Article Text
Abstract
Aims Identification and characterisation of monoclonal gammopathies of renal significance (MGRS) is critical for therapeutic purposes. Amyloidosis represents one of the most common forms of MGRS, and renal biopsy remains the gold standard for their classification, although mass spectrometry has shown greater sensitivity in this area.
Methods In the present study, a new in situ proteomic technique, matrix-assisted laser desorption/ionisation mass spectrometry imaging (MALDI-MSI), is investigated as an alternative to conventional laser capture microdissection MS for the characterisation of amyloids. MALDI-MSI was performed on 16 cases (3 lambda light chain amyloidosis (AL), 3 AL kappa, 3 serum amyloid A amyloidosis (SAA), 2 lambda light chain deposition disease (LCDD), 2 challenging amyloid cases and 3 controls). Analysis began with regions of interest labelled by the pathologist, and then automatic segmentation was performed.
Results MALDI-MSI correctly identified and typed cases with known amyloid type (AL kappa, AL lambda and SAA). A ‘restricted fingerprint’ for amyloid detection composed of apolipoprotein E, serum amyloid protein and apolipoprotein A1 showed the best automatic segmentation performance (area under the curve >0.7).
Conclusions MALDI-MSI correctly assigned minimal/challenging cases of amyloidosis to the correct type (AL lambda) and identified lambda light chains in LCDD cases, highlighting the promising role of MALDI-MSI for amyloid typing.
- amyloid
- glomerulonephritis
- hematology
Data availability statement
Data are available on reasonable request.
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Data availability statement
Data are available on reasonable request.
Footnotes
Handling editor Runjan Chetty.
GB and AS contributed equally.
Contributors VL'I and AS defined the study design; GCaz, AE, SV and FA performed the data collection; GB, AS and GO carried out experiments; SG and GCap performed the data analysis; VL, GB and AS performed the data interpretation; FM, FP and VL'I provided the funding acquisition and administrative support. VL'I is responsible for the overall content as guarantor. All authors were involved in writing the paper and had final approval of the submitted and published versions.
Funding This work was supported by the Regione Lombardia, regional law n° 9/2020, resolution n° 3776/2020; Italian Ministry of Health under the grant 'Ricerca Finalizzata' GR-2021-12374235 and PNRR-MR1-2022-12375735.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
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