The Successful Diagnosis and Typing of Systemic Amyloidosis Using A Microwave-Assisted Filter-Aided Fast Sample Preparation Method and LC/MS/MS Analysis

Prevalence, clinical characteristics and treatment outcome of factor X deficiency in a consecutive cohort of primary light-chain amyloidosis

Factor X (FX) deficiency is prevalent in light-chain (AL) amyloidosis but its clinical significance was not investigated deeply. We conducted a retrospective analysis of a consecutive cohort with 207 primary AL amyloidosis patients. FX deficiency was present in 129 patients (62.3%). Those with FX deficiency had higher dFLC (299.6 mg/L vs. 102.3 mg/L, P < 0.001), higher cardiac troponin I (0.05 μg/L vs. 0.02 μg/L, P < 0.001) and N-terminal pro-brain natriuretic peptide (3115 ng/L vs. 392 ng/L, P < 0.001), and more patients with bone marrow plasma cells > 10% (18.0% vs. 4.3%, P = 0.008). The prevalence of FX deficiency increased with the Mayo 2004 stage. FX-deficient patients exhibited inferior overall survival (P < 0.001) and progression-free survival (P < 0.001) than others. Fifty-five patients with FX deficiency received retesting of FX activity after anti-plasma cell therapy. The median variation in FX activity was + 6.8% (range, -24.5% ~ +73.4%). Better improvement of FX activity was observed in patients with complete hematologic response (+18.2% vs. +4.0%, P = 0.036) and at least one organ response (+14.4% vs. +3.4%, P = 0.024). FX deficiency is associated with a heavier disease burden and poorer survival in primary AL amyloidosis. Improvement of FX activity tends to appear in patients with better hematologic and organ responses after chemotherapy.

A stepwise data interpretation process for renal amyloidosis typing by LMD-MS

Backgrounds

Systemic amyloidosis is classified according to the deposited amyloid fibril protein (AFP), which determines its best therapeutic scheme. The most common type of AFP found are immunoglobulin light chains. The laser microdissection combined with mass spectrometry (LMD-MS) technique is a promising approach for precise typing of amyloidosis, however, the major difficulty in interpreting the MS data is how to accurately identify the precipitated AFP from background.

Objectives

The objective of the present study is to establish a complete data interpretation procedure for LMD-MS based amyloidosis typing.

Methods

Formalin-fixed paraffin-embedded specimens from patients with renal amyloidosis and non-amyloid nephropathies (including diabetic nephropathy, fibrillary glomerulonephritis, IgA nephropathy, lupus nephritis, membranous nephropathy, and normal tissue adjacent to tumors) were analyzed by LMD-MS. Forty-two specimens were used to train the data interpretation procedure, which was validated by another 50 validation specimens. Area under receiver operating curve (AUROC) analysis of amyloid accompanying proteins (AAPs, including apolipoprotein A-IV, apolipoprotein E and serum amyloid P-component) for discriminating amyloidosis from non-amyloid nephropathies was performed.

Results

A stepwise data interpretation procedure that includes or excludes the types of amyloidosis group by group was established. The involvement of AFPs other than immunoglobulin was determined by P-score, as well as immunoglobulin light chain by variable of λ-κ, and immunoglobulin heavy chain by H-score. This achieved a total of 88% accuracy in 50 validation specimens. The AAPs showed significantly different expression levels between amyloidosis specimens and non-amyloid nephropathies. Each of the single AAP had a AUROC value more than 0.9 for diagnosis of amyloidosis from non-amyloid control, and the averaged level of the three AAPs showed the highest AUROC (0.966), which might be an alternative indicator for amyloidosis diagnosis.

Conclusions

The proteomic data interpretation procedure for LMD-MS based amyloidosis typing was established successfully that has a high practicability in clinical application.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02785-9.

The amyloid proteome: a systematic review and proposal of a protein classification system

Amyloidosis is a disease caused by pathological fibril aggregation and deposition of proteins in different tissues and organs. Thirty-six fibril-forming proteins have been identified. So far, proteomic evaluation of amyloid focused on the detection and characterization of fibril proteins mainly for diagnostic purposes or to find novel fibril-forming proteins. However, amyloid deposits are a complex mixture of constituents that show organ-, tissue-, and amyloid-type specific patterns, that is the amyloid proteome. We carried out a comprehensive literature review on publications investigating amyloid via liquid chromatography coupled to tandem mass spectrometry, including but not limited to sample preparation by laser microdissection. Our review confirms the complexity and dynamics of the amyloid proteome, which can be divided into four functional categories: amyloid proteome-category 1 (APC1) includes exclusively fibrillary proteins found in the patient; APC2 includes potential fibril-forming proteins found in other types of amyloid; and APC3 and APC4 summarizes non-fibril proteins-some being amyloid signature proteins. Our categorization may help to systemically explore the nature and role of the amyloid proteome in the manifestation, progression, and clearance of disease. Further exploration of the amyloid proteome may form the basis for the development of novel diagnostic tools, thereby enabling the development of novel therapeutic targets.

Validation of the composite organ and hematologic response model for prognostic prediction in a Chinese light chain amyloidosis cohort

To achieve prompt and comprehensive assessment of treatment, we investigated the feasibility of composite hematologic and organ response (CHOR) model in a Chinese light chain (AL) amyloidosis cohort. Three hundred and eighty-eight newly diagnosed patients were assigned scores of 0-3 for complete response, very good partial response, partial response, no response, or progression at 6 months. Organ response (OR) was scored as follows: 0 - all OR (AOR), 1 - mixed OR (MOR), and 2 - no OR (NOR). Finally, patients were divided into CHOR group 1 (total score 0-3) and group 2 (total score 4-5). The patients who achieved AOR and MOR had similar outcomes, which were much better than those of patients with NOR. Group 1 had significantly better overall survival than group 2 (p< .001). The CHOR model had a significantly higher predictive power of survival than hematologic response and OR. We validated the value of the CHOR model as an early indicator of treatment benefit.

Genomic profiling in amyloid light-chain amyloidosis reveals mutation profiles associated with overall survival

Background: Amyloid light chain (AL) amyloidosis is characterized by tissue deposition of amyloid fibres derived from immunoglobulin that can lead to irreversible organ damage. Information about genomic profiles of AL amyloidosis is lacking.Methods: In this study, we adopted a two-step strategy to investigate the mutational profile of AL amyloidosis bone marrow plasma cells (PCs) and their clinical implications. In step one, whole-exome sequencing was performed in bone marrow PCs and paired with normal tissue from 10 AL amyloidosis patients, by which we identified 10 significantly mutated genes (SMGs). In step two, we constituted a targeted gene sequencing (TGS) panel covering the frequently mutated genes identified in step one, genes reported in prior AL amyloidosis studies, and known cancer driver mutations. Then, we analysed an expanded cohort of AL amyloidosis patients (N = 48) with this panel comprising 98 genes.Results: Four recurrent mutations were identified by TGS and verified by Sanger sequencing: ASB15 (c. 844 C > T), ASCC3 (c. 1595 A > G), HIST1H1E (c. 311 C > T) and KRAS (c. 35 G > A), among which the first three mutations were associated with inferior overall survival (OS). Additionally, we found that the number of mutations identified by the TGS panel of 98 genes could be a prognostic predictor for OS.Conclusions: In summary, we revealed genomic profiling in AL amyloidosis and found mutation profiles associated with OS.

Bortezomib-based chemotherapy reduces early mortality and improves outcomes in patients with ultra-high-risk light-chain amyloidosis: a retrospective case control study

Background: Patients with amyloid light-chain (AL) amyloidosis who have advanced cardiac damage are at risk of premature mortality. Currently, bortezomib is the mainstay in the treatment of AL amyloidosis, but the benefits of bortezomib in patients with ultra-high-risk (2004 Mayo stage IIIb or 2012 Mayo stage IV) AL amyloidosis have not been proved definitively. Methods: We performed a retrospective analysis of patients newly diagnosed with ultra-high-risk AL amyloidosis who received a bortezomib-based regimen or supportive treatment. We aimed to establish the effects of bortezomib on early mortality and long-term outcomes in this high-risk population. Results: Patients receiving bortezomib-containing chemotherapy (n = 62) and patients receiving no chemotherapy (n = 24) were included. Median overall survival (OS) was 30 months in the bortezomib group and 2 months in the control group (p < .001), and median progression-free survival (PFS) was 15.8 months (bortezomib) and 2 months (control; p < .001). The early-death rate (within 6 months of treatment) was 32.3% (bortezomib) and 66.7% (control; p < .001). In a landmark analysis assessing outcomes in patients surviving beyond 6 months, the 2-year OS and PFS in the bortezomib group were 77.3% and 65.8%, respectively. Conclusions: Bortezomib-based regimens can help to reduce early mortality and improve long-term survival in patients with ultra-high-risk AL amyloidosis.

Outcome of Cardiac Light-Chain Amyloidosis in the Era of Novel Therapy - A Single-Center Cohort Study of 227 Patients

BACKGROUND

Cardiac involvement occurs in more than half of the patients with light-chain amyloidosis (AL), but the characteristics, treatment and prognosis of cardiac AL (CAL) are not fully described. Methods and Results: A total of 227 patients with CAL diagnosis between January 2009 and March 2017 at Peking Union Medical College Hospital were included. Patients with Mayo stages I, II and III AL accounted for 0.9%, 49.8% and 49.3%, respectively. Autologous stem cell transplantation, bortezomib combinations, non-bortezomib regimens and palliative treatment were given as first line therapy in 3.1%, 44.1%, 30.8% and 22.0% of patients, respectively. Overall hematological response and cardiac response were achieved in 60.6% and 37.2% of evaluable patients, respectively. The median overall survival (OS) was 17 months in all patients, and 10 months in those with Mayo stage III. In patients with Mayo stage III disease who survived for >1 month, the bortezomib group survived significantly longer than the non-bortezomib group (median OS, not reached vs. 12 months, P=0.019). Three independent prognostic factors for survival were identified: N-terminal fragment of B-type natriuretic peptide (NT-proBNP) ≥5,000 pg/mL, bone marrow plasma cells ≥10%, and systolic blood pressure <100 mmHg.

CONCLUSIONS

CAL patients had poor prognosis, but those treated with bortezomib combinations had a better outcome than the non-bortezomib group.

At least partial hematological response after first cycle of treatment predicts organ response and long-term survival for patients with AL amyloidosis receiving bortezomib-based treatment

AL amyloidosis is a rare plasma cell dyscrasia characterized by multi-organ involvement and poor prognosis. We retrospectively evaluated the organ response (OR) and long-term survival of newly diagnosed AL amyloidosis patients who received first-line bortezomib-containing induction therapy, aiming to identify the clinical indication of a 50% reduction in the difference between involved and uninvolved free light chains (dFLC) after first cycle of treatment. Among the 89 patients included, 78.7% had cardiac involvement and 42.7% were diagnosed with 2004 Mayo stage III disease, while 75.3% of patients achieved a hematological response, including 37.1% with complete response and a median response time of 1 month. Cardiac and renal responses were observed in 44.3 and 53.1% of patients, respectively. Sixty-one (68.5%) patients achieved at least 50% reduction in dFLC after the first cycle of therapy. After a median follow-up duration of 12 months, the estimated 3-year progression-free survival (PFS) and overall survival (OS) rates were 61.3 and 61.7% respectively. At least 50% reduction in dFLC after the first cycle of therapy was predictive of achieving an OR (p = 0.002), as well as superior PFS (HR = 0.119; 95% CI = 0.045-0.313; p < 0.001) and OS (HR = 0.206; 95% CI = 0.078-0.541; p = 0.001). Additionally, the median PFS and OS were not reached for patients with rapid reduction of dFLC. These results demonstrated that early reduction of dFLC after the first cycle of treatment is predictive of achieving an OR and long-term survival in AL patients receiving bortezomib.

Systemic amyloidoses and proteomics: The state of the art

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Proteomics is an established approach for diagnostic amyloid typing.

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Mass spectrometry-based methods to analyze amyloid precursors have been developed.

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Proteomic studies are ongoing to identify novel biomarkers and clarify disease mechanisms.

Systemic amyloidoses are caused by misfolding-prone proteins that polymerize in tissues, causing organ dysfunction. Since proteins are etiological agents of these diseases, proteomics was soon recognized as a privileged instrument for their investigation. Mass spectrometry-based proteomics has acquired a fundamental role in management of systemic amyloidoses, being now considered a gold standard approach for amyloid typing. In parallel, approaches for analyzing circulating amyloid precursors have been developed. Moreover, differential and functional proteomics hold promise for identifying novel biomarkers and clarifying disease mechanisms. This review discusses recent proteomics achievements in systemic amyloidoses, providing a perspective on its present and future applications.