Background: Light-chain amyloidosis (AL) is the most common form of systemic amyloidosis. This study aimed to evaluate the usefulness of laboratory tests for light-chain clonality and bone marrow (BM) findings in AL amyloidosis.
Methods: We retrospectively enrolled patients newly diagnosed with AL amyloidosis on pathological examination who underwent a BM biopsy. Laboratory test data for light-chain clonality were collected and compared. Amyloid deposits were identified with H&E, Congo red, and PAS stains.
Results: We reviewed 98 patients with AL amyloidosis. Light chain clonality (λ, 64 cases; κ, 34 cases) was detected by serum immunofixation electrophoresis (IFE) (63.3%), urine IFE (70.8%), serum protein electrophoresis (PEP) (44.9%), urine PEP (44.8%), serum free light chain (SFLC) ratio (79.5%), and BM immunohistochemistry (IHC) (85.7%). Flow cytometric (FCM) assay identified aberrant BM plasma cells in 92.9% of cases. BM amyloid deposits were identified in 35 of the 98 cases (35.7%); 71.4% (25/35) were Congo red-positive, and 100.0% (35/35) were PAS-positive.
Conclusion: Laboratory tests for detecting light-chain clonality in AL amyloidosis in order of sensitivity include FCM assay for aberrant plasma cells, IHC for light chains on BM biopsy or clot section, SFLC ratio, and serum and urine IFE. Congo red staining of BM samples remains an important tool for identifying amyloid deposits in BM. Periodic acid-Schiff (PAS) staining can be useful in diagnosing some cases of Congo red-negative amyloidosis.
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http://dx.doi.org/10.5045/br.2023.2022232 | DOI Listing |
Arch Pathol Lab Med
January 2025
the Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles (Petersen, Stuart, He, Ju, Ghezavati, Siddiqi, Wang).
Context.—: The co-occurrence of plasma cell neoplasm (PCN) and lymphoplasmacytic lymphoma (LPL) is rare, and their clonal relationship remains unclear.
Objective.
Hum Pathol
January 2025
University Health Network and University of Toronto, Canada.
Indolent clonal lymphoid disorders are not recognized as lymphomas as they generally need no systemic treatment, and depending on the lesion, need only limited clinical follow-up. These lesions are usually incidentally diagnosed during the work up for other disease. The recognition of indolent clonal lymphoid disorders is important to avoid misdiagnosis as lymphoma and unnecessary treatment.
View Article and Find Full Text PDFBr J Haematol
January 2025
Department of Haematology, University College London Hospital, London, UK.
Systemic light chain (AL) amyloidosis is a rare clonal plasma cell disorder characterized by the production of amyloidogenic immunoglobulin light chains, which causes the formation and deposition of amyloid fibrils, leading to multi-organ dysfunction. Current treatment is directed at the underlying plasma cell clone to achieve a profound reduction in the monoclonal free light chain production. The standard-of-care first-line therapy is a combination of daratumumab, cyclophosphamide, bortezomib and dexamethasone (D-VCd regimen), resulting in high rates of haematological and organ responses.
View Article and Find Full Text PDFMymensingh Med J
January 2025
Dr Md Mahbubul Alam, Junior consultant (Medicine), National Gastroliver Institute and Hospital, Dhaka, Bangladesh; E-mail:
Multiple myeloma (MM) is a haematological neoplasm of mature B-cell lineage origin. It is characterized by abnormal clonal proliferation of plasma cells and presence of monoclonal protein in serum and / or urine. This study was conducted to observe the International Staging System (ISS) status and trends of relapse.
View Article and Find Full Text PDFBlood Cancer J
December 2024
Faculty of Medicine, University of Iceland, Reykjavík, Iceland.
Light-chain (LC) monoclonal gammopathy of undetermined significance (MGUS) is a precursor of multiple myeloma (MM) and related conditions. LC-MGUS is characterized by free light-chain (FLC) levels outside defined reference intervals, indirectly indicating underlying plasma cell (PC) monoclonality. Next-generation flow cytometry (NGF) was used to evaluate clonal PC presence in bone marrow (BM) samples from individuals with LC-MGUS in the iStopMM study, aiming to assess the predictive value of the FLC ratio for clonal PC presence and its prognostic implications.
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