Tregs, type-M2 macrophages and an increased expression of negative immune-regulators. Our results highlight that the immunogenomics of NHL in patients with immunodeficiency primarily relies on the tumor EBV status, while T cell recognition of tumor- and IgH-specific neoepitopes is conserved in EBV-negative patients, offering potential opportunities for future T cell-based immune therapies.

Prevalence, Characteristics, and Impact on Prognosis of Aortic Stenosis in Patients With Cardiac Amyloidosis.

BACKGROUND: Cardiac amyloidosis (CA) is frequently found in older patients with aortic stenosis (AS). However, the prevalence of AS among patients with CA is unknown. The objective was to study the prevalence and prognostic impact of AS among patients with CA. METHODS AND RESULTS: We conducted a retrospective analysis of a prospective registry comprising 976 patients with native aortic valves who were confirmed with wild type transthyretin amyloid (ATTRwt), hereditary variant transthyretin amyloid (ATTRv), or immunoglobulin light-chain (AL) CA. CA patients' echocardiograms were re-analyzed focusing on the aortic valve. Multivariable Cox regression analysis was performed to assess the mortality risk associated with moderate or greater AS in ATTRwt CA. The crude prevalence of AS among patients with CA was 26% in ATTRwt, 8% in ATTRv, and 5% in AL. Compared with population-based controls, all types of CA had higher age- and sex-standardized rate ratios (SRRs) of having any degree of AS (AL: SRR, 2.62; 95% Confidence Interval (CI) [1.09-3.64]; ATTRv: SRR, 3.41; 95%CI [1.64-4.60]; ATTRwt: SRR, 10.8; 95%CI [5.25-14.53]). Compared with hospital controls, only ATTRwt had a higher SRR of having any degree of AS (AL: SRR, 0.97, 95%CI [0.56-1.14]; ATTRv: SRR, 1.27; 95%CI [0.85-1.44]; ATTRwt: SRR, 4.01; 95%CI [2.71-4.54]). Among patients with ATTRwt, moderate or greater AS was not associated with increased all-cause death after multivariable adjustment (hazard ratio, 0.71; 95%CI [0.42-1.19]; P=0.19). CONCLUSIONS: Among patients with CA, ATTRwt but not ATTRv or AL is associated with a higher prevalence of patients with AS compared with hospital controls without CA, even after adjusting for age and sex. In our population, having moderate or greater AS was not associated with a worse outcome in patients with ATTRwt.

Prognostic mortality factors in advanced light chain cardiac amyloidosis: A prospective cohort study.

AIMS: Predicting mortality in severe AL cardiac amyloidosis is challenging due to elevated biomarker levels and limited thresholds for stratifying severe cardiac damage. METHODS AND RESULTS: This prospective, observational, cohort study included de novo, confirmed cardiac AL amyloidosis patients at the Henri Mondor National Reference Centre. The goal was to identify predictors of mortality to enhance prognostic stratification and improve informed decision-making regarding therapy. Over the 12-year study period, among the 233 patients included, 133 were NYHA III-IV and 179 Mayo 2004 III. The independent predictors for mortality identified were hsTnT, NT-proBNP, cardiac output, and conjugated bilirubin. A novel prognostic, conditional stratification, Mondor amyloidosis cardiac staging (MACS) was developed with biomarker cut-off values for Stage 1: hsTnT ≤ 107 ng/L and NT-proBNP ≤ 3867 ng/L (n = 77; 33%); for stage 2 NT-proBNP > 3867 ng/L (n = 72; 30%). For stage 3, if troponin >107 ng/L, regardless of NT-proBNP then CB 4 µmol/L, was added (n = 41; 17.5%) and stage 4: CB > 4 µmol/L (n = 43; 18.5%). The median overall survival was 8 months 95% CI [2-24]. At 1 year, 102 (44%) patients died and the Kaplan-Meier median survival with MACS Stage 1 was not reached, while stage 2 was 15.2 months (95% CI [11-18]) and stage 3, 6.6 months (95% CI [1-13]). Notably, among European stage II patients, 17.1%, n = 8 were MACS stage 3 and European stage IIIb 21.4% (n = 23) were MACS stage 4. Importantly, among European stage IIIb patients 42.2% (n = 29) were classified MACS stage 4 and 12.5% n = 9 were only MACS stage 2. CONCLUSIONS: The Mondor prognostic staging system, including conjugate bilirubin may significantly improve prognostic stratification for patients with severe cardiac amyloidosis.