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    Background. Renal amyloidosis is associated with a variety of underlying disease processes. Although amyloid is identical in appearance in these diseases, the precursor proteins are different. Immunofluorescence microscopy has been used as the primary tool in the diagnostic evaluation of the underlying cause of renal AL-amyloidosis. The purpose of this study was to document the sensitivity of immunofluorescence microscopy in AL-amyloidosis.
    Amyloid (mycology)
    Immunofluorescence
    AL amyloidosis
    Citations (94)
    In 2012, the International Society of Amyloidosis (ISA) established the criteria for assessment of haematologic response to treatment in light chain (AL) amyloidosis [1]. The criteria were identifi...
    Chain (unit)
    AL amyloidosis
    Abstract: Quantitative measurements of circulating free immunoglobulin light chains (FLC) and of biomarkers such as N-terminal pro-brain natriuretic peptide (NT-proBNP) and cardiac troponins (cTnT ...
    AL amyloidosis
    Immunoglobulin D
    Chain (unit)
    Bence Jones protein
    Plasmacytosis
    Paraproteins
    Amyloid (mycology)
    AL amyloidosis
    Mediastinal mass
    This case report describes the primary manifestation of systemic light chain deposition disease as bilateral nodules on chest radiographs. Although this case was initially classified as amyloidosis, a subsequent renal biopsy and ultrastructural, histochemical, and immunohistochemical studies allowed its distinction from amyloidosis. Kappa light chains were expressed with immunoperoxidase studies on paraffin-embedded tissue, and ultrastructural studies showed the dense, granular deposits characteristic of systemic light chain deposition disease. Serum and urine electrophoresis showed a monoclonal spike, but no plasmacytosis was identified at bone marrow biopsy and autopsy. The literature on this subject is also herein reviewed, with particular attention to the extrarenal manifestations of systemic light chain deposition disease.
    Immunoperoxidase
    AL amyloidosis
    Plasmacytosis
    Abstract Context.—Amyloidosis represents a group of diseases with extracellular deposition of congophilic fibrils of similar morphology but differing chemical composition. The types commonly involving the kidney are AL (light chain amyloid) and AA (serum amyloid A). Familial amyloidosis can also affect the kidney, but we have not encountered such a case during the study period. Distinguishing between the AL and AA forms of amyloid is clinically important because of the different treatments and outcomes. The classification of amyloidosis is made by immunostaining with antibodies to κ and λ immunoglobulin light chains and for serum amyloid A protein. Objective.—To draw attention to the nonspecific immunofluorescence staining patterns in renal biopsies with amyloidosis, causing potential diagnostic pitfalls. Design.—Renal biopsies from 15 patients, including 13 cases of AL and 2 cases of AA amyloidosis, were studied. Immunofluorescence staining with routine antibody panel and immunoperoxidase staining for amyloid A were performed. Results.—Of the 13 cases of AL amyloidosis, 2 cases showed little difference in staining intensity between κ and λ light chains (2+ and 3+, respectively) and 4 cases showed only moderate intensity (2+) of the predominant light chain. The 2 cases diagnosed as AA amyloidosis also exhibited staining for light chains. One case had strong (3+) signal for κ and moderate (2+) for λ light chain, while the other showed weaker staining. Conclusions.—Immunofluorescence staining for immunoglobin light chains on renal biopsy, as the first step to differentiate between AL and AA amyloidosis, may sometimes be inconclusive or even misleading. Applying amyloid A immunostain on a routine basis and detailed clinical history are essential to avoid misclassification.
    Immunostaining
    Amyloid (mycology)
    Immunoperoxidase
    AL amyloidosis
    Immunofluorescence
    Citations (104)