Amyloidosis and the lungs and airways

Amyloidosis can both complicate long-standing respiratory conditions and be deposited within the respiratory system itself. In acquired systemic amyloidosis, control of the underlying condition that is producing the circulating amyloid precursor protein is paramount. Systemic AA amyloidosis can result from unremitting chronic inflammation or infection such as in bronchiectasis. Control of the inflammation is paramount to amyloid regression. For systemic AL amyloidosis, treatment requires the use of chemotherapy or novel immunotherapies targeting the underlying plasma cell dyscrasia or lymphoproliferative disease that produce the abnormal amyloidogenic light chain. Localised amyloidosis can occur anywhere along the respiratory tract and can present with marked heterogeneity. In localised amyloidosis, management generally involves resection or ablation of symptomatic deposits. On occasion, localised pulmonary amyloidosis can be a manifestation of underlying Sjögren syndrome. Novel treatments are beginning to become available, including specific drug therapies to prevent translation of amyloidogenic proteins, stabilise amyloid precursor proteins and interfere with amyloid fibrillogenesis

Amyloidosis: Incidence, Prognosis, Investigation and Management

Background: Amyloidosis is a rare disorder of protein folding in which a variety of proteins deposit as fibrils in the extracellular space. The two most commonly affected organs are the kidneys and heart. Deposition of amyloid in these two critical organs is of major prognostic importance. Aims: To identify the burden of systemic amyloidosis in the English population. To characterise the phenotype and diagnostic features of wild type transthyretin amyloidosis and identify the type and frequency of arrhythmic activity in cardiac amyloidosis. To evaluate outcome in renal amyloidosis, and assess the role of renal replacement therapy. Results and Conclusions: Amyloidosis was mentioned in 0.58/1000 deaths in England between 2000 and 2008. Sensitivity of death certificates in identifying patients with amyloidosis was 79%. The estimated true incidence of the disease is ~1/100000 population in England. Wild type transthyretin amyloidosis (ATTRwt) is increasingly diagnosed in the UK. Age of the patient at diagnosis and N T-proB N P level can aid in distinguishing ATTRwt from cardiac AL amyloidosis. Median survival is significantly better in ATTRwt than in cardiac AL amyloidosis. A positive troponin T, a pacemaker and NYHA class IV symptoms are all associated with worse outcome. Complex ventricular arrhythmias are seen more frequently on Holter monitoring in patients with transthyretin cardiac amyloidosis compared to cardiac AL which are in turn more frequent than patients without myocardial amyloid infiltration. There does not appear to be an association between the frequency of complex ventricular arrhythmi as and disease severity in cardiac amyl oi dosi s. Renal and overall outcome in AL amyl oi dosi s are both strongly associated with FLC response and are best among patients who achieve >90% suppression of the monoclonal component of the FLC. Survival on dialysis is improving. Outcome following renal transplantation is dependent on the amyloid fibril type and suppression of the precursor protein

Paraprotein-related renal disease

Paraprotein-related renal disease represents a diverse group of rare diseases characterized by distinct renal injury caused by the direct or indirect effects of a nephrotoxic paraprotein secreted by a clone of B cells. Early diagnosis and use of rapidly effective chemotherapy agents have improved patient and renal outcomes for these disorders. Patients can present with proteinuric renal impairment or tubular dysfunction. Diagnosis is often challenging because of the wide range of disease manifestations, difficulties with detection of the pathogenic clone and the common finding of an incidental paraprotein in elderly individuals. A renal biopsy along with haematological work-up is required to link a paraprotein with kidney disease. Chemotherapy directed at the plasma cell clone can halt the production of the paraprotein, which can in turn benefit renal function

Systemic amyloidosis in England: an epidemiological study.

Epidemiological studies of systemic amyloidosis are scarce and the burden of disease in England has not previously been estimated. In 1999, the National Health Service commissioned the National Amyloidosis Centre (NAC) to provide a national clinical service for all patients with amyloidosis. Data for all individuals referred to the NAC is held on a comprehensive central database, and these were compared with English death certificate data for amyloidosis from 2000 to 2008, obtained from the Office of National Statistics. Amyloidosis was stated on death certificates of 2543 individuals, representing 0·58/1000 recorded deaths. During the same period, 1143 amyloidosis patients followed at the NAC died, 903 (79%) of whom had amyloidosis recorded on their death certificates. The estimated minimum incidence of systemic amyloidosis in the English population in 2008, based on new referrals to the NAC, was 0·4/100 000 population. The incidence peaked at age 60-79 years. Systemic AL amyloidosis was the most common type with an estimated minimum incidence of 0·3/100 000 population. Although there are various limitations to this study, the available data suggest the incidence of systemic amyloidosis in England exceeds 0·8/100 000 of the population

Senile Systemic Amyloidosis: Clinical Features at Presentation and Outcome

Background Cardiac amyloidosis is a fatal disease whose prognosis and treatment rely on identification of the amyloid type. In our aging population transthyretin amyloidosis (ATTRwt) is common and must be differentiated from other amyloid types. We report the clinical presentation, natural history, and prognostic features of ATTRwt compared with cardiac‐isolated AL amyloidosis and calculate the probability of disease diagnosis of ATTRwt from baseline factors. Methods and Results All patients with biopsy‐proven ATTRwt (102 cases) and isolated cardiac AL (36 cases) seen from 2002 to 2011 at the UK National Amyloidosis Center were included. Median survival from the onset of symptoms was 6.07 years in the ATTRwt group and 1.7 years in the AL group. Positive troponin, a pacemaker, and increasing New York Heart Association (NYHA) class were associated with worse survival in ATTRwt patients on univariate analysis. All patients with isolated cardiac AL and 24.1% of patients with ATTRwt had evidence of a plasma cell dyscrasia. Older age and lower N‐terminal pro‐B‐type natriuretic peptide (NT pro‐BNP) were factors significantly associated with ATTRwt. Patients aged 70 years and younger with an NT pro‐BNP <183 pmol/L were more likely to have ATTRwt, as were patients older than 70 years with an NT pro‐BNP <1420 pmol/L. Conclusions Factors at baseline associated with a worse outcome in ATTRwt are positive troponin T, a pacemaker, and NYHA class IV symptoms. The age of the patient at diagnosis and NT pro‐BNP level can aid in distinguishing ATTRwt from AL amyloidosis

Renal outcome in patients with newly diagnosed multiple myeloma: results from the UK NCRI Myeloma XI trial

Renal injury is a common complication of multiple myeloma (MM) and is associated with adverse outcome. Despite this, the natural history of renal injury in patients with MM remains uncertain especially in the context of intensive therapy and novel therapies. To address the lack of data, we evaluated the renal function of 2334 patients from the UK National Cancer Research Institute Myeloma XI trial at baseline and at 12 months to assess renal function over time and the factors associated with change. Patients who had severe acute kidney injury or a requirement for dialysis were excluded. At 12 months of the 1450 evaluable patients planned for autologous transplantation; 204 (14%) patients had a decline in estimated glomerular filtration rate (eGFR) ≥25% from baseline, 341 (23.5%) had an improvement and 905 (62%) had no significant change in eGFR. Renal outcome at 12 months for the 884 evaluable patients who were not planned for transplant was similar. Improved renal function was more likely if patients were 1000 mg/L, and/or a free light chain response of >90%. It did not correlate with monoclonal–protein response, transplantation, or use of a bortezomib-based regimen. We show that with current therapies the proportion of patients who have a significant decline in renal function in the first 12 months is small. The greatest relative improvement in eGFR is seen in patients with high free light chain at baseline and a high light chain response. This trial was registered at http://www.isrctn.com as #49407852

Urinary retinol binding protein predicts renal outcome in systemic immunoglobulin light-chain (AL) amyloidosis

Summary: Renal risk stratification in systemic immunoglobulin light-chain (AL) amyloidosis is according to estimated glomerular filtration rate (eGFR) and urinary protein creatinine ratio (uPCR), the latter attributed to glomerular dysfunction, with proximal tubular dysfunction (PTD) little studied. Urinary retinol binding protein 4 (uRBP), a low molecular weight tubular protein and highly sensitive marker of PTD, was prospectively measured in 285 newly diagnosed, untreated patients with systemic AL amyloidosis between August 2017 to August 2018. At diagnosis, the uRBP/creatinine ratio (uRBPCR) correlated with serum creatinine (r = 0·618, P 30 ml/min/1.73 m2 [HR 4·11, (95% CI 1·45–11·65); P = 0·008] and those who failed to achieve a deep haematological response to chemotherapy within 3 months of diagnosis [HR 6·72, (95% CI 1·83–24·74); P = 0·004], and also predicted renal progression [HR 1·91, (95% CI 1·18–3·07); P = 0·008]. Elevated uRBPCR indicates PTD and predicts renal outcomes independently of eGFR, uPCR and clonal response in systemic AL amyloidosis. The role of uRBPCR as a novel prognostic biomarker merits further study, particularly in monoclonal gammopathies of renal significance

Changing epidemiology of AA amyloidosis: clinical observations over 25 years at a single national referral centre

Objective: Systemic AA amyloidosis is a serious complication of chronic inflammation; however, there are relatively few published data on its incidence. We investigated the changing epidemiology of AA amyloidosis over a 25-year period at a single national referral centre. // Methods: We conducted a retrospective study of all patients diagnosed with AA amyloidosis who had attended the centre between 1990 and 2014 inclusive. Six hundred and twenty-five patients were studied in three cohorts: C1: 1990–1997; C2: 1998–2006; C3: 2007–2014. // Results: Mean age at presentation increased from 46 in C1 to 56 in C3 (p < .0001). The proportion of South Asian patients increased from 4% in C1 to 17% in C3 (p = .0006). Comparison of underlying diseases between C1 and C3 revealed a reduction in patients with juvenile idiopathic arthritis from 25% to 2% (p < .0001), but an increase in patients with chronic infection due to intravenous recreational drug use from 1% to 13% (p < .0001), and uncharacterized inflammatory disorders from 10% to 27% (p <.0001). More patients were in end-stage renal failure at presentation in C3 (29%) than C1 (15%) (p = .0028). Median age at death was later in C3 (62 years) than C1 (54 years) (p = .0012). // Conclusion: These data suggest both falling incidence and better outcome in AA amyloidosis over a quarter of a century, reflecting advances in therapeutics and overall management of complex chronic disease in an ageing population. AA amyloidosis of uncertain aetiology presents an emerging major problem. Newer techniques such as next-generation sequencing may aid diagnosis and effective treatment, thereby improving overall survival

Prolonged renal survival in light chain amyloidosis: speed and magnitude of light chain reduction is the crucial factor

Renal involvement causing progressive chronic kidney disease (CKD) is present in 70% of patients with systemic Ig light-chain (AL) amyloidosis at diagnosis. Chemotherapy that substantially suppresses free light chain production is associated with improved patient survival, but its benefit in delaying the onset of renal replacement therapy among patients who present with established advanced CKD has not been studied. To evaluate this, we studied 1000 patients enrolled in the prospective UK AL amyloidosis chemotherapy study (ALchemy). Of these, 84 patients had advanced amyloid-related CKD defined by an estimated glomerular filtration rate (eGFR) under 20 ml/min/1.73 m(2). We determined outcomes among these 84 patients, who had a median eGFR of 10 ml/min/1.73 m(2), in relation to response to chemotherapy evaluated at three, six, and 12 months from baseline. Patients who achieved suppression of 90% or more in their amyloidogenic free light chain (dFLC) within three months of baseline had significantly better overall survival, prolonged time to dialysis, and prolonged time to the composite endpoint of 'death or dialysis' compared to those who achieved lesser degrees of clonal response at the same time point. Even when this target of greater than 90% dFLC response was achieved but was delayed beyond 3 months, it was associated with worse outcomes. Cox regression analyses confirmed that a 90% or better dFLC response within 3 months was the only significant independent predictor of all three of these outcome measures. Thus, renal survival among patients with systemic immunologic light chain amyloidosis who present with advanced CKD is strongly dependent upon the magnitude and speed with which the underlying hematologic disorder is suppressed by chemotherapy

Computational Analysis of HIV-1 Resistance Based on Gene Expression Profiles and the Virus-Host Interaction Network

A very small proportion of people remain negative for HIV infection after repeated HIV-1 viral exposure, which is called HIV-1 resistance. Understanding the mechanism of HIV-1 resistance is important for the development of HIV-1 vaccines and Acquired Immune Deficiency Syndrome (AIDS) therapies. In this study, we analyzed the gene expression profiles of CD4+ T cells from HIV-1-resistant individuals and HIV-susceptible individuals. One hundred eighty-five discriminative HIV-1 resistance genes were identified using the Minimum Redundancy-Maximum Relevance (mRMR) and Incremental Feature Selection (IFS) methods. The virus protein target enrichment analysis of the 185 HIV-1 resistance genes suggested that the HIV-1 protein nef might play an important role in HIV-1 infection. Moreover, we identified 29 infection information exchanger genes from the 185 HIV-1 resistance genes based on a virus-host interaction network analysis. The infection information exchanger genes are located on the shortest paths between virus-targeted proteins and are important for the coordination of virus infection. These proteins may be useful targets for AIDS prevention or therapy, as intervention in these pathways could disrupt communication with virus-targeted proteins and HIV-1 infection